BackForward Satellite Programme: Low Earth Multi-Use Receiver 

Programme details
Programme description
  • Constellation of satellites (175 at regime) for radio occultation sounding and ship tracking.
  • Commercial programme implemented by Spire Global Inc., San Francisco, CA, USA.  Data possibly bought by NOAA.
  • The platforms are actively stabilised over 3 axes.
  • The design life time is 2 years for individual satellites, undetermined for the full constellation.
  • The replacement policy is based on launching a new satellite cluster before the status of the constellation is unacceptably degraded, taking advantage of launch opportunities.
  • The orbit heights, ranging from 400 to 600 km, and inclinations, are determined by the launch opportunity.
  • The ESA PROGRES (Polarimetric Radio Occultation for Global Rain Estimation) project uses a subset of the satellites with polarimetric RO capability.
  • See detailed description at
Data circulation
  • The data are made available by Spire Globa lnc., San Francisco, CA, USA., on a commercial basis.
Agencies SPIRE
Programme lifetime 2015 - 2040
Associated satellites and instruments

Note: red tag => no longer operational , green tag => operational , blue tag => planned