Wednesday, August 24, 2011

Using Columbia to begin bringing the moon to America (1996)

Assembly of NASA's first spaceworthy Space Shuttle orbiter, OV-102 Columbia (middle image above), commenced in November 1975. The 111-ton reusable winged spaceship first reached low-Earth orbit on STS-1 (April 12-14, 1981), the Space Shuttle Program's first mission. Named for the first American sailing ship to circle the globe and the Apollo 11 Command and Service Module, Columbia completed 27 successful flights.

NASA's oldest Orbiter was also its heaviest. Unlike its sisters Atlantis, Discovery, and Endeavor, Columbia could not reach the 51.6° orbital inclination of the Russian Mir station and the International Space Station (ISS) with a useful payload in its 15-by-60-foot payload bay. This performance constraint meant that, in the Shuttle-Mir/ISS era, NASA increasingly relegated to Columbia its few remaining low-inclination, non-space station missions, such as Hubble Space Telescope servicing. Extended-Duration Orbiter modifications also permitted Columbia to remain in orbit for more than two weeks to serve as a science research platform, but such missions would become increasingly rare after research commenced on board ISS.

In an April 1996 paper presented at the 33rd Space Congress in Cocoa Beach, Florida, Carey McCleskey of the Vehicle Engineering Directorate at NASA's Kennedy Space Center proposed using the oldest Orbiter's excess mission capacity "to ignite a billion dollar, sustained enterprise on the Moon." Specifically, he advocated using Columbia as a joint NASA/private sector Earth-orbital launch platform for rocket stages bearing small lunar landers. Columbia would remain in space for only a few hours during each of its lunar lander deployment missions.

The landers would deliver to the moon teleoperated "micro-robots" akin to Mars Pathfinder's Sojourner rover (bottom image above). These would serve as proxy lunar explorers for paying visitors at "space theme parks" on Earth.

Confident that his proposal would help to build public support for U.S. astronauts to return to the moon, McCleskey wrote that
use of Columbia only makes sense for the start-up and initial take-off phases of the enterprise. The Shuttle system. . .will reach a limit which will drive the nation toward advanced space delivery systems. The use of the Shuttle for starting a lunar enterprise, therefore, is not the answer for space delivery, but rather our next opportunity.
Columbia lifted off at the start of STS-107, its 28th mission, on January 16, 2003. Eighty-two seconds after launch, a piece of foam insulation about 20 inches long broke free from its External Tank and struck its left wing. Engineers examining high-resolution video images of the impact warned of possible wing damage, but Shuttle management elected to disregard their warnings.

The oldest Orbiter's seven-person crew conducted wide-ranging science research for 16 days - long enough for the moon to wax from nearly full to full, then wane to last quarter and new. The crew beamed to Earth a breathtaking image of the last quarter moon taken on January 26 (top image above).

On February 1, 2003, the day of the new moon, Columbia fired its twin Orbital Maneuvering System engines to slow itself and reenter Earth's atmosphere. Temperatures on the Orbiter's belly tiles, nose cap, and wing leading edge panels began to climb as Columbia reentered at an altitude of 400,000 feet. About 40 minutes after the deorbit burn the wing leading edge temperature neared its peak value of about 3000° Fahrenheit.

As Columbia crossed the California coast in predawn darkness en route to its planned landing in Florida, hot plasma began to penetrate its internal structure through a breach in its left wing leading edge. Flight controllers in Mission Control in Houston puzzled over the cause of sensor failures in the Orbiter's left wing. The failures progressed aftward from the leading edge.

For observers on the ground in California, Nevada, Utah, Arizona, Colorado, New Mexico, and Texas, many of whom had observed pre-dawn Shuttle reentries before, Columbia was a fast-moving, brilliant point of light leaving behind a luminous, sky-spanning ionization trail. Veteran observers along Columbia's reentry path noted more than 20 unusual flashes around the Orbiter and peculiar bright streaks in the trail.

As Columbia crossed from New Mexico into Texas, it began to shed pieces. Meanwhile, thrusters fired automatically to compensate for increased drag on the left wing. Columbia did not give up without a fight.

Radio contact with Columbia was lost about 10 minutes after hot plasma first entered the left wing. Less than a minute later, the gutted wing folded over the fuselage. The oldest Orbiter disintegrated at an altitude of 203,000 feet just west of Dallas, Texas, killing its crew and raining wreckage over parts of eastern Texas and western Louisiana.

The STS-107 accident triggered far-reaching changes in the U.S. space program that have yet to play out fully. The most obvious of these was President George W. Bush's January 2004 call to end the Space Shuttle Program when ISS was completed, which at the time was scheduled for 2010. The 135th and last flight of the Shuttle, designated STS-135, concluded on July 21, 2011, with the landing of Atlantis in Florida. On August 16, 2011, Space Shuttle Program Manager John Shannon announced that the Shuttle Program would end officially on August 31, 2011.
"Using the Space Shuttle Columbia to Begin Bringing the Moon to America," Carey M. McCleskey; paper presented at the 33rd Space Congress in Cocoa Beach, Florida, April 23-26, 1996.

No comments:

Post a Comment