Sabtu, 25 April 2020

Robert Miller: The telescope that went from grave to rave - CT Insider

Bud Rigby is 90 years old. When asked if he still cares about the great project of his life — the Hubble Space Telescope — the answer comes back strong.

“You better believe it,” Rigby, of Ridgefield, said.

On April 24, 1990 — 30 years ago — the space shuttle Discovery took off carrying Hubble. Rigby was part of the team at PerkinElmer in Danbury, now Goodrich Corp., that built the nearly 8-foot-wide mirror that lets Hubble see what it sees.

What it has seen so brilliantly, in our own solar system and beyond still can, and should, make people pause in wonder. Along with the Apollo mission to the moon, Hubble is NASA’s greatest triumph.

It’s the most famous telescope in the world. It’s captured more than a million images and astronomers have published more than 10,000 papers based on what they’ve learned from its pursuits — to boldly see what no one has seen before.

“It was science-shaking,” said Diana Hannikainen, observing editor of Sky & Telescope Magazine, of the impact Hubble had on the world.

And if the general public may be a little blasé about Hubble, it’s nice to remember when its images were a revelation.

“It was headline news,” Hannikainen said. “You’d watch the evening news, and there would be another image from Hubble.”

“Hubble images are so spectacular,” said Hubble project scientist Jennifer Wiseman. “They inspire people around the world to reflect again on the beautiful universe. They connect us to something.”

The Hubble Space Telescope is named after American astronomer Edwin Hubble, who discovered that the universe is expanding, rather than being fixed. It sits about 340 miles in space above the earth and has orbited it every 97 minutes, year after year.

Wiseman said it’s Hubble’s place out in space that makes its work so impressive. It doesn’t have to peer through the murk of our atmosphere to study the firmament.

“Its perch gives us really clean science,” she said.

Hubble’s mirror gives it its phoenix story — the telescope that went from grave to rave.

The team at PerkinElmer received the 1,800-pound, 94.5-inch-wide mirror from Corning Glass Works in Ithaca, NY, in 1978.

The PerkinElmer team set about refining and polishing the mirror to an extraordinary degree of fineness — a surface finish never achieved before on a mirror so large.

But because of a slight flaw in the test system PerkinElmer built for polishing the mirror, the final product was, while essentially perfect, was ever so slightly flat — by one-fiftieth of the width of a human hair. Because of that mistake, the first images Hubble sent back to NASA were fuzzy and out-of-focus. There was a huge uproar.

The PerkinElmer optics team believe, then and now, they were denied the chance to complete their work and correct that error. NASA — dissatisfied because of missed deadlines and budget overruns — simply shut the PerkinElmer team down in 1982 and stored the mirror until NASA assembled the telescope at its Lockheed Martin facility in California.

“We had $150,000 in the budget to do the planned cross-check tests and recertification analyses to make sure there were no mistakes,” said Lou Montagnino of Southbury, manager of manufactured optics analytics at PerkinElmer for the project. “There were other things I and others had requested. They said no to that $150,000. They then spent more than $1.5 billion on repairs.”

But because the PerkinElmer team did such meticulous record-keeping of its work, NASA was able to use that record to devise a new camera and corrective relay optics for Hubble, which shuttle astronauts installed in 1993. Since then, it’s all been glory.

Wiseman can easily list some of Hubble’s greatest achievements — its images of a comet crashing to Jupiter, and its deep field study that showed that even in one small corner of the universe, there are thousands of galaxies, each containing billions of stars.

It’s studied the weather on Neptune and Uranus, and found evidence of water vapor escaping from Europa, one of Jupiter’s planets. It’s studying the atmosphere of newly discovered exoplanets.

Wiseman said great credit should go to all the people responsible for Hubble over the decades. And because NASA’s last repair mission to Hubble in 2009 was so complete an overhaul, we can expect to be astonished for years to come.

“We are confident that it will be providing earth with excellent science through the next decade,” she said. “And maybe beyond.”

Contact Robert Miller at earthmattersrgm@gmail.com

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2020-04-26 01:10:27Z
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