OSGC-000-000-007-127

GEOScan Planning Workshop Report March 27-‐30, 2011, Annapolis, MD A planning workshop to place geoscience instrumentation on the Iridium Inc. NEXT global satellite constellation was held on March 27-‐30. The attendees included over 120 discipline scientists, cube-‐sat and low-‐cost satellite engineers, systems engineers and student participants, government officials and industry representatives. Numerous candidate science and sensor options were presented, and working groups are forming to follow up on these necessary items prior to proposal as an NSF MREFC. This document summarizes the candidate sensors and science themes that were presented for consideration. Eds., Lars Dyrud, Jonathan T. Fentzke Johns Hopkins Applied Physics Laboratory 06/24/2011

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Table of Contents

Introduction.................................................................................................................5

GEOScan Program Themes ...........................................................................................6 System Sensors ...........................................................................................................................................................6 Hosted PI Sensors ......................................................................................................................................................7 Iridium NEXT & GEOScan..............................................................................................7

NEXT SensorPOD for GEOScan......................................................................................8

Workshop Summary & Next Steps ...............................................................................9 GEOScan Working Groups...................................................................................................................................10 Science Themes and Instrumentation.........................................................................10 GPS/Geodesy.............................................................................................................................................................11 Brian Gunter – Using Iridium NEXT to observe global time-variable gravity..............................11 Kerri Cahoy – GPS Radio Occultation for GEOScan.................................................................................13 Gary Bust – Ionospheric Measurements and Ionospheric Data Assimilation ...............................14 Rebecca Bishop – Compact Total Electron Content Sensor .................................................................18 Thomas Gaussiran & David Rainwater – DORIS on Iridium-NEXT: Ionospheric & Tropospheric Science and Precise Orbit Determination ........................................................................19 Glenn Lightsey – FOTON Software Defined GPS Receiver ......................................................................23 Sam Yee – COTS GPS System Science Sensor Overview..........................................................................25 Tom Meehan – Synoptic Tropo-ionospheric Occulations via NEtworked Sensors (STONES)25 Bill Schreiner – Use of NASA’s TriG (Tri-GNSS) RO receiver as a GEOScan Hosted Sensor .....27 Kenn Gold – Global Broadband Operationally Responsive Navigator .............................................29

Climate/Atmosphere .............................................................................................................................................31 Warren Wiscombe & Steven Lorentz – Earth Radation Budget Bolometer ..................................31 Sebastian Schmidt – Tracking the Global Radiative Energy Budget with GEOScan..................33 Larry Paxton – Novel Integrated Applications ...........................................................................................34 Earle Williams – Scientific Interest in Global Lightning from IRIDIUM Satellite Measurements ...........................................................................................................................................................34 Bob Erlandson- GEOScan Multi-Purpose Imager (MPI) .........................................................................35 Shawn Murphy – Compact Hyperspectral Imaging Module for Earth Science (CHIMES).......37 William J. Blackwell – Minature Microwave Atmospheric Sounder (MiniMAS) .........................38 John Boldt – MicroCam..........................................................................................................................................39 Hugh Christian – Global Lightning Imaging Sensor (GLIS) ..................................................................40 Steve Jaskeluk – SmartCam.................................................................................................................................42 Andrew Kalman – GHVCam ...............................................................................................................................42 Alan Marchant – DISC ...........................................................................................................................................45 A. Deepak and M. Schoeberl – The CAPE GEOScan Concept .................................................................46 William Heaps – High Spatial resolution Greenhouse Gas column Sensor ....................................47

Space Environment ................................................................................................................................................49 David Byers – Chip Dosimeter, Charge Plate Analyzer, Micrometeoroid Acoustic Sensor ......49 Rick Doe – GEOScan Thermosphere Ionosphere Photometer - GTIP ................................................51

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Alan Marchant – DISC ...........................................................................................................................................53 John Noto – Fabry Perot Sensor for GEOScan .............................................................................................54 Steve Watchorn & John Noto – Spatial Heterodyne Spectrometer ....................................................55 Qian Wu – SANDI Hosted Sensor Overview..................................................................................................57 Tom Woods – FUVI..................................................................................................................................................58 Tom Woods – RePTile ............................................................................................................................................59 Luke Goembel – SCM Sensor ...............................................................................................................................59 Sven Bilén – Hybrid Plasma Probe for Space Weather Measurements............................................60 Marcin Pilinski and Scott Palo – Thermospheric Ionospheric Velocity Energy Analyzer (TIVEA).........................................................................................................................................................................61 Ted Fritz – Mini-Imagine Electron Spectrometer (MIES).....................................................................63 Steve Cummer – Lighting-Upper Atmospheric Coupling ......................................................................64 R. Lin – Stein-X ..........................................................................................................................................................65 Gerald Fishman – Gamma-ray Detector Constellation for Earth and Sky Observations .........66 Andrew Stephan – Miniature UV Spectrographic Experiment (MUSE)...........................................67 Greg Earle – UT Dallas Thermal Ion Instruments .....................................................................................68 Mihaly Horanyi – GEOScan Cosmic Dust and Debris Experiment ......................................................70 Michael Kiedar – GEOScan Micro-Vaccum Arc Thruster for Nanosatellites .................................71

Appendix I – Workshop Abstract Titles and Authors...................................................72

Appendix II – Workshop Attendees ............................................................................75

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Introduction Iridium Communications Inc. is launching Iridium NEXT, a new-generation of low-Earth orbiting (LEO) polar communication satellites in 2015-2017. Iridium NEXT's 66+ global satellites have each been designed to accommodate a standard payload, which provides a unique capability to host scientific sensors with 24/7 real-time visibility over the entire Earth's surface and atmosphere. We plan to take advantage of this opportunity through a program we are calling GEOScan. Four primary factors make this an unprecedented opportunity for geoscience discovery, while holding the potential to affect a paradigm shift in the way we conduct science from space:

• Truly global coverage provided by the constellation allows us to address open scientific questions never before possible! These grand challenges will likely not be addressed without GEOScan for the next 15-20 years.

• Massively dense space-based measurements enable revolutionary new techniques such as tomographic imaging and provides truly novel datasets for the community to investigate.

• Because Iridium is a the world's farthest reaching network, the logistical and cost barrier of transmitting massive amounts of data from 66+ satellites is REMOVED!

• Because we plan to build nearly 70 uniform GEOScan SensorPODs, we can take advantage of the cost savings of scale for science from space instead of the extremely costly "one of a kind" methods of the past.

GEOScan is pursuing this opportunity via a grass-roots effort to propose a geoscience facility from space to the National Science Foundation that will benefit a broad cross-section of the scientific community and society in general. But, in order to increase community awareness and support as well as gather ideas, proposals and feedback from the geoscience (Solid Earth, Atmosphere, Ocean, and Geospace) community for the purposes of selecting overarching scientific goals and the sensors and measurements needed to accomplish these goals we held a planning workshop in Annapolis, MD from March 28-30th. The workshop was extremely well attended and allowed the community to advance this ongoing effort is to mature the GEOScan concept to the next stage of NSF MREFC planning and implementation. Below we summarize the workshop and provide a number of examples and outcomes gleaned from the productive sessions that were held over the course of two and a half days. We conclude with remarks about future planning and time lines that resulted due to community feedback during the workshop. The GEOScan program can be broken down into two highly complementary themes (see Figure 1 for a high level outline of program theme goals): the System Sensor program and the Hosted PI Sensor program. In total we expect two or three System

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Sensors and one Hosted PI Sensor to be accommodated by each GEOScan SensorPod. The engineering extent of GEOScan involves producing 66+ GEOScan SensorPods, integrating two SS, one PI provided HS together with the GEOScan SensorPod bus and associated data and power handling electronics. Because we expect to build 66+ GEOScan SensorPods, we can, for the first time, finally utilize the advantage scale in production and realize a dramatic cost savings.

GEOScan Program Themes The GEOScan program can be broken down into two highly complementary themes (see for a high level outline of program theme goals): the System Sensor program and the Hosted PI Sensor program. In total we expect two or three System Sensors and one Hosted PI Sensor to be accommodated by each GEOScan SensorPod. The engineering extent of GEOScan involves producing 66+ GEOScan SensorPods, integrating two SS, one PI provided HS together with the GEOScan SensorPod bus and associated data and power handling electronics. Because we expect to build 66+ GEOScan SensorPods, we can, for the first time, finally utilize the advantage scale in production and realize a dramatic cost savings.

Figure 1: Outline of the main themes of the GEOScan program components. System Sensors The overarching goal of the System Sensor Program is to enable revolutionary science by making dense and global measurements that enable new techniques for imaging the Earth environment. While one of the primary tasks of both the Steering Committee and the Working groups is the selection of the three System Sensors, we can at this time identify the necessary characteristics that the sensors must possess. The sensors must be

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comparatively low cost (~100k per sensor or less), they must be readily available in large quantities for delivery within 2 years, and they must reliably operate in the radiation and thermal environment of low earth orbit. This leads us primarily, but not exclusively, to COTS sensors that have been adapted for space use, two clear examples are GPS and white light or visible color imaging. Further these System Sensors must also enable dramatic new scientific capabilities and provide data that is of highest level of interest to a broad range of Geoscience disciplines. Hosted PI Sensors The overarching goal of the Hosted Sensor program is to provide an unprecedented opportunity to expand educational and small business involvement in science and space engineering by dramatically reducing the barriers to entry. Within each GEOScan SensorPod, we plan to have approximately 1U (10x10x10 cm) of available volume with either a ram or nadir face opening available. This presents the opportunity to offer community involvement with a "cube-sat like" program with significant differences and advantages over traditional cube-sat missions. Primarily, the overhead, risk, and cost of producing a space craft bus and acquiring ground systems for data transfer are eliminated. This will free the scientists and students to focus on the engineering of the instrument and the science of the acquired data. We expect the Hosted Sensor PI's to be funded independently with integration costs and guidance provided by JHU/APL and other team members.

Iridium NEXT & GEOScan Iridium is a mobile satellite services (MSS) provider -‐ the only network provider offering 100% worldwide coverage. The network is a very unique, resilient Low-‐Earth Orbiting (LEO) satellite constellation of 66 satellites plus in-‐orbit spares. A comprehensive plan to replenish the Iridium constellation, known as Iridium NEXT will launch 66 new satellites to replace the current constellation, with launches expected to begin in 2015. Also planned are 6 in-‐orbit spare satellites and 9 ground spares. Iridium NEXT features increased subscriber capacity, higher data speeds, and capacity for hosting payloads. Each Iridium NEXT satellite has an allocation of 50 kg in mass, 30 x 40 x 70 cm in volume, 50 watts of average power, and 100 Kbps average data rate for each hosted payload. Thales Alenia Space (TAS) has been awarded a $2.2B contract by Iridium to build 81 satellites for this next-generation constellation. Space Exploration Technologies (SpaceX) has been contracted as primary launch provider. Iridium has also closed on loans by a consortium of banks to fund the NEXT system development. Coface, the France's export credit agency (ECA), has guaranteed 95% of $1.8B credit facility. Thales is expected to select a US company to be the satellite integrator and to manage hosted payload integration.

