Thiokol's Star family of space motors provides propulsion for spacecraft and launch vehicle upper stages.  The Star number for each motor indicates its approximate principal diameter in inches, while the letter designations are used to denote configurations tailored to a particular set of needs.  The Star 37 currently comes in two models, the FM and the XFP.

The Star 37FM rocket motor was developed and qualified for use as an apogee kick motor on FLTSATCOM.  The motor is a replacement for the Star 37E Delta, which has been discontinued.  The Nozzle assembly uses a 3D carbon-carbon throat and a carbon-phenolic exit cone.  Maximum propellant weight is 2350 pounds, while the motor has been qualified for propellant off-loading to 2257 pounds. The Star 37XFP rocket motor has been qualified as the orbit insertion motor for Rockwell International's (now Boeing) Global Positioning Satellite (GPS), and as the apogee motor for the RCA SATCOM Ku-Band satellite.  The Star 37XFP motor can be used as a replacement for the Star 37F motor, which has been discontinued.