The Mirror Makers
The fight is on for the chance to build the world's most advanced space telescope.
- By Ben Iannotta
- Air & Space magazine, November 2001
(Page 2 of 6)
John C. Mather, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland, says that between measurements of cosmic background radiation and observations of young galaxies lies a cosmic “dark ages”—a period in the formation of the universe as yet unseen. Mather, who used the Cosmic Background Explorer to confirm the existence of background radiation left over from the Big Bang, looks to NGST to provide insight into the period when the universe was between about one million and a few billion years old—when galaxies and stars began forming.
Last June, NASA released the ground rules for the competition to build the NGST spacecraft and instruments. The company that wins the competition will then decide who will build the telescope’s mirror: Ball Aerospace in Boulder, Colorado, Goodrich in Danbury, Connecticut, or Eastman Kodak in Rochester, New York.
The three companies have been experimenting with different mirror materials through a $20 million project called the Advanced Mirror System Demonstrator (AMSD), which is funded jointly by NASA, the Air Force, and the National Reconnaissance Office, which operates spy satellites. The three companies each received about $3 million to build competing versions of lightweight mirrors and test them in vacuum chambers.
Each contractor will have to show that mechanical actuators on the back of the mirror can adjust the instrument’s shape, or “figure.” Phasing experiments, in which the contractors will prove that different segments can work together without losing focus, will come later.
For the contractors, the creation of the Hubble’s primary mirror provides a benchmark and, of course, a cautionary tale. It was here at Danbury, back in 1980, that Hubble’s primary mirror was ground and polished very precisely to the wrong specifications. The mirror’s curve was off by just one-fiftieth of the width of a human hair, but that was enough to spread Hubble’s light across multiple focal points instead of one. Here is the plot twist: The engineers and physicists at Ball, Danbury’s rival in Colorado, are the same happy few who stepped in to build the optics that corrected the images bouncing off Hubble’s flawed mirror.
Danbury officials deny that the real reason they are chasing the NGST contract is to redeem the company’s reputation. Facey insists the Hubble error was an “anomaly” in a long list of groundbreaking company triumphs, which includes the new Chandra X-ray observatory and the soon-to-be-launched Space Infrared Telescope Facility. Chandra is giving astronomers unprecedented information about black holes, and SIRTF will obtain images of not only the early universe but also planets in our solar system and the cosmic dust and gas surrounding nearby stars.
Ball, Danbury, and Kodak have teamed up with California-based aerospace giants that know how to integrate sensitive optical equipment and powerful satellite frames. Danbury is working with Lockheed Martin of Sunnyvale, and Ball and Kodak are joined up with TRW of Redondo Beach. But the prime NGST contractor must select the best mirror, regardless of any teaming arrangements—otherwise, NASA won’t approve the design.
Out in Boulder, in the same low-slung buildings at the foot of the Rocky Mountains where Hubble’s corrective optics were built, members of the Ball team make it clear that the competition is a fierce one.