by finnish centre of excellence in sustainable space · 3u cubesat standard (isi-pod variant)...
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Foresail satellites for space science by Finnish Centre of Excellence in
Sustainable Space
GTO orbit, radiation tolerant design, deorbiting systemsJaan Praks, Minna Palmroth, Rami Vainio, Pekka Janhunen, Emilia Kilpua, Rizwan Mughal, Andris Slavinskis, Alexandre Bosser, Foresail team
Aalto University, Department of Electronics and NanoengineeringFinnish Centre of Excellence in Research of Sustainable Space
Aalto UniversityThe biggest Technology University in Finland
Facts
18 000 students400+ professors390 M€/y budgetQS Univ rank 137
science and art together with technology and business
Aalto UniversityVision, Mission and Strategies2016–2020
Aalto University Campus: Otaniemi
Otaniemi is the biggest Technology Campus in Finland. The campus integrates Technology, Business and Art, tech institutes and countless technology companies nearby.
Space Education
Aalto satellite projects are integrated to Space Science and
Technology curriculum.
Students get hands on design, integration, testing experience and
operation.
Aalto Space Science and Technology Major in Electronics and Nanoengineering
Student missions
Aalto UniversityStudent Satellite Program
Hands-on learningStudent designed missionsStudent CubeSat Program
Aalto-1The Finnish Student Satellite
Typical thesis projects
Active Student CommunityHackathons and societiesStart-up and spin-off activities
Infra for education
Ground Station
Lab and cleanroom
Anechoic chambers
Testing equipment
Aalto Missions
Planning the
satellite 2010
Aalto-1
Aalto-1 student satellite
Aalto University, University of Turku, VTT, Finnish Meteorological Institute, University of Helsinki
4 kg 3U CubeSat
Satellite designed and largely built by Aalto Students2010-2016
Payloads:
• Spectral Imager AaSI (VNIR)
• Radiation Monitor RADMON
• Plasma Brake deorbiting device
Aalto-1
Aalto-1The Finnish Student Satellite
Aalto-1The Finnish Student Satellite
• Launch 23th June 2017 03:59 UTC on Indian PSLV-C38• Deployed 04:22 UTC to 486 x 519 km, sun synchronous
inclination 94.45°orbit
Aalto-1
Aalto-1 satellite subsystems and payloads
AaSI spectral imager
RADMONPlasma Brake
Aalto-1The Finnish Student Satellite
System temperatures
First IOD of miniature Fabry-Perot EO spectral imager August 2018:
Mass: 592 gPower: max 2.5 W500-900 nm Configurable ~20 nm spectral lines
Aalto-1
VTT Fabry-Perot Spectrometersfor CubeSat
AaSI VNIR spectral imager (400-900 nm)
(IOD Aalto-1 2017)HW SWIR Specral imager (900-1400 nm)
(IOD Hello World 2018)
VISION Solar Occultation Imager
(Launch 2019-2020)
Asteroid Spectral Imaged Concept (500-2500 nm)(designed for APEX/HERA mission)
TEKES funded research project to build a swarm satellite for international QB50 constellation.
Aalto-3
In-house developed complete CubesatsolutionsAalto has developed two complete CubeSats and launched three.
Aalto has developed all avionics subsystems in-house.Currently three more CubeSats are under development.
Aalto-1The Finnish Student Satellite
On- line systems engineering documentation
Master thesis
Bachelor thesis
Project documentProject
documentProject document
Project documents(deliverables of special assignments)
Col
labo
rativ
eIn
divi
dual
Not Assessed Assessed
NotesNotesNotesNotes and Logs
Tailored documentation approach for student projects
A documentation approach was developed which includes systems engineering, supervising and assessment.
Made in Aalto University
Spin-off companies
Aalto-1The Finnish Student Satellite
Aalto Space spin-off companies
2014 Aalto Iceye SAR protype
2018 Iceye Oy launched the worlds
smallest SAR satellites X1 and X2
Iceye has collected over 55 M$
investments to build the world first
small SAR satellite constellation.
