OSTM/Jason-2

OSTM/Jason-2 measures sea-surface height using a Poseidon-3 radar altimeter that bounces microwave pulses off the ocean surface to determine distance to within a few centimeters. This data tracks global ocean circulation patterns and monitors long-term sea-level rise. The measurements are essential for climate science, hurricane intensity forecasting, and El Niño monitoring.

OSTM/Jason-2, launched in 2008, continued an uninterrupted sea-level measurement record begun by TOPEX/Poseidon (launched 1992) and continued by Jason-1 (launched 2001). All three satellites flew in the same orbit at approximately 1,336 kilometers altitude, enabling cross-calibration between missions. Together these satellites created a multi-decade record crucial for detecting millimeter-per-year changes in global sea level.

OSTM/Jason-2 was launched on June 20, 2008, aboard a Delta II rocket from Vandenberg Air Force Base, California. The acronym OSTM stands for Ocean Surface Topography Mission. The mission was originally designed for a three-to-five-year operational life but far exceeded that duration.

OSTM/Jason-2 was a collaborative mission between four agencies: NASA, NOAA, CNES (the French space agency), and EUMETSAT (the European Organisation for the Exploitation of Meteorological Satellites). This four-agency partnership built on earlier collaborations established for TOPEX/Poseidon and Jason-1. The follow-on mission Jason-3, launched in 2016, continued this same international partnership.