Space Shuttle Challenger
Published on Apr 5, 2006 at 3:23 pm.
6 Comments.
Filed under space exploration, space shuttle.
So, what’s so special about April 4, 1983? This was the first flight of the Space Shuttle Challenger.
OK, so this blog entry is a day late. I know. Things have been pretty crazy around here, so I’ve not been keeping up. Next week should be smoother, I hope. Still, I wanted to go ahead and do this entry about the Challenger.
The Challenger, designation OV-099, was the second space shuttle to fly into space. The shuttle frame used was actually older than the one used for Columbia, the fist shuttle to fly in space. OV-099 was oritinally designed to be a test frame, with plans to outfit the Enterprise, the shuttle used in test atmospheric flights, for space. However, NASA determined that modifications needed to make Enterprise spaceworthy would cost more than what it would take to make Challenger spaceworthy.
Challenger’s first mission, STS-6, which began April 4, 1983, was itself the sixth space shuttle mission flown. The launch had been delayed by about two and a half months due to a hydrogen leak discovered prior to the original launch date of January 20 of that year. For this first fligh of Challenger, a crew of only four astronauts flew about the shuttle. Highlights of the mission included deployment of the first Tracking and Data Relay Satellite (TDRS) as well as the first spacewalk of the Shuttle program. This first spacewalk, performed by Donald Peterson and Story Musgrave, lasted a bit over 4 hours. This mission was also the first to fly with the lighter external fuel tank haivng only the foam coating, without the outer coating of protective white paint.
Just two months later, Challenger again blasted into space on mission STS-7, this time with Sally Ride aboard — NASA’s first woman astronaut in space. Two communication satellites were deployed on this mission.
Only about a month after landing from STS-7, Challenger again blasted into space on STS-8 to deploy another satellite. Challenger was the shuttle of another first in space with this mission, as Guion Bluford, Jr., became the first African American in space. Here, we see with the rapid turnaround for Challenger between the STS-7 and STS-8 missions NASA’s goal of quick turnarounds that were supposed to make spaceflight routine and inexpensive. STS-8 also marked both the first night launch and the first night landing of the Space Shuttle program.
Challenger’s fourth flight was STS-41B, which began February 3, 1984. Two more satellites were deployed, as well as a space pallet flown on STS-7 that was refurbished and flown back into space — another NASA first. STS-41B also marked the first untethered spacewalk and a test of the foot restraints on the remote manipulator arm that would be used for another NASA first planned for the next shuttle flight — the retrieval and repair of a satellite in orbit.
That flight, STS-41C, also marked Challenger’s fifth flight. Challenger deployed the Long Duration Exposure Facility (LDEF), which was to remain in orbit conducting experiments while the shuttle returned to Earth. The LDEF was to be retrieved on a later mission. This did, in fact occur, however the deployment was far longer than originally planned due to stoppage of shuttle flights after the Challenger explosion on STS-51L. In addition to deployment of LDEF, Challenger rendesvoused with the Solar Max satellite and conducted repairs.
Challenger flew into space a sixth time October 5, 1984, on mission STS-41G. Another satellite was deployed on this mission. STS-41G marked the first time seven astronauts flew aboard a shuttle, as well as marking the first mission with two women aboard, as well as the first spacewalk by a woman of any nationality, Kathryn Sullivan.
On April 29, 1985, Challenger again flew into space carrying a spacelab module in the payload bay. This mission, STS-51B, carrying Spacelab 3, was primarily a science mission, though another satellite was deployed.
Spacelab 2 was carried into space on July 29, 1985, on Challenger’s eighth mission, STS-51F. Three communication satellites were also deployed. This mission got off to a rocky start, though, as one of the Shuttle’s main engines prematurely shut down. The boost phase of the flight, though, was far enough along that a return to Earth would have not been safe or practical, so an order was given to abort to orbit. This abort scenario puts the Shuttle safely into orbit until a decision can be made as to the fate of the mission, but the orbit is not the one orginally planned for the spacecraft. In this case, controllers decided to continue the mission in this lower orbit, and STS-51F was declared a success.
Challenger’s ninth trip into space began October 30, 1985, with the launch of STS-61A, another science mission. In this mission, the first with eight astronauts aboard, the shuttle carried the German Spacelab D-1. This was also the first mission financed primarily by another nationality. A couple of small satellites were deployed, as well.
