The ESA-‐SSA programme: the NEO and SST segments
Fabrizio Bernardi
The ESA-‐SSA Programme
• SSA stands for Space Situa9onal Awareness • “The objec<ve of the Space Situa<onal Awareness (SSA) ini<a<ve is
to support the European independent u<lisa<on of and access to space for research or services, through providing <mely and quality data, informa<on, services and knowledge regarding the environment, the threats and the sustainable exploita<on of the outer space.”
From the SSA Programme Declaration, ESA/C/SSA-PP(2008)2 Translated: We will provide a service to inform the customers
(governments, disaster management, scientists, the public/press…) about the situation of natural and artificial objects in space. This will allow us to better protect our satellites and our planet.
Where SSA is in the ESA plan
Mandatory Op<onal
Science General Studies Programme (GSP) Microgravity
research
Interna<onal Space Sta<on
Telecommu-‐nica<ons Earth Observa<on
Space Situa<onal Awareness All others…
studies on future projects, technology research, shared technical investments, information systems and training programmes
Pay based on Gross Domestic Product (GDP)
Pay based on interest
(From: http://www.esa.int/spaceinimages/Images/2015/01/ESA_Budget_2015_by_domain)
SSA phases
– Preparatory phase (2009 – 2012) approved at ESA’s council meeting on ministerial level in Nov 2008 (50 M€) as an optional programme
– After confirmation at ESA’s council meeting on ministerial level in Nov 2012: Phase – 46 M€
Preparatory Phase 2009 - 2012
Phase 2 2013 - 2016
Operational Phase 2017 - ???
time
SSA segments
• The SSA programme is divided into three segments:
Space Situa<onal Awareness
Space Weather segment Surveillance and Tracking
segment (man-made objects) Near-Earth object
segment
SSA in the ESA framework
Director General
ESA SSA Core Team
ESA Technical Staff
Programme Board
advises
directs
directs
supports
report
Director of HSO
directs
User Group
Contractors (Industry, institutes)
HSO = Directorate of Human Spaceflight and Opera<ons
Advisory Group
for D/HSO
advises
ESA-‐SSA core team and management
• Director of the Human Spaceflight and Operations directorate (HSO): Thomas Reiter
• ESA Core Team – Programme Manager SSA: Nicolas
Bobrinsky – SSA-SWE Segment Manager: Juha-
Pekka Luntama (‘Jussi’) – SSA-NEO Segment Managers:
Detlef Koschny, Gerhard Drolshagen
– SSA-SST Segment Manager: Emmet Fletcher
– Ground Segment Manager: Gian Maria Pinna
– Public Relations: Daniel Scuka – Project Controller: Andreas
Ottenbacher
TR NB
JPL
DVK
GD
EF GMP
DS AO
SSA yearly procurement
Segment 2013 2014 2015
SW 12260k€ 2650k€ 2420k€
NEO 2320k€ 8500k€ 720k€
SST 2050k€ 1300k€ 510k€
COMMON 3900k€ 700k€ 640k€
NEOs: What was there before 2008
• NEOs surveys: mostly American, they had mandate from the US congress to discover at least 90% of killer asteroids within 2008 (D>1km,1998), extended since 2005 to D>140m un<l 2020
• USA invested a lot of resources for the NEO problem: – Ini<ally 4 M$/year – Now 20M$/year and increasing – Several American NEOs surveys operated since early 1990s:
• Spacewatch, NEAT, LINEAR, LONEOS, CSS – Catalina, Pan-‐STARRS – They discovered most of the more than 12,000 NEOs discovered so far
(but also most of the 550,000 asteroids: MBs, Trojans, KBOs…) • Europe and the rest of the world did quite lille for the surveying
ac<vi<es: – Few NEOs surveys and with lille resources
NEOs: What was there before 2008
• NEODyS: Near Earth Objects Dynamic Site à performs Impact Monitoring ac<vi<es on a daily basis since 1999 hlp://newton.dm.unipi.it/neodys2. This is in Pisa (Univ. of Pisa, prof. Andrea Milani) The other similar service in the world is Sentry @JPL-‐NASA
• EARN DB: Database of physical proper<es of NEOs, hosted by DLR
• Europe did a lot of work for the physical characteriza9on of NEOs (spectroscopy, photometry and light curves, polarimetry …)
• Don Quijote phase A study: performed early 2000 for ESA, for a deflec<on experiment mission
NEOs: SSA program purposes
• Federate exis<ng assets • Provide surveying and follow-‐up capabili<es • Be an authorita<ve en<ty providing informa<on to:
– Decision makers – Scien<sts – General public
• Provide services: – Impact monitoring – Orbits DB – Physical parameters DB
A two-tier approach
Exis<ng assets
Mission requirements
User requirements
System requirements
Precursor system
Final system
Top-down
Bottom-up
SSA-‐NEO Development approach
Customer Requirements
System requirements Architecture
Precursor Service
Agreements w/ data centres
Agreements w/ telescopes
2010 Definition of final service
Studies related to SSA paid by other ESA programmes
TIME
Policy, interfaces to other related
activities (UN…)
2011 2012-14
SSA-‐NEO setup -‐ context
