WASHINGTON, Jan. 10 (UPI) -- Representatives from several space agencies described the devices and mission of the Next-Generation Space Telescope to attendees of the American Astronomical Society's winter meeting Thursday.
Planned as the successor to the Hubble Space Telescope, the NGST will float 1.5 million kilometers -- more than 932,000 miles -- outside of Earth's orbit, said John Mather, the telescope's project scientist at NASA.
It will monitor light from the middle of the visible spectrum well into the infrared frequencies, and be about twice as sensitive as the Hubble, he told the scientists and astronomers at the meeting.
"We want to look back towards the beginning of time, to see how and from what galaxies were assembled," Mather said. "The hope is we can (add to our) picture of the Big Bang ... and understand how little things flowed together to form big things, or vice versa, whichever way it went."
In order to obtain the sensitivities needed to capture light from so far in the universe's past, segments of the NGST's 6-meter-wide, ultralight mirrors must avoid distortions from stress. Instruments aboard the device must be cooled to about 50 degrees above absolute zero.
The stress-free conditions will be met by having the telescope sit basically motionless at one of Earth's Lagrange points, where gravitational forces from the sun and other celestial bodies are perfectly balanced.
To help cool the device, the Earth's shadow will block much of the sun's energy, with a multilayer shield stopping the remainder. Even with the telescope's need to remain in shadow, it will be able to scan close to half of the observable sky.
The NGST development schedule calls for the project's prime contractor to be chosen by late this winter, Mather told the audience. Contractors for the telescope's three main sensors will be chosen in the next few years, and the NGST should launch on its five-year mission by 2009.
Eric Smith, a scientist at NASA headquarters, said the agency is working with the European Space Agency and the Canadian Space Agency to develop the NGST sensors. Existing agreements with the ESA are being updated, Smith said, and negotiations with the CSA are underway.
In return for their contributions, the ESA will control 15 percent of the telescope's available observation time and the CSA will have 5 percent, he said.
Peter Jakobsen, an ESA scientist, told the meeting his agency's efforts focus on a device for simultaneously measuring the composition of more than 100 several stellar objects. The key to this near-infrared spectrograph will be creating an adaptable filter to screen out light from unwanted sources, basically opening and closing microscopic pinholes throughout the filter.
The only technology that appears up to the task involves micro-electromechanical systems or MEMS, Jakobsen said. These devices operate at the millionth-of-an-inch scale, but they remain unproven in outer-space-like conditions.
Several members of the audience challenged Jakobsen on this, saying MEMS devices are already in use today for light-processing systems, similar to what NGST would need.
Jakobsen disagreed, saying today's MEMS devices are actually too small for the job by about half. It remains to be seen how an array of thousands or tens of thousands of devices could be practically controlled, he said.
