STS-41-C - Mission Summary

Mission Summary

Liftoff took place at 8:58 am EST on 6 April 1984. The mission marked the first direct ascent trajectory for the Space Shuttle, which reached its 288-nautical-mile-(533-km)-high orbit using its Orbiter Maneuvering System (OMS) engines only once, to circularize its orbit.

The flight had two primary objectives. The first was to deploy the Long Duration Exposure Facility (LDEF), a passive, retrievable, 21,300 pounds (9,700 kg), 12-sided cylinder, 14 feet (4.3 m) in diameter and 30 feet (9.1 m) long, carrying 57 scientific experiments. The second objective was to capture, repair and redeploy the malfunctioning Solar Maximum Mission satellite – "Solar Max" – that had been launched in 1980.

The five-man crew included Robert L. Crippen, commander, on his third shuttle flight; pilot Francis R. Scobee; and mission specialists James D. A. van Hoften, Terry J. Hart and George D. Nelson.

During the launch phase (ascent) the main computer in Mission Control failed, as did the backup computer. For about an hour the controllers had no data on the space shuttle.

On the second day of the flight, the LDEF was grappled by the "Canadarm" Remote Manipulator System (RMS) arm and successfully released into orbit. Its 57 experiments, mounted in 86 removable trays, were contributed by 200 researchers from eight countries. Retrieval of the passive LDEF had been scheduled during 1985, but schedule delays and the Challenger disaster of 1986 postponed the return until 12 January 1990, when Columbia retrieved LDEF on mission STS-32.

On the third day of the mission, Challenger's orbit was raised to about 300 nautical miles (560 km), and it maneuvered to within 200 feet (61 m) of Solar Max. Astronauts Nelson and van Hoften, wearing spacesuits, entered the payload bay. Nelson, using the Manned Maneuvering Unit (MMU), flew out to the satellite and attempted to grasp it with a special capture tool, called the Trunnion Pin Acquisition Device (TPAD). Three attempts to clamp the TPAD onto the satellite failed. The Solar Max began tumbling on multiple axes when Nelson attempted to grab it by hand, by a solar array, and the effort was called off. CDR Crippen had to perform excessive maneuvers of the shuttle to keep up with Nelson and SMM and nearly ran out of fuel.

During the night, the Solar Max POCC, at Goddard Space Flight Center, Greenbelt, Maryland, was able to establish control over the satellite by sending commands ordering the magnetic torque bars to stabilize the tumbling action. This was successful, and the Solar Max went into a slow, regular spin.

The next day, Crippen maneuvered Challenger back to Solar Max, and Hart was able to grapple the satellite with the RMS. They placed Solar Max on a special cradle in the payload bay using the RMS. They then began the repair operation, replacing the satellite's attitude control mechanism and the main electronics system of the coronagraph instrument. The ultimately successful repair effort took two separate spacewalks. Solar Max was deployed back into orbit the next day. After a 30-day checkout by the Goddard POCC, the satellite resumed full operation.

Other STS-41-C mission activities included a student experiment located in a middeck locker to determine how honeybees make honeycomb cells in a microgravity environment. They did so successfully, just as on Earth.

Highlights of the mission, including the LDEF deployment and the Solar Max repair, were filmed using an IMAX movie camera, and the results appeared in the IMAX movie The Dream is Alive.

The 6-day, 23-hour, 40-minute, 7-second mission ended on 13 April 1984, at 5:38 am PST, when Challenger landed on Runway 17, at Edwards AFB, having completed 108 orbits over the course of STS-41-C. Challenger was returned to KSC on 18 April 1984.