Saturday’s breakup of the space shuttle Columbia was not an anomaly, according to Dr. Jonathan McDowell, astrophysicist and Harvard professor, who discussed the explosion last night at an event sponsored by the Harvard-Smithsonian Center for Astrophysics.
‘What I want to do is to try and put what happened into context,’ McDowell said. ‘Space flight is a very dangerous business at 18 times above the speed of sound, you don’t have a lot of leeway.’
McDowell listed many past ‘accidents and near misses’ to show similar problems are not uncommon in the space program. He chose to exclude accidents happening on the ground because ‘most happen on the ground,’ he said.
Among the near misses, McDowell said, was an onboard fire on the Mir Space Station in 1997, a reentry fire on Columbia in 1983 and a minor collision between Progress, a cargo ship, and the Mir Space Station in 1997.
‘Reentry, historically, has been a pretty dangerous time, ‘ McDowell said.
According to McDowell, the possibility that damaged ceramic tiles, protecting the shuttle from heat damage during reentry, could have caused it to break apart depends on the amount of damage the tiles suffered and on the location of the tiles. Losing a tile on the underside of a wing, he said, is more dangerous than losing tiles from the nose, which had occurred in earlier missions. Since the wings are most severely affected by heat, missing tiles make the wings more susceptible to damage, he added.
The chance of an astronaut dying in a space mission, McDowell said, is not much greater than the probability of dying in an automobile accident.
In contrast with the other space shuttles, Columbia had more day to night transitions, which meant more thermal changes affecting the shuttle, McDowell said.
However, despite the theories, McDowell said he did not know what actually caused the accident, and NASA probably would not know for several weeks.
Columbia first flew in 1981, and spent a total of 300 days in space, the most days of any space shuttle, McDowell said. Columbia was ‘used for really long duration missions,’ he said, noting that the shuttle ‘could stay in orbit for 16 days.’
The International Space Station, McDowell said, will have to be serviced only by Russian vehicles until NASA is prepared to launch another shuttle. If Russians can no longer transport supplies to the space station, the astronauts from the station will be forced to return home. If this happens, ‘there are not a lot of places for the shuttles to go if [they are] fixed,’ he said.
NASA built the space shuttle Endeavor to replace the Challenger in 1992, but McDowell said that replacing Columbia is ‘not going to happen.’ After the Challenger explosion, McDowell said, another shuttle was not launched for another two and a half years.
‘NASA is in much better shape than it was [after the Challenger explosion],’ McDowell said.
He said another shuttle will probably fly in a year, but noted a chance the shuttles will never fly again. Once the cause is determined, McDowell said, the extent of the problem and any redesigning of the shuttles would affect the planning of future missions.
David Aguilar, director of public affairs at the Harvard-Smithsonian Center for Astrophysics, chose the theme for the evening, ‘When Things Go Bad,’ two months ago, he said. After the Columbia breakup Saturday, ‘I really felt bad about that [choice],’ he said.
After the discussion, Aguilar said he chose to show the movie ‘Blue Planet,’ which shows Earth from the astronaut’s perspective, ‘as a memorial.’
‘Astronauts are a very different breed of people,’ he said.