2011 07-12 adrian yanes - aalto 1

Aalto-1 The Finnish Student Satellite

Adrian Yanes, Jaan Praks and Aalto-1 Team

http://aalto-1.tkk.fi http://blogs.aalto.fi/satellite/


History

Aalto-1 The Finnish Student Satellite Aalto-1 The Finnish Student Satellite

Aalto University, Finland Established in 2010 … Where science and art meet

technology and business.

•  School of Art and Design •  School of Economics •  School of Chemical Technology •  School of Electrical Engineering •  School of Engineering •  School of Science

•  20 000 students •  338 professors


University Campus in Espoo

by Alvar Aalto


Professorship of Space Technology was established in 1987 in response to Finland joining the European Space Agency

In Finland M.Sc. and Ph.D. education in Space Technology is provided only by Aalto University

Aalto University (and previously Helsinki University of Technology, now part of Aalto University) has participated in space projects in remote sensing, material technology, radio astronomy, robotics, etc.

Aalto University presently participates in the European Erasmus Mundus Space Master degree program and has international Master’s program in Radio Science and Space Technology

Space Technology at Aalto University


•  1992 – 1995 HUTSAT, several year project,

reached prototype building phase.

•  1992 - 1993 FIMSAT , Finnish remote sensing satellite, preliminary design.

Student satellites in TKK (Aalto)


Latest achievements Aalto University designed SMOS satellite receivers

Image © ESA


Space as an Inspiration in

Education


Space has inspired human beings from the beginning of civilized times and led us to the

greatest adventures of history.

We attempt to harness this inspiration to promote the engineering education in Finland and in Aalto

University.

Motivation and Challenge for Modern Engineering Student


•  CanSat •  CubeSat •  Other designs •  Constantly growing topic

•  Often open source, open standards, community supported

•  Spinoff companies selling parts for Cubesat systems

•  Cheap launches •  Nanosatellites < 10 kg

•  OTS mobile electronics to small satellites •  Whole satellite industry driving towards smaller

size

Student satellites

AAUSAT-II Aalborg University, Denmark


•  During the spring term 2010 we arranged experimental course:

•  S-92.3192 Special Assignment in Space Technology •  “Feasibility study of a Nanosatellite” •  Teachers Jaan Praks, Antti Kestilä

•  During the course, 7 students made a realistic preliminary design for the first Finnish nanosatellite.

•  The course introduced several new concepts in our teaching

•  The course was project based, all teaching was given in the form of project meetings.

•  The course was Wiki based, using online collaboration as a main cooperation tool.

AET 2010 course


•  Nanosatellite with adjoint picosatellites •  Biological material in nanosatellite •  Synthetic aperture radiometer as satellite

swarm •  Mobile phone in space •  Synthetic Aperture Radar (SAR) •  Deep space mission •  Propulsion test •  Asteroid mission •  Cosmic file server

Starting with wild Ideas


•  Make realistic preliminary design for first Finnish nanosatellite

•  Constrains: •  Design has to be realistic •  The satellite has to be possible to build mostly

with student work (thesis and special assignments)

•  Satellite instruments should be made in Finland (if possible)

•  The satellite main payload and mission should be related to our department research and teaching topics

Refinement of the goal


•  The satellite started to shape when the main payload was found and selected.

•  Main payload defined scientific goals and most mission parameters.

•  The main payload introduced also “client” relationship to the project.

The Main Payload is Found!

A miniature imaging spectrometer developed in VTT Technical Research Centre of

Finland Prototype for usage in UAV


Requirements •  The satellite has to accommodate hyperspectral camera •  The satellite has to be stabilized •  The best orbit is sun synchronous mid-day orbit •  The satellite has to be affordable •  The satellite has to be usable in education •  The satellite should have high speed data link •  There should be common standards for cooperation and

continuity •  Some subsystems should be available

Main Concept

CubeSat standard based nanosatellite design

ü Open standard ü Community ü Organization ü Platform ü Education


MIDE student project 2011-2013 Project leader Martti Hallikainen

Project coordinator Jaan Praks Steering group and Science Team

Domestic collaboration

Aalto University (4 departments) VTT Technical Research Centre of Finland University of Helsinki University of Turku Finnish Meteorological institute

