terça-feira, 28 de outubro de 2008

Europe's station resupply ship concludes mission


Posted: September 29, 2008

An historic chapter in Europe's space program came to a close Monday when Jules Verne, a human-rated supply ship for the international space station, completed its mission with a fiery suicidal plunge into Earth's atmosphere.

Credit: ESA
Two engine firings Monday morning slowed the spacecraft's velocity by about 224 mph and lowered its orbit into the upper atmosphere. The 30,000-pound ship first encountered the outer fringes of the atmosphere at 1331 GMT (9:31 a.m. EDT) over an uninhabited part of the South Pacific.

"The trajectory was pin-point and this, together with a break-up behavior close to our models, means that the re-entry posed no safety hazard," said Bob Chesson, head of the European Space Agency's human spaceflight and exploration operations.

Chesson said telemetry from the doomed spacecraft showed the ship's four X-shaped solar arrays shearing away at an altitude of about 100 kilometers, or 62 miles.

Engineers at the ATV control center in Toulouse, France, continued to receive data from the craft's transmitters at an altitude of 80 kilometers, or about 50 miles, Chesson said.

Telemetry indicated the vehicle begin breaking apart a few moments later at an altitude of 75 kilometers, or 47 miles, according to Chesson.

Burning up along with Jules Verne Monday was more than 1,800 pounds of discarded dry cargo and 582 pounds of liquid waste from the station. The crew filled the ship's pressurized cargo carrier and water tanks with garbage during its five-month stay at the outpost.

Jules Verne delivered more than 10,000 pounds of supplies to the complex in early April. The Automated Transfer Vehicle employed a futuristic rendezvous and docking system using lasers to automatically approach the station.

"Credit has to go to everyone involved in such a flawless mission," said John Ellwood, ATV project manager.

The spacecraft, the first of its kind developed by Europe, launched March 9 aboard an Ariane 5 rocket from the Guiana Space Center in South America.

The first ATV was named Jules Verne after the visionary 19th science fiction writer.

Four more ATV missions are on the books through 2015 for more cargo delivery missions to the station. The next ATV launch is scheduled for the middle of 2010, according to ESA.

"This is truly a wonderful spacecraft, and vital to the continued service of the ISS following shuttle retirement in 2010," Ellwood said.

Since undocking from the space station Sept. 5, the first Automated Transfer Vehicle spent more than three weeks undergoing further tests and moving its orbit below the complex.

The orbit maneuvers set up nighttime re-entry opportunities over the South Pacific and allowed the station's three-man crew to observe the demise of Jules Verne.

Two NASA airplanes, a Gulfstream V research jet and a DC-8 airborne laboratory, flew from California to Tahiti Friday night with a group of more than 30 scientists and instruments to view the ATV's re-entry.

The planes included optical, infrared and ultraviolent imagers and spectrometers, according to ESA officials.

The scientists returned images and video to NASA and ESA when they returned to their staging base in Tahiti a few hours after Jules Verne's re-entry.

The observation campaign was headed by NASA's Ames Research Center, ESA and the SETI Institute. It was similar to research missions that studied the re-entry of NASA's Stardust and Genesis probes.

Officials hoped to gain insight into how spacecraft break apart during the heating of re-entry. Scientists were also interested in comparing data from the ATV entry to information about the fragmentation of meteorites burning up in Earth's atmosphere. 


Lucimary Vargas
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil



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