is based on primary mirror support assemblies used in SWATH, a small explorer developed for the U.S. Air Force, and NIXT, a set of rocket flights flown by the Smithsonian Astrophysical Observatory (SAO) five times between 1983 and 1993. Many of the designs and some of the space flight hardware from the MDI instrument on Solar and Heliospheric Observatory (SoHO) was also used. Image gallery See also Explorer program References External links TRACE website by Lockheed Martin TRACE Data Center by Lockheed Martin TRACE website (archived) by NASA's Goddard Space Flight Center Spacecraft launched in 1998 Explorers Program Missions to the Sun Solar telescopes Ultraviolet telescopes Solar space observatories Spacecraft launched by Pegasus rockets