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Iridium has developed a schedule milestone that provides an enhanced support for the hosted payload integration. The initial hosted payload Interface Control Document (ICD) is available. Payloads conforming to the ICD have until Satellite CDR to (1Q 2013) to make first launch with delivery happening as late as 6 months prior to each launch. Non-conforming payloads must begin commitment by Satellite PDR (1Q 2012).

Figure 2: Iridium NEXT Schematic including their entire hosted payload bay.

NEXT SensorPOD for GEOScan A portion of the hosted payload allocation has been assigned for a new concept called SensorPOD for the Cubesat class payloads. This concept leverages the popular Cubesat form factor, and is able to accommodate 5.6U volumes. These can however not be more than 4-‐5 kg total mass, and the power is limited to ~5 Watt average. The design supports hosting multiple SensorPODs on a single SV depending on the mass and volume available out of primary hosted payload allocation. The NEXT bus provides a three-‐axis stabilized platform, providing power, and data communication, allowing the entire volume and up to 5 Kg mass to be dedicated to the scientific payload. NEXT satellites have a design life of 10 years +, making longer term scientific missions viable. The GEOScan program plan uses a single 5.6U SensorPOD slot on each of the 66 NEXT satellites as depicted in Figure 3. The following section describes the proposed plan for the GEOScan SensorPods and resulting GEOScan program.

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Figure 3: Iridium NEXT SensorPod Schematic. The GEOScan SensorPod will consist of 1 of these 5.6U boxes shown in the diagram. The SensorPod will have access to both ram and nadir facing directions.

Workshop Summary & Next Steps We had over 100 registered participants with peak attendance approaching 120 in the conference room. The planning workshop attracted a diverse cross section of the community, which included: individual PIs and scientists, students, small business owners or representatives from small business, industry representatives, and sponsors [i.e. program managers or those representing major sponsor organizations]. There were more than 50 presentations made on a wide array of science and sensor topics with excellent question and answer sessions during presentation and planning sessions. The planning workshop’s main goals were defining science/measurement objectives and instrumentation to support those objectives that would provide the highest level of intellectual merit and broader impacts for the geoscience community as a whole.

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GEOScan Working Groups Pursuant to the workshop completion working groups and a steering committee formed to follow up on these necessary items prior to program proposal. The following items are in preparation and GEOScan working groups are tasked with making recommendations to the steering committee:

• Evaluate, in detail, the potential scientific value of the proposed GEOScan program for each of the Geosciences disciplines.

• Help select three baselined system sensors that will fly on all 66+ satellites. • Define System Sensor Science goals based up on the baselined sensor's

capabilities. • Define hosted sensor program, estimate participant readiness, numbers of

capable PI and candidate science based on relevant launch timeline and feasibility requirements.

• Establish GEOScan SensorPod science and engineering requirements and conduct flow down analysis for each.

• Make final recommendations to steering committee for the NSF program proposal.

Science Themes and Instrumentation The primary goal of the workshop was to identify the most compelling geoscience themes that required simultaneous global measurement for major progress, and to identify if sensors existed that fit the stringent volume, mass and power requirements of the GEOScan program. While some presented sensors did not meet these requirements, many did, and they largely fell into three main measurement/scientific themes: GPS/Geodesy, Climate and Atmosphere, and Space Environment. The remainder of this document continues with a summary of the presentations and reports from the meeting participants grouped into these themes. For full resolution versions of the included charts and figures see the website geoscan.jhuapl.edu

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GPS/Geodesy

Brian Gunter – Using Iridium NEXT to observe global time-‐variable gravity The proposed Iridium NEXT constellation will be the next generation of the well-‐known satellite communication network. It will consist of 66 satellites spread across six orbit planes, with the initial launches set to begin in 2015. While the primary mission goal is devoted to communications, each satellite has been designed to host a secondary payload capable of carrying a suite of remote sensing instruments. One of the instruments under consideration for this hosted payload is a multi-‐channel, dual-‐frequency GPS receiver that can be used for both radio occultation experiments, as well as precise orbit determination (POD). Another sensor under investigation is a DORIS receiver, which would generate similar high-‐quality orbits, as well as complementary space weather data [4]. Earlier studies [1,3] have shown that if the POD of the Iridium satellites is sufficiently accurate, i.e. at the 2-‐3 cm 3D RMS level, then you have the opportunity to observe short term (< 1 month), large scale (> 1000 km) global gravity field variations. This is possible because the positions and/or velocities that would be derived from the GPS/DORIS receivers can be used to compute a time series of accelerations acting on each spacecraft [2]. If knowledge of the spacecraft orientation (attitude) and environment (i.e., atmospheric drag, etc.) are known, then the non-‐gravitational accelerations acting on the spacecraft can be removed, leaving only those accelerations due to gravity remaining. These gravitational accelerations can then be used to infer “snapshots” of Earth’s global gravity at a particular epoch, and to ultimately observe the evolution of the gravity field over time. Temporal gravity field variations are of great interest to the Earth sciences, and provide a unique source of information about Earth’s mass transport processes. These processes involve everything from ocean currents, sea-‐level change, atmospheric variations, continental hydrology, movements of the solid earth, and the melting of ice in the cryosphere. Dedicated gravity field missions, such as the Gravity Recovery and Climate Experiment (GRACE), have demonstrated how valuable this time-‐variable gravity data can be [5]; however, as a single instrument pair, the spatial and temporal resolution of the GRACE mission is inherently limited by its ground track coverage. As a general rule of thumb, it takes approximately one month for the ground track coverage of a single satellite (or satellite pair in the case of GRACE) to become sufficiently dense enough to observe relatively small (~350km) spatial variations in Earth’s gravity. There are many mass transport processes (e.g., atmospheres, continental hydrology, tides, etc.), that have cycles much shorter than one month, which GRACE cannot observe and which need to be removed with models in the data processing. This highlights the fact that, with only one satellite pair, to get higher spatial resolution, you must sacrifice temporal resolution, and vice-‐versa; the only way to improve both is to increase the number of satellites involved. The Iridium NEXT constellation could help with this by providing a continuous set of globally distributed gravity measurements. The measurements from the

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constellation would not be nearly as accurate as those collected from GRACE, but would be sufficient to observe the large scale gravity variations. More importantly, these variations would be observed at time scales as short as six hours, covering a spectrum of the gravity field not possible from dedicated gravity missions such as GRACE. In this context, the Iridium NEXT gravity data would provide new information about Earth’s global gravity field that would fully complement those from dedicated gravity missions. Furthermore, the gravity data from Iridium NEXT might serve as the only time-‐variable gravity measurements available in the event there is a gap between the end of the current GRACE mission (est. 2015-‐2016) and the proposed GRACE follow-‐on mission. While the general concept of the gravity measurements outlined above is straightforward, the technical implementation of such a setup does have certain instrument requirements. The underlying principle relies on accurate orbits, and as communication satellites, the default POD requirements of the Iridium satellites are not as strict as those from dedicated gravity field missions. As a result, additional sensors or spacecraft data might be needed to ensure that the necessary POD can be achieved. For example, the Iridium satellites have complex shapes, with articulating solar panel arms, creating complications both in terms of tracking the location of the center of mass (CoM) of the spacecraft, but also creating potential multi-‐path interference for the GPS receivers. The GPS/DORIS antenna would also not be located near the spacecraft CoM, requiring accurate satellite attitude information to correct for this offset (i.e., rotational accelerations). The Iridium satellites are currently designed to have star-‐trackers installed for this attitude information, but it is unclear whether the precision of these instruments is sufficient to achieve the necessary POD required. Finally, the broadcast frequency of the GPS system is close to that used by the Iridium satellites for their primary communication tasks (both are L-‐band), which may cause interference and errors in the GPS positioning. The DORIS receiver would not suffer from this potential interference, but the advantages and disadvantages of both positioning systems would need to be studied further to determine which option is best suited for the Iridium NEXT constellation. The potential use of inter-‐satellite ranges generated from time-‐tagged communication packets may help resolve some of these POD issues, and is currently being investigated. In short, while the potential is there for the Iridium NEXT constellation to provide valuable information on Earth’s time varying gravity field, the instrumentation on-‐board would have to enable accurate orbits in order for this to be realized. References 1) Ditmar, P., Bezdek, A., Liu, X., and Zhao, Q., (2009). On a feasibility of high-precision gravity field modeling based on data from non-dedicated satellite missions. In: M.G. Sideris (Ed.), Observing our changing Earth. International Association of Geodesy Symposia, volume 133. Springer, Berlin. pp. 307-313. 2) Ditmar, P. and van Eck van der Sluijs, A. A. (2004), “A technique for modeling the Earth's gravity field on the basis of satellite accelerations” Journal of Geodesy, 78, 12-33

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3) Gunter, B.C., Encarnação, J., Ditmar, P., Klees, R.(2011), “Using satellite constellations for improved determination of Earth's time-variable gravity,” Journal of Spacecraft and Rockets, Vol 48 (2), pp. 368-377. 4) Rainwater, D., and Gaussiran, T. (2011), “DORIS sensor package for Iridium-NEXT,” GEOScan Workshop, Annapolis, MD, March 28-30, 2011. 5) Tapley, B.D., Bettadpur, S., Ries, J.C., Thompson, P.F., and Watkins, M.M. (2004), “GRACE measurements of mass variability in the Earth system,” Science, 294, pp. 2342-2345.

