The Star is a family of US solid-propellant rocket motors originally developed by Thiokol and used by many space propulsion and launch vehicle stages. They are used almost exclusively as an upper stage, often as an apogee kick motor. Three Star 37 stages, and one Star 48 stage, were launched on solar escape trajectories; fast enough to leave the Sun's orbit and out into interstellar space, where barring the low chance of colliding with debris, they will travel past other stars in the Milky Way galaxy and survive potentially intact for millions of years. Star 24 The Star 24 (TE-M-640) is a solid fuel apogee kick motor, first qualified in 1973. It burns an 86% solids carboxyl-terminated polybutadiene (CTPB) fuel. Thiokol Star-24 family Star 27 The Star 27 is a solid apogee kick motor, with the 27 representing the approximate diameter of the stage in inches. It burns HTPB fuel with an average erosion rate of 0.0011 inches per second. When used on the Pegasus air-launch rocket payloads are capable of leaving Earth orbit. A version of the Star 27, designated Star 27H, was used in the launch of the IBEX spacecraft. The spacecraft had a mass of 105 kg by itself and together with its Star 27 motor, 462 kg. The Star 27H helped it get to a higher orbit, beyond Earth's magnetosphere. Star 37 The Star 37 was first used as the engine for the Thor-Burner upper stage in 1965. The Burner I used the Thiokol FW-4 (TE 364-1) engine and the Burner 2 used the Thiokol (TE-M-364-2). The "-37" designation refers to the approximate diameter of the fuel casing in inches; Thiokol had also manufactured other motors such as the Star-40 and Star 48. Internally, Thiokol's designation was TE-M-364 for early versions, TE-M-714 for later ones, and TE-M-783 for a special HTPB model used for FLTSATCOM launches. Subtypes are given one or more letter suffixes after the diameter number, or a trailing number (i.e., "-2") after the internal designation. Not surprisingly, the "T" prefix stands for Thiokol, and the following letter refers to the company division that developed the rocket motor. In this case, "M" refers to the Magna, UT Division. "E" refers to the Elkton, MD division. 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