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This date in history
Space shuttle Columbia launches on the STS-52 mission on October 22, 1992 carrying the LAGEOS laser ball and package of microgravity research experiments. (2min 59sec file)
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Full launch experience
This longer-length broadband movie covers the launch of Columbia from T-minus 3 minutes through jettison of the external fuel tank after reaching space. (12min 43sec file)
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Re-entry trail
A space station camera captured this incredible view of the Soyuz's fiery trail during re-entry in the predawn morning sky. (1min 46sec file)
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Hatch opening
Russian recovery forces at the landing site work to open the Soyuz capsule hatch and roll the craft on its side in preparation for the crew's exit. (2min 23sec file)
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Commander exit
Expedition 9 commander Gennady Padalka is pulled from the Soyuz capsule following landing in Kazakhstan. (1min 38sec file)
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Fincke returns
Expedition 9 flight engineer Michael Fincke rests in a reclining chair and speaks to the media about the importance of spaceflight just after exiting the Soyuz. (2min 46sec file)
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Public Service Announcements
The space station's new commander, Leroy Chiao, urges Americans to vote in these Public Service Announcements recorded inside the Destiny Laboratory module. (2min 30sec file)
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Crew news conference
The five crew members aboard the International Space Station answer questions during this in-flight news conference from Wednesday, Oct. 20. (29min 26sec file)
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San Fran. interview
Expedition 10 commander Leroy Chiao and Expedition 9 flight engineer Michael Fincke answer questions from a reporter with KPIX television in San Francisco. (8min 52sec file)
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CBS Radio interview
CBS Radio's Peter King and Bill Harwood chat with space station astronauts Leroy Chiao and Michael Fincke during the handover activities between Expedition crews. (11min 06sec file)
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As the world turns, it drags space and time
NASA NEWS RELEASE
Posted: October 24, 2004

An international team of NASA and university researchers has found the first direct evidence the Earth is dragging space and time around itself as it rotates.

The researchers believe they have measured the effect, first predicted in 1918 by using Einstein's theory of general relativity, by precisely observing shifts in the orbits of two Earth-orbiting laser-ranging satellites. The researchers observed the orbits of the Laser Geodynamics Satellite I (LAGEOS I), a NASA spacecraft, and LAGEOS II, a joint NASA/Italian Space Agency (ASI) spacecraft.

The research, reported in the journal Nature, is the first accurate measurement of a bizarre effect that predicts a rotating mass will drag space around it. The Lense-Thirring Effect is also known as frame dragging.

The team was led by Dr. Ignazio Ciufolini of the University of Lecce, Italy, and Dr. Erricos C. Pavlis of the Joint Center for Earth System Technology, a research collaboration between NASA's Goddard Space Flight Center, Greenbelt, Md., and the University of Maryland Baltimore County.

"General relativity predicts massive rotating objects should drag space-time around themselves as they rotate," Pavlis said. "Frame dragging is like what happens if a bowling ball spins in a thick fluid such as molasses. As the ball spins, it pulls the molasses around itself. Anything stuck in the molasses will also move around the ball. Similarly, as the Earth rotates, it pulls space-time in its vicinity around itself. This will shift the orbits of satellites near Earth." The study is a follow-up to earlier work in 1998 where the authors' team reported the first direct detection of the effect.

The previous measurement was much less accurate than the current work, due to inaccuracies in the gravitational model available at the time. Data from NASA's GRACE mission allowed for a vast improvement in the accuracy of new models, which made this new result possible.

"We found the plane of the orbits of LAGEOS I and II were shifted about six feet (two meters) per year in the direction of the Earth's rotation," Pavlis said. "Our measurement agrees 99 percent with what is predicted by general relativity, which is within our margin of error of plus or minus five percent. Even if the gravitational model errors are off by two or three times the officially quoted values, our measurement is still accurate to 10 percent or better." Future measurements by Gravity Probe B, a NASA spacecraft launched in 2004, should reduce this error margin to less than one percent. This promises to tell researchers much more about the physics involved.

Ciufolini's team, using the LAGEOS satellites, previously observed the Lense-Thirring effect. It has recently been observed around distant celestial objects with intense gravitational fields, such as black holes and neutron stars. The new research around Earth is the first direct, precise measurement of this phenomenon at the five to 10 percent level. The team analyzed an 11-year period of laser ranging data from the LAGEOS satellites from 1993 to 2003, using a method devised by Ciufolini a decade ago.

The measurements required the use of an extremely accurate model of the Earth's gravitational field, called EIGEN- GRACE02S, which became available only recently, based on an analysis of GRACE data. The model was developed at the GeoForschungs Zentrum Potsdam, Germany, by a group who are co-principal investigators of the GRACE mission along with the Center for Space Research of the University of Texas at Austin.

LAGEOS II, launched in 1992, and its predecessor, LAGEOS I, launched in 1976, are passive satellites dedicated exclusively to laser ranging. The process entails sending laser pulses to the satellite from ranging stations on Earth and then recording the round-trip travel time. Given the known value for the speed of light, this measurement enables scientists to precisely determine the distances between laser ranging stations on Earth and the satellite.

NASA and Stanford University, Palo Alto, Calif. developed Gravity Probe B. It will precisely check tiny changes in the direction of spin of four gyroscopes contained in an Earth satellite orbiting 400-miles directly over the poles. The experiment will test two theories relating to Einstein's Theory of General Relativity, including the Lense-Thirring Effect. These effects, though small for Earth, have far- reaching implications for the nature of matter and the structure of the universe.

Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
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Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
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Expedition 21
The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.
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Hubble Patch
The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.
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Viking patch
Available now from the Astronomy Now Store: the embroidered mission patch for NASA's Viking Project which reached the Red Planet in 1976.
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Mars Rover mission patch
A mission patch featuring NASA's Mars Exploration Rover is now available from the Astronomy Now Store.
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