SATELLITE SPECIFICATIONSICEYE-X2 SAR Baseline Configuration
FEATURE ICEYE-X2
Unit mass 85 kg
Imaging and
polarizationX-band SAR, VV polarization
Resolution 20x20 / 3x3 / 1.5x1.5 / 1x1 meters
Dynamic range 16 bit
Imaging mode Stripmap
Imaging modes
under
development
Spotlight, Stripmap High, ScanSAR
Communications
(downlink)X-band radio, 100Mbits/s optical
Product formats SLC, GRD, GeoTIFF
Routine
operations24/7
Chirp bandwidth Up to 300MHz
Geolocation Under 50 meters
ADCSReaction wheels, magnetorquers, star
trackers
Propulsion Ion engines
Tenerife
Iceye X1
6/7/201939
Credit: Iceye
CubeSat generation is grown up
Now one of the biggest
space companies in Finland
Hello WorldSNIR spectrometer
Reaktor Hello World
Launched and operational since 11/2018Payload successfully demonstrated:
Single band Pseudo-RGB Analysis
Peshawar, Pakistan
Hyperspectral
Science / TelecomW-Cube (ESA)
First ever W-band frequencies to be transmitted fromspace to Earth. Provides information for atmosphericand ionospheric propagation models. Higherfrequencies will provide higher communicationspeeds for future telecom satellites.
- W-band (75 GHz) & Q-band (37.5 GHz) beacons- Novel concentric ring antennas- Left and right handed polarization switching
Asteroid prospectingASPECT / APEX (ESA)
Space WeatherXFM (ESA)
X-ray spectrometer in orbit demonstration
Launch Q1/2021
Science missions with CubeSat
Increasing amount of debris is a serious problem for future business and science.
Space Debris
Payload traffic to LEO
Combining best space environment models, particle instruments and nanosatellites in Finland to develop technology for more sustainable space.
Goals• Better knowledge of radiation physics in space• Awareness of sustainability issues• Science Space Program for Finland• Deorbiting technologies for small satellites• Solutions for radiation tolerant CubeSat platform• Science instruments for future space• Renewal of space scientists and engineers
Modelling teamUniversity of Helsinki
Instruments teamUniversity of Turku
Propulsion teamFinnish Meteorological Institute
Platforms teamAalto University
Observations teamUniversity of Helsinki
Aalto-1
Foresail technology development
Particle detectors for CubeSat
RADMONMeasuring the flux of >700 keV electrons and >10 MeV protonsMass: 354 g, power consumption: 1 W
PATETwo perpendicular particle telescopes electrons in the range 80–800 keVions/ENAs in the range 300–8000 keVMass: 1000 g (TBC), power consumption: 1 W (TBC)
REPETBD
Aalto-1
Aalto-1The Finnish Student Satellite
Aalto-1The Finnish Student Satellite
RADMONUniversity of Turku, University of Helsinki
Particle detector measuring the flux of >700 keV electrons and >10 MeV protonsMass: 354 gPower consumption: 1 W
Status: Calibrated and carrying out science mission.
Aalto-1The Finnish Student Satellite
Aalto-1The Finnish Student Satellite
Electron density maps by RADMON
Solar storm
RADMON vs GOES-15
Coulomb drag deorbiting devices
Plasma Brake (Aalto-1)Mass: 259 gPower consumption: 1 – 1.6 WTether length: 100 mApplied voltage: 1000 V
Plasma Brake (Foresail-1)Mass: 300 gPower consumption: 1 – 1.6 WTether length: 300 mApplied voltage: 1000 V
Solar Sail TBD
Aalto-1
Aalto-1The Finnish Student Satellite
Plasma BrakeFinnish Meteorological Institute
Mass: 259 gPower consumption: 1 – 1.6 WTether length: 100 mApplied voltage: 1000 V
Status: Commissioned. Ready for deployment.
