Aalto-1 The Finnish Student Satellite

Aalto-1 The Finnish Student Satellite Jaan Praks, Antti Kestilä, Martti Hallikainen, Heikki Saari, Jarkko Antila, Pekka Janhunen, Rami Vainio

Aalto-1 The 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-1 The 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-1 The 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 standard Community Organization Education Common launch platfrom

Aalto-1 The Finnish Student Satellite

Aalto-1 The Finnish Student Satellite Aalto-1 Project Timeline Phase A - Feasibility study B - Preliminary design definition CD – Detailed design and building E - Comissioning Launch Spectrometer experiments RADMON experiments Deorbiting experiment

Aalto-1 The Finnish Student Satellite Aalto-1 system overview

Aalto-1 The Finnish Student Satellite Aalto-1 satellite CubeSat 3U compatible Dimensions: 34×10×10 cm Mass: 4 kg Orbit: Sun-synchronous mid-day LEO Attitude control: 3 axis stabilized Communication: VHF-UHF telecommand S-band data transfer Lifetime: 2 years Solar powered: max power 8 W Payloads: Imaging Spectrometer (VTT) Radiation detector (Univ. of Helsinki, Univ. of Turku, FMI) Electrostatic Plasma Brake (FMI)

Aalto-1 The Finnish Student Satellite

Aalto-1 The Finnish Student Satellite Mass: 4 kg Dimensions: 34x10x10 cm

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

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

Aalto-1 The Finnish Student Satellite Modular design compatible with CubeSatKit parts

Aalto-1 The Finnish Student Satellite Payload I IMAGING SPECTROMETER

Aalto-1 The 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-1 The Finnish Student Satellite Fabry-Perot interferometer working principle Fabry-Perot Mirrors Air gap Order sorting filter Object of the hyperspectral imager Image of the hyperspectral imager Front optics for collimation Focusing optics for imaging

Aalto-1 The Finnish Student Satellite Fabry-Perot interferometer working principle Fabry-Perot Mirrors Air gap Order sorting filter Object of the hyperspectral imager Image of the hyperspectral imager Front optics for collimation Focusing optics for imaging

Aalto-1 The Finnish Student Satellite Current model for UAVI Major specifications of the spectral camera Spectral range: 500 – 900 nm Spectral Resolution: 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: m height Weight: 350 g (without battery) Size: 62 mm x 61 mm/76mm x 120 mm Power consumption: 3 W

Aalto-1 The Finnish Student Satellite VTT miniature spectrometers UAV test flights

Aalto-1 The Finnish Student Satellite Aalto-1 The Finnish Student Satellite Spectral imager

Aalto-1 The Finnish Student Satellite Spectrometer unit for Aalto-1 satellite Mass: 400 g Dimensions: 5x10x10 cm

Aalto-1 The 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: m Up to 3 channel simultaneous measurement Capable to measure spectral cube Produced by VTT Technical Research of Finland Aalto-1 Imaging Spectrometer

Aalto-1 The Finnish Student Satellite

Aalto-1 The Finnish Student Satellite Payload II PLASMA BRAKE

Aalto-1 The Finnish Student Satellite  Each solar photon carries momentum, doubled if reflected  About 9 uN/m 2 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/s 2  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

Aalto-1 The Finnish Student Satellite  Solar wind – Plasma stream emitted from Sun in all directions – Speed 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/s 2 Electric solar wind sail

Aalto-1 The Finnish Student Satellite E-sail, traveling in interplanetary space without fuel

Aalto-1 The Finnish Student Satellite pieces trackable space junk orbits the Earth Image © ESA

Aalto-1 The Finnish Student Satellite Electrostatically charged long tether

Aalto-1 The Finnish Student Satellite Aalto-1 The Finnish Student Satellite Plasma brake

Aalto-1 The Finnish Student Satellite Dimensions: 10x10x2,5 cm Mass: 150 g Reel for 100 m tether Controlled unwinding Tether: 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-1 The Finnish Student Satellite Payload III RADiation MONitor

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

Aalto-1 The Finnish Student Satellite 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-1 The Finnish Student Satellite Education The project has brought together specialists nd teachers all over Finland more than 20 special assignments 6 bachelor thesis 1 Master thesis on the way 1 PhD student 1 PostDoc

Aalto-1 The Finnish Student Satellite

Aalto-1 The Finnish Student Satellite Aalto-1 team in spring 2011

Aalto-1 The Finnish Student Satellite Thank you!