Last Flight of the Columbia - questions and answers
What happened in the earlier Challenger disaster?
On 28th January 1986 the Challenger space shuttle exploded 73 seconds after lift-off, killing all seven astronauts on board - Francis Scobee, Michael Smith, Ronald McNair, Ellison Onizuka, Judith Resnik, Gregory Jarvis and Christa McAuliffe, the first teacher in space. The whole shuttle programme was grounded as a result of the disaster until 1988 as NASA made major changes to the shuttle and programme management.
After extensive investigations it was reported that the Challenger accident was caused by a faulty joint on the solid booster rockets of the shuttle. It was agreed that the cold weather on the day that Challenger was launched was a major contributing factor to the disaster as the cold caused the ‘o’ rings (rubber seals) in the booster rockets to fail. As a result hot gases in the booster rockets leaked out and melted the joint that held the booster to the shuttle which ultimately caused the shuttle to explode.
What sorts of experiments did the astronauts do on board Columbia?
Once they were 240 km’s above the Earth, the shuttle crew divided in to 2 teams, to conduct over 140 different scientific experiments. For this they needed nearly 4 tonnes of scientific equipment. The crew worked on a wide range of studies, from cancer cells to novel fragrances, from many scientific disciplines.
In one of the experiments, the astronauts were monitored to measure the effects of spaceflight on the human respiratory system. In another experiment the astronauts tested a new system designed to extinguish fires with a fine water vapour. And in another, the crew tested the effect of microgravity on the webs spun by Australian spiders. All of the experiments are considered important in their contributions to scientific research.
What is space junk?
There are thousands of pieces of debris from space missions and old satellites which are all part of an enormous orbiting rubbish dump, whizzing around the Earth at tremendous speeds. It presents a very real and serious hazard to spacecraft.
A 1999 study estimated that there are some 1.8 million kilogrammes of space junk in low-Earth orbit (just one area of space). This works out at roughly 110,000 objects larger than 1 centimetre in size, each big enough to damage a satellite or space-based telescope.
Space debris can threaten the lives of astronauts out on a space walk, a space shuttle during a mission, or even the International Space Station. For example a tiny speck of paint, perhaps from a satellite, once collided with a space shuttle window and left damage that was nearly a quarter of an inch wide.
Space debris is largely monitored by the U.S. Space Command, who then report directly to NASA and other agencies whenever there's threat of an orbital impact.
Could the shuttle have landed straight after lift off, after the foam from the fuel tank broke off and damaged the wing?
Shuttles have a long history of impact damage during lift off due to the forces and speeds that the process involves. Because these impacts have happened on nearly every mission and not caused any serious damage to the shuttle concerned, this particular impact was considered by NASA to be of very little risk to the intrinsic safety of the shuttle and its crew.
Once lift off has begun the space shuttle would almost certainly have to reach orbit before it could prepare for re-entry to the Earth’s atmosphere and subsequently land safely back on Earth. So if the foam strike was considered to have caused serious damage to the shuttle straight away, the shuttle would not have been able to abort the mission immediately.
Could the crew have bailed at the first sign of trouble during re-entry, or was it too late?
Although no formal requirements or plans exist for crewmembers to bail out of the shuttle during uncontrolled flight, they may be able to do so under certain circumstances. The crew in this case certainly had the right equipment to do so and were suited up correctly for the re-entry phase.
In order for the crew members to bail out of the doomed shuttle and stand the best possible chance of survival the shuttle itself would have needed to be below 40,000 feet - a point at which it would have re-entered the Earth’s atmosphere. Columbia never managed to get this low before she broke up over Texas. As the crew did not know the extent of what had happened during lift off 16 days earlier, they did not have the chance to adjust the shuttle’s position to consider bailing out.