Kerri Cahoy – GPS Radio Occultation for GEOScan A modified GPS receiver easily fits within the GEOScan payload volume, mass, data rate, and power constraints of Iridium/NEXT and can be used to perform radio occultation experiments. Signals from the 22,000 km altitude GPS constellation are regularly occulted by the Earth from the perspective of a GPS receiver on board the low-‐Earth orbiting Iridium/NEXT platform. Before they disappear below the horizon, these signals capture the vertical density structure of the neutral atmosphere as well as the ionosphere, since radio waves interact with both ionized and neutral gases. The raw measurements of ionospheric and atmospheric density are “excess phase” at the receiver, and can be transmitted to the ground at a very low data rate. The raw measurements can be converted into profiles of electron

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density, neutral density, temperature, and pressure. From the 66+ satellite Iridium/NEXT constellation, GPS radio occultation would be able to provide global, real-‐time coverage of temperature, pressure, and electron density in Earth’s atmosphere and ionosphere. Space-‐qualified, inexpensive GPS receivers exist that fit within the Iridium/NEXT payload constraints that can easily be modified to act as a GPS receiver. The ability of GPS radio occultation experiments to correctly sample the troposphere is a function of the signal to noise and antenna surface area of the GPS receiver and should be quantified given the constraints of the Iridium/NEXT noise levels and the surface area available on the Iridium/NEXT spacecraft for antennas (e.g., in the zenith and ram directions). The GPS Radio Occultation experiment is an excellent candidate for a system sensor not only because it is clearly achievable in a very short time frame, but also because these measurements are synergistic with other experiments such as spectrometers and sounders. In fact, there would be a benefit to not only having GPS radio occultation receivers as the GEOScan system sensor, but also as a hosted sensor that can take input from an antenna at a different location and give other collaborators the opportunity to test new GPS receiver designs in tandem with the system sensor. A GPS radio occultation system sensor for GEOScan would result in a revolutionary real-‐time capability of monitoring Earth’s space weather, weather, and climate.

Gary Bust – Ionospheric Measurements and Ionospheric Data Assimilation

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Upper Left: Overarching Science Theme and Goals The most important goal is to improve our first principle, theoretical and numerical models of the ionosphere-‐thermosphere systems. When we are honest about our modeling, we realize that despite our best efforts, the best minds and computational abilities around, our models very rarely reproduce experimental results within error bars, nor are they capable of quantitatively predicting observations. This simply demonstrates the complexity inherent quantitatively understanding our own Earth system. This is a very hard problem, with non-‐linear coupled systems from the Sun to the Earth, each with multiple species of energy and momentum equations. It is tremendously exciting and challenging to me personally that here in 2011 we cannot realistically model nor predict our own system we live in!! It should be a major challenge and goal for the community to understand what the weaknesses and limitations in the models are, and what we need to do (measurements, model improvements) to improve the modeling to the point where we can show model results fitting within experimental errors on a routine basis. I would argue that for us to move forward as a high-‐tech society, with increased satellite communications etc, it is critical for us to be able to know we understand the complex environment we live in. Upper Right: Measurement/Sensor Feasibility Based on the above, then, we can ask what instruments can we employ that will best allow us to improve our models and theoretical knowledge. Such instruments will most likely remotely sense electron density, but instruments that sense electric fields, winds, temperatures and precipitation are all necessary if we want to truly understand the dynamics and inputs to the models. These instruments can provide observations to data assimilative models, which in turn, can evaluate the different data sources and help to constrain and improve understanding of the importance of the various data sets to first principle models. Lower Left: This provides a concept plot of ground GPS data. Its purpose is to illustrate that when good data coverage is available, accurate retrieval of electron densities (or other state variables) is possible. The point is, combine good ground GPS data coverage with 66 radio occultations – and we will be able to accurately retrieve electron density globally. Lower Right: The lower right panel, “instrument and science team”, is left blank by design, since this presentation focused on overall goals and instruments for the community, not a particular team.

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Anthea Coster – GEOScan Overarching Science Themes and Goals There are two “overarching” scientific areas that require the need for global measurements of ionospheric parameters. These fall into the general category of space weather and furthering our understanding of the coupling between different regions of the atmosphere. Space weather has the further constraint that it requires real-time observations. In our technological society, the recognition of space weather is growing. Space weather can pose serious threats to many space-based and land-based systems. Many of the serious space weather effects are produced by ionospheric storms. To monitor the development of these space weather events, a global distribution of ionospheric sensors is needed. Currently, the distribution of ionospheric sensors is severely limited over the oceans and in remote, difficult to access areas (Africa, some parts of Australia and South America.) Many questions remain about influence of longitude, the offset of the geomagnetic and geographic poles, and the South American Anomaly on the development of total electron content (TEC) gradients, enhancements, and depletions. A major goal in solar-terrestrial science now is to explain how energy is transferred between different atmospheric regions. A comprehensive observational program combined with theoretical and empirical modeling efforts is necessary to achieve this

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goal. To do this accurately, however, requires an understanding of the Earth’s global behavior as it exists, rather than in an idealized representation. The current distribution of sensors, as shown in Figure 1 for a two-hour period, makes it difficult to infer connections or to separate out one effect from another (for example the changes in winds versus electric fields). Data assimilation models and models of the thermosphere-ionosphere general circulation need to be developed using data sets that cover the entire system.

Figure 1. A plot of TEC data from ground-based GPS sensors and from the GPS occultation

sensors on COSMIC. Data shown is of a two hour average from 27 January 2009.

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Rebecca Bishop – Compact Total Electron Content Sensor The Aerospace Corporations Compact Total Electron Content Sensor (CTECS) is a GPS occultation sensor comprising of a commercial NovAtel receiver with modified software and a custom designed antenna. Currently, CTECS is manifested on the MTV picosat that will be deployed from the last space shuttle mission, STS-135, this summer. Thus, by August the TRL for CTECS will be 8. Currently the mass of the combined receiver and antenna is <200g, power consumption is <1.5 W, and the volume is ~120 cm3. With the current antenna design and modified software, CTECS tracks and processes only GPS satellites. However, the receiver is capable of tracking GLONASS satellites and only minor software modifications are required along with an appropriate antenna to utilize this capability. CTECS can track 16 satellites simultaneously and can be programmed to sample at varying rates (up to 50 Hz) as a function of time and/or GPS satellite elevation. The cost per CTECS sensor is dependent on the level of reliability assurance and testing which depends on the specific mission. The initial cost estimate is $85K per sensor. In its current state, CTECS provides slant TEC and scintillation data for the ionosphere. It may also provide plasmaspheric measurements with an appropriate antenna. The relatively low cost of the sensor enables hosting the sensor on multiple satellites, which will provide tomographic inversion data to produce an “ionospheric map” of TEC. CTECS can be used to investigate global ionospheric changes resulting from geomagnetic disturbances as well as characterize horizontal structure of density depletions and enhancements.

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Thomas Gaussiran & David Rainwater – DORIS on Iridium-‐NEXT: Ionospheric & Tropospheric Science and Precise Orbit Determination We propose a DORIS receiver for Iridium-‐NEXT to make ionospheric TEC and tropospheric TWV measurements. The DORIS frequency lever arm is superior to that of GPS for ionospheric purposes, and DORIS data is now being used to generate TWV data sets of comparable precision to GPS and VLBI data. This instrument would also allow one to obtain precise orbits, to the 2 cm level, adding a vast data set to Earth gravity science and geodesy. Study of the upper and lower atmosphere has advanced to the point where a compelling need has emerged for global real-‐time specification of the most important observations as inputs to climate models. For the ionosphere, plasmasphere and magnetosphere this is the local free electron density, while for the troposphere it is the local water vapor content. We propose an instrument for Iridium-‐NEXT that would provide precise measurements of both, as well as orbit determination with such precision as to be valuable to the Earth gravity science community. DORIS is a Doppler-‐based radio navigation system developed and operated by France. It consists of about 60 stations distributed approximately evenly across the

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globe, including the oceans.; cf. Fig. 1. It’s dual-‐band nature, at 401 and 2036 MHz, allows for extremely precise ionospheric TEC measurement along a ray path – more accurate than GPS, in fact, owing to the larger frequency lever arm. Instrument error is in the milli-‐TEC range. Representativeness error for bulk ionospheric measurement from LEO is also smaller than from ground-‐based GPS measurement, because LEO observations separate the F layer from the topside. Additionally, as there are no GPS stations at sea, DORIS observations from LEO can cover the remaining 70% of Earth’s bulk ionosphere that GPS stations cannot. Scientists began using DORIS for both ionosphere electron content and troposphere water vapor content measurement in the 1990s. In spite of the popularity of GPS, France committed to a system-‐wide upgrade of the transmitter stations to geodesy-‐grade: monumented, surveyed precision antennas with phase-‐center calibration, etc. DORIS stations and LEO observations have become an integral part of the IGA global fit analysis for Earth orientation and absolute station position determination, on par with GPS data [1, 2]. Science of the ionosphere began over a century ago, in 1901, with its discovery by Marconi at the dawn of radio. Only at the turn of this century did a true three-‐dimensional (3D) picture begin to emerge, with the use of 3DVAR data-‐assimilative techniques. Radio navigation system data sets from GPS, DORIS and TRANSIT have become rich enough to enable longitudinal study of ionospheric dynamics on a local level. Modern ionospheric physics is now a mature field, focused on the detailed dynamics, including:

• Structure: bubbles, profile shape, auroral ovals and other anomalies, sporadic E

• Ionospheric reponse to solar input • Global ionospheric response to magnetic storms

• Traveling ionospheric disturbances (TIDs) • Connection to lower atmospheric climate science: temperature profiles,

winds However, while data sources such as GPS or ionosonde observations have become much richer, they are of varying quality (sometimes useless, in the case of GPS, depending on reporting station), sparse, not over the oceans (i.e. most of the Earth), and not always delivered reliably. The best global 3DVAR ionosphere specifications achievable with these data sets are only about 4! (400 km) horizontally, but many ionospheric structures and dynamics are known to be smaller scale. The need for higher resolution is best met by trans-‐ionospheric data, i.e. pierces the F layer at a single horizontal cell. A DORIS receiver as part of the Iridium-‐NEXT constellation would provide an incredibly dense horizontal data set, directly imaging about 13% of the F-‐layer every 15 minutes. Thus, the entire F-‐layer would be re-‐imaged solely by Iridium every two hours. Including standard data sets from other sources (ground-‐based

