Swot

Surface Water and Ocean Topography

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General

Designation	54754 / 22173A
Launch date	16 Dec 2022
Country of origin	France and United States
Mission	Remote sensing (Oceanography)
Perigee/Apogee	890 km
Inclination	77.6°
Period	102.2 min
Launch vehicle	Falcon 9 #199

Launch initially planned in 2020. For CNES, built in collaboration with US NASA JPL. Will follow achievements from the Jason program.

SWOT comprises both an oceanography and a hydrology mission:

_ For oceanography, the satellite will provide measurements of ocean surface and wave height. This data will be used to analyse and understand the effects of coastal circulation on marine life, ecosystems, water quality and energy transfers, resulting in more accurate models of the interactions between oceans and the atmosphere.

_ The hydrology mission will evaluate continental surface water, to study changes in water storage in humid zones, lakes and reservoirs, as well as flow rates in rivers.

Technical data

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Specifications

Prime contractor	Thales Alenia Space
Platform	new one
Mass at launch	2200 kg
Dry mass
Dimension	5 x 14.9 m
Solar array
Stabilization
DC power
Design lifetime	3 years

TT&C in S-band

The SWOT payload comprises two subassemblies, KaRIn and NADIR.

Built by JPL, KaRIn (Ka-band Radar INterferometer) comprises two Ka-band antennas, located 10 meters apart but precisely positioned in relation to each other. It offers two-dimensional observation capability over a 120-kilometer swath, with horizontal resolution of 50-100 meters, programmable on either side. The interferometry type altimeter will provide coverage of lakes, rivers, reservoirs and oceans, at a repeat rate of twice every 21 days. Thales Alenia Space is also offering to supply the RFU (Radio Frequency Unit), which is at the heart of this instrument.

The NADIR module comprises the same instruments as on the Jason satellites, including the Poseidon dual-frequency altimeter made by Thales Alenia Space. It also includes the Thales-built Doris system for precision orbital determination, an AMR (Advanced Microwave Radiometer), the GPSP (GPS Payload) and the LRA (Laser Retro-reflector Array) built by JPL.

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