Like its two predecessors, OSTM/Jason-2 uses high-precision ocean altimetry to measure the distance between the satellite and the ocean surface to within a few centimeters. OSTM/Jason-2 was launched at 07,46 UTC on June 20,2008, from Space Launch Complex 2W at the Vandenberg Air Force Base in California, USA, the spacecraft separated from the rocket 55 minutes later. It is now in a 1,336 km circular, non-sun-synchronous orbit at an inclination of 66 degrees to Earths equator, Jason-1 has been moved to the opposite side of Earth and now flies over the same region of the ocean that Jason-2 flew over five days earlier. Jason-1s ground tracks fall midway between those of Jason-2, which are about 315 kilometers apart at the equator and this interleaved tandem mission provides twice the number of measurements of the oceans surface, bringing smaller features such as ocean eddies into view. The tandem mission also helps pave the way for a future ocean altimeter mission that would much more detailed data with its single instrument than the two Jason satellites now do together. With OSTM/Jason-2, ocean altimetry makes the transition from research into operational mode and these instruments send a microwave pulse to the ocean’s surface and time how long it takes to return. A microwave radiometer corrects any delay that may be caused by water vapor in the atmosphere, other corrections are also required to account for the influence of electrons in the ionosphere and the dry air mass of the atmosphere. Combining these data with the location of the spacecraft makes it possible to determine sea-surface height to within a few centimetres. The strength and shape of the signal also provides information on wind speed. These data are used in models to calculate the speed and direction of ocean currents and the amount and location of heat stored in the ocean. Another payload aboard Jason-2 is the T2L2 instrument, T2L2 is used to synchronize atomic clocks at ground stations, and to calibrate the on-board clock of the Jason-2 DORIS instrument. On 6 November 2008 CNES reported the T2L2 instrument was working well, OSTM/Jason-2 is a joint effort by four organizations. After completing the on-orbit commissioning of the spacecraft, CNES handed over operation, CNES will process, distribute and archive the research-quality data products that will become available in 2009. EUMETSAT will process and distribute operational data received by its station to users in Europe. NOAA will process and distribute operational data received by its stations to non-European users. NOAA and EUMETSAT will generate the products and distribute them to users. NASA will evaluate the performance of its instruments, the microwave radiometer, the Global Positioning System payload. In addition, NASA and CNES will validate scientific data products, NASAs Jet Propulsion Laboratory in Pasadena, California, manages the mission for NASAs Science Mission Directorate in Washington
Artist's interpretation of the Jason-2 satellite
Jason-2 after separation from its carrier rocket
Jason 2 just before launch.
OSTM/Jason-2's predecessor TOPEX/Poseidon caught the largest El Niño in a century seen in this image from Dec. 1, 1997.