Nokia Aboa Space Research Oy (ASRO)

Oxford Instruments Analytical Oy

Project

International collaboration

University of Tartu TU Delft CalPoly TU Berlin

etc


Evolution of Aalto-1

design


Science

SPECTROMETER


World smallest hypespectral camera for remote sensing applications by VTT VTT Technical Research Centre of Finland has developed a tiny hyperspectral camera suitable for many applications based on MEMS Fabry-Perot interferometer. Aalto-1 provides a test platform to demonstrate space readiness of this technology.

The Fabry-Perot Interferometer based hyperspectral hand held imager by VTT


Fabry-Perot Mirrors

Air gapOrder sorting

filter

Object of the hyperspectral

imager

Image of the hyperspectral

imager

Front optics for collimation Focusing optics

for imaging

Fabry-Perot interferometer working principle


Current model for UASI

Major specifications of the spectral camera Spectral range: 500 – 900 nm Spectral Resolution: 9..45 nm @ FWHM Focal length: 9.3 mm F-number: 6.8 Image size: 5.7 mm x 4.3 mm, 5 Mpix Minimum total exposure time: 30 ms Field of View: 32° (across the flight direction) Ground pixel size: 3.5 cm @ 150 m height Weight: 350 g (without battery) Size: 62 mm x 61 mm/76mm x 120 mm Power consumption: 3 W


VTT miniature spectrometers UASI test flights


Satelliteborne hyperspectral remote sensing •  Vegetation •  Water quality •  Geology


Science

PLASMA BRAKE


§  Each solar photon carries momentum, doubled if reflected

§  About 9 uN/m2 thrust density for perfect mirror §  At 1 AU, 1 N sail would be 330x330 m, membrane

mass 1200 kg if made of 7.6 um polyimide sheet, characteristic acceleration 0.8 mm/s2

§  Thrust vectoring is possible, but thrust magnitude and direction change in unison for flat sail

§  Solar sail is old idea (roughly 100 years), implemented in space first time in 2010 (IKAROS, Japan)

§  Technical challenges of solar sail: –  Membrane should be very thin –  Membrane's support structures should be very lightweight

as well –  Everything must be tightly packaged and folded during

launch

Solar photon sail


§  Solar wind –  Plasma stream emitted from Sun in all directions –  Speed 350-800 km/s (lowest in ecliptic plane,

higher elsewhere)‏ –  Mean density 7 cm-3 at Earth –  Variable, but always present –  Dynamic pressure ~2 nPa at Earth (1/5000 of

photon pressure)‏ §  Electric sail (E-sail)‏

–  Slowly rotating system of long, thin, conducting and centrifugally stretched tethers which are kept positively charged (~ +20 kV) by spacecraft electron gun

–  Only modest amount of electric power needed, obtained from solar panels

–  ~500 nN/m thrust per length –  For example, 100x20 km tethers, 1 N thrust, 100

kg mass, specific acceleration 10 mm/s2

Electric solar wind sail


E-sail, traveling in interplanetary space without fuel


Electrostatic Plasma Brake is designed as an “end of life” mission to bring satellite after service down.

Based on Electric Space Sail concepts by Pekka Janhunen (FMI) Developed and produced by Finnish Meteorological Institute (FMI)

Electrostatic Plasma Brake


20 000 pieces trackable space junk orbits the Earth

Image © ESA


Science

RADiation MONitor


Radiation environment in Earth orbit

•  Radiation in LEO is the most significant threat to electronics.

•  Need for simple and small radiation detector.

•  Trapped proton environment on LEO needs to be taken into account in the design of any spacecraft.

