by finnish centre of excellence in sustainable space · 3u cubesat standard (isi-pod variant)...

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