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GPS, ionosondes, etc.) in a 3DVAR data assimilation program, dense global re-‐imaging could realistically be made sub-‐hour. Tropospheric Science Tropospheric water vapor content (WVC) is one of the critical inputs to climate models, and techniques for measuring it with radio signals are long-‐established. In recent years, upgrades of the DORIS stations to geodesy grade has enabled DORIS data to be on par with GPS and VLBI data for WVC [3, 4]. In fact, bias shifts in GPS data due to antenna or radome replacement indicate that GPS errors have been underquoted [4]. The more important observation is that DORIS, GPS and VLBI data all agree within a couple sigma of each other’s uncertainties, which are of comparable size [4]. A DORIS LEO measurement would vastly increase the number of ground locales for which data is available, and for which updates would be available sub-‐hour. Precise Orbit Determination (POD) can be performed numerous ways, and often is obtained using multiple techniques simultaneously. GPS has been used for many LEO satellites quite suc-‐ cessfully, and can achieve sub-‐decimeter precision fairly straightforwardly. DORIS has similarly been demonstrated to provide such accuracy on numerous LEO satellites, even achieving 1–3 cm on Jason-‐2 this past decade [2]. Our preliminary analysis shows that comparable resolution should also be achievable with a DORIS instrument on Iridium-‐NEXT. This would meet the need called for by the Earth gravity community [5]. The existing CNES space-‐qualified DORIS instrument for navigation and ionospheric mea-‐ surement is far too large, massive and power-‐hungry to be used on Iridium-‐NEXT. As there is no other COTS solution, we propose to modify ARL’s existing software-‐defined receiver, proven in several different applications (cf. e.g. Ref. [6]) and currently being delivered to the GPS Direc-‐ torate as a monitor-‐grade instrument. Modifications include switching to the DORIS frequencies, lowering the power required, and adding software for radiation soft-‐fault tolerance. Ionospheric science has a compelling need for vastly increased data density, ideally specifi-‐ cation on a 1! (100 km) grid in latitude and longitude. It also needs to be of uniformly high quality, truly global, persistent, and updated on a very short timescale. Climate science has a similar need for tropospheric water vapor measurement. DORIS receivers on board the LEO polar-‐orbiting Iridium-‐NEXT satellite constellation can provide both of these at the accuracies required, at a density and temporal update that cannot be matched by any other measurement, and at a higher precision for the ionosphere than GPS data, due to the superior frequency lever arm of DORIS. It is also a comparatively low-‐risk instrument, since unlike GPS it wouldn’t suffer interference from Iridium’s L-‐band communication antenna [7]. Ionospheric measurement would be phase-‐difference-‐based, while WVC data would come out of the precise orbit determination, which itself would be of such high quality that it would be valuable to the Earth gravity measure-‐ ment community in support of other geodesy. There is a clear path to evolve an existing

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ARL:UT radio instrument to fulfill this role in the short timeframe of the Iridium-‐NEXT program.

References [1] P. Willis, Y. E. Bar-‐Sever and G. Tavernier, J. Geodyn. 40 (4-‐5), 494-‐501 (2005). [2] N. P. Zelensky et al. , Adv. Space Res. 46, 1541-‐1558 (2010). [3] M. Flouzat et al. , Geophys. J. Int. bf 178, 1246-‐1259 (2009). [4] O. Block, P. Willis, M. Lacarra and P. Bosser, Adv. Space Res. 46, 1648-‐1660 (2010). [5] Talk by B. Gunter at the GEOScan 2011 Workshop. [6] J. York, J. Little, D. Munton and K. Barrientos, Navigation 57 (4), 297 (2010). [7] UNAVCO Study of Iridum & GPS/GNSS Interference, Feb. 9, 2011, http://facility.unavco.org/kb/questions/675/Update

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Glenn Lightsey – FOTON Software Defined GPS Receiver FOTON is a low cost, dual frequency (L1CA and L2C), software defined GPS receiver that is well positioned to fly as an instrument on GEOScan and other CubeSat applications. FOTON fits within 0.5U CubeSat form factor (8.3 cm x 9.6 cm x 3.8 cm) and is space capable. The current demonstrated performance is better than 0.5 mm carrier phase tracking on both frequencies. The receiver has 60 channels and is completely reconfigurable downstream of signal analog to digital conversion. FOTON’s software can be modified on-‐orbit to support multiple autonomous radio occultation and space weather sensing science objectives, including: ionospheric scintillation event triggering, open-‐loop tracking of rising satellites for tropospheric sounding, raw capture of IF samples, and tracking of new radio navigation signals as they become available. FOTON uses 5 W power when operating continuously, which is acceptable for CubeSat applications. We are currently pursuing ways to reduce the operating power in addition to duty-‐cycling. The current hardware, which is based on COTS parts, is expected to be radiation hardened to 5-‐10 krad total dose; although at only 350 grams, shielding is an option to increase radiation hardness if needed. A radiation-‐hardened version of FOTON is being planned as part of the product development. As of May 2011, FOTON is operating at TRL 4 in a Low Earth

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Orbit dynamic environment simulation on a Spirent GPS Signal Simulator at The University of Texas Center for Space Research. UT-‐Austin is planning to fly the FOTON on a 3U CubeSat mission in 2013-‐14, raising its TRL to 6 or 7 prior to flight on the first GEOScan opportunity. FOTON is being commercialized for CubeSat applications under a separately funded Phase 1 SBIR. The COTS version of FOTON is expected to cost between $10k and $50k based on quantity delivered.

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Sam Yee – COTS GPS System Science Sensor Overview

Tom Meehan – Synoptic Tropo-‐ionospheric Occulations via NEtworked Sensors (STONES) Going forward, compelling GNSSRO science will most benefit from a large number of profiles (10000+/day), with lower latency and greater accuracy in the lowest 5 km altitude. For weather, latencies below 90 mins are required, 30 mins desired. Space weather latency requirements are more stringent, with 30 secs being a long sought goal. Climate measurements benefit from the averaging of many millions of points over a decade with local time sampling errors minimized by dense coverage or well designed orbits. There’s much more of course, because space GNSS science is still nascent but with gathering momentum among the international community. The GEOScan-‐Iridium opportunity is tantalizing for its promise to meet much of the above needs and yet challenging from the limitations of the very tight schedule and minimal accommodations. Current and upcoming JPL/NASA RO instruments do not fit within the very small power and volume envelope allocated to GEOScan. As a further complication, only a ram facing RF antenna is allowed. This diminishes the accuracy of the orbit solution and requires the RO instrument be capable of modeling the refracted path of the GPS signal accurately enough to observe the very weak signals rising through the lower troposphere. JPL’s RO instruments perform

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this modeling in real-‐time and consistently produce open-‐loop high-‐rate RO measurements from ram facing antennas. But, it is a CPU intensive process coupled with special DSP logic not well suited for an extremely low power situation. The proposed STONES sensor adapts the TriG RO instrument and leverages the Iridium real time communications feature. Key features of the STONES sensor:

• All-‐in-‐view capable, GPS, Galileo, GLONASS. Simple, low cost components (< $3k est.).

• Minimal flight HW complexity for fast V&V on tight schedule/budget. • Not autonomous because there’s no need with R/T comm. Most of TriG

processing (and mass, power, volume) moved to ground computer. Sensors are fairly “dumb” individually but become powerful when activated; i.e. the “hive mind” from the Star Trek Borg.

• Open, reconfigurable architecture (both flight and ground HW/SW) provides greatest access to science community.

• Two, digitally beam formed antennas yield wide FOV for POD and iono science as well as higher gain for tropical soundings

Despite challenges, the GEOSCan-‐Iridium proposal offers a tremendous opportunity for capturing globally distributed, dense, calibrated, vertical profiles of the ionosphere and neutral atmosphere in real-‐time. We believe the STONES technical approach maximizes this opportunity.

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Bill Schreiner – Use of NASA’s TriG (Tri-‐GNSS) RO receiver as a GEOScan Hosted Sensor

Measurements from low Earth orbiting (LEO) Global Navigation Satellite System (GNSS) radio occultation (RO) receivers have proven extremely useful for weather, space weather, and climate change research and operational applications. The success of the COSMIC radio occultation mission has prompted the NOAA to initiate plans for a follow-‐on mission (called COSMIC-‐2) with twelve satellites that is due to launch in the 2015 time frame. The COSMIC-‐2 satellites will fly a high performance GNSS RO instrument capable of tracking rising and setting RO signals from multiple GNSS systems. This receiver, called TriG (Tri-‐GNSS), is currently being developed by JPL and will track GNSS signals from GPS, Galileo, and GLONASS. NOAA plans to procure an additional flight spare TriG instrument and fly it as a pathfinder mission on an upcoming communication constellation to evaluate RF interference issues and potential real-time communication architectures. For the mission concept being presented here, NOAA would provide the spare TriG instrument to NSF at no cost to be used as a GEOScan Hosted Sensor. NSF or other agencies would have to provide funding to integrate and test the TriG instrument on the Iridium spacecraft and to make necessary firmware modifications. The operation of the TriG payload, data processing, open dissemination, and archiving of these data could be performed at minimal cost by the UCAR COSMIC Data Analysis and Archive Center.

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This GEOScan TriG concept would not only provide valuable RO datasets for science studies and observational campaigns, but would also give NSF a space-‐based laboratory for the community to investigate innovative GNSS technology and science applications such as receiver firmware tracking loop improvements, wide-‐band buffering of high-‐rate (20 MHz) data for on-‐board post-‐processing or downlink, use of digital antenna beam-‐forming for high-‐gain lower tropospheric studies, tracking of new GNSS signals from Japan’s QZSS or China’s COMPASS, ice/ocean GNSS surface reflections, and heavy precipitation events if a dual polarization antenna is used. These investigations are made possible by fully reconfigurable firmware architecture of the TriG Navigation and Science processors.

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Kenn Gold – Global Broadband Operationally Responsive Navigator The Global Broadband Operationally Responsive Navigator (GBORN) is a unique multi-‐frequency GPS receiver which utilizes a Software Defined Radio (SDR) implementation. The instrument is able to acquire and track GNSS and other broadband RF signals from both ground and space based sources, without explicit knowledge of any code structure imposed on the signal, and to utilize this data for both position velocity and time calculation and for atmospheric profiling (Radio Occultation) studies. If combined with an onboard accelerometer, the receiver has the potential to enable neutral density measurements with a commercial grade IMU. The receiver design and methodology has a common heritage with the JPL Blackjack receiver and uses identical multi-‐frequency cross correlation techniques to recover ionosphere delay values. The system is capable of extracting the fundamental sinusoids from all existing GPS and other GNSS system transmissions and all planned modernized code types, and can be modified via software update to handle future and unanticipated code types. The only limiting physical hardware requirement involves the RF front end which must be capable of receiving signals at the frequency of interest, and down converting to a manageable RF frequency. Multiple vendors have produced space qualified radios which would allow direct porting of the software functionality to achieve the operation of the receiver. The resulting form factor is small and light and is suitable for inclusion into a cubesat

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architecture, with low power requirements (less than 1 Watt for PVT, and less than 3Watts for basic RO). Significant simulation testing has occurred with a Spirent GPS simulator and a terrestrial prototype of the receiver system, which has demonstrated an ability to produce highly accurate positioning in even the most hostile GPS environments (GEO, high Earth Orbit) with accuracy rivaling the state of the art. The nature of the codeless system allows for acquisition at low power levels, which enables the ability to track all GNSS satellites geometrically in view with either direct or side lobe transmissions. The spectral compression capabilities of the GBORN also enable Radio Occultation studies with a significant reduction in required data bandwidth and power over state of the art RO and POD receivers.

