STS-55

STS-55
Mission insignia
Mission statistics
Mission name	STS-55
Space shuttle	Columbia
Launch pad	39-A
Launch date	26 April 1993, 10:50 am EDT
Landing	6 May 1993, 10:30 am EDT. Edwards AFB Runway 22
Mission duration	9/23:39:59
Number of orbits	160
Orbital altitude	302 kilometres (163 nmi)
Orbital inclination	28.45 degrees
Distance traveled	6,701,603 kilometres (4,164,183 mi)
Crew photo
Related missions
Previous mission Subsequent mission STS-56 STS-57

STS-55 (Space Transportation System 55), or D-2 was the 55th overall flight of the US Space Shuttle and the 14th flight of Shuttle Columbia. This flight was a multinational Spacelab flight involving 88 experiments from eleven different nations. The experiments ranged from biology sciences to simple earth observations.

Crew

Position	Astronaut
Commander	Steven R. Nagel Fourth spaceflight
Pilot	Terence T. Henricks Second spaceflight
Mission Specialist 1	Jerry L. Ross Fourth spaceflight
Mission Specialist 2	Charles J. Precourt First spaceflight
Mission Specialist 3	Bernard A. Harris, Jr. First spaceflight
Payload Specialist 1	Ulrich Walter, DFVLR First spaceflight
Payload Specialist 2	Hans Schlegel, DFVLR First spaceflight

Backup crew

Position	Astronaut
Payload Specialist 1	Gerhard Thiele, DFVLR
Payload Specialist 2	Renate Brümmer, DFVLR

Mission parameters

• Mass:
  • Orbiter landing with payload: 103,191 kilograms (227,500 lb)
  • Payload: 11,539 kilograms (25,440 lb)
• Perigee: 304 kilometres (189 mi)
• Apogee: 312 kilometres (194 mi)
• Inclination: 28.5°
• Period: 90.7 min

Mission highlights

Columbia carried to orbit the second reusable German Spacelab on the STS-55 mission and demonstrated the shuttle's ability for international cooperation, exploration, and scientific research in space. The Spacelab Module and an exterior experiment support structure contained in Columbia’s payload bay comprised the Spacelab D-2 payload. (The first German Spacelab flight, D-1, flew Shuttle mission 61-A in October 1985.) The U.S. and Germany gained valuable experience for future space station operations.

The D-2 mission, as it was commonly called, augmented the German microgravity research program started by the D-1 mission. The German Aerospace Research Establishment (DLR) had been tasked by the German Space Agency (DARA) to conduct the second mission. DLR, NASA, the European Space Agency (ESA), and agencies in France and Japan contributed to D-2's scientific program. Eleven nations participated in the experiments. Of the 88 experiments conducted on the D-2 mission, four were sponsored by NASA.

View of Columbia's payload bay showing Spacelab

The crew worked in two shifts around-the-clock to complete investigations into the areas of fluid physics, materials sciences, life sciences, biological sciences, technology, Earth observations, atmospheric physics, and astronomy. Many of the experiments advanced the research of the D-1 mission by conducting similar tests, using upgraded processing hardware, or implementing methods that take full advantage of the technical advancements since 1985. The D-2 mission also contained several new experiments which were not previously flown on the D-1 mission.

The D-2 Mission conducted 88 experiments to study life sciences, material sciences, technology applications, Earth observations, astronomy, and atmospheric physics. It surpassed the 365th day in space for the Space Shuttle fleet and the 100th day of flight time in space for Columbia, the fleet's oldest Orbiter on its fourteenth flight.

D-2 marked the first tele-robotic capture of a free floating object by flight controllers in Germany. The crew conducted the first intervenus saline solution injection in space as part of an experiment to study the human body's response to direct fluid replacement as a countermeasure for amounts lost during space flight. They also successfully completed an in-flight maintenance procedure for collection of orbiter waste water, which allowed the mission to continue.

STS-55 crewmembers participated in two amateur radio experiments, SAREX II from the United States and the German SAFEX. These experiments allowed students and amateur radio operators from around the world to talk directly with the Space Shuttle in orbit and participated in a SpaceMedicine conference with the Mayo Clinic.

Launch

Columbia was initially scheduled to launch in late February however this date slipped to early March due to concerns with the tip-seal retainers in the main engines' oxidizer turbopumps. All three turbopumps were replaced at the pad but later inspection revealed the retainers to be in good condition.

Further delays were caused by the burst of a hydraulic flex hose in the aft compartment during the Flight Readiness Test. The lines were removed and inspected and three replacements were installed.

The launch attempt on 22 March was aborted automatically at T-3 seconds when computers detected an incomplete ignition of the number three Space Shuttle Main Engine. The problem was traced to a leak in the liquid oxygen preburner check valve. All three SSMEs were replaced as a precaution.

Another launch attempt on 24 April was scrubbed due to a possible faulty reading with one of the inertial measurement units.

The final launch attempt was successful with liftoff at 10:50 am EDT on 26 April 1993.

See also

• Space science
• Space shuttle
• List of space shuttle missions
• List of human spaceflights chronologically
• Space Shuttle abort modes

External links

• NASA mission summary
• STS-55 Video Highlights