URBANA - Twenty years is a long time in modern science. For more years than that, NASA has been using a space shuttle that could benefit from a redesign with better technology, a University of Illinois professor says.
UI aeronautical and astronautical engineering Professor Rod Burton has been working in the lab on air-breathing rocket engines for the past two years and believes NASA should consider replacing its combination solid fuel/liquid oxygen with the design.
?Once they picked this particular setup,? Burton said Monday, ?there's not a whole lot you can do with that design. They put in better pumps and control systems. With these tiles in the design, there's not much you can change.
?It takes a clean sheet of paper.?
Burton said completely redesigning the rocket to use an air-breathing engine would make it smaller, lighter, cheaper and safer - at an enormous cost to build, but with enormous savings each time it went into space.
NASA first looked at the idea in the late '50s and began looking at it again in 1996. According to a NASA Web site, an air-breathing rocket engine inhales oxygen from the air for about half the flight, so it doesn't have to store the oxygen gas on board.
At take-off, an air-breathing rocket vehicle weighs much less than a conventional rocket vehicle, which carries all of its fuel and oxygen onboard. Getting off the ground is the most expensive part of any mission to low-Earth orbit, so reducing a vehicle's weight decreases cost significantly. Oxygen in the atmosphere helps fuel the rocket until it reaches space, where it switches to conventional rocket fuel.
It costs about $500 million every time the shuttle is launched. With fuel savings and other economies inherent in using the atmosphere's oxygen as fuel, Burton said, each flight could cost more like $5 million.
More importantly, less explosive fuel equals more safety.
?Everything gets better if you make it lighter,? Burton said. ?It could take off horizontally, and land much more easily and safely. The goal would be airplane-like.?
But such a system is an extremely low priority at NASA, he added, because the existing shuttle has generally worked well on more than 100 missions, and there's little money in the federal budget to replace it entirely.
?There's some interest if there's money,? Burton said. ?We are writing proposals for NASA.?
The current shuttle design is a low-lift glider, the professor said, which has to slow down very quickly from speeds many times the speed of sound.
?Calling it a brick is not fair,? he said, referring to those who say it is difficult to land.
NASA had a ?second generation? shuttle plan until last November, but it lost funding. Burton said an air-breathing engine would constitute a third generation.
?The university is interested in funding some of the research on an air-breathing engine,? he said. ?It has never been a first priority, but things change.?