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Climate/Atmosphere

Warren Wiscombe & Steven Lorentz – Earth Radation Budget Bolometer The Earth Radiation Budget (ERB) represents the difference between incoming radiation from the Sun and the sum of (1) outgoing reflected solar radiation and (2) outgoing longwave thermal radiation emitted by the Earth’s surface and atmosphere. All climate models are tuned using ERB as an input, making this the most fundamental dataset for understanding climate change. This is conceptually very simple, but has proven to be a difficult experimental measurement to achieve at the levels required for climate trending. How ERB changes both regionally and globally is critical to the understanding of climate change. Iridium NEXT provides a unique opportunity to contribute to the understanding of ERB and climate. Through the use of a large number of simple bolometric radiometers (qualitatively similar to those flown on previous ERB satellites), a complete map of ERB with high temporal and moderate spatial resolution can be created, providing critical data for climate modeling and prediction. The ERB instrument consists of two radiometers, one total channel (0.2 to 200 μm) and one shortwave channel (0.2 to 5 μm). The difference between the channels provides the longwave thermal emission from the Earth. The radiometers have no complex optics or moving parts. The only moving part is a single use contamination door, which is opened after the spacecraft finishes outgasing in orbit. The data product will be the shortwave and longwave outgoing irradiances every 5 seconds, which are later averaged to an hourly mean with roughly 500 km resolution, using proven mathematical methods developed for representing the Earth’s gravity field. The impact of this experiment will be to demonstrate that such a system can measure the Earth’s energy exchange with space to the accuracy required for climate (0.1 Wm-‐2). If so, it would be revolutionary in terms of the way ERB is measured in the future. A minimum of 10 years of flight will be necessary to extract the very small trends that are expected as a result of global warming. Our ERB instrument is perfectly suited in terms of power, mass and impact on a critically important Earth observation for inclusion as a system level instrument in the GEOScan SensorPODs.

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Sebastian Schmidt – Tracking the Global Radiative Energy Budget with GEOScan

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Larry Paxton – Novel Integrated Applications

Earle Williams – Scientific Interest in Global Lightning from IRIDIUM Satellite Measurements Lightning is responsive to local air temperature, but its global response to temperature is yet to be established. It is a matter of common experience that lightning is more frequent in the warm afternoon than in the cool of night, and more frequent in the hot summer than in winter. The water vapor source for thunderstorm convection is controlled in part by the strong temperature dependence in the Clausius Clapeyron relation. Yet the response of the global totality of lightning to global temperature change is still out of reach. On the basis of local measurements, it has now been established that lightning is responsive to temperature on the diurnal, the 5-‐day, the intraannual, the semiannual, the annual and the interannual (ENSO) time scales. Yet we lack measurements on the global totality of lightning on any of these time scales. From a climatological standpoint, we know that lightning waxes and wanes systematically in response to warming and cooling of continental land masses exposed to the Sun. Indeed, the systematic UT time variation of the global electrical

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circuit is a cornerstone of atmospheric electricity. Yet we lack quantitative documentation of this behavior on any single day, toward seeing the day-‐to-‐day variability, and understanding the feedbacks of water vapor and cloud on surface air temperature. The so-‐called tropical ‘chimneys’—the Maritime Continent, Africa and South America—are fundamental players in the overturn of the global atmosphere and mediation of global water vapor, the primary greenhouse gas. Yet these chimneys are in remote regions and are poorly measured at the surface, where 1C of temperature difference makes a substantially greater difference in behavior than at mid-‐ and high-‐latitude. Lightning is a sensitive indicator of surface conditions in these regions. On all time scales on planet Earth, air is rising one place and sinking in another, warming in one place and cooling in another. The global totality of lightning is needed to assess real global change on all time scales. The global electrical circuit provides a natural framework for the measurement of global change, but unfortunately, the ionospheric potential (the primary measure of the DC global circuit) is difficult to measure continuously, and the Earth’s Schumann resonances (the primary measure of the AC global circuit) requires multi-‐station measurements and are challenging to interpret. The constellation of IRIDIUM satellites, equipped with optical sensors for lightning of a kind that are tried and true, would provide for this measurement on a continuous basis. The global warming now underway is most pronounced at high latitudes—northern Siberia and Alaska—where lightning is known to occur but is out of reach of the Lightning Imaging Sensor on the TRMM satellite. The polar orbits of the IRIDIUM satellites would serve to document thoroughly the regions of greatest temperature increase. The tropics maintains quasi-‐thermal equilibrium by cooling itself by moist convection. One important component of the moist convection is thunderstorms. The responsiveness of moist convection and lightning to warming on the diurnal time scale is without question. The responsiveness on the interannual (ENSO) time scale is increasingly evident. The responsiveness to warming on time scales longer than the interannual one is subtle and deserving of further study. The evolution of global convective adjustment is involved, with temperature changes both at the surface and throughout the atmosphere, and is largely unknown.

Bob Erlandson-‐ GEOScan Multi-‐Purpose Imager (MPI) We are pursuing a multi-‐purpose imaging approach for GEOScan. The concept involves placing the camera system on all of the Iridium Next satellites. The camera concept is a dual band imager. One band uses a narrow-‐band (0.02 nm) potassium line imager and the second band is a 770-‐780 nm imager. Both imagers would use the same camera and share the camera controller. We propose to use the custom potassium line filter on six satellites (one per plane) and standard dielectric filter (band TBD) on the other satellites. Band 1 (770-‐780 nm) would be used on all 66

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satellites and would enable observations of clouds during the daytime and aurora, lightning and forest fires at night. The specialized potassium line imager would be used on six satellites, one in each plane and would enable the measurement of chlorophyll fluorescence (F). The measurement of F is described in detail by Joiner et al. (Biogeosciences Discuss., 7, 8281-‐8318, 2010.). Basically, the potassium line imager measures F by taking the ratio of the fluorescence in the potassium Fraunhoffer line and the guard band from 770-‐7890 nm. The F fills in part of the Fraunhoffer absorption line. This Is measured using the ratio of 769 to 770-‐780 nm, allowing the determination of F to depend on the ratio of the two bands rather than an absolute measurement of F in the Fraunhoffer line. The measurement of F occurs only during the daytime. The guard-‐band at 770-‐780 nm is used to determine the cloud “mask” so that the vegetation observations can be made only in pixels without clouds. The placement of the potassium line filter on 6 satellites will provide global coverage in a time period of 3 days. The measurement of F from space has been performed using MODIS, however the use of a dedicated filter with an imaging sensor; use of the potassium band, and use of the Iridium Next constellation provides unprecedented coverage and measurement frequency of F and the ability to measure stressed vegetation. This same dual band imager can be used to detect the aurora at 777.4 nm using the Band-‐1 imager from 770-‐780 nm at night. A field of view of 15x15 degrees from the iridium satellite will provide continuous nighttime polar coverage of the aurora in both hemispheres. Comparisons with the on-‐going AMPERE program will provide unprecedented sampling of both the electrodynamics and auroral emissions. Lightning can also be detected in the 770-‐780 nm at night. Lightning is a transient phenomenon that is very bright. We are currently evaluating whether additional software would be required to detect lightning. For example, using a Time Delay Integration (TDI) mode may not be appropriate for this application. Biomass burning (forest fires) can be detected using the potassium line imager and the 770-‐780 nm imager at night. The MPI is proposed to use a 15 x15 degree FOV with a pixel array of 1024x1024 pixels. Pixel binning capability of 4x4 is needed to reduce the data rate to fit within the Iridium Next bandwidth. The total data rate for MPI (two imagers) is 67 kbps. The spatial resolution at nadir is 200x200m (800x800m with pixel binning). A quick radiometric analysis has been conducted to determine the required aperture size and integration time needed for these applications. We have focused on the fluorescence and auroral measurements so far. Our estimates suggest that a 2 inch aperture is required and that use of Time Delay Integration (TDI) will significantly improve the signal to noise ratio for the auroral and vegetation measurements. This is also true for observations of forest fires at night. Estimates of lightning signatures is still pending.

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The baseline camera for this is the MicroCam. John Boldt has submitted a quad chart describing this camera. John and I will be evaluating the measurement requirements in order to determine, if indeed, this camera will work. The potassium filter is shown below:

Shawn Murphy – Compact Hyperspectral Imaging Module for Earth Science (CHIMES)

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William J. Blackwell – Minature Microwave Atmospheric Sounder (MiniMAS) The need for low-‐cost, mission-‐flexible, and rapidly deployable spaceborne sensors that meet stringent performance requirements pervades Earth Science measurement programs, including especially the recommended NRC Earth Science Decadal Survey missions. The importance of millimeter wave sounding has been highlighted demonstrated for studying the hydrologic cycle in the atmosphere, with applications from weather forecasting to climate research. New technologies have enabled a novel approach toward this science observational goal that would substantially improve both the performance and cost of multiple NRC Earth Science Decadal Survey missions related to weather and climate study. The MiniMAS system, hosted on Iridium/NEXT, profoundly exploits new technology to reduce size and power consumption, while providing complementary observations to GPS radio occultation sensors, which are largely blind in the critically important atmospheric boundary layer. The MiniMAS sounding system comprises a compact passive millimeter wave radiometer system with integrated high-‐efficiency antennas that are scanned cross-‐track +/-‐ 50 degrees. MiniMAS nominally employs two receivers, one operating near the 118.75-‐GHz oxygen line for temperature sounding and one operating near the 183.31-‐GHz water vapor line for moisture sounding. Each receiver comprises a scalar feedhorn antenna with an integrated MMIC superheterodyne receiver illuminating a compact parabolic reflector. MiniMAS fits

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within the SensorPod size, weight, and power requirements and provides spatial resolutions as fine as 15km.

John Boldt – MicroCam

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Hugh Christian – Global Lightning Imaging Sensor (GLIS)

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Steve Jaskeluk – SmartCam

Andrew Kalman – GHVCam The General-‐Purpose High-‐Resolution VIS Camera (GHVCam) is an open imaging platform intended for applications like imaging clouds, surfaces and wildfires; terrain relative navigation; and real-‐time disaster monitoring, all from LEO. It is based on a CubeSat payload design from Pumpkin, Inc. coupled with software from Stanford’s Space & Systems Design Laboratory (SSDL). GHVCam’s architecture supports multiple post-‐capture image processing threads, for on-‐orbit data reduction to match downlink options, via a 16MP full-‐frame (24x36mm) VIS sensor controlled by a 1.6GHz x86 Linux-‐based SBC. GHVCam’s ability to support additional USB-‐based mini-‐experiments can be used to add multispectral capability and to support additional student-‐built mini-‐experiments (e.g., Flash Memory Reliability experiment, UV LED testing). GSD is 8-‐75m depending on optics fitted. It is ideally suited for NSF-‐sponsored student-‐executed projects at Stanford University with sponsor(s) providing image processing algorithms.