SSA-‐NEO situa<on and major assets
• The NEO Coordina9on Centre: – Is actually the PRECURSOR SERVICE that federates several exis<ng European Assets: NEODyS/AstDyS, EARN, Priority List
– Located in ESRIN, Frasca<, Italy, near Rome – The personnel allocated:
• Two Front Desk Operators (Micheli & Borgia) • ESA staff: Koschny and Drolshagen à NEO managers • Scien<fic coordina<on and consultancy: Perozzi (DEIMOS), myself (SpaceDyS), Milani (UniPi), Valsecchi (IASF-‐INAF) and others
SSA-‐NEO situa<on and major assets
• The NEO Coordina9on Centre: – Provides:
• Web portal hlp://neo.ssa.esa.int – NEODyS: NEO orbits and Impact Risk tables – AstDyS: all numbered and mul<-‐opp asteroids orbits – Comets orbits – EARN data for NEO physical proper<es – DB query – Image DB (OGS and La Sagra) – Close approaches – Priority List – Orbit visualizer
• Interface with decision makers (ESA, ONU, governments,…) • NEO follow-‐up ac<vi<es (ESA-‐OGS, VLT, BLT, Faulkes …) • Coordina<on of NEO observa<ons between astronomers and amateurs • Monthly newslelers • Outreach and informa<on (mass media, schools, …)
SSA-‐NEO situa<on and major assets
• The Fly-‐Eye telescope: – A new telescope design developed in Europe by CGS-‐OHB (Italy) – The approach is different from the American surveys:
• Search for IMMINENT IMPACTORS, that is small asteroids, 10-‐200 m in diameter range, which are going to collide within few days or weeks. (US surveys look in general for events occurring in the next decades)
• Need wide field of view • Goal is to cover all the visible sky from ground each night!
Fly-‐Eye Wide Survey
• Wide survey observes the full visible sky from one sta<on down to mag. 21.5
• Having at least 4 or 5 sta<ons spread both in la<tude (in both hemispheres) and longitudes, allows to cover all the visible sky from ground except near the Sun, the Moon and the galac<c plane more than four <mes a night
Earth
Wide Survey
Deep Survey
• Low weather correla9on ! survey system capable to observe many nights a year
The Fly-‐Eye parameters
FoV° 6.7°x6.7° (>44 sq. deg.)
Class Aperture Diameter 1 meter
Pixel Size 15 µm
Pixel Resolution 1.5’’ (>80% Encircled Energy in 1” radius)
Readout timeframe 3-5 s
Time accuracy for image acquisition
~ 10-3 s
A Wide Survey strategy imposes to observe twice in one night ALL the visible Sky from one sta9on down to Vmag. = 21.5, thus an extremely large FoV is required (>44 sq. deg.), joined to 1 meter class telescope and exposure 9me of about 40s. To obtain a good sampling of typical CCD pixel size, a fast op9cs architecture is needed (F/# <2)
The Fly-‐EyE optomechanical structure
Fly-‐Eye Op9cal Architecture
The Fly-‐Eye Telescope is equivalent to 16 one meter class telescopes sharing the same primary mirror. Light arriving from the same direc9on is imaged in a single pixel therefore each pixel collects the light coming from the whole primary mirror surface (one meter diameter class)
The FoV is decomposed in 16 sub FoVs, each one exploi9ng the full primary mirror aperture (from different direc9ons), thus allowing reduced op9cs size and complexity
The Fly-‐Eye architecture
• The Fly-‐Eye Telescope detailed architecture can be d e c ompo s e d i n t o t h e following subsystems:
– Primary Mirror – Fly Eye Secondary Op9cs – Equatorial mount – Camera Assembly – Telescope Structure – The telescope is about
5,5 m high with an envelope of about 6 m and weight of 25 tons
Fly-‐Eye Secondary Op9cs Camera Assembly
Fly-‐EyE network architecture
• Goal: observe all the visible sky on ground each night • Need telescopes in both hemispheres • Need at least two telescopes in different sites for each
hemisphere to avoid weather correla<on • Need follow-‐up capabili<es • Forbidden regions:
– Near Sun (less than 40 deg in solar elonga<on) – Near Moon (depending oh phase) – Near galac<c plane (less than 15 deg in gal-‐lat, TBC) to avoid crowded fields
Proposed Fly-‐Eye architecture for NEOs
• 4 F-‐E telescopes for survey: 2 in the northern hemisphere, 2 in the southern (beler 5)
• 1 follow-‐up telescope (near equator?) – beler 2 • Good observing sites: high eleva<on, dry, no light pollu<on • Possible sites: Canary Island (Spain), Campo Imperatore
(Italy), Cipro, Chile, South Africa, Australia, … • Observed sky per night per telescope: ~8,000 sq. degrees –
four 9mes! • Each image is 256 Mpixels à each file is ½ Gb • Each night one single telescope provides 350-‐400 Gb of
images
Consequences of the F-‐E architecture
• Needs local (at site) capabili<es for image processing (through internet is too slow)
• Needs a Remote Opera<on Room to perform remotely the telescope opera<ons and coordinate ac<vi<es among telescopes
• Needs a data centre to perform correla<on and orbit determina<on à evolu<on of the NEOCC?
