In what they termed “a call to arms,” an organization of American university astronomers said last week that NASA should begin planning now to launch a sort of supersize version of the Hubble Space Telescope in the 2030s to look for life beyond Earth.
This High Definition Space Telescope would be five times as big and 100 times as sensitive as the Hubble, with a mirror nearly 40 feet in diameter, and would orbit the sun about a million miles from Earth.
Such a telescope, the astronomers said, would be big enough to find and study the dozens of Earthlike planets in our nearby neighborhood. It could resolve objects only 300 light-years in diameter — the nucleus of a small galaxy or a gas cloud on the way to collapsing into a star and planets, say — anywhere in the observable universe.
The case for the telescope is laid out in “From Cosmic Birth to Living Earths,” a report on the future of astronomy commissioned by the Association of Universities for Research in Astronomy (AURA), which runs the Hubble and many other observatories on behalf of NASA and the National Science Foundation. It was written by a committee headed by Sara Seager of the Massachusetts Institute of Technology and Julianne Dalcanton of the University of Washington.
“We hope to learn whether or not we are alone in the universe,” said Matt Mountain, the president of AURA and the former director of the Hubble, at a news conference at the American Museum of Natural History.
Only once in the arc of our species, Dr. Mountain said, will we turn a corner and be able to determine how the universe and our planet were formed and whether we are alone. “We can be that generation,” he said.
But only if we start now.
In releasing the report, the AURA group is putting down a marker in the long, elaborate and very political process by which major scientific projects are chosen and funded. Every 10 years, a committee of the National Academy of Sciences surveys the astronomical community and produces a prioritized wish list for the next decade. This survey, which happens next in 2020, serves as a blueprint for Congress and NASA.
AURA has done this before. Back in 1995, the organization put out a report, led by Alan Dressler of the Carnegie Observatories, calling for a space telescope to succeed the Hubble. That became the James Webb Space Telescope, designed to look for the first stars and galaxies in the universe, and it is on target for launching in 2018, 23 years later.
“In the modern era,” Dr. Mountain said, “only space scientists are this patient.”
But the cost of the Webb telescope swelled from an initial budget in 1996 of $1.6 billion to nearly $9 billion, acting like a wrecking ball to the rest of NASA’s space science budget. To avoid retracing that trail of tears, the AURA astronomers said NASA should start investing now in the critical technologies needed to make future telescopes work.
So the High Definition telescope is not destined to be the next item on NASA’s list, or even next to next. After Webb in the pipeline is the ungainly named Wfirst-Afta (don’t ask) designed to investigate dark energy, the mysterious something that is speeding the expansion of the cosmos. That mission was the first priority of the 2010 survey, and it could lift off in 2024 if all goes well.
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SOURCE: NY Times, Dennis Overbye