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Larry Gordley – Doppler Wind and Temperature Sounder (DWTS)

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Alan Marchant – DISC

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A. Deepak and M. Schoeberl – The CAPE GEOScan Concept Coronagraph Aerosol Photogrammetric Experiment (CAPE) is a concept that will make solar aureole measurements from the Iridium platform. CAPE is basically a coronograph. Using a blocking element – a Lyot stop – the CAPE instrument looks at the glow around the sun – the solar aurole. The aureole is formed by forward Mie scattering of aerosols. The aureole earth-‐limb measurement is made during sunrise and sunset. The instrument uses a mirror to lock on the sun during these periods. Solar corona measurements are made when the sun is above the limb. CAPE data is taken twice per orbit. From the aureole measurement, size distribution of aerosols and thin clouds in the upper troposphere can be determined. This measurement will provide new science about the pervasiveness of thin cirrus and the amount of smoke and dust in the upper troposphere. The thin clouds and aerosols are key elements of overall atmospheric radiative forcing and thus relevant to climate change.

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William Heaps – High Spatial resolution Greenhouse Gas column Sensor Detection of greenhouse gas emissions will become increasingly important as we face the continuing global warming process driven to some extent by anthropogenic emissions of these gases. Although Water vapor is the dominant greenhouse gas in the atmosphere most of the expected change comes from increases in carbon dioxide and methane arising from a number of sources. The possibility of sudden large increases in methane released from the permafrost as warming causes melting in this region is particularly worrying as it represents a very large positive “feedback” in the modeling of global warming. We propose a small yet sensitive complement of instruments based upon the Fabry-‐Perot interferometer to map the column content of these greenhouse gases with high spatial resolution enabling the rapid discovery of the sudden appearance of new sources. Modest mass, power and data rate are possible at modest cost using largely off the shelf components. This work is part of an ongoing effort at Goddard Space Flight Center by William Heaps, Elena Georgieva and Wen Huang and supported in sporadic bursts by NASA’s Earth Science Technology Office as well as Goddard Internal Research and Development funds.

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Space Environment

David Byers – Chip Dosimeter, Charge Plate Analyzer, Micrometeoroid Acoustic Sensor

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Rick Doe – GEOScan Thermosphere Ionosphere Photometer -‐ GTIP GTIP was presented at the GEOScan workshop as an evolutionary dual-channel UV photometer, based on the CubeSat Tiny Ionospheric Photometer (CTIP) currently on schedule for delivery to the US Air Force SENSE mission. GTIP provides common volume measurements at 135.6-nm (atomic oxygen) and at the 170 nm region of the Lyman-Birge-Hopfield band of molecular nitrogen (LBH-L) in a compact package to address global nightside investigation of ionospheric morphology, high-latitude studies of auroral energetics and conductance, and dayside assessment of thermospheric O/N2 response to magnetic storms. GTIP

thus addresses a wide-ranging core of heliophysics and space weather science topics including global M-I coupling, evolution of scintillation producing ionospheric structures (i.e. polar patches and equatorial bubbles), and thermospheric compositional response to stormtime heating and enhanced winds. GTIP was designed by incorporating low size-weight-power elements from the prior CTIP sensor with flight heritage multi-reflection filters from the POLAR satellite UVI sensor into a dual channel photometer.

GTIP has sufficient photometric sensitivity, wide dynamic range, and assured flight heritage to provide high fidelity data products at every node of the GEOScan constellation and at all local time phases of the Iridium satellite orbit. GTIP is fully compliant with the GEOScan Sensor Pod baseline for system sensor form factor, mass, power, and costs and is at a high state of design maturity and delivery readiness.

GTIP occupies ¼ of a Sensor Pod.

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Alan Marchant – DISC

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John Noto – Fabry Perot Sensor for GEOScan Predictive Space Weather models must be physics based, and these models will require realistic state parameters, temperatures, winds, and densities, measured with high temporal resolution and global coverage for effective operation. Emissions in the mesosphere, lower thermosphere, and upper thermosphere that can be exploited for stand-‐off wind and temperature measurements include the O2 A-‐band at 763 nm, the OI green and red lines (lower thermosphere and F-‐region, respectively), the OI 844.6 nm emission (topside), and the He 1083 nm emission. The first three of these have been measured on orbit by Fabry-‐Perot interferometers (HRDI on UARS, and TIDI on TIMED), and by the WINDII instrument aboard UARS. Previous incarnations of Doppler capable optical interferometers on satellites are too large, too heavy, and consume too much power for the smaller payloads envisioned for future space research missions. Fortunately, Fabry-‐Perot technology has evolved to permit robust performance in significantly lighter, lower power configurations. We have developed and patented a solid-‐state Fabry-‐Perot interferometer that uses liquid crystal in the resonant cavity, which permits tuning through the application of an electric field that is generated by applying very low current to an Indium Tin Oxide substrate coating. This coating may be etched, to

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allow multiple, independently tunable cavities within a single substrate. This allows simultaneous viewing of multiple emissions, and simultaneous acquisition of the horizontal wind field, and temperatures at multiple altitudes. The liquid crystal Fabry-‐Perot (LCFP) technology has been successfully radiation tested in an environment consistent with low earth orbit, and a successful Pegasus level shake test has demonstrated its robust mechanical nature. To examine the effects of long-‐term exposure of the LCFP materials, an LCFP etalon is currently aboard the International Space Station in a Getaway Special package. The LCFP instrument that we envision of GEOScan weights less than a kilogram, and consumes less than 5 watts of power.

Steve Watchorn & John Noto – Spatial Heterodyne Spectrometer

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Qian Wu – SANDI Hosted Sensor Overview

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Tom Woods – FUVI

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Tom Woods – RePTile

Luke Goembel – SCM Sensor High energy-‐resolution charged particle spectrometers are needed for some applications in space. Useful applications for such devices include: 1) accurate spacecraft floating potential measurement without the need for booms or probes, and 2) the remote sensing of upper atmosphere plasma densities (the transparency of the plasma along the flux tube from 250 km to satellite altitude). Neither measurement can be made with spaceborne spectrometers that are now flown. High quality spectra collected by the SCM would prove valuable in gauging space weather conditions in the region of the spacecraft and may prove synergistic with other GEOScan measurements. Goembel Instruments proposes the flight of either the SCM-‐1 or the SCM-‐2 on GEOScan. The SCM-‐1 sensor is a breakthrough high energy-‐resolution electron spectrometer. The sensor includes patented charged particle optics that enable an order of magnitude better performance (geometric factor and/or energy resolution) than any comparable instruments flown today. The construction of the SCM-‐1, a flight-‐ready 650-‐gram instrument, was funded through NASA SBIR contracts. For a cost of $99k, the SCM-‐1 could be flown as-‐is. If needed, the chassis could be custom-‐built to fit optimally within the GEOScan pod for no additional cost.

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For additional cost the SCM-‐2, a vastly improved version of the SCM-‐1, could be custom built for GEOScan. The SCM-‐2 was developed for the DoD Transitional Satellite Communications System (TSAT) but has not yet been built. The SCM-‐2 would energy analyze ions as well as electrons. Ion energy analysis would enable full orbit spacecraft charge determinations over a greater voltage range and would return ion as well as electron energy spectra of unprecedented quality. A SCM-‐2 of slightly larger size and mass of the SCM-‐1 could be built for $299k, or ten could be built for $99k each. For $599k a miniaturized, 1U version of the SCM-‐2 could be built. The flight of any version of the Goembel Instruments SCM would advance the state of the art in spaceborne charged particle spectroscopy and advance our knowledge of spacecraft charging and the low energy plasma environment of the upper atmosphere. Further information is available upon request from Goembel Instruments.

Sven Bilén – Hybrid Plasma Probe for Space Weather Measurements The Hybrid Plasma Probe (HPP) is a unique combination of instruments to provide in situ measurements of the ionosphere. In particular, the HPP provides an ability to simultaneously take high resolution and high accuracy absolute density and ∆ne/ne measurements by combining a fixed biased Langmuir probe and the Plasma Frequency probe. Additionally, introducing a Fast Temperature Probe (FTP) based on a Druyvesteyn probe, the HPP can provide high resolution temperate data as an alternative operating mode.

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This combination of instruments allows the probe to be used to address a number of different space weather research and provide space weather critical measurements. These include observations at conjugates points, and a space-‐based platform could provide simultaneous in situ measurements that will help the understanding of plasma transport through the magnetic field lines. Additionally, this instrument will allow observations of natural phenomenon such as naturally occurring space weather and mesoscale convective systems. For all mentioned experiments, multipoint measurements will resolve spatial and temporal ambiguities and help to create a more holistic picture of the current state of the ionosphere. This instrument is built on the experience Penn State’s Communications and Space Systems Laboratory has gained from over 50 Langmuir probes launched on sounding rocket platforms and further research by faculty and students into plasma frequency measurement techniques.

Marcin Pilinski and Scott Palo – Thermospheric Ionospheric Velocity Energy Analyzer (TIVEA) Observations of ion drifts (and electric fields) are crucial to assimilative modeling of the ionosphere as well as to the understanding of the coupled ITM system. Without this information, there is little hope of understanding the energy flow within the system. The TIVEA instrument addresses the need to provide in situ measurements of ion-‐drifts while fitting within the SWaP envelope of 10c10x10 cm, 1W of power consumption and 1kg. The TIVEA instrument is an energy spectrometer using a Small Deflection Energy Analyzer (SDEA) as the energy selection device. The

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instrument concept was developed by Dr. Fred Herrero at NASA GSFC and adapted by CU students for use on Drag and Neutral Density Explorer (DANDE) satellite, a spin-‐stabilized spacecraft. For the purpose of GEOScan, we intend to update the DANDE instrument design for a 3-‐axis stabilized platform and reduce the SWaP from 11.5x6.4x18.1cm, 2W of power and 1.8 kg. The existing laboratory sensor head is at a TRL level of 5 but will undergo vibration and thermal vacuum testing in the summer of 2011 to bring the TRL level to 7. The DANDE version of this instrument is anticipated to fly in the first quarter of 2012. It is important to note that deflection energy analyzers such as the one on TIVEA provide information complementary to retarding potential analyzers by measuring the kinetic energy directly rather than the integral thereof. In order to turn TIVEA measurements into meaningful electric field estimates the spacecraft attitude must be known to within 0.03 degrees and the instrument aperture must point within 5 degrees of RAM. Furthermore the spacecraft velocity must be known to within 5 m/s and its position within 1000 m. Other requirements include pre-‐launch nitrogen purge of the sensor heads and a 10-‐20 inch radius equipotential surface surrounding the sensor head. The data products are expected to total ~9 Mbytes per day and will be comprised of three dimensional velocity distribution once every 2-‐5 seconds along orbit. This will lead to a post processed mean drift velocity vector, “temperature” and number densities at the same cadence. The estimated cost per unit is $0.3M. The development cost to miniaturize and prepare the instrument for the radiation and thermal environment of GEOScan is approximately $2.0M.

