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Atlantis rolls to pad
After a six-hour trip along the three-and-a-half-mile crawlerway from the Vehicle Assembly Building, space shuttle Atlantis arrives at launch pad 39A for the STS-117 mission.

 Roll starts | Pad arrival

Atlantis rollover
Space shuttle Atlantis emerges from its processing hangar at dawn February 7 for the short trip to the Vehicle Assembly Building at Kennedy Space Center's Complex 39.

 Leaving hangar | To VAB

Time-lapse movies:
 Pulling in | Sling

Microgravity laboratory
Shuttle Columbia carried the first United States Microgravity Laboratory during its summer 1992 flight to orbit. The Spacelab science expedition was the longest shuttle mission to date, thanks to the new Extended Duration Orbiter equipment flown for the first time. The crew of STS-50 narrate the highlights in this post-flight film.


Research Project: X-15
The documentary "Research Project: X-15" looks at the rocketplane program that flew to the edge of space in the effort to learn about the human ability to fly at great speeds and aircraft design to sustain such flights.


Apollo 1 service
On the 40th anniversary of the Apollo 1 fire that took the lives of astronauts Gus Grissom, Ed White and Roger Chaffee, a remembrance service was held January 27 at the Kennedy Space Center's memorial Space Mirror.

 Part 1 | Part 2

Technical look at
Project Mercury

This documentary takes a look at the technical aspects of Project Mercury, including development of the capsule and the pioneering first manned flights of America's space program.


Apollo 15: In the Mountains of the Moon
The voyage of Apollo 15 took man to the Hadley Rille area of the moon. Astronauts Dave Scott and Jim Irwin explored the region using a lunar rover, while Al Worden remained in orbit conducting observations. "Apollo 15: In the Mountains of the Moon" is a NASA film looking back at the 1971 flight.


Skylab's first 40 days
Skylab, America's first space station, began with crippling problems created by an incident during its May 1973 launch. High temperatures and low power conditions aboard the orbital workshop forced engineers to devise corrective measures quickly. Astronauts Pete Conrad, Paul Weitz and Joe Kerwin flew to the station and implemented the repairs, rescuing the spacecraft's mission. This film tells the story of Skylab's first 40 days in space.


Jupiter flyby preview
NASA's New Horizons space probe will fly past Jupiter in late February, using the giant planet's gravity as a sling-shot to bend the craft's trajectory and accelerate toward Pluto and the Kuiper Belt. Mission officials describe the science to be collected during the Jupiter encounter during this briefing.


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Integral points to the fastest spinning neutron star
Posted: February 19, 2007

Astronomers using the European Space Agency's gamma-ray observatory, Integral, have detected what appears to be the fastest spinning neutron star yet. This tiny stellar corpse is spinning 1122 times every second. If confirmed, the discovery gives astronomers the chance to glimpse the insides of the dead star.

The neutron star, known by its catalogue number XTE J1739-285, was discovered during one of its active phases on 19 October 1999 by NASA's Rossi X-Ray Timing Explorer (RXTE) satellite. In August 2005, while Integral was monitoring the bulge of the Galaxy, XTE J1739-285 started to come back to life. About a month later Integral discovered the first short bursts of X-rays from the object.

Erik Kuulkers of the ESA Integral Science Operations Centre, Spain, who leads the Galactic bulge monitoring programme, informed Philip Kaaret, University of Iowa, via email that things were still hotting up near the end of October. Kaaret arranged for the RXTE satellite to observe XTE J1739-285 between 31 October and 16 November. Together the two satellites recorded about twenty bursts between September and November.

Just because a star dies, it doesn't mean its life is over. A neutron star is the tiny heart of a collapsed star. Measuring about 10 kilometres across, yet containing something like the mass of the Sun, the interior of a neutron star is the most exotic realm that astronomers can imagine. According to their calculations a thimbleful of neutron star material weighs a hundred million tonnes.

When a neutron star orbits another star, its strong gravitational field can pull gas from the other star. This coats the surface of the neutron star. When the coating reaches a height of between 5-10 metres, the gas ignites in a thermonuclear explosion. This massive release of energy generally lasts from between several seconds to several minutes and a burst of X-rays is released.

Previous observations of other neutron stars have shown that the X-rays emitted during bursts display oscillations that correspond to the rotation rate of the neutron stars. So the team began analysing the XTE J1739-285 bursts for oscillations. What they found was astounding. In the brightest burst, which RXTE recorded on 4 November, there were indeed oscillations but they were nearly twice as fast as any previously observed.

"It was quite a surprise to us," admits Kuulkers. However, after running a series of checks, the team satisfied themselves that the oscillations were indeed taking place 1122 times a second (1122 Hz).

Previously, the fastest neutron stars were known to spin with frequencies between 270-619 Hz. This had led some astronomers to estimate, using statistical arguments, that the fastest a neutron star could spin was 760 Hz. If the new observations are confirmed, XTE J1739-285 smashes this limit.

"Our detection is just above the level where we think there is something real. We definitely need more observations. If we see the signal again, then everyone will believe it," says Kuulkers.

This doesn't mean that neutron stars can spin as fast as they like. If the spin is too fast, even the crushing gravity of the star will be unable to hold matter to the surface and the star will break up. The exact break-up speed depends on the internal conditions of a neutron star and as yet, astronomers do not know these precisely.

"Our putative 1122 Hz detection places a serious constraint on neutron star models. If we can find more stars that spin in this range, it will certainly allow us to exclude some models of their interior structure," says Kuulkers.

So, now it is just a matter of patience. The astronomers will keep watch, not only for XTE J1739-285 to burst again, but also for other fast-spinning X-ray neutron stars.