Search

ARCHIVES
CONTACT US
WORLD NEWS

University delivers arrays for NASA space telescope

A scientist on Monday delivered the last of three detector arrays for an experiment on NASA's Space InfraredTelescope Facility (SIRTF), slated for launch in late 2001.

"We started on this project in 1983," said George Rieke, a professor at the University of Arizona's Steward Observatory and principal investigator for the SIRTF's Multiband Imaging Photometer (MIPS) experiment. "There were so many big headaches - you don't want to hear the list."

"This is the culmination of all that work," he added.

Rieke delivered the new array to Ball Aerospace, in Boulder, Colo., where the $32 million MIPS - one of three scientific experiments being launched with SIRTF - is now being assembled.

A team of scientists at UA's Steward Observatory built two of the MIPS' three arrays; the other was made by The Boeing Company.

"It's kind of a relief - we've been working on it so long," said James Davis, an instrument maker and designer with Steward Observatory who played a central role in building the new arrays.

Rieke said previous arrays were ungainly and inefficient because they relied on a few individually wired detectors. He said that the new integrated arrays built by his team are a major leap forward in this area.

"It's a much more efficient way to make circuits by making them all at once," Rieke said. "The result of doing it in an integrated way is that you can make a much bigger array."

One of the UA-built arrays works at 70 micrometers, which is roughly 130 times longer than the visible wavelength of light.

The more sensitive array operates at 160 micrometers - about 300 times the visible wavelength of light.

Each array is comprised of a series of tiny detectors - each roughly half the width of a facet on the side of a pencil - that had to be individually glued on.

"All this work is under a microscope," Davis said. "The detectors are on one solid bar but they are separated by etched surfaces."

Davis said that the tiniest imperfection in the assembly process would have rendered the arrays useless.

"There's no room for error or you have to start all over again," Davis said. "I'm still building backup models, so it's not over yet."

Once the SIRTF is deployed, scientists hope the MIP's arrays will illuminate parts of the solar system that up until now have been mostly hidden from view.

Researchers have discovered that all celestial objects with a temperature above absolute zero, or minus 459 degrees fahrenheit, emit infrared radiation.

The new arrays will be able to detect radiation from objects that range roughly from minus 430 degrees to minus 300 degrees Fahrenheit.

This range includes the outer reaches of potential planetary systems orbiting nearby stars where researchers have identified an ancient group of small, icy objects known as the Kuiper Belt. The belt is named after the late UA planetary scientist Gerard Kuiper.

Rieke said the arrays may also reveal the youngest galaxies that may lie at the edge of the known universe.

These distant regions are impossible to detect at visible wavelengths of light because they are obscured by dust that forms during the birth of massive stars. Areas such as these can only been seen at the infrared wavelength.

With the far-infrared picture-taking capability provided by the new arrays, scientists hope to get a glimpse of what has, so far, eluded the view of existing space telescopes.

Assembly of the MIPS should be completed in the next few weeks. The instrument will then be tested to ensure launch readiness before being delivered to the Jet Propulsion Lab in Pasadena, Calif., for integration into the SIRTF.

Rieke said that to date, there has not been a "really big advance" in the field of infrared astronomy.

"This (SIRTF) will be the first really big step forward," Rieke said.