Shuttle pilot: flight risks still a mystery

The pilot who will take the controls of the Shuttle Discovery for its Friday launch says the craft hasn't been flown enough times for anyone to figure out what the real safety risks are.

Mark Kelly, as ex-combat and test pilot, said if Shuttle was an airplane in testing, the 114 flights it has racked up would be regarded as a tiny number. But more importantly, the small number of failed missions means it is hard to know what could go wrong.

"To really quantify a risk in a vehicle, you actually don't need a lot of flights," Kelly told the Florida Today. "You need a lot of failures. Hopefully we won't have any more failures, but we've only had two, so it's hard to get your hands around what the real risk of flying the space shuttle is."

The most recent of those failures is, of course, the loss of the Shuttle Columbia early in 2003. During the launch some insulation foam fell off the craft, damaging the heat shielding and ultimately causing the shuttle to break up on re-entry, with the loss of all seven astronauts on board.

Foam again fell from the Shuttle when it returned to flight two and a half years after the accident.

Now, just days before it is scheduled to launch Discovery, NASA is still struggling to solve the foam issue, despite spending $1.2bn on modifications to the Shuttle over the last two years.

"Foam will come off. There's no way around that. It is an expected event," NASA external tank project manager John Chapman told The Boston Globe. "Our objective is to make sure if it does come off, it comes off in small enough pieces that it doesn't cause any harm."

The space agency has removed around 15 kilos of foam from the Shuttle since the flight last year, in a redesign described as the greatest aerodynamic change ever made to the launch system.

The mission, which is regarded as a test flight, will deliver European astronaut Thomas Reiter to the International Space Station, along with more than 2,300 kilos of cargo, including a new oxygen generator.

Two of the seven astronauts will also go on spacewalks to test external repair techniques. ®