# STS-54

STS-54 was a NASA Space Transportation System (Space Shuttle) mission using Space Shuttle Endeavour. This was the third flight for Endeavour, and was launched on January 13, 1993 with Endeavour returning to the Kennedy Space Center on January 19, 1993.

## Crew

| Position | Astronaut | Astronaut |
| Commander | John Casper Second spaceflight | John Casper Second spaceflight |
| Pilot | Donald R. McMonagle Second spaceflight | Donald R. McMonagle Second spaceflight |
| Mission Specialist 1 | Mario Runco Jr. Second spaceflight | Mario Runco Jr. Second spaceflight |
| Mission Specialist 2 Flight Engineer | Gregory J. Harbaugh Second spaceflight | Gregory J. Harbaugh Second spaceflight |
| Mission Specialist 3 | Susan Helms First spaceflight | Susan Helms First spaceflight |

### Crew seat assignments

| Seat | Launch | Landing | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 1 | Casper | Casper | | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 2 | McMonagle | McMonagle | | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 3 | Runco | Helms | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 4 | Harbaugh | Harbaugh | | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 5 | Helms | Runco | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 6 | Unused | Unused | | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
| 7 | Unused | Unused | | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |

## Mission highlights

The primary payload was the fifth TDRS satellite, TDRS-F, which was deployed on day one of the mission. It was later successfully transferred to its proper orbit by the Inertial Upper Stage (IUS). Also carried into orbit in the payload bay was a Hitchhiker experiment called the Diffuse X-ray Spectrometer (DXS). This instrument collected data on X-ray radiation from diffuse sources in deep space.
Other middeck payloads to test the effects of microgravity included the Commercial General Bioprocessing Apparatus (CGPA) for-life sciences research; the Chromosome and Plant Cell Division in Space Experiment (CHROMEX) to-study plant growth; the Physiological and Anatomical Rodent Experiment (PARE) to examine the skeletal system and the adaptation of bone to space flight; the Space Acceleration Measurement Equipment (SAMS) to measure and record the microgravity acceleration environment of middeck experiments; and the Solid Surface Combustion Experiment (SSCE) to measure the rate of flame spread and temperature of burning filter paper.
Also, on day five, mission specialists Mario Runco Jr. and Gregory J. Harbaugh spent nearly 5 hours in the open cargo bay performing a series of space-walking tasks designed to increase NASA's knowledge of working in space. They tested their abilities to move about freely in the cargo bay, climb into foot restraints without using their hands and simulated carrying large objects in the microgravity environment. The EVA completed after 4 hours, 28 minutes.
The EVA was a late addition to the mission plan as part of NASA's objectives to hone EVA skills required for hardware assembly anticipating the International Space Station.
The mission completed on January 19, 1993, with a landing at Kennedy Space Center.