33105 - JASON 2

JASON 2 is a French-American ocean monitoring satellite that was launched by a Delta 2 rocket from Vandenberg AFB at 07:46 UT on 2008 June 20. The initial orbital parameters of JASON 2 were period 112 min, apogee 1,335 km, perigee 1,324 km, and inclination 66 deg.

The 510-kg, 500-W craft carries instruments to enable derivation of sea surface levels with an accuracy of 2.5 cm. It is a cooperative mission involving the French CNES, the European EUMETSAT, and the American NOAA and NASA.

The altimeter is a radar sounder operating at two frequencies, 5.3 and 13.6 GHz, and provides the surface-to-satellite distance. The use of dual-frequency helps to eliminate the extra delay caused by the free electrons in the ionosphere.

AMR is the Advanced Microwave Radiometer that receives thermal radiation at three frequencies, 18, 21, and 37 GHZ from atmospheric water vapor which is another source of delay in the altimeter measurements. It is easy to correct for this delay with the measured water vapor content.

DORIS (Determination d'Orbite et Radiopositionement Integre par Satellite) helps in orbit propagation by measuring the satellite's position. Ground-based beacons transmit at two frequencies, 401.25 and 2,036.25 MHz, which are received by the satellite. The received doppler-shifted frequencies provide the velocity of the satellite required for orbit determination.

LRA is a Laser Retroreflector Array and provides a target for laser ranging. It is a reflector on-board JASON 2 (and many other satellites) for orbit determination under the ILRS (International Laser Ranging Service) program. The reflector consists of nine quartz surfaces.

Also used by JASON 2 is the orbit determination by means of continuous monitoring of GPS transmissions.

Alternate Names

OSTM
Ocean Surface Topography Mission

Facts in Brief

Launch Date: 2008-06-20
Launch Vehicle: Delta II
Launch Site: Vandenberg AFB, United States
Mass: 510.0 kg
Nominal Power: 500.0 W