March 7, 2006 6:42 PM PST
NASA tests next-generation space capsules
MOUNTAIN VIEW, Calif.--To paraphrase astronaut Neil Armstrong, a test of three scale models of NASA's next-generation crew capsules Tuesday was a small step for the space agency and a big step for mankind.
That's because the tests--in which scientists from NASA's Ames Research Center here put two models of the so-called crew exploration vehicle, or CEV, through a series of wind tunnel experiments--are among the very earliest actions in the development of the capsules for future manned missions to space.
A group of observers got to see behind the scenes of some very groundbreaking work Tuesday, with the loud rushing of wind through the tunnels making it somewhat hard to hear and a very cool 1,200-pound model of the space shuttle being set up for its own tests in the wind tunnel in the background.
"The tests are the first look we have at the aerodynamics of the next generation of the crew exploration vehicle," said Thomas Edwards, director of aeronautics at NASA Ames. The space shuttle marks the final stages of the first era of space exploration, and the CEV models are kicking off the next stage, according to Edwards.
Visitors to the site were shown two wind tunnels: one supersonic tunnel that measures 9 feet by 7 feet and can create winds from Mach 1.55 to 2.6 (Mach 1 is equal to the speed of sound); and a trans-sonic tunnel that produces winds from Mach .2 to 1.5.
The first two CEV models could easily have been mistaken for gussied-up shower heads. But in fact, one is a 2.77 percent-size scale model of the current design of the CEV that is covered with pink, oxygen-sensitive paint. It is designed to measure how pressure from winds up to Mach 2.6 would affect the capsule. The other is a shiny, metal model of the same size that measures forces like lift and drag in the wind tunnel.
The final model is a 7 percent-size scale that is covered with the special paint and is bathed in ultraviolet light and held at the end of a long arm in the wind tunnel. Edwards explained that each of the models is used for testing different elements that will confront any capsule in space.
"The airflow properties (of each model) are different, even if they're geometrically the same," said Edwards.
Not just a fashion statement
Of course, the final capsule that shoots into space--bound for Mars or the moon--won't be pink. But to the scientists here at NASA Ames, the pink paint is crucial for understanding how the models perform under intense wind conditions and therefore how the real-life capsules will fare while hurtling through space.
The paint is sensitive to oxygen. As the painted models are put through their paces in the wind tunnels, the amount of oxygen varies with the force of the wind. UV light allows the scientists to measure the reflectivity of the paint, making it possible to measure the oxygen and therefore discover how much pressure the model is under.
On one of the painted models, there were several small areas where chips had come off during wind tunnel testing. But to Donald Nickison, chief of the wind tunnel division at NASA Ames, the chips were par for the course.
"When you're running in Mach 2.5 winds, you're likely to lose a few paint chips," Nickison said. "I imagine my house would suffer something like that in a hurricane."
Nickison also explained the way the paint performs under the UV light.
He said that the 7 percent-scale model had about 130 pressure points built onto it. Under the UV light, he said, the paint appears to change colors as the force of the wind varies.
"If only you could paint your house with this paint," Nickison said, "you'd have a house that would be different colors depending on the wind."
For now, the CEV models are in the earliest stages of testing. NASA is hoping to send an unmanned mission to the moon by 2011, Edwards said. At the same time, he explained, the new CEV is designed to supplant the space shuttle as the vehicle that takes astronauts into space, and will hopefully allow a manned trip to the moon by the end of the next decade.
"We're in the first hour of a very long development cycle," said Edwards.
Meanwhile, alongside one of the wind tunnels here, George Sarver, project manager for CEV activities at Ames, was explaining to several observers why the wind tunnels are important.
He said there is a constant series of tests that must be run, and that the CEV capsules will have to go through many sets of revisions and subsequent tests before they're ready for space.
"Every time you change something," Sarver said, "you're right back into the wind tunnel to understand what the change is."
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