Posted on 02/07/2003 8:26:29 AM PST by RCW2001
MATTHEW FORDAHL, Associated Press Writer
Friday, February 7, 2003
©2003 Associated Press
URL: http://www.sfgate.com/cgi-bin/article.cgi?f=/news/archive/2003/02/07/state1114EST0040.DTL
(02-07) 08:14 PST SAN FRANCISCO (AP) --
Federal scientists are investigating whether electricity or some other little-understood phenomena in the upper atmosphere might have doomed the space shuttle Columbia.
Investigators also are reviewing data recorded by a network of instruments that might have detected a faint thunderclap at the same time a purplish bolt of lightning may have struck the shuttle high above Earth, the San Francisco Chronicle reported.
Researchers at NASA's Kennedy Space Center raised concerns in a report last year that electromagnetic phenomena or ice crystals from the highest clouds could pose a danger to shuttles on re-entry. Though conditions Saturday were not right for the most dangerous occurrences, some experts caution that much remains unknown about the part of the atmosphere the shuttle was in when it crossed California.
The shuttle was 39 miles above the earth as it disintegrated early Saturday in the searing heat of re-entry, for reasons still unknown. All seven astronauts were killed.
NASA administrators said Thursday that Columbia crash investigators were looking at the photograph of the purplish bolt, captured as a digital image by an amateur astronomer in San Francisco. But Shuttle Program Manager Ron Dittemore told reporters in Houston that NASA isn't sure how important the image may be -- or whether it's authentic.
Meanwhile, scientists at a federal lab in Colorado that listens for ghostly electromagnetic phenomena in the upper atmosphere told the Chronicle they were evaluating whether their sensors picked up any strange sounds around the time the shuttle began experiencing problems.
"We're working hard on the data set. We have an obligation," said Alfred Bedard, a scientist at the federal Environmental Technology Laboratory in Boulder, Colo.
The lab has a global network of electronic ears that can pick up the hiss of space craft re-entering the atmosphere thousands of miles away.
Bedard told the Chronicle that the lab was providing data to NASA but it was too early to draw any conclusions from sounds of the shuttle's re-entry.
Columbia broke up in an area so little understood and difficult to study that scientists once dubbed it the "ignorosphere." The shuttle was speeding at 12,000 mph through the mesosphere, or middle atmosphere, which extends from about 30 miles to 50 miles above the surface. It's also called the ionosphere, because of the presence of free electrons -- or ions.
"We're discovering the middle atmosphere has got a lot of electrical phenomena," Walt Lyons, president of the research firm FMA Research in Fort Collins, Colo., said Thursday. "The key message here is that there may be more things going on up there that we just don't understand or have no inkling of yet."
The region is too high for balloons and aircraft, yet too low and the air is too heavy for satellites, which would be unable to stay in orbit because of the drag, said Umran Inan, a physicist at Stanford University.
"You can't make local measurements with any regularity," he said. "You can have a single rocket shot through the region, but the phenomena are dynamic and change from place to place and time to time."
In the ionosphere, ultraviolet energy from the sun as well as cosmic rays from faraway stars separate electrons from atomic nuclei. The free electrons give the area a characteristic not unlike metal, in that it can reflect electromagnetic energy.
In 1901, radio pioneer Guglielmo Marconi took advantage of that when he bounced a signal from North America to Europe, and today's shortwave radio is based on the same principle.
But the presence of free electrons also creates strange electrical effects, with fanciful names like "elves," "sprites" and "blue jets." Until recently, they were largely dismissed as illusions, noticed only by bleary-eyed airline pilots.
All those phenomena are related to thunderstorms, which were not recorded in the area at the time of Columbia's descent.
The first image of a sprite was captured by University of Minnesota researchers in 1989 while they were testing a camera for a shot of a rocket. They have since been seen several times by shuttle crews, including those aboard Columbia during its final mission.
Sprites, which are the result of free electrons colliding with atmospheric molecules when lightning discharges to the ground, last anywhere from 10 milliseconds to 100 milliseconds, slightly shorter than the blink of a human eye. They often appear red and delicately filled with electrical streamers, or tendrils, when captured by cameras.
"Elves" also are the result of free electrons colliding with atmospheric molecules but are believed to be the result of an electromagnetic pulse created by the lightning. They appear as reddish rings of light that shoot skyward in less than a thousandth of a second.
"Blue jets" are less often seen, possibly because of their color. They shoot out like trumpets extending as far as 30 miles from the tops of clouds.
Citing internal NASA studies, the 2002 report by Kennedy researchers for the American Institute of Aeronautics and Astronautics said the risk of a shuttle encountering sprites, elves or blue jets when flying over a thunderstorm is 1 in 100 or less.
"Expert panels so far have concluded that sprites, blue jets and elves do not pose a hazard to the space shuttle, which is designed to withstand a harsh electrical environment," the report said.
However, the report also said there was some risk from "noctilucent" clouds, which are the highest clouds in the atmosphere. During hypersonic flight, ice crystals in the clouds could pose a corrosion or abrasion hazard to shuttles and "certainly" increase drag.
"The most severe effect of entry through a noctilucent cloud would probably be the erosion of the thermal protection system during the most critical heating region," the report said. "Depending on the particle size, sufficient damage could be done to result in loss of vehicle."
It's not likely the shuttle passed through such a cloud, since they tend to occur from May to August.
Still, scientists are just starting to understand phenomena in the upper atmosphere.
"The research we've been able to do has made us realize it's even weirder than we thought," Lyons said. "There may be other things that happen up there that we just don't know about. Maybe we just encountered a new phenomenon the hard way."
FMA Research: www.fma-research.com/
©2003 Associated Press
Foam would have a LOT less momentum than the rocket itself. once it loses contact with the rocket, the air resistance is going to stop it quite quickly. However the rocket, still going, crashes into it, and it does enough damage to a small bit of tile to start the chain reaction upon reentry. A tornado can drive a plastic straw through a piece of plywood, so don't say the foam couldn't cause some damage when it would impact at much greater than the speed at which tornadoes whip things around.
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