presentaz roma trieste 4

ATMOCUBE: 

University of Trieste Department of Physics and Astronomy Department of Engineering – DEEI National Institute for Astrophysics - INAF Trieste Astronomical Observatory University of Bologna Radiology Science Department CNR Bologna Institute of Atmospheric Sciences and Climate Solar-Terr. Influences Laboratory-BAS, Sofia Bulgaria A (mostly) educational satellite for the study of space-weather effects ATMOCUBE

Overview: 

Overview Introduction: scientific measurement AtmoCube requirements Instrumentation: system analysis Status of the project Conclusions & future

ATMOCUBE/CUBESAT: 

ATMOCUBE/CUBESAT SPACEWEATHER: to build a MAP of Earth Magnetic Field Radiation Flux impinging on AtmoCube INVOLVE STUDENTS ! and ...

SPACE WEATHER 1/2: 

SPACE WEATHER 1/2 “Space Weather: conditions on the Sun and in the solar wind, magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health.” ESA website: www.esa.int

SPACE WEATHER 2/2: 

SPACE WEATHER 2/2 Effects on Spacecraft & Aircraft: total dose, lattice displacement, single events upsets (SEU), spacecraft charging, drag Power Distribution Networks: Power-line failures and corrosion effects observed in pipelines (e.g., Quebec March 1989) Communication Systems: changes to the structure of the ionosphere: increased absorption, unexpected reflections, radio interference, disruption of mobile phone communications Risks to Human Health: astronauts and aircrews are exposed to high doses of cosmic radiation Climate Change: - the Sun varying UV emissions modify the Earth ozone layer and affect the large-scale circulation of air - the solar wind gusts affect the electrical properties of the atmosphere - during the solar minimum the weaker solar wind enables GCR rays to enter the Earth atmosphere more easily promoting the formation of low-altitude clouds

REQUIREMENTS: 

REQUIREMENTS Scientific Measurement : Study of the Earth Atmosphere “SPACE-WEATHER” Measurement of the Radiation Flux impinging on the satellite Dosimeter Measurement of the Magnetic Field Magnetometer Constraints/issues: Low cost: very simple, small and light system Quasi-standard structure - CubeSat-like 13 cm side cube, 1.5 kg mass, 23 W power Avoid moving parts (mechanisms) if possible Use of any available launcher: non-optimized orbit Non-dedicated instrumentation: commercial off-the-shelf (COTS) devices Limited accuracy of the measurement Limited data rate (radio-amateur band) Avoid interference with measurements (magnetic field) Limited use of electro-magnetic systems (coils)

ORBIT: 

ORBIT DNEPR ISCK: 5 December 2005 Different conditions analyzed: h = 400 km 500 km 650 km i  98.2°

SPECTRO-DOSIMETER: 

SPECTRO-DOSIMETER

MAGNETIC FIELD: 

MAGNETIC FIELD Honeywell HMC 2003: dimensions 25.419.1 mm mass 4 g power 120300 mW range 40 mG  2 G Available: tested and calibrated !

GPS: 

GPS Trimble M-Loc MPM Module dimension 25.4  25.4  6.9 mm dimension 20.1  20.0  8.0 mm (antenna) mass 5.7 g power 68 mW, max 86 mW (antenna included) accuracy  7 m horizontal position  10 m altitude position 0.1 m/s velocity rate 1 Hz SGR-05U by SSTL highly recommended !

ATTITUDE DETERMINATION: 

ATTITUDE DETERMINATION SOLAR CELLS PHOTO-DIODES MAGNETOMETER SENSORS Earth

ATTITUDE CONTROL 1/2: 

ATTITUDE CONTROL 1/2 COIL Compromise between maximum gravity gradient and minimum displacement of the center of mass Cylinder dimensions: 18  18  18 mm Cylinder mass: 40 g Strip dimensions: 2.5 m  18 mm  0.3 mm Strip mass: 124 g BOOM Compromise between minimum mass and maximum magnetic moment Number of wires: 300 Wire diameter: 0.2 mm Coil side: 11 cm Mass: 37 g

ATTITUDE CONTROL 2/2: 

Below 400 km, under maximum (or average) solar activity conditions, the gravity gradient CAN NOT overcome aerodynamic torques and the coil should be also used ATTITUDE CONTROL 2/2

STRUCTURE SIMULATIONS: 

STRUCTURE SIMULATIONS Static and pressure loads T = 2.151 107 N/m2 T = 2.372 109 N/m2 Dynamic loads Aluminum 6061 LAUNCHER:

TEMPERATURE: 

TEMPERATURE QABSORBED - QCELLS + QGENERATED = QIRRADIATED MORE ACCURATE ANALYSIS NEEDED !

POWER SYSTEM: 

POWER SYSTEM SOLAR CELLS BATTERIES PARTLY TESTED…

POWER (1/2): 

POWER (1/2) Worst condition: TSUN = 3549 s TECL = 2135 s PMIN = 2 W OK !

POWER (2/2): 

POWER (2/2)

Data Rate: 

Data Rate Scientific measures: one each 10° -> about 150 s (5400 s x 10°/360°) i.e. 400 Kb/revolution -> 6.4 Mb/day With 3.7 passages/day -> 282 s*3.7~1000 s/day -> 6.4 Kb/s -> 19.2 Kb/s should be enough

The transmission system: 

The transmission system

Ground STATION: 

Ground STATION Radio-amateur Band Uplink: 145.835 MHz, FSK Downlink: 437.490 MHz, FSK

Conclusions & future: 

Conclusions & future Analysis of Scientific Measurements Rough Definition of Attitude Determination and Control system First Structure simulation First Thermal analysis First Analysis of Power system First Analysis of Telecommunication system On Board Data Handling (hardware & software) Power System tests Structure tests in climatic chamber Dynamic tests on the structure Complete calibration and tests of detectors … … … what we still have to do what we are, more or less, doing