• Each year such a system would roughly produce more than 100 millions astrometric observa9ons of asteroids (not only NEOs!) – Presently there are 120 millions astrometric observa<ons for ALL telescopes and for ALL history
Data exploita<on
• Imminent impactors: need reliable methods for computa<on of a possible imminent impact with very few observa<ons (3-‐4) à need fast computa<on and alert
• Huge data and higher precision data à increase the impact monitoring horizon (to the next 2-‐3 centuries)
• More data to compute non-‐grav. effects, such as the Yarkovsky effect, rad. pressure, cometary effects (obviously, only for comets) … à beler with radar observa<ons, at present
• Asteroid families: a higher sta<s<cs allows the determina<on of more and more families à Solar System dynamical history and evolu<on, families ages
• Light curves with sparse data? à rota<onal status of several asteroids
• More targets for space missions
SST: the past in Europe
• Strong dependency from US Space Command • Na<onal ini<a<ves in Europe, lille coordina<on and planning • Tracking and surveillance instruments allocated for SSA-‐SST were a few • Op<cal sta<ons:
– Surveillance: • OLS (E) Loca9on: Granada, Spain • Starbrook (UK) & S. North (UK) Loca9on: Troodos, Cyprus • TFRM (E) Loca9on: Lleida, Spain • ZimSMART (CH) Loca9on: Zimmerwald, CH
– Tracking: • GRAZ SLR (A) Loca9on: Graz, Austria • Matera MLRO (I) Loca9on: Matera, Italy • OGS (ESA) Loca9on: El Teide, Spain • Tarot (F) & Tarot S (F) Loca9on: Calern, France / La Silla, Chile • ZIMLAT (CH) Loca9on: Zimmerwald, CH
SST: Mo<va<ons
• It is es<mated there are about 700,000 space debris poten<ally dangerous for space assets (> few cm)
• Most of them are not catalogued yet • In the future the exploita<on of space around the Earth will
increase • à MAIN MOTIVATION: PROTECT THE INVESTMENT • In fact a bullet of 1-‐2 cm hiung a satellite at speed of several
km/s may limit the func<onality of the satellite • If the space debris is bigger, it may destroy the satellite and
create further sets of debris • Europe needs independence (but s<ll cooperate with allies)
ESA-‐SST: 2013-‐16 ac<vity domains
• Evalua<on of the enhancements required to improve the systems developed in the SSA Preparatory Phase
• Development of SST systems • Research and development within the area of satellite laser
ranging (SLR) • Research and development within the areas of op<cal
surveillance • Research and development for the security aspects of the SST
system • Enhancement and exploita<on of the deployed IT
infrastructure • Technical support specific to SST ac<vi<es
Space debris distribu<on
Density of objects as a function of altitude for three different size thresholds: objects with diameter larger than 1 mm, 1cm and 10 cm
Low Earth Orbits
LEO is by far the most crowded zone in the circumterrestrial space
Density of objects with diameter larger than 10 cm in LEO, as a func<on of al<tude. The ver<cal lines mark the loca<on of the three known accidental collisions happened in orbit
The possible solu<on
• Have a full independent and centralized EU SST system • The system must have:
– Survey Sensors: radar, op<cal – Tracking Sensors: radar, op<cal, laser ranging – Data centre for processing astrometric data – Services:
• Catalogue • Orbit determina<on and correla<on • Collision warning • Fragmenta<on detec<on and tracking
Sensors for dynamical regimes
• Problem with LEOs:
– The radar S/N decreases like r4 ! the higher you go the more power you need à too expensive and dangerous
– Op<cal telescopes sensi<vity decreases like r2, but space debris very low are also too fast and the Earth shadow limit the visibility of space debris
