Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Jaan Praks, Antti Kestilä, Martti Hallikainen, Heikki Saari, Jarkko Antila, Pekka Janhunen, Rami

Vainio

Aalto-1 AN EXPERIMENTAL NANOSATELLITE

FOR HYPERSPECTRAL REMOTE SENSING

Aalto-1The Finnish Student

Satellite

Funded by:• Aalto University MIDE (platform)• ESA (spectrometer payload)• EU (e-sail payload)• And many others

Aalto-1– the first Finnish Remote Sensing Satellite

Core consortium• Aalto University (Satellite bus, ground segment, project PI)• VTT Technical Research Centre of Finland (Spectrometer payload)• University of Helsinki (RADMON payload)• University of Turku (RADMON payload)• Finnish Meteorological institute (Plasma Brake payload)

Supported by wide international network and Cubesat community

Aalto-1The Finnish Student

Satellite

1. To design, build and operate first Finnish Earth Observation (EO) nanosatellite.

2. Technology demonstration of of very small spectral imager for spaceborne EO.

3. Development and demonstration of deorbiting device for nanosatellites based on e-sail concept and measurement of its performance.

4. Technology demonstration of very small radiation detector for future satellites.

5. Promotion of engineering education in Finland with the aid of satellite project.

Aalto-1 mission goals

Aalto-1The Finnish Student

Satellite

Requirements• The satellite has to accommodate spectral camera

and other payloads• The satellite has to be affordable • The satellite needs flexible, affordable launch• The satellite has to be usable in education• There should be common standards for cooperation and continuity• Some subsystems should be available

Main Concept

CubeSat compatible nanosatellite

Open standardCommunityOrganizationEducation

Common launch platfrom

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Aalto-1 Project Timeline

Phase 2010 2011 2012 2013 2014 2015

A - Feasibility study

B - Preliminary design definition

CD – Detailed design and building

E - Comissioning

Launch

Spectrometer experiments

RADMON experiments

Deorbiting experiment

29.7.2011

Aalto-1The Finnish Student

Satellite

Aalto-1 system overview

Aalto-1The Finnish Student

Satellite

Aalto-1 satellite

CubeSat 3U compatibleDimensions: 34×10×10 cmMass: 4 kgOrbit: Sun-synchronous mid-day LEO Attitude control: 3 axis stabilizedCommunication: VHF-UHF telecommand

S-band data transferLifetime: 2 yearsSolar powered: max power 8 W

Payloads: Imaging Spectrometer (VTT)Radiation detector (Univ. of Helsinki, Univ. of Turku, FMI)Electrostatic Plasma Brake (FMI)

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Mass: 4 kgDimensions: 34x10x10 cm

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

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Subsystems

Aalto-1The Finnish Student

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Modular design compatible with CubeSatKit parts

Aalto-1The Finnish Student

Satellite

Payload I

IMAGING SPECTROMETER

Aalto-1The Finnish Student

Satellite

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.

World smallest hypespectral camera for remote sensing applications by VTT

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

Aalto-1The Finnish Student

Satellite

Fabry-Perot interferometer working principle

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

Aalto-1The Finnish Student

Satellite

Fabry-Perot interferometer working principle

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

Aalto-1The Finnish Student

Satellite

Current model for UAVI

Major specifications of the spectral cameraSpectral range: 500 – 900 nmSpectral Resolution: 9..45 nm @ FWHMFocal length: 9.3 mmF-number: 6.8Image size: 5.7 mm x 4.3 mm, 5 MpixMinimum total exposure time: 30 msField of View: 32 (across the flight direction)Ground pixel size: 3.5 cm @ 150 m heightWeight: 350 g (without battery)Size: 62 mm x 61 mm/76mm x 120 mmPower consumption: 3 W

Aalto-1The Finnish Student

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VTT miniature spectrometers UAV test flights

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Spectral imager

Aalto-1The Finnish Student

Satellite

Spectrometer unit for Aalto-1 satellite

Mass: 400 gDimensions: 5x10x10 cm

Aalto-1The Finnish Student

Satellite

Spectral filter: MEMS Fabry-Perot filter

(or piezo-actuated Fabry-Perot filter)

Sensor: 5 Mpx CMOS

Dimensions: 5x10x10 cm

Mass: 400 g

Axial lenght of optics: 6 cm

Spectral range: visible

Spectral resolution: 7-10 nm

Spectral and spatial binning

Field of view: 10 deg

Ground resolution: 40-100 m

Up to 3 channel simultaneous measurement

Capable to measure spectral cube

Produced by VTT Technical Research of Finland

Aalto-1 Imaging Spectrometer

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

Payload II

PLASMA BRAKE

Aalto-1The Finnish Student

Satellite

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

Aalto-1The Finnish Student

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E-sail, traveling in interplanetary space without fuel

Aalto-1The Finnish Student

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20 000 pieces trackable space junk orbits the Earth

Image © ESA

Aalto-1The Finnish Student

Satellite

Electrostatically charged long tether

Aalto-1The Finnish Student

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Aalto-1The Finnish Student

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Plasma brake

Aalto-1The Finnish Student

Satellite

Dimensions: 10x10x2,5 cm

Mass: 150 g

Reel for 100 m tether

Controlled unwinding

Tether: 10-100 m

Tether material: Aluminium

Tether dimeter: 50 μm

Negative and positive tether charge control

Cold cathode electron guns for positive mode

Voltage source for negative mode

Plasma Break

Aalto-1The Finnish Student

Satellite

Payload III

RADiation MONitor

Aalto-1The Finnish Student

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Aalto-1The Finnish Student

Satellite

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 in LEO

Aalto-1The Finnish Student

Satellite

Aalto-1The Finnish Student

Satellite

RADMON

Aalto-1The Finnish Student

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Dimensions: 10x10x4 cm

Mass: 500 g

Si detector and CsI(Tl) scintillator

Measurement range

Electrons > 60 keV (5 energy channels)

Protons > 1 MeV (7 energy channels)

Counting rate up to 1 MHz

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

RADMON

University of Helsinki

Aalto-1The Finnish Student

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Education

The project has brought together specialists nd teachers all over Finland

more than 20 special assignments6 bachelor thesis1 Master thesis on the way1 PhD student1 PostDoc

Aalto-1The Finnish Student

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Aalto-1The Finnish Student

Satellite

Aalto-1 team in spring 2011

Aalto-1The Finnish Student

Satellite

Thank you!http://aalto-1.tkk.fi