January 28, 1986, Challenger sat on Pad B of Launch Complex 39 awaiting liftoff for its tenth flight into space. This mission, STS-51L, was the first to use Pad B at the Kennedy Space Center since the days of Apollo. Launch Complex 39 consists of the Vehicle Assembly Building, where the Saturn V rockets were assembled, and which was converted to assemble the Shuttle components for flight, the launch control firing rooms, and two launch pads, Pad A and Pad B, each located several miles from the Vehicle Assembly Building. All previous Space Shuttle Launches had been from the more directly accessible Pad A. However, January 1986 had two flights scheduled only days apart. Pad A was used to launch Columbia on STS-61C just two weeks prior to Challenger’s STS-51L mission. So, that meant that Pad A was occupied during the time that Challenger was being rolled out to the launch pad for final launch preparations. Launching from Pad B is not a problem, though, as both launch pads have identical systems. It simply means that the Transporter Crawler has to make an additional turn and carry the orbiter and its mobile launch platform a bit farther. However, it was cold on the morning of the launch. That was a problem. Later investigations showed that the cold caused O-rings on the solid rocket boosters to harden. These O-rings were designed to seal in the hot gasses formed by the burning fuel in the Shuttle’s solid rocket boosters. Being hardened, though, meant that the O-rings did not seal properly. The hot gasses escaped, and like a blowtorch cut into the soft and unprotected main fuel tank below the Shuttle’s belly. This tank, filled with two parts hydrogen and one part oxygen, ignited in a giant fireball. The orbiter was suddenly thrown sideways, creating enormous atmospheric stresses on the frame of the spacecraft. The fuel tank explosion did not destroy the orbiter. However, the atmospheric stresses did, and the orbiter disintegrated. A tribute to how solid and securely the crew compartment was constructed is that the crew compartment remained largely intact after the disintegration of the orbiter. In fact, the crew compartment remained largely intact all the way until it struck the surface of the Atlantic Ocean several minutes later, at which time all seven astronauts aboard were killed.
The explosion destroying the Challenger put a halt to space shuttle flights until STS-26 on September 29, 1988. During this time, an investigation into the Challenger accident highlighted bad decisions, bad decision chains, bypassed safety protocals, poor communication, and a bureaucratic mentallity that emphasised schedules over safety, all of which doomed the Shuttle. Interestingly enough, after the Apollo 1 accident killing three astronauts on the launch pad, the investigation came to about the same conclusions, as did the one following the Columbia accident.
You may have noticed that the numbering scheme for Space Shuttle missions changed during all of this. The STS stands for Space Transportation System, the official name for the Space Shuttle program. The first missions were simply numbered in order of the mission. Then, in 1984, a new numbering system came into being. Here, the first digit of the number was the federal fiscal year of the mission, with the second number designating the launch side (1 = Kennedy Space Center, 2 = Vandenberg Air Force Base). Vandenberg was never used, though orginal plans called for an eventual shift of military missions to Vandenberg. The letter following the numbers indicated the sheduled mission during the year (A = first mission, B = second mission, C = third mission, etc). When Space Shuttle missions returned to flight after the Challenger explosion, then NASA returned to a sequential numbering scheme. However, now the numbers were the scheduled mission, not necessarily the flight order. So, if a mission were delayed or rescheduled, then the flight order might not match the number.
So, yesterday got me to thinking about the shuttle Challenger, and I decided to blog about it. I just didn’t have time until today. So, you got a NASA history lesson today. I hope that it didn’t bore you too much!
-Astroprof
PS: I’ll be at the Johnson Space Center for the next few days, so I don’t know if I’ll get a chance to add to my blog. I’ll try if I get the time, but I’ll be working pretty hard the whole time.
jose on May 29, 2007 at 3:55 pm: 1
In the challenger’s last mission did it make it back to earth.explain why
jose on May 29, 2007 at 3:57 pm: 2
I’m waiting for your response
Astroprof on May 29, 2007 at 4:51 pm: 3
Challenger was destroyed, with loss of all crewmembers, in the explosion on its final mission: STS-51L.
Charlie on June 29, 2007 at 5:49 am: 4
What you think of Chirivella’s theory of “phantom fires” of LH2 leaking from the ET at lower altitudes to have caused the ET explosion?
Charlie on August 14, 2007 at 1:43 am: 5
I’m waiting for your response
Astroprof on August 14, 2007 at 10:36 am: 6
Oh. I didn’t see this comment earlier. I don’t regularly check postings over a year old! I don’t know all the details of Chirivella’s theory. However, images show that there appears to be a jet of gas coming from the solid rocket booster. That is consistent with what you’d expect from rigid O-rings. Also, didn’t Chirivella work for the industry that made the solid rockets? There may have been motivation to deflect blame away from the solid rockets. Of course, the real blame goes to the decision makers who decided to launch even though the launch conditions were outside of the accepted safety range.