Aalto-1The Finnish Student Satellite
Plasma brake technology involves long tether deployment,
Aalto-1The Finnish Student Satellite
Based on E-SAIL technology
Long (100m) tether charged
with high voltage (1000 V)
Experiences electrostatic Coulomb force in plasma
Negatively charged mode and Positively charged mode
Does not increase collision area and probability
Plasma Brake working principle
Aalto-1The Finnish Student Satellite
Deorbiting Experiment with Plasma Brake
Aalto-1The Finnish Student Satellite
Two cold-redundant ARM AT91RM9200 OBCs
Governed by arbiter and watchdog
Linux OS
256 MB RAM
Clock speed 150 MHz
Mass: 75.0 g
Power consumption(EM): 0.25 W - 0.45 W from 3.3 V
Non-volatile memory
OBC
Aal
to O
BC
EM
Aalto-1The Finnish Student Satellite
Foresail missions
Foresail-3
Foresail-1
Foresail-2
2024Mission to Solar Wind
2022Mission to GTO
2020Mission to LEO
• Radiation tolerant avionics• Radiation tolerant software• Modular shielding structure• CubeSat attitude solution for
GTO• (developed in collaboration with
Aurora Propulsion)
CubeSat platform for Foresail GTO mission
FORESAIL-1 mission
Mission goals
• Measure the energy and flux of energetic particle loss to the atmosphere with a representative energy and pitch angle resolution over a wide range of magnetic local times.
• Measure energetic neutral atoms (ENAs) of solar origin, to improve solar eruption energy budget estimations.
• Demonstrate a orbit maneuver with e-sail technology.
M. Palmroth et al. “FORESAIL-1 cubesat mission to measure radiation belt losses and demonstrate de-orbiting”JGR: Space Physics on 21 May 2019, arXiv:1905.09600 [physics.space-ph]
FORESAIL-1Payloads
Plasma Brake (PB):Deploying a long charged tether; measuring the strength of Coulomb drag in ionospheric plasma ram flowParticle Telescope (PATE): Defining pitch-angle and energy signatures of electrons precipitating from the radiation belts, and measuring solar ENAs.
Orbit: ≈ 600 km altitudeMission duration: 5 yearsLaunch date: 2020
Particle Telescope
CoulombDragExperiment
Design drivers and constraints
3U CubeSat standard (ISI-POD variant) compatibilityLifetime for 5 years in LEO3-axis attitude knowledge at accuracy (1°)3-axis attitude stabilization in terms of rotation modes• Rotation mode for PB payload (Rotation rate 180°/s)
• Pointing mode for PATE (3° pointing accuracy of rotation axis)
Communication to ground station with average daily download capacity (TBD) Power for payloads missions during mission lifetime (TBD)Pointing ability after the PB experimentAttitude control ability with deployed tether and changed center of massConductivity requirement for spacecraft surface area (TBD)Openings and access ports for payloads (TBD)Retro-reflector for platform (TBD).
Foresail-1 mission
Foresail-1 satellite
FORESAIL-2 mission
FORESAIL-2Support ULF plasma wave modeling in Vlasiator
Coulomb Drag Experiment (CDE): Deploying a long charged tether; measuring ambient plasma density, and the strength of Coulomb drag in different plasma densities Relativistic Electron and Proton Experiment (REPE): Measuring electron and proton spectra, to monitor the dynamics of the most penetrating radiation in the Van Allen beltsMagnetic field measurements
Mission duration: 6 monthsLaunch date: 2022Required orbit: Geostationary Transfer Orbit;
Very demanding, will impose heavy constraints on the platform
FS2
Orbit
ADCS
Thermal
Radiation
COM
Bus
Mission drivers for platform
• Access GTO orbit with CubeSat• Survive in GTO for 6 months• Deliver power to payloads• Deliver data and telemetry to ground • Maintain lean process and mostly COTS
components• Use innovative ways to improve reliability
and radiation tolerance
FORESAIL-2Mission constraints : Orbit
Procurement and budgetNo CubeSat launched to GTO yet;no standard launch procurement procedures exist.
