STS-29

STS-29 was a NASA Space Shuttle mission, during which Space Shuttle Discovery inserted a Tracking and Data Relay Satellite (TDRS) into Earth orbit. It was the third shuttle mission following the Challenger disaster of 1986, and launched from Kennedy Space Center, Florida, on 13 March 1989. STS-29 was the eighth flight of Discovery and the 28th Space Shuttle mission overall; its planned predecessor, STS-28, was delayed until August 1989.

Mission summary
Discovery lifted off from Pad B, Launch Complex 39, Kennedy Space Center, at 9:57 am EST on 13 March 1989. The launch was originally scheduled for 18 February, but was postponed to allow for the replacement of faulty liquid oxygen turbopumps on the three main engines. The amended target date of 11 March also proved unviable because of the failure of a master event controller when it was powered up during prelaunch checkout; the controller was quickly replaced. On the rescheduled launch day of 13 March, the launch was delayed for nearly two hours because of ground fog and high upper winds. A waiver was approved for the orbiter's wing loads.

The primary payload was the third and final component of the Tracking and Data Relay Satellite (TDRS) constellation in geosynchronous orbit. The three on-orbit satellites were stationed over the equator at about 22,300 miles above Earth; two of them were positioned 130 degrees apart, while the third was located between them as an on-orbit spare.

On Flight Day 1, one of three cryogenic hydrogen tanks which supplied shuttle's electricity-generating fuel cells exhibited erratic pressure fluctuations. It was deactivated while engineers studied the problem, and the crew was told to conserve electrical power. The tank was reactivated on Flight Day 3, 15 March, and operated successfully thereafter.

Discovery landed on 18 March 1989, after orbit 80, one orbit earlier than planned, in order to avoid possible excessive wind buildup expected at the landing site. The shuttle touched down on Runway 22 at Edwards Air Force Base, California, at 9:35 am EST. The total mission duration was 4 days, 23 hours, and 39 minutes.

Payload and experiments
The mission's primary payload was a Tracking and Data Relay Satellite (TDRS-D), which became TDRS-4 after deployment, and its attached Inertial Upper Stage (IUS). The satellite was deployed from the shuttle's payload bay less than six hours after launch, at 3:12 am EST. The first-stage orbit burn of the IUS took place an hour later, and the second burn to circularize the orbit occurred 12 hours and 30 minutes into the mission. The satellite was stationed at 41 degrees west longitude.

Discovery also carried eight secondary payloads, including two Shuttle Student Involvement Program experiments. One student experiment, using four live rats with tiny pieces of bone removed from their bodies, was to test whether the environmental effects of space flight inhibit bone healing. The other student experiment was to fly 32 chicken eggs to determine the effects of space flight on fertilized chicken embryos.

One experiment, mounted in the payload bay, was only termed "partially successful." The Space Station Heat Pipe Advanced Radiator Element, a potential cooling system for the planned Space Station Freedom, operated continuously for less than 30 minutes under powered electrical loads. The failure was blamed on the faulty design of the equipment, especially the manifold section.

All other experiments operated successfully. Crystals were obtained from all the proteins in the Protein Crystal Growth experiment. The Chromosomes and Plant Cell Division in Space (CHROMEX), a life sciences experiment, was designed to show the effects of microgravity on root development. An IMAX (70 mm) camera was used to film a variety of scenes for the IMAX film Blue Planet, including the effects of floods, hurricanes, wildfires and volcanic eruptions on Earth. A ground-based US Air Force experiment used the orbiter as a calibration target for the Air Force Maui Optical Site (AMOS) in Hawaii.

Wake-up calls
NASA began a tradition of playing music to astronauts during the Gemini program, and first used music to wake up a flight crew during Apollo 15. Each track is specially chosen, often by the astronauts' families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.