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Ted Fritz – Mini-‐Imagine Electron Spectrometer (MIES) The Energetic Particle Group from Boston University’s Center for Space Physics has proposed a 1U Mini-‐Imagine Electron Spectrometer (MIES) with an energy range E = 20-‐500 keV and multiple look directions for the GEOScan program. The instrument would be ready for production and comes from a long heritage of the energetic electron instrument flown successfully on the Polar, Cluster, and soon to be launched on DSX. In the polar GEOScan orbit, this detector would allow for a number of magnetospheric and ionospheric problems to be studied. In the realm of lightning induced precipitation tt would be able to help solve questions such as: how are VLF wave from lightning transmitted through the ionosphere, what role do ionspheric waves from lightning play in emptying the radiation belt, and how does lightning induced precipitation change seasonally? Near the poles the energetic measurements from the detector would help solve the problem of what is causing the isotropic trapping boundary? There has never been more than one spacecraft observing this polar boundary, so the contribution from using just a few GEOScan space to study this would be original and significant. In terms of instrumental requirements, the detector is well developed and low impact. The estimated cost for a single detector is 10k. It requires less than 3 Watts, weighs ~0.3 kg, and would require a data rate of <1.5kb/s. In order to make the necessary directional measurements, the detector would need to have open exposure to the zenith and ram directions. As the GEOScan payload overhangs by ~10cm from the rest of the spacecraft, this orientation in the spacecraft is possible in that position. For more details on the detector and it’s capabilities, please contact Ted Fritz at [email protected].

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Steve Cummer – Lighting-‐Upper Atmospheric Coupling Lightning-‐upper atmosphere coupling occurs in many spectacular forms, and the understanding of the physics behind and effects of this coupling, while far from complete, has been greatly improved by satellite optical, radio, and high-‐energy particle measurements. At present the science in this field is observation-‐limited, and could be advanced tremendously with relatively modest instrumentation on multiple satellite platforms. Flying instruments on several spacecraft (but not all) seems like the best balance of cost-‐benefit for this science target. The kinds of instruments that could conceivably fly on the GEOScan platform cover the range of radio, optical, and high-‐energy particle and photon observations that have already proven valuable. The simplest would be VLF-‐bandwidth electric and magnetic field sensors that would measure the strength and characteristics of the source lightning discharges. Importantly, they would also probe the not-‐understood observations of unexpectedly high trans-‐ionospheric VLF attenuation that has been highlighted in recent literature and that has significant implications for radiation belt particle loss. Such instruments can be designed to meet the space and power constraints of the GEOScan platform.

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Optical and high-‐energy photon instrumentation for detecting lightning-‐driven mesospheric optical emissions and terrestrial gamma ray flashes are also scientifically valuable possible GEOScan instruments for lightning-‐upper atmosphere coupling. Gamma ray detectors (which will also detect high energy electron and positron beams also produced by lightning) efficiency is proportional to mass, making design a challenge. Optical instruments are more flexible, and designing a system with scientifically valuable capabilities (imaging, spectophotometry, etc.) that meets the GEOSCan constraints seems very possible.

R. Lin – Stein-‐X Stein-‐X provides imaging (~1-‐3 degrees E-‐W) spectroscopy (~1 keV FWHM) of both ~4-‐200 keV ENAs and ~2-‐20 keV auroral X-‐rays in a ~1 kg, 1 Watt, 1 U volume instrument. Stein-‐X on every Iridium spacecraft will obtain global imaging of ENAs (in stereo) and of auroral X-‐rays every <~9 minutes, to follow the dynamical evolution of the ring current and electron precipitation -‐ key elements of space weather. Stein-‐X takes advantage of a breakthrough in thin-‐window, silicon semiconductor detectors (SSDs), recently developed for the STE (SupraThermal Electron) instruments on the STEREO mission to detect interplanetary electrons down to ~2 keV with ~50 times higher sensitivity than the electrostatic analyzers used previously. STE also detects ~4-‐100 keV ENAs and ions with very high

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sensitivity, as well as ~2-‐20 keV X-‐rays from galactic sources. These are the first SSDs in space (still operating nominally after ~4.5 yrs) to detect particles to well below ~20 keV energy, and they are insensitive to the geocoronal UV/EUV emissions that must be attenuated by a factor of >~105 for MCP-‐based ENA instruments. A STEIN (SupraThermal Electron, Ion, Neutral) instrument is being developed for the CINEMA (Cubesat for Ions, Neutrals, Electrons, & Magnetic fields) mission (June, 2012 launch) with an electrostatic deflector to separate electrons from ions from ENAs, and a single ASIC (developed for a French-‐Italian astrophysics mission) providing the electronics for 32 SSDs. Stein-‐X has 1-‐D imagers for ENAs and for X-‐rays, each with a 32 SSD array behind a coded aperture grid (similar to solar hard X-‐ray/gamma-‐ray imaging systems). Thus, the key technologies for Stein-‐X have already been developed by STEIN, so only minor modifications are needed.

Gerald Fishman – Gamma-‐ray Detector Constellation for Earth and Sky Observations We propose to include a constellation of gamma-ray detectors in the Iridium-Next GEOScan program. There has never been an all-sky, full-Earth gamma-ray observational capability. The baseline system consists of 30, 2U-size instrument modules, each weighing about 2 kg and utilizing 3 w of power. The objectives would include continuous observations of gamma-ray emissions from Solar flares, transient high-energy astrophysical objects, terrestrial gamma-ray flashes, and the tracking of the propagation of radioactivity from man-made accidents (such as power plants) and terrorist acts (dirty

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bombs and small nuclear devices). These observations would be of interest to NASA, DoD and the Dept. of Homeland Security. The Lead institution is NASA-Marshall Space Flight Center. Significant hardware collaborators include NASA-GSFC and NRL. Participation of perhaps as many as ten Universities is also expected.

Andrew Stephan – Miniature UV Spectrographic Experiment (MUSE) MUSE is a compact, high-‐sensitivity UV spectral imager designed to measure key ion and neutral species in the ionosphere-‐thermosphere (IT) system. MUSE has a passband of 60-‐140 nm from which altitude profiles of O, N2, O2, O+, as well as other minor species can be derived using mature modeling and data inversion techniques. MUSE data can be used in synergy with a wide variety of alternate sensing data to provide a comprehensive view of structure, dynamics, chemistry, and coupling that occurs throughout the IT system. MUSE would fill the data gap to understanding how the IT system responds to solar and geomagnetic storms – a need suggested in the Heliophysics Roadmap 2005-‐2035. The MUSE sensor would be designed to fit in a 3U volume with mass not to exceed 5 kg. Power consumption is 5W, orbit-‐averaged. The expected data rate is estimated at 100 kbps, with the possibility of compression. The sensor concept has significant heritage in several rocket flights, putting the current TRL at 6-‐7. During operations, the MUSE sensor would view toward the limb of the Earth, imaging altitude profiles of emissions from terrestrial ion and neutral species. MUSE is a passive sensor that does not contain any moving

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parts, making it compatible with most spacecraft hosts. If the line of sight is oriented in the orbital plane, significant advances could be made by connecting one set of MUSE measurements to others made simultaneously by another MUSE other complementary sensors hosted on adjacent, co-‐planar platforms. Any combination of 2-‐6 sensors, however, would create significant advances in IT research over current single-‐sensor approaches, with each additional sensor improving temporal, spatial, and/or local time resolution over these historic data sets.

Greg Earle – UT Dallas Thermal Ion Instruments The University of Texas at Dallas has been building and flying state-‐of-‐the-‐art thermal ion instruments for more than 40 years, on satellites such as DMSP, AE, DE, ROCSAT, and C/NOFS. These instruments have recently been repackaged for accommodation on micro-‐ and nano-‐satellite platforms. Together the retarding potential analyzer (RPA) and ion drift meter (IDM) measure more state variables of the ionosphere than any other single instrument, including the plasma density, temperature, vector velocity, and light/heavy ion composition ratio. All such measurements are made in-situ, so there is no ambiguity regarding spatial location of irregularities. The Iridium-‐Next platform provides an outstanding opportunity to conduct such measurements simultaneously over a global grid, providing high-‐

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resolution data on the plasma medium, and resolving spatial-‐temporal ambiguities that have hampered progress in space science since the dawn of the space age.

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Mihaly Horanyi – GEOScan Cosmic Dust and Debris Experiment

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Michael Kiedar – GEOScan Micro-‐Vacuum Arc Thruster for Nanosatellites

Micro/Nano-satellite position control •  What measurements do you need conduct you

proposed science? o  Thruster duty cycle control measurement o  Thrust force test o  Power supply system testing for

cubsatellite.

GEOScan: Micro-Vacuum Arc Thruster for Nanosatellites

µCT for precision orbit maneuvers •  Cube-satellite latitude and attitude control •  Microthruster with extended life time is

developed and characterized •  Thruster is well suited for nanosatellites: •  20-30V, <1W power requirements •  2000-3500s Isp •  1-10 mN thrust during pulse (1-12x10-7 Ns) •  Small footprint and system mass •  Applied magnetic field leads to uniform cathode

erosion and ability to throttle the thrust

The George Washington University Micro-propulsion and Nanotechnology Lab •  Michael Keidar •  George Washington University, MpNL •  Taisen Zhuang, Alex Shashurin, Lubos Brieda, Tom

Denz, Samudra Haque •  Acknowledgment: NSF-DOE Partnership on Plasma

Science •  Air Force Office of Scientific Research •  DC NASA Space Grant

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Appendix I – Workshop Abstract Titles and Authors

Name Affiliation Title

Sven Bilén The Pennsylvania State University

Hybrid Plasma Probe for Space Weather Measurements

Rebecca Bishop The Aerospace Corporation

The Compact Total Electron Content Sensor: CTECS Sensor on the MTV Mission and its Potential Use of Future Opportunities

Gary Bust ASTRA Ionospheric Measurements and Ionospheric Data Assimilation

David Byers Naval Research Laboratory

Targeted Space Weather Sensors and LF-HF Radio Telescope

Kerri Cahoy MIT GPS Radio Occultation Opportunities with Iridium/NEXT

Hugh Christian

University of Alabama in Huntsville Continous Lightning Observations from LEO

Anthea Coster MIT Haystack Observatory

Importance of Filling Data Gaps in Studies of Atmospheric Coupling

Geoff Crowley ASTRA The Scanning Imaging Photometer System (SIPS) for UV Ionospheric Remote Sensing

Steve Cummer Duke University Lightning-Upper Atmosphere Coupling Ann Darrin JHU/APL Intoduction

Adarsh Deepak Science and Technology Corp.

