Space Missions scenarios: key parameters for spacecraft architecture Orbit and mission - environment - Communications to ground - Vessel to vessel communications - technology - fabrication - Lissajou orbits  TM/TC 2 par satellite terre/anti- terre  Liaison RF sensing (type SimbolX) inter-satellite pour la formation ecliptic plane sun small Lissajou typically:period: 6 months 1 avoidable eclipse every 6 years acceptable depointing angle of the line of sight = total shield angle protection – Earth, Sun and Moon covering (fonction of the L2 orbit) sun ecliptic plane Earth Moon worst case every 28 days L2 200 000 km 8° 14° Fresnel lens light shield line of sight  TMI Reflector Array (0 à 40°) 1 on receptor spacecraft facing earth fixed RA Antenna & GS Possible a partir de 100 000km from Earth
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