• There is a transi<on between regions observable by radar and observable by telescopes – 1000-‐1100 km of al<tude of perigee – Lower the costs, but need technological investment
SST-‐Survey
• Radar à 1000-‐1100 km detect and track Lower-‐LEOs • Fly-‐Eye like telescope may cover the Upper-‐LEOs from 1000
km and above • Fly-‐Eye telescopes and other exis<ng EU telescopes may
provide surveying and tracking capabili<es for MEOs, HEOs and GEOs
Space debris dynamics challenge
• Sparse data à new methods for correla<on and OD (several works from Milani and Gronchi)
• Computa<onal challenge à lot of data to process within a short <me à parallel compu<ng
• Dynamical model à high harmonics for Earth, rad. pressure, drag, Earth shadow …
The Upper-‐LEOs challenge
• The ESA-‐SARA study demonstrated the possibility to use the F-‐E telescope for surveying the Upper-‐LEOs
• Challenges: – The telescope must be fast, VERY FAST! Image processing will deal with long trails, several hundreds of pixels
– Exposure <me of 1 s, re-‐poin<ng and read-‐out in less than 3-‐4 s – Huge quan<ty of images à they are processed locally, sent only astrometric posi<on to data centre
– Data processing for correla<on and OD must deal necessarily with sparse data (objects re-‐detected few orbits later!)
– Correla<on and OD of mixed data (radar+op<cal) – Sensors must be spread over the world à geopoli<cal issue
Possible SST telescope sites
Possible SST telescope sites
l Three telescopes per sta<on l FoV ~45 sq. degrees
STATION ID Geographic Coordinates
Latitude [deg] Longitude [deg] Height[m]
TEIDE (Spain) Z00 28° 18' 03.3'' N 16° 30' 42.5'' W 2393
HAO (FRance) Z01 18° 08' 45.0'' S 140° 52' 54.0'' W 6
FALKLAND ISLAND (UK) Z05 51° 42' 32.0'' S 57° 50' 27.0'' W 30
NEW NORCIA (Australia) Z08 31° 02' 54.0'' S 116° 11' 31.0'' E 245
MALARGUE (Argentina) Z09 35° 46' 24.0'' S 69° 23' 59.0'' W 1518
GRAN SASSO (Italia) Z10 42° 29' 60.0” N 13° 33' 04.0'' E 1448
PICO DE VARA, San Miguel Azzorre (Portogallo)
Z11 37° 47' 48.0'' N 25° 13' 10.0'' W 583
Major differences SST and NEO
• NEO à collabora9ve: observa<ons are necessarily shared between the astronomers and even amateurs
• SST à compe99ve: there are military implica<ons
• NEO à needs very good observing site: high eleva<on, dry, … • SST à the driver is the geographical loca<on: must spread
over the world, must be, preferably EU land
The BIG problem of SST
• The future of the SST segment within ESA is quite uncertain • Reasons:
– Deal necessarily with classified data – Military implica<ons à going under EDA (European Defence Agency)?
– No common agreement between EU countries (that’s a news!!) – In this period a possibility is coming from European Commission H2020 investment for the cri<cal infrastructure security… we’ll see
The links
Money and poli<cal decisions
Instruments and data centres
More data for dynamicists!!!
Conclusion, synthesis and future
• SSA-‐NEO and SST programs are very promising for the ac<vi<es of dynamicists for the next decades
• New challenges to deal with: efficient, precise and robust OD algorithms for both NEOs and SST
• NEOs: – Imminent impactors: determine the Impact Probability with few data
– Very precise orbits à Impact Monitoring dominated by non grav. Effects à extension to next centuries
– Data processing of huge data sets: correla<on and OD challenge à parallel compu<ng
Conclusion, synthesis and future
• SSTs: – Sparse data correla<on – Data processing of huge data sets: correla<on and OD challenge
à parallel compu<ng • MAIN UNKNOWN FOR BOTH NEO AND SST in Europe:
– FUNDING!!!! – Phase 3 will start in 2017. Research EU ministers will decide late 2016 in a conference
– NEO will probably con<nue to the road already started – SST depends a lot on poli<cal and strategic (read military) issues
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