One-Question Interview: The Shuttle After Columbia

Earl Dowell is J.A. Jones Professor of Mechanical Engineering and dean emeritus of the Pratt School of Engineering.

Q: NASA has now lost two space shuttles. Challenger was replaced. Should NASA replace Columbia too, and if so, with what? Or should NASA steer more in another direction, like more unmanned space flights? Despite the growing budget deficit, President Bush seems committed to humans in space.

A: The history of NASA broadly is the following: President Kennedy decided to go to the moon. That Apollo program was funded very generously by comparison to how NASA is funded today or has been for the last 20 years. The Apollo program was funded with as close as you ever get to a blank check.

The space shuttle program has always been funded on a shoestring. Its proponents had to say they were going to do all sorts of wonderful things that most people, probably including themselves, thought they really couldn't do with available funding. But their choice was, if they didn't say they were going to do those wonderful things they were not going to get funded at all. So they over-promised. But that's not unusual in Washington.

What happened after the Apollo's success was the budget of NASA was depleted very substantially. What happened after the Challenger disaster is the budget was brought back up from a very low point, but still less than it was in the Apollo days.

Clearly NASA would like to build a new space shuttle. The agency's officials have wanted to do that for at least 10 years. But they've never had money in their budget. Neither the present president nor his predecessors have been willing to put that in their budgets. Whether this president or his successors will now provide that money is I think a very interesting question.

There are two kinds of possible "new" shuttles. One would be a replica of the three remaining current shuttles. The main rationale for today's shuttle fleet is to service and provide transportation to and from the International Space Station. A replacement craft would cost more than those built before it because there are no spare original parts left. But it would be cheaper than a daring and brand new design that would incorporate all the new technology that has become available in the last 20 or 25 years. We could build a much better vehicle now of a newer design than the current shuttles. But it would be a lot of money. And we would be building an untried craft.

NASA already spends about $3 billion yearly on space science, the category that would include unmanned space flight. That's as much as the entire budget of the National Science Foundation, making it the best funded area of science in the United States except for health-related research. The annual budget for the shuttle and International Space Station programs is $6-8 billion, depending on how it is accounted. That's an amount about equal to all National Institutes of Health research funding to universities.

It is too early to know, three days after the disaster, what brought down the Columbia. The current speculation that a piece of hardened foam from the booster hit and damaged one or more thermal protection system tiles on the orbiter's wing certainly needs to be carefully examined. But similar incidents have happened before without significant harm. Was this a particularly unlucky case where an especially vulnerable location of the orbiter was struck? Or was it a case of the tiles having become more vulnerable with each flight due to the structure's aging? Were some of the original tiles still there from Columbia's maiden flight? Or had most or all of them been replaced over the years during normal between-flight refurbishments? From the shuttle program's beginnings, the thermal protection system has been perceived as the program's largest engineering challenge, and the one with the greatest risk. The thermal protection system may not have been involved at all. But that would surprise me, given the detected temperature increases at the point in its path when Columbia was lost.

Editor's Note: Dowell was on the original panel that reviewed the technology of the Space Shuttle's thermal protection system before the first shuttle -- the Columbia -- was ever built. Later, he was on the national academy panel that recommended that Congress fund the International Space Station. He was questioned three days after the Columbia was destroyed Feb. 1 while reentering Earth's atmosphere from orbit.