Space Shuttles - Are these safe ?

Lets start with - What is a space shuttle ?

Space Shuttle, officially called Space Transportation System (STS), is the United States government's current manned launch vehicle. A total of five usable orbiters were built, of which three remain. The winged shuttle orbiter is launched vertically, usually carrying five to seven astronauts (although eight have been carried and eleven could be accommodated in an emergency) and up to 50,000 lb (22,700 kg) of payload into low earth orbit (the thermosphere). When its mission is complete, it fires its maneuvering thrusters to drop out of orbit and re-enters the Earth's atmosphere. During the descent and landing, the shuttle orbiter acts as a glider and makes a completely unpowered landing.

Evolution story(thats what it was meant to be)

The first orbiter, Enterprise, was not built for actual space flight, and was used only for testing purposes. Enterprise was followed by four operational space shuttles: Columbia, Challenger, Discovery and Atlantis. Challenger was destroyed on launch in 1986, and Endeavour was built as a replacement. Columbia was destroyed on re-entry in 2003.

Space Shuttle Columbia (NASA Orbiter Vehicle Designation: OV-102) was the first spaceworthy space shuttle in NASA's orbital fleet. Its first mission, STS-1, lasted from April 12 to April 14, 1981. On February 1, 2003, Columbia disintegrated during re-entry over Texas, on its 28th mission. All seven crew members aboard perished.

The Space Shuttle Columbia disaster occurred on February 1, 2003, when the Space Shuttle Columbia disintegrated over Texas during re-entry into the Earth's atmosphere, shortly before concluding its 28th mission, STS-107.

The loss of the Columbia was caused by damage sustained during launch when a piece of foam insulation the size of a small briefcase broke off the main propellant tank under the aerodynamic forces of launch. The debris struck the leading edge of the left wing on the number 8 reinforced carbon-carbon (RCC) tile, damaging the Shuttle's thermal protection system (TPS). While Columbia was still in orbit, some engineers suspected damage, but NASA managers limited the investigation on the grounds that little could be done even if problems were found.

Space Shuttle Challenger (NASA Orbiter Vehicle Designation: OV-099) was NASA's second Space Shuttle orbiter to be put into service. Its maiden flight was on April 4, 1983, and it completed nine missions before disintegrating 73 seconds after the launch of its tenth mission, on January 28, 1986, killing all seven crew members. Challenger was replaced by the space shuttle Endeavour which made its first flight in 1992, six years after the disaster.

The Space Shuttle Challenger disaster occurred in the United States, above the state of Florida, at 11:39 a.m. EST (16:39 GMT) on January 28, 1986, when the Space Shuttle Challenger disintegrated 73 seconds into its flight after an O-ring seal in its right solid rocket booster (SRB) failed. The seal failure caused a flame leak from the solid rocket booster, which impinged upon the adjacent external fuel tank. Within seconds, the flame caused structural failure of the external tank, and aerodynamic forces promptly broke up the orbiter. The shuttle was destroyed and all seven crew members were killed. The crew compartment and many other vehicle fragments were eventually recovered from the ocean floor after a lengthy search and recovery operation.

Space Shuttle Discovery (NASA Orbiter Vehicle Designation: OV-103) is one of three remaining spacecraft in the Space Shuttle fleet belonging to the U.S. National Aeronautics and Space Administration (NASA), along with Atlantis and Endeavour. First flown in 1984, Discovery is the third operational Space Shuttle and the oldest shuttle in service. Discovery has performed both research and International Space Station (ISS) assembly missions.

Space Shuttle Orbiter Atlantis (NASA Orbiter Vehicle Designation: OV-104) is one of the fleet of space shuttles belonging to the U.S. National Aeronautics and Space Administration (NASA). It was the fourth operational shuttle built. Following the destruction of Challenger and Columbia, it is one of the three fully operational shuttles remaining in the fleet. The other two are Discovery and Endeavour. After it completes STS-125, the final Hubble Space Telescope service mission, Atlantis is scheduled to be the first shuttle retired from the fleet.

NASA officials have decided the Atlantis crew will need to fix a loose thermal blanket on the outside of the space shuttle, extending their 11-day mission.

The work is expected to delay the crew's return flight by two days. But managers have not said whether the repair work will require an extra spacewalk. more


None other than an experienced former Nasa space shuttle astronaut, Mike Mullane, has seriously questioned the safety levels of the shuttle. In his fascinating book, Riding Rockets which was published last year, Mullane has stated that the "space shuttle is significantly more dangerous to fly than anything that had preceded it." Mullane himself has flown three space shuttle missions, and has logged a total of 356 hours.
The reason: the space shuttle did not have an in-flight escape system. Says Mullane: "The shuttle design did accommodate two ejection seats for the commander and pilot positions, but this was a temporary feature intended to to protect only the two-man crews that would fly the first four shake down missions." Subsequently, he said, the ejection seats were removed, and 10 crew members were booked for each flight. "We would have no hope of surviving a catastrophic rocket failure," he said.
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