Space Transportation System (STS)
The Space Transportation System (STS), also known as space shuttle, was developed by NASA as a means to move both men and material into low earth orbit. At launch the space shuttle is attached to a ET (external tank) an two SRB (solid rocket booster). The SRB jettison at 126 seconds in-flight and fall back down to earth where they will picked up and refurbished for another launch. The ET will not be reused.
Differences between the orbiters
Columbia
Columbia(OV-102) was the first space-rated orbiter and was always the heaviest of the fleet. She was always the unique one with her SILTS(Shuttle Infrared Lee-side Temperature Sensing) pod on her vertical tail and the black wing chines. She was the only orbiter that never flew an ISS or Mir mission due to her mass.
However, her next mission following STS-107 was STS-118 which was going to ISS to deliver and install the S5 truss segment. She was also capable of 16-day Extended Duration Orbiter(EDO) missions thanks the EDO cryokit in her payload bay.
Challenger
Challenger(OV-099) started out as Structural Test Article-099(STA-099) but when NASA decided against modifying Enterprise(OV-101) they decided to upgrade STA-099 into a spaceflight capable condition. During this refurbishment process she was known as OV-101M for a short while until she was later redesignated OV-099 keeping her STA number.
She was also a bit lighter than Columbia allowing her to perform IUS(Inertial Upper Stage) missions. Challenger had been modified at KSC to be able to support the Centaur G/G Prime upperstages, but she was destroyed during the launch of STS-51L prior to carrying any Centaur upperstages.
Discovery
Discovery(OV-103) was originally slated to become the "Air Force orbiter" stationed at Vandenberg AFB flying polar-orbit missions from Space Launch Complex-6(SLC-6, pronounced "slick six" ). However, the Challenger accident happened prior to the first Vandenberg AFB flight and the Air Force withdrew from the Shuttle program. She was then selected to fly the Return To Flight mission, STS-26R carrying TDRS-C.
Discovery also carried significant payloads such as the Ulysses Solar Polar Mission spacecraft and the Hubble Space Telescope. After Columbia, it looked for a while that Atlantis would fly STS-114, the Return To Flight mission. However, when engineers found problems with the actuators in the Rudder/Speedbrakes of the fleet, Discovery was selected once again to return the fleet to flight
Same deal happened after the grounding of fleet following STS-114. In order to eliminate the need of performing back-to-back flights with Atlantis(STS-121 and STS-115), Discovery was selected to fly STS-121. Her next mission is STS-122/1E, carrying the Columbus Orbital Facility module to ISS.
She will during the most part of 2007 receive a new modification called Station To Shuttle Power Transfer System(SSPTS) which will allow her to remain docked longer to ISS.
Atlantis
Atlantis(OV-104) is pretty similar to Discovery, not much difference in mass or exterior appearance. Atlantis was used to launch Galileo to Jupiter and Magellan to Venus. Atlantis was the first orbiter to ever dock with Mir on STS-71 in July 1995.
Endeavour
Endeavour(OV-105) was built as replacement for Challenger utilising spare parts NASA opted to build along with Discovery and Atlantis. Endeavour was the first orbiter delivered with an EDO capability and a 40 ft diameter drag chute used after touchdown to brake the orbiter on the runway.
Endeavour will be the first orbiter to fly with the SSPTS mod that has been installed during 2006.
STS addons for Orbiter
- Shuttle Fleet, a collection of the whole vehicle fleet, by David413 and Don 'Donamy' Gallager.
- Slats Pad 39 and Edwards addons
- The STS payloads project.
- The high-detail ETs by David Sundstrom
References
See also