Trapped proton environment anisotropies


Payloads: Radiation Monitor •  Sensor unit based on Si detector and

CsI(TI) scintillator •  Readout electronics consist of a

pulse shaping and peak-hold circuitry with a pre-amplifier signal being digitised with high sampling rate

•  FPGA based logic to count particle events hitting the sensor

University of Helsinki


BepiColombo is ESA mission to Mercury. Spacecraft will set off in 2014, arrives to Mercury 2020, planned operation till 2022. Onboard will be the pioneering SIXS instrument (Solar Intensity X-ray and particle Spectrometer) developed in a Finnish consortium. The main task of SIXS is to provide observations of X-ray and particle radiation on Mercury’s surface.

Consortium: Finnish Meteorological Institute, FMI (project

managing, FPGA coding, EGSE design), Space Systems Finland Oy, SSF (software, systems engineering), Ideal Product Data Oy (thermal modelling) and Patria Oyj (Digital Processing Unit). The collaboration includes also UK contribution by the Rutherford Appleton Laboratory, RAL (readout ASIC for the particle detector system), Oxford Instruments Analytical OY

BepiColombo SIXS

Illustration: Oxford Instruments Analytical OY


TECHNOLOGY


Static acceleration Shocks and vibrations

–  Recall problems with Space Shuttle tiles! Acoustic stress Declining pressure Temperature changes Satellite has to be strong

Launch is most critical part of the mission


Extremely big variability in speed and distance during the lifespan of spacecraft Signal attenuation Dopler effect Ionospheric effects

Extreme speed and distance make communication difficult

Nasa Deep Space Network


•  The Sun is a variable star –  Strong variations at short (UV, X, gamma) and

long (radio) waves

•  Black space is cold –  The illuminated side gets heated, the opposite

side radiates the heat (IR) and cools –  Thermal design is very tricky

•  Extreme example: BepiColombo between the Sun and Mercury

Space environment: Electromagnetic radiation


Cosmic rays are very energetic charged particles •  Galactic: > 100 MeV •  Solar: < 1 GeV •  Anomalous: around 10 MeV

–  Note these energies are much higher than the energy of solar wind particles

Cause single events in electronics

Most energetic cosmic rays penetrate through the Earth’s magnetic field and are stopped in the atmosphere causing air showers

Cosmic radiation


No air means that there is no convection. The only heat exchange way is radiation Nothing to grab, you cannot fly Some materials can just evaporate Very tricky to lubricate mechanisms There is no electrical conduction, a satellite can build up static electric charge which can damage electronics

Vacuum, there is no air


Debris is a growing concern •  20,000 pieces larger than 10 cm •  500,000 in the range 1 – 10 cm •  Tens of millions smaller pieces

Large relative speeds – large momentum in collisions Sources

•  Old satellites •  Left-overs from lauchers,pieces of surface

materials and paint, etc. •  Collisions, e.g., Kosmos-2251 – Iridium 33

collision in February 2009 Micrometeoroids

•  ”Natural space debris”

Micrometeoroids and space debris


Satellite subsystems


Aalto-1 satellite

Based on CubeSat 3U standards (34cm×10cm×10 cm) Weight: 3 kg. Orbit: Sun-synchronous mid-day LEO . Attitude control: 3 axis stabilized. Communication: VHF-UHF telecommand

S-band data transfer. Solar powered, max power 8 W. Payloads:

Imaging spectrometer (VTT). Radiation detector (HY, UTU). Electrostatic Plasma Brake (FMI).


The new mechanical structure is under development Base model for subsystems

Mechanical structure


Antennas


•  CubesatKit PCB layout and Connector

•  RS-422 / LVDS for all the interfaces

•  PicoADACS (BST/Delft)

System design


System design


Bus interface/protocol

•  Bus is created with stack-trough connectors (CubeSatKit).

•  Bus is used for all electrical connections (power, data).

•  3.3V, 5V and 12V available.

•  Data interface will be differential system (RS-422/LVDS).

•  I2C will be used for zombie control.

•  Separate pins for all data connections => star topology

•  Separate kill switch pins?

