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Discovery's astronauts
Take a behind-the-scenes look at the seven astronauts who will fly aboard the space shuttle return-to-flight mission in this movie that profiles the lives of the STS-114 crew. (10min 04sec file)

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Walking with Discovery
Walk alongside space shuttle Discovery as the motorized transporter hauls the ship a quarter-mile from the Orbiter Processing Facility to the Vehicle Assembly Building. (3min 21sec QuickTime file)
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Discovery leaves hangar
This time-lapse movie captured from an overhead camera shows space shuttle Discovery's middle-of-the-night departure from its processing hangar at Kennedy Space Center to the roll to the Vehicle Assembly Building. (4min 30sec file)
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Rolling into VAB
Discovery arrives in the Vehicle Assembly Building as viewed in this time-lapse movie. The shuttle will be mated to the redesigned external fuel tank and twin solid rocket boosters in the VAB before rolling to the launch pad for the first post-Columbia mission. (5min 00sec file)
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Nanosat toss overboard
A foot-long Russian nanosatellite is flung overboard by the spacewalking International Space Station Expedition 10 crew. Station cameras watched the hand-launched deployment and the nanosat as it floated away. (4min 52sec file)
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Spacewalk highlights
Highlights of the second spacewalk of the International Space Station's Expedition 10 crew is compiled into this movie. The crew completed external outfitting of gear that will guide European cargo ships to the outpost during dockings starting in 2006. (5min 00sec file)
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ISS EVA preview
Mission managers preview the next spacewalk by the Expedition 10 crew aboard the International Space Station, which will install external equipment on the Russian segment and hand-launch a tiny nanosatellite. (37min 00sec file)

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Shuttle history: STS-49
This video retrospective remembers the first flight of space shuttle Endeavour. The maiden voyage set sail in May 1992 to rescue the Intelsat 603 communications spacecraft, which had been stranded in a useless orbit. Spacewalkers attached a rocket booster to the satellite for the critical boost to the correct altitude.
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Shuttle history: STS-109
This video retrospective remembers the 2002 mission of Columbia that made a long distance service call to the Hubble Space Telescope, giving the observatory a new power system and extending its scientific reach into the Universe. Astronauts performed five highly successful spacewalks during the mission.
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Shuttle history: STS-3
This retrospective remembers the third voyage of space shuttle Columbia. The March 1982 mission served as another developmental test flight for the reusable spacecraft, examining performance of its systems while also conducting a limited science agenda. STS-3 is distinguished by making the first landing at Northrup Strip in White Sands, New Mexico.
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'Super-starburst' galaxies hide active black holes
Posted: April 5, 2005

A team of European scientists has used Virtual Observatories to compare observations of distant "starburst" galaxies made at radio and X-ray wavelengths. This is the first study to combine the highest resolution and sensitivity radio and X-ray images which penetrate the dust hiding the centres of some of these distant galaxies.

The team focused on galaxies so far away that their radiation took more than six billion years to reach us. The galaxies are seen as they were when they were less than half the age that the Universe is today.

Speaking on Tuesday 5 April at the RAS National Astronomy Meeting in Birmingham, Dr. Anita Richards (Jodrell Bank Observatory, University of Manchester) will explain how the team used the UK's MERLIN array of radio telescopes and the Very Large Array to investigate how galaxies in the early Universe differ from those nearby.

"The more remote starburst galaxies, so called because of their high rate of star formation, typically produce 1,000 or more solar masses of stars per year - at least 50 times more than the most active star-forming galaxies in the nearby Universe," said Dr. Richards.

"Each distant starburst region is tens of thousands of light years across, equivalent to about the inner quarter of the Milky Way - also vastly larger than any such regions found in our part of the Universe."

The radio search took place in an area known as the Hubble Space Telescope Deep Field North - a patch of sky smaller than the full Moon that contains tens of thousands of galaxies.

Apart from Hubble, radio telescope arrays are the only instruments that can see detailed structures within these galaxies. Moreover, only radio or X-ray emissions can penetrate the dense dust in the innermost regions of some of these galaxies.

The two main sources of radio waves and X-rays are star formation and emissions from Active Galactic Nuclei (AGN) that are generated when material is sucked into a massive black hole and ejected in jets. The team found about twice as many starbursts as AGN, where these could be distinguished in radio images.

The UK AstroGrid and the European AVO - parts of the international Virtual Observatory - were used to find counterparts for the radio sources from a variety of other data held by archives and observatories around the world. In this way it was discovered that 50 distant X-ray sources with measured redshifts had also been detected by the Chandra space observatory.

Virtual Observatory tools made it easy to calculate the intrinsic brightness of the sources, corrected for distance and redshift. However, the team found that there was no obvious relationship between radio and X-ray luminosity. This was a surprise since there is such a link in most local starburst galaxies.

Some of the faintest radio sources were found to emit the most X-rays and vice versa - suggesting that two separate mechanisms within each galaxy were generating powerful emissions at opposite extremes of the spectrum.

Members of the European Virtual Observatory team had earlier used the Chandra X-ray data and Hubble images to find 47 AGN in the Hubble Deep Field North. These appeared to be seen sideways on, so that the dusty torus surrounding the black hole blocked all but the most energetic X-rays from emerging in our direction.

"Astonishingly, only 4 of these looked like AGN in the radio observations," said Richards. "10 had radio emissions characteristic of starbursts, 4 could not be classified, and the rest went undetected by radio telescopes."

The 10 super-starburst/AGN hybrids tended to be at a higher redshift " indicating that they are much further away from Earth than the rest of the radio galaxies. Over half of them were among the enigmatic 'SCUBA sources'. These objects are very bright at wavelengths just under a millimetre, probably as a result of dust being strongly heated by violent star formation, but almost invisible to most other instruments.

"We concluded that, not only were these young galaxies undergoing much more violent and extended star formation than we see today, but they were simultaneously feeding active, supermassive black holes responsible for the X-ray emission," said Richards.

"One clue to the origin of this phenomenon is that the Hubble Space Telescope often reveals two or more distorted galaxies associated with these sources, suggesting that galaxy interactions were commoner when the Universe was young. The ensuing collisions of gas and dust clouds trigger star formation and also feed the central black hole.

"Modern starburst galaxies are not only slower at star formation, but mostly have much quieter AGN, if any. This is not surprising as the super-starbursts must run out of fuel quite quickly (by cosmological standards), when all the available material has either turned into stars or fallen into the black hole."