In the midst of a serious meeting about the dangers of the mission they were getting ready to fly, the crew of the STS-61-F meeting decided to take a break.
After turning on the TV for a few minutes, they never returned to the discussions.
61-F was one of two flights for a new type of Shuttle mission, which would use a liquid-fuel rocket to send satellites into deep space. Previous shuttle flights had used smaller, solid-fuel boosters to deploy satellites into higher orbits, and the Centaur liquid-fuel booster had been used with other rockets, including Atlas and Titan. But it had never been used in manned spaceflight before.
Two flights were planned that would be the first tests of the Shuttle-Centaur system. STS-61-F would launch the Ulysses spacecraft, which would study the sun from outside the plane of the solar system. STS-61-G would launch five days later, and deploy the Galileo spacecraft, which would study Jupiter. The tight schedule needed to get the two spacecraft in the proper trajectories would require having two shuttles, Challenger and Atlantis, in space at the same time.
While the use of the Centaur booster with the shuttle would allow the orbiters to launch spacecraft through the solar system, the combination was not without risks. The Centaur was originally designed to sit atop an unmanned rocket, not inside a crewed vehicle. If something went wrong in the flight, having a giant canister of volatile fuels in the orbiter's payload bay could be a recipe for disaster.
Astronauts and NASA engineers were working together to figure out how to decrease the risks posed by flying the Centaurs, but some believed the risk was too high. John Young, the head of the Astronaut Office at the time and who had walked on the moon and commanded the first space shuttle mission, jokingly referred to the Centaur as the "Death Star" because of the danger it posed. Nonetheless, NASA was proceeding with the missions, and so the crews assigned to them were doing their best to prepare to fly them as safely as possible, agreeing to accept the risk involved.
On the day of the meeting in question, the astronauts were working to figure out the safest way of ejecting the Centaur or its fuel in the event of a problem.
During the discussions, they took a break to watch on television the space shuttle carry some of their friends into space.
The day was January 28, 1986. The launch they were watching was the 51-L flight of the space shuttle Challenger.
During the break, they watched as their friends died in the Challenger disaster.
It took NASA years to recover from the tragedy, but when it did, the agency had a new focus on safety. Risk will always be a part of spaceflight, but the agency began working hard to eliminate taking chances unnecessarily. Among the projects that were cancelled was the use of the Centaur boosters on the space shuttle.
The Ulysses and Centaur spacecraft would still fly, but it would be years later. And when they did, instead of using the powerful Centaur booster, they would use smaller -- and safer -- solid-fuel boosters. The alternative rockets were too weak to carry out the missions, but NASA figured out a way to replace some of the rocket power with brain power to make the missions work.
Galileo was the first of the two to launch, this week in 1989. When it did, to make up for the thrust lost by not using Centaur, Galileo flew a more complicated trajectory, complete with gravitational assist maneuvers in which it used the gravity of Earth and Venus to "slingshot" it to greater velocity so that it could reach Jupiter. When Ulysses launched a year later, it used Jupiter's gravity to slingshot it out of the solar system's plane. Both spacecraft were able to successfully accomplish their missions, even without taking on the risk of the Centaur booster.
Visitors to the U.S. Space & Rocket Center can see a Centaur booster, and can now tell the David-and-Goliath story about how the mighty Death Star was beat by a simple slingshot.
Contributing Author: David Hitt