Space-Borne Solar-Aureole Method for Determining Atmospheric Aerosol Size Distributions

Matt Desch Iridium GEOScan Welcome - Iridium

Rick Doe SRI International Impact of Multipoint UV Photometry on Ionospheric System Science

Lars Dyrud JHU APL GEOScan Overview

Greg Earle University of Texas at Dallas

Thermal Plasma Measurements with Small Retarding Potential Analyzers

Bob Erlandson JHU/APL Detection of Biomass Burning Using a Potassium Line Image

Chad Fish Space Dynamics Laboratory Hosted SensorPOD Science

Gerald Fishman NASA - Marshall Space Flight Center

A Gamma-ray GeoScan Constellation for Earth Observation

Dave Fritts NWRA-CoRA Div.

Science Enabled by Continuous Measurements of Atmospheric Winds and Temperatures from 10 to 200 km Aboard Iridium

Luke Goembel Goembel Instruments

Spacecraft Charge Monitor / Electron Spectrometer

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Kenn Gold Emergent Space Technologies

Global Broadband Operationally Responsive Navigator- Enabling Radio Occultation Studies With Signals of Opportunity

Larry Gordley GATS, Inc. Doppler Modulated Gas Correlation:A Breakthrough in Passive Sensing from LEO

Thomas Gaussiran ARL:UT Global, High-Res, Real-Time Ionosphere Specification

Brian Gunter Delft University of Technology

Using Iridium NEXT to observe global time-variable gravity

Om Prakash Gupta Iridium Iridium Hosted Payload Program

William Heaps NASA Goddard High Spatial Resolution Greenhouse Gas Column Sensor

Mihaly Horanyi LASP - U. of Colorado GEOScan Cosmic Dust and Debris Experiment

Steve Jaskulek JHU/APL Space-based Microcam Andrew Kalman Pumpkin, Inc. Multispectral Solid-State Imager

Michael Keidar George Washington University Micro-cathode thruster for nanosatellite propulsion

David M. Klumpar Montana State University

The Suitability of Small Space Weather Payloads on LEO Satellite Constellations: Research and Operations

Bill Kuo UCAR COSMIC Applications of GPS Radio Occultation Measurements to Hurricane Prediction

E. Glenn Lightsey The Univ. of Texas at Austin

FOTON: A software-defined, compact, low-cost, GPS radio occultation sensor

Steven Lorentz L-1 Standards and Technology, Inc.

Earth Radiation Budget Measurements Aboard Iridium Next

Alan Marchant Utah State University DISC technology for limb scanning and other compact imaging instruments

Shawn D. Murphy C.S.Draper Laboratory, Inc.

Compact Hyperspectral Imaging Module for Earth Science (CHIMES)

John Noto Scientific Solutions Inc.

Small Interferometers for Measuring Neutral Dynamics from Small(er) Satellites

Larry Paxton JHU/APL Novel Integrated Applications

Marcin Pilinski University of Colorado, Boulder In Situ Electrostatic Ion-Drift Sensor

Dave Rainwater ARL:UT DORIS Sensor package for Iridium-NEXT

Bill Schreiner UCAR

Use of NASA's TriG GNSS RO Receiver as a GEOScan Hosted Sensor & Data processing and science applications of space-based GNSS radio occultation data

Andrew Stephan NRL Miniature UV Spectrographic Experiment

Paul Straus The Aerospace Corporation

Opportunities for scientific collaborations cosmic/ssaem program and space weather sensors on iridium

Brian Walsh Boston University

Small scale energetic electron detector as a probe for multiple ionospheric and magnetopheric processes

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Earle Williams MIT-Licoln Laboratories Scientific Interest in Global Lightning

Thomas Woods University of Colorado

Laboratory for Atmospheric and Space Physics Far UltraViolet Imager (FUVI) as Hosted Sensor Option for GEOScan

Dong Wu Climate and weather sensors on Iridium

Dong Wu Jet Propulsion Laboratory Thermospheric Wind Measurement

Qian Wu NCAR/HAO Space based COTS GPS

Eftyhia Zesta Air Force Research Laboratory

SESSAME (Scintillation and Energy input for Space Situational Awareness and Monitoring the Environment) Suite

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Appendix II – Workshop Attendees Name Affiliation Email Stephen Ambrose NASA [email protected] George Andrew NASA-GSFC [email protected] Steven Arnold JHU/APL [email protected]

Kultegin Aydin Penn. State University [email protected]

Ben Barnum JHU/APL [email protected]

Riccardo Bevilacqua Rensselaer Polytechnic Institute [email protected]

Sven Bilén The Pennsylvania State University [email protected]

Rebecca Bishop The Aerospace Corporation [email protected]

Richard Blakeslee NASA/MSFC [email protected]

Brian Bradford ITT Geospatial Systems [email protected]

Gary Bust ASTRA [email protected]

David Byers Naval Research Laboratory [email protected]

Kerri Cahoy MIT [email protected] John Carey NASA-GSFC [email protected]

Glen Cameron Orbital Sciences Corporation [email protected]

Peter Chi UCLA [email protected]

Hugh Christian University of Alabama in Huntsville [email protected]

Clark Cohen Coherent Navigation, Inc. [email protected]

Nathan Colvin USAF [email protected]

David COOKE Air Force Research Lab [email protected]

Anthea Coster MIT Haystack Observatory [email protected]

Geoff Crowley ASTRA [email protected] Steve Cummer Duke University [email protected] Ann Darrin JHU/APL [email protected]

Adarsh Deepak Science and Technology Corp. [email protected]

Matt Desch Iridium [email protected] Rick Doe SRI International [email protected] Lars Dyrud JHU APL [email protected] Greg Earle University of Texas at [email protected]

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Dallas

Bob Erlandson JHU/APL [email protected] Jonathan T. Fentzke JHU/APL [email protected] Cassandra Fesen AFOSR [email protected]

Chad Fish Space Dynamics Laboratory [email protected]

Gerald Fishman NASA - Marshall Space Flight Center [email protected]

Dave Fritts NWRA-CoRA Div. [email protected] Anthony Galasso The Boeing Company [email protected] Thomas Gaussiran ARL:UT [email protected] Jesper W Gjerloev JHU-APL [email protected] Luke Goembel Goembel Instruments [email protected]

Kenn Gold Emergent Space Technologies

[email protected]

Larry Gordley GATS, Inc. [email protected] Michael Gregory ITT Corporation [email protected]

J. Eric Grove Naval Research Laboratory [email protected]

Brian Gunter Delft University of Technology [email protected]

Om Prakash Gupta Iridium Satellite LLC [email protected]

Samudra E. Haque George Washington University [email protected]

Philip Hattis Draper Laboratory [email protected] William Heaps NASA Goddard [email protected] Liang Heng Stanford University [email protected] Robert Holloway ITT Corp. [email protected]

Mihaly Horanyi LASP - U. of Colorado [email protected]

BJ Jaroux NASA Ames Research Center [email protected]

Steve Jaskulek JHU/APL [email protected]

Scott Jensen Space Dynamics Laboratory [email protected]

Farzad Kamalabadi NSF [email protected] Andrew Kalman Pumpkin, Inc. [email protected] Suk Jin Kang Drexel University [email protected]

Ashok Kaveeshwar

Science and Technology Corporation [email protected]

Michael Keidar George Washington University [email protected]

Larry Kepko NASA Goddard Space Flight Center [email protected]

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Omid E. Kia ITT Geospatial Systems [email protected]

Haklin Kimm East Stroudsburng University [email protected]

David M. Klumpar Montana State University [email protected]

Satya Kotaru NASA Langley [email protected] Bill Kuo UCAR COSMIC [email protected]

E. Glenn Lightsey The Univ. of Texas at Austin [email protected]

Bryant Loomis SGT Inc [email protected]

Steven Lorentz L-1 Standards and Technology, Inc. [email protected]

Tim Maclay Celestial Insight, Inc. [email protected] Alan Marchant Utah State University [email protected] John McCarthy Orbital Sciences [email protected] Tom Meehan NASA/JPL [email protected]

Shawn D. Murphy C.S.Draper Laboratory, Inc. [email protected]

John Noto Scientific Solutions Inc. [email protected]

Corwin Olson a.i. solutions [email protected] Larry Paxton JHU/APL [email protected]

Marcin Pilinski University of Colorado, Boulder [email protected]

Amanda Preble USAF [email protected]

Dave Rainwater ARL:UT [email protected] Cheryl L. B. Reed JHU/APL [email protected]

Rex Ridenoure

CEO, Ecliptic Enterprises Corporation

[email protected]

Christopher T. Rodgers ITT Geospatial Systems [email protected]

Scott Schaire NASA-GSFC Wallops [email protected]

Sebastian Schmidt University of Colorado/LASP [email protected]

Mark Schoeberl

Science and Technology Corporation [email protected]

Bill Schreiner UCAR [email protected] Joshua Semeter Boston University [email protected] Susan Skone University of Calgary [email protected] Stefan Slagowski Draper Lab [email protected] Andrew Stephan NRL [email protected] Paul Straus The Aerospace [email protected]

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Corporation

Elsayed Talaat JHU/APL [email protected] Don Thoma Iridium [email protected] Brian Walsh Boston University [email protected]

Earle Williams MIT-Licoln Laboratories [email protected]

Kirk Woellert Space Policy Institute [email protected] Thomas Woods University of Colorado [email protected]

Cinnamon Wright A.I. Solutions [email protected]

Chin-Chun Wu Naval Research Laboratory [email protected]

Dong Wu Jet Propulsion Laboratory [email protected]

Qian Wu NCAR/HAO [email protected] Sam Yee JHU/APL [email protected]

David Yoel American Aerospace [email protected]

Lawernce J. Zanetti JHU/APL [email protected]

Eftyhia Zesta Air Force Research Laboratory [email protected]

Taisen Zhuang

The George Washington University [email protected]

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