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STS-51 was a Space Shuttle Discovery mission that launched the Advanced Communications Technology Satellite ACTS in September 1993. The flight also featured the deployment and retrieval of the SPAS-ORFEUS satellite and its IMAX camera, which captured spectacular footage of Discovery in space. A spacewalk was also performed during the mission to evaluate tools and techniques for the STS-61 Hubble Space Telescope servicing mission later that year. STS-51 was the first shuttle mission to fly a GPS receiver, a Trimble TANS Quadrex. It was mounted in an overhead window where limited field of view and signal attenuation from the glass severely impacted receiver performance. (Full triple-redundant 3-string GPS would not happen until 14 years later with STS-118.)

The five white stars and one yellow star of the insignia symbolize the flight's numerical designation in the Space Transportation System's mission sequence. The insignia also depicts the triangular SPAS-ORFEUS on the right.

STS-57 was a Shuttle-Spacehab mission of Space Shuttle Endeavour that launched 21 June 1993 from Kennedy Space Center, Florida.

During the course of the ten-day flight, the astronauts successfully conducted scores of biomedical and materials sciences experiments inside the pressurized SPACEHAB module. Two astronauts participated in a spacewalk and EURECA (European Retrievable Carrier) was retrieved by the crew and stowed inside Endeavour’s payload bay. EURECA was deployed from the Space Shuttle Atlantis in the summer of 1992 and contains several experiments to study the long-term effects of exposure to microgravity.

The five stars and shape of the robotic arm of the insignia symbolize the flight's numerical designation in the Space Transportation System's mission sequence.

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.

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.

STS-56 was a Space Shuttle Discovery mission to perform special experiments. The mission launched from Kennedy Space Center, Florida, on 8 April 1993.

The primary payload of the flight was the Atmospheric Laboratory for Applications and Science-2 (ATLAS-2), designed to collect data on the relationship between the sun's energy output and Earth's middle atmosphere and how these factors affect the ozone layer. It included six instruments mounted on a Spacelab pallet in the cargo bay, with the seventh mounted on the wall of the bay in two Get Away Special canisters. Atmospheric instruments included the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment, the Millimeter Wave Atmospheric Sounder (MAS), and the Shuttle Solar Backscatter Ultraviolet/A (SSBUV/A) spectrometer (on the cargo bay wall). Solar science instruments were the Solar Spectrum Measurement (SOLSPEC) instrument, the Solar Ultraviolet Irradiance Monitor (SUSIM), and the Active Cavity Radiometer (ACR) and Solar Constant (SOLCON) experiments.