STS-54

STS-54 was Endeavour's January 1993 Space Shuttle mission to deploy the Tracking and Data Relay Satellite F spacecraft and fly the Diffuse X-ray Spectrometer payload. NASA lists John Casper as commander, Donald McMonagle as pilot, and Mario Runco Jr., Gregory Harbaugh, and Susan Helms as mission specialists. Endeavour launched from Kennedy Space Center's Launch Complex 39B on January 13, 1993, and landed on Runway 33 at the Shuttle Landing Facility on January 19 after 5 days, 23 hours, 38 minutes, and 19 seconds in orbit. The primary payload was TDRS-F, later known as TDRS-6, which Endeavour deployed on the first day of the mission for transfer toward geosynchronous orbit by an Inertial Upper Stage. The flight also carried the Diffuse X-ray Spectrometer in the payload bay to collect low-energy X-ray data from diffuse sources, along with middeck experiments in life sciences, plant development, rodent physiology, acceleration measurement, and combustion. STS-54 also included an EVA by Gregory Harbaugh and Mario Runco Jr. on January 17, 1993. The spacewalk tested crew movement, foot-restraint entry, large-object handling, and other techniques meant to build operational experience for later orbital assembly work. The mission adds an important link between Casper's command record, Runco's missing astronaut profile, Harbaugh's EVA career, Helms' first flight, and the TDRS communications network that supported Shuttle and low-Earth-orbit spacecraft operations.