4/20


System Design

Satellite Segment

Ground Segement

Command and Data Handling

System

Thermal System

Payloads

Spectrometer

Electrostatic Plasma Brake

Power System

Solar Panels

Batteries

Communication System

S-band Antenna

Orbit Determination System

GPS Antenna GPS module

Attitude Determination and Control System ADCS

Sensors

Actuators

Control System

S-band Transmitter

UHF-VHF Antennas

Command and Data Handling

Ground Computer

System GCSMission

Database

Communication Subsystem

Receiver

Modem

Tracking

S-band Antenna

UHF-VHF Antennas

Radiation MonitorOnboard Computer

OBC

Housekeeping Structural System

Modem

Beacon

Legend: Data Interfaces ____Power Interfaces ____Thermal Interfaces ____Mechanical Interfaces ____

Power Regulation and Control

UHF-VHF Transceiver


3/20


Electrict Power System


Power generation

•  Energy generated via solar cells.

•  Average power (eclipse included) is ca. 4.7 W –  No panels on nadir-side, 6 panels on other sides.

•  A crude simulation for 15 orbits (ca. 1 day) has been

done. –  It seems like we have plenty of energy. –  However, fully charging the batteries (20Wh) will take around

6-7 orbits in power saving mode.


Energy Budget

Direct Sun

Earth Total

Polar 7.7 W 0.51 W 8.21 W 45 deg 7.7 W 0.51 W 8.13 W Average 7.7 W 0.51 W 8.17 W

Energy budget simulations for optimal attitude and orbit


Mid-day Sun-synchronous orbit would be preferable for main instruments.

Orbit


Based on ARM920T 180MHz RAM: 256MB (ECC) Mass-storages: •  OS (~256MB)

•  Data (1GB) Interfaces: SSP/I2SI2C/SPI/61 GPIO/JTAG

On Board Data Handling Hardware


Single Board Computer as a central computer Separate DSP Digital Signal Processing performed onboard in order to reduce the downlink data stream Backup system is based on microcontrollers and is able to re-flash the system

Data System


Software

•  OS: GNU/Linux •  Client-server architecture for payloads •  ASM / C / C++ (µlibc). •  Really tiny and tested. •  Designed to run in user space. •  Dispensable. •  Extensible from Earth (re-programming).


Software


–  Highly customized: focused in I2C and process scheduling. –  Real-time patches (http://www.kernel.org/pub/linux/kernel/

projects/rt/) –  OpenEmbedded as basement for the distro. –  Deterministic system. –  Autonomous: non human-interaction needed. –  Inter-process communication: D-Bus.

Kernel & OS


Ground station


Ground station

Location: Espoo, Finland Coordinates: 60.188444N, 24.829981E UHF operational from July 2011! Future equipment (really soon): -S-band antenna -VHF – antenna -Receivers and transmitters & tracking mechanisms.


VHFdownlink /UHF uplink S-band Downlink

Link duration per day – simulation for selected orbit Min. Duration 65.313 sec Max. Duration 637.889 sec Avg. Duration 475.298 sec Total Duration 14258.926 sec

Telecommunications

Transreceiver examples

VHF downlink/UHF uplink

S-band downlink

Frequency 130-160 MHz 2100-2500 MHz RF output 300 mW PEP / 150

mW average 500 mW

Power consumption 1,7 W/0,2 W 2 W

Data transfer up to 9,6 kbps up to 115 kpbs Mass 85g <125g Size 90mmx96mmx40m

m 90mmx96mmx40m

m


Ground station


STATUS and

COMMUNITY


The satellite project is tightly integrated with teaching, it will be designed and constructed as a part of special assignment courses and thesis works, supported by Space Technology and Radio Engineering main subject teaching. The satellite project brings together a consortium of Finnish space industry and Finnish top universities for the benefit of our students. The project has involved already five departments in Aalto University

Tightly integrated with teaching


Student activities are important part of the project. Learning can be fun!

Active students


Part of student satellite team meeting with NASA astronaut Timothy Kopra

Meeting people


Learning together


Conferences and Workshops


Participating Conferences


Proto-storm 18.3.2011


Gracias!

2011 07-12 adrian yanes - aalto 1

Technology

Transcript of 2011 07-12 adrian yanes - aalto 1