About Us

Teacher in Space · Mission 51-L · Jan 28, 1986 · Aftermath

Mission STS-51-L

Flight 51-L was the second shuttle flight of 1986. Over the remaining months, another 14 missions were scheduled to fly.

The Challenger shuttle's primary payload was the second of NASA's Tracking and Data Relay satellites (TDRS). Working in concert with the first Tracking and Data Relay satellite (which was deployed in 1983 by an earlier Challenger mission), the two satellites were expected to provide about 85 percent real time coverage of each orbit of a user spacecraft. Challenger Pilot Michael Smith said, "It will give us almost global coverage for Shuttle missions of the future. That's going to be a big improvement not only for the shuttle, but also for the space station when it gets up later on." The satellite was scheduled to be deployed on the first day of the flight.

Experiments and Responsibilities

The 51-L mission also included 40 hours of comet Halley observations. NASA's Goddard Space Flight Center and the University of Colorado's Laboratory for Atmospheric and Space Physics had produced a low-cost spacecraft that could measure the ultraviolet spectrum of comet Halley when it was too close to the sun for other observatories to do so. The project, named Spartan-Halley, would help scientists determine how fast water is broken down (or dissociated) by sunlight. The data was to be saved on what was then a very robust 500 megabytes of storage.

Mission Specialist Ellison Onizuka was also going to use a camera with an image intensifier to photograph Halley's comet from the crew cabin. In a pre-flight interview, he told journalists, "I will have about two minutes on four different orbits to photograph Halley's comet in both the visible and ultraviolet spectrum. The objective it to try to get this data as the comet approaches perihelion, which is just as it goes around behind the sun and starts to head back out. It's a regime where we do not have any data at the present time so I've also been told we'll probably be the only human beings to see it at that time."

In addition to the lessons that Christa McAuliffe was to deliver from space, she was also supposed to assist in operating three student experiments that were carried aboard the Shuttle. The experiments included a study of chicken embryo development in space (in which recently fertilized White Leghorn chicken eggs were to be subjected to weightlessness and radiation from space); research on how microgravity affects a titanium alloy; and an experiment in crystal growth.

Payload Specialist Greg Jarvis, who was selected from over 600 engineer applicants from Hughes Aircraft, was scheduled to conduct fluid dynamics experiments that would have tested the reactions of satellite propellants to various shuttle maneuvers and simulated spacecraft movements.

The Challenger Space shuttle was also supposed to carry the first legal tender American coinage into orbit. Two complete sets of the U.S. Liberty coins, recently minted to honor the Statue of Liberty's centennial anniversary, were on board.

Countdown

Mission 51-L was originally set to launch at 3:43 p.m. (ET) on January 22, 1986. Its launch pad was familiar yet unique; Pad 39-B, which was last used for the Apollo Soyuz test Project in July 1975, had been recently modified to support the Shuttle program. 51-L was the first Shuttle to use the historic launch site.

Over the next few days, the launch date would be rescheduled several times more due to, among other causes, inclement weather, high winds, and a malfunctioning indicator switch for the Shuttle's hatch.

At 8:23 a.m., January 28, the crew again climbed aboard the spacecraft. The launch was delayed almost three hours more to assess ice buildups on the launch pad, and to allow more time for temperatures to rise and ice to melt. The countdown clock began ticking at 11:29 a.m. at T-minus nine minutes to launch.

Next: January 28, 1986