Thursday, February 03, 2005
But with the crash on February 1, 2003, of the space shuttle Columbia, a manned mission to repair Hubble is not worth the risk, said Rep. Dana Rohrabacher, R-California.
"Some people just want to dive back in and use the shuttle as if these catastrophic accidents didn't happen. ... To the degree that we don't have to use the shuttle, we shouldn't use the shuttle," he said.
What is worth the risk of using the shuttle, if not the Hubble? Using the shuttle to service the ISS is almost pointless considering that the Soyuz is a safer delivery vehicle than the shuttle is. If we lose another shuttle, it will be on lift-off or re-entry, the two riskiest phases of any mission. It doesn't matter what you do between those two phases of any shuttle mission. Columbia functioned fine up until re-entry. Here's a letter I sent the Honorable Representative although I feel like quoting Mark Twain:
"Dear Reader. Suppose you are an idiot and then suppose you are a member of Congress, but I repeat myself."
The Space Shuttle was always an experimental space delivery vehicle. There is always some risk associated with strapping rocket boosters onto a vehicle that is as complicated as the shuttle. Engineers know that things fail. The more complicated the machinery, the more likely something is to fail. That said, I think if you asked most people for the opportunity to fly on the shuttle even if the risk were significantly higher, most would eagerly agree despite the risk. Most astronauts are volunteers. They know the dangers when they sign up. The shuttle isn't a commercial airliner. It's a compromise design that NASA made when NIxon cut NASA's budget back in the 1970s. The shuttle has the flight safety record of carrier jets, something approaching 98% success rate. What do we lose if we don't fly a mission to Hubble. We lose a valuable scientific instrument that has changed our view of the cosmos. We've expended billions of dollars to kept the Hubble going, but that was the original mission of the shuttle to repair satellites and orbiting observatories. Also, $2 billion dollars to maintain the telescope is money well spent. It's already in orbit. How much would it cost NASA to build a new Hubble (and get it right this time by testing the optics on the ground), significantly more than $2 billion, I assure you. If you don't want risky shutttle missions though, then may I suggest we contract out our IIS missions to the Russians. The Soyuz is a tried and true space delivery vehicle and it's got a proven safety record even better than the shuttle. NASA can't have it both ways. Any mission to the IIS is just as risky as to the Hubble. If we lose another shuttle it will be on either lift off or re-entry. Those are the two riskiest periods of any shuttle flight. However, if safety is the main criteria that Congress will go by, then by all means offshore the space delivery missions to the Russians. The US government will save money and lives and the Russians need the funding.
John Moore, Ph.D.