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NASA narrows wish list for future studies
« on: 2004-08-02 16:33:50 » |
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Article can be found at : http://www.newscientist.com/news/news.jsp?id=ns99996227
NASA has narrowed its wish list for future studies of the birth and evolution of the Universe. It has winnowed a list of 26 proposals for its Search for Origins Program down to just nine.
These nine will be developed further over eight months. Then, two of those may be launched by 2014 at a cost of about $600 million each
Among the nine contenders is a plan for a replacement for the Hubble Space Telescope. The venerated telescope is expected to fail in 2007 or so unless it receives life-saving batteries and gyroscopes.
But in the wake of the shuttle Columbia's breakup in 2003, NASA cancelled a manned mission to Hubble to replace those parts and add two new instruments that would sharpen its observational skills.
Despite pleas from astronomers, lawmakers, and the public and a recent study showing that such a manned mission could be done in accordance with recommendations from the Columbia Accident Investigation Board, the telescope's future remains uncertain.
"If you could do a manned rendezvous or a robotic mission, that would be best," says Colin Norman, an astronomer at Johns Hopkins University in Baltimore, Maryland, and principal investigator of the proposed Hubble double, called the Hubble Origins Probe. "But this is a very reliable, no-brainer, fallback option if those don't work."
Star formation
The proposed probe, which could be ready for launch in 2008, would have a 2.4-metre mirror like its predecessor but would not contain Hubble's full suite of instruments.
It would be fitted only with the two instruments that were intended to be installed on the cancelled shuttle mission - the Cosmic Origins Spectrograph and the Wide Field Camera 3 (WFC 3) - and perhaps two others from international collaborators. A "very" wide-field Japanese camera - which covers an area of the sky equivalent to two Full Moons - is one of the additional instruments under consideration.
"The mission is worth considering because these instruments are worth getting up there," Norman told New Scientist. "It will keep hammering away at the last 80 per cent of the history of the Universe, where Hubble has been so successful - [studying] star formation, black hole growth, and galaxy formation."
Another finalist also follows up on the success of a previous space mission. The Origins Billion Star Survey (OBSS) aims to catalogue the location and brightness of a billion stars in our Galaxy, improving on the European Space Agency's Hipparcos satellite that in 1997 published its survey of 100,000 stars.
Wobbles and dips
The OBSS's 1-metre optical telescope would orbit the Sun for five years. It would view each star about 400 times to pinpoint stellar positions to a precision of 100 microarcseconds - 10 times the accuracy of Hipparcos.
"You're getting a 3-D picture of the Galaxy," says principal investigator Kenneth Johnston, scientific director of the US Naval Observatory in Washington, DC.
The vast haul of data would be expected to reveal 24,000 stars that host planets, which produce wobbles and dips in starlight. And by watching how stars move, it could provide a map of the Galaxy's dark matter, which can attract objects gravitationally.
Other proposed projects include infrared telescopes to peer back to the earliest galaxies and to search for organic compounds in space, which may reveal how the materials form and reach the surfaces of planets.
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