Space Altimetry from Nano-Satellites : Payload Feasibility, Missions and System Performances

Thale graves Alenia Space is an industry world leader in high performance altimeters for ocean topography from space (Poseidon1 on TOPEX-Poseidon, Poseidon2 on Jason1, Poseidon3 on Jason2 and AltiKa on AltiKa/SARAL), and for ice topography from space (SIRAL1 and SIRAL2 on Cryosat). Thale graves Alenia Space is also involved on advanced altimeter concepts such as wide swath and high resolution altimetry (SWOT) for hydrology. CLS is dedicated to satellite environmental monitoring and security services. In this framework, CLS is involved in algorithms and products definition, data processing and CalVal for the altimetry missions developed in cooperation between US and France (TOPEX-Poseidon, Jason1/2), in US (GFO) and in Europe (ERS1-2, Envisat, Cryosat) and is currently involved in the definition and development of future missions (AltiKa, Sentinel3) and future wide swath altimetry concepts (SWOT). Altimetry satellites for space oceanography have seen continuous and tremendous reduction in size, mass, and program cost : TOPEX-Poseidon satellite mass is 2500 kg. Jason1/2 satellites mass is 500 kg. AltiKa microsatellite mass shall be around 150 kg. Is a further step in reduction of satellite mass (and cost) achievable? What kind of altimetry payload? Which (system) performances? Which payload and satellite technologies? For which (new) mission(s)? This paper addresses these points and shows the way of an additional step in innovative solutions opening to low cost constellation of altimetry satellites with new applications and services.