GTO CubeSat launches are expected to be significantly more expensive than LEO launches
StabilityGTO are inherently unstableevolution strongly depends on launch parameters (perigee, inclination, etc… but also launch date and time)
Initial perigee: 200 km
Area-to-mass ratio: 5.0·10-3 m2/kg
A. Lamy, C. Le Fevre and B. Sarli. "Analysis of geostationary transfer orbit long-term evolution and lifetime."Journal of Aerospace Engineering, Sciences and Applications, vol. 4, no. 3, pp. 12-27, 2012
FORESAIL-2Mission constraints : Communications
Free space lossLong distance from apogee to ground station
Much higher signal attenuation than in LEO Lower data rates (but longer visibility time)
Ground visibilityDepending on orbit evolution:
- FS2 may not be visible from Otaniemi around perigee- Passage at apogee may occur on the other side of the
Earth Contact with FS2 may be impossible for over 15 hPartner ground stations?
Doppler shiftAt perigee, FS2 ground speed will be over 10 km/s
Higher Doppler shift than on regular GTO orbits
FORESAIL-2Mission constraints : Thermal management
Heat managementOn average, FS2 will be in sunlight over 95% of the time
EclipsesDepending on orbit evolution:
- Orbit apogee may drift into Earth’s shadow=> Eclipse duration from 22 min and 1 hour=> Will require large batteries and internal heaters
Sun pointing
Weak magnetic
field
Need to rotate
fastHigh
angular momen-
tum
Atmo-spheric
drag
FORESAIL-2Mission constraints : Attitude
FS2
ADCS
Sun-pointingREPE requires keeping the rotation axis pointed at the Sun.
Need for fast rotationDeployment of CDE tether requires fast initial rotation; limits subsequent attitude corrections
High angular momentumAfter tether reel-out, high momentum will hamper attitude corrections
High atmospheric dragSignificant disturbing torque around perigee
Weak magnetic fieldAlong most of the orbit, geomagnetic field too weak for magnetorquers to be effective
Proton flux > 10 MeV
Electron flux > 1 MeV
Source: SPENVISFORESAIL-2Mission constraints : Radiation environment
Mission TID vs. shielding thickness:2 mm 315 krad4 mm 41 krad6 mm 7 krad
Mission DDD vs. shielding thickness:(equ. 10 MeV protons)
2 mm 7.0*109
4 mm 2.6*109
6 mm 1.3*109
Dose levels beyond those of most COTS parts
Source: SPENVIS
FORESAIL-2Mission constraints : Radiation
Heavy shielding
Van Allen belts
Cumulativeeffects
Single Event
Effects
COTS liability
FORESAIL-2Mission constraints : Radiation environment
FS2
Radiation
Harsh environmenGTO will take FS2 through the core of the Van Allen belts
Very high particle fluxes High energy particles, difficult to shield
Unreliable commercial componentsFS2 will include COTS, not designed to withstand radiation
Need for exhaustive parts screeningWill leverage emerging, affordable radiation-tolerant parts
Radiation shieldingUnusually heavy shielding needed to ensure mission success beyond one week (!)5 - 6 mm Al shielding envisioned
High shielding mass complicates attitude control, reduces available volume Additional launch cost
FORESAIL-2Mission constraints : Bus format
Heavy structureHeavy radiation shielding
Large moment of inertia Reduced available volume inside body
PropulsionWill be needed to start spacecraft rotationMay be needed to raise perigeeMost likely resistojet
Limited volumeFS2 payloads similar to FS1Additional propulsion and shielding take up volume3U envelope may not be feasible6U envelope adds considerable cost
Thank you!http://spacecraft.aalto.fi
First Finnish satellite 2017
Space Legislation - 2018
Governmental support –New Space Economy funding program
Growing amount of New Space companies find business from space segment, upstream and downstream
Start-up friendly environmentInterested investors- SLUSHHackathon culture - Junction
www.spaceworkshop.fi
Finnish SatelliteWorkshop 2019
Aalto-1 Mission