NASA
This artwork shows one of the concepts for the Wide-Field Infrared Survey Telescope, also known as WFIRST. NASA officials say that the telescopes being made available by the National Reconnaissance Office could address some of the questions to be resolved by the WFIRST mission, including the nature of dark energy and characteristics of extrasolar planets.
By Alan Boyle
A gift of space telescope hardware from America's spy agency could knock $250 million off the billion-dollar-plus cost of a mission to study dark energy and extrasolar planets, NASA says. But scientists and space agency officials say the super-Hubble telescope won't replace the multibillion-dollar James Webb Space Telescope.
After more than a year of deliberation, NASA today revealed that it's taken possession of two optical mirror assemblies that had been built for the National Reconnaissance Office but were rendered surplus when the NRO decided they were unneeded. Although the spy agency has declined to say what the hardware would have been used for, it almost certainly was designed for next-generation spy satellites.
The assemblies fit inside a barrel that's about half the length of the Hubble Space Telescope, sparking the nickname "Stubby Hubble." The size of each primary mirror is the same as Hubble's: 94 inches or 2.4 meters in diameter. But the focal length is shorter, which would give the telescopes "about 100 times bigger area that you can image well," said Alan Dressler, an astronomer at the Carnegie Institution for Science.
That would make the mirrors perfectly suited for a wide-field telescope that could survey the cosmos to gauge the effect of dark energy, a mysterious factor that is speeding up the acceleration of the universe, Dressler and NASA officials told journalists today. Such a telescope could also detect Earthlike planets beyond the solar system by looking for an effect known as microlensing, and study supernovae and other astronomical phenomena as well.
"It's perfectly useful for astronomy in the infrared," Dressler said.
Such a telescope was rated as one of the highest priorities for astronomical research over the next decade in a report prepared for the National Academy of Science, titled "New Worlds, New Horizons." In the report, the mission concept was known as the Wide-Field Infrared Survey Telescope, or WFIRST. Mission cost was estimated at $1.6 billion.
"Depending on the instruments chosen to go with the new telescopes, NASA could address many of the science goals of the WFIRST mission," said Paul Hertz, NASA Headquarters' director of astrophysics.
Hertz's acting deputy director, Michael Moore, declined to put a price tag on the telescope that could be built using the NRO's surplus hardware. But Moore told me that building the kind of mirror assembly that the NRO has now provided would cost somewhere along the lines of $250 million. He said the optical hardware was space-qualified and "completely ready to be integrated into a spacecraft."
However, the transferred hardware doesn't include camera equipment or other key components that are needed to turn the optical assembly into a true space telescope. "There's still a lot of investment work and coordination that's required," Moore said.
Right now, the assemblies look like "cylinders with shiny foil wrapped around them," he said. Moore, an engineer, said he thought they were "gorgeous" pieces of hardware. But a non-technical person might not be as impressed, he said: "I gotta admit, they're not all that glamorous."
A. Dressler via National Academies
A redacted photo shows one of the telescopes transferred from the National Reconnaissance Office to NASA.
Moore said the project began in January 2011, when he took the phone call from NRO officials who were offering the surplus hardware. For months, NASA officials have been considering whether it'd be worth trying to use the equipment. After discussions with Dressler and other astronomers, they finally decided to go ahead with the transfer.
The hardware is currently in storage at ITT Exelis' manufacturing facility in Rochester, N.Y., Moore said. He estimated that it was costing about $75,000 to $100,000 a year for "care and feeding" of the equipment.
Hertz emphasized that NASA did not yet have the funding to go ahead with space telescope assembly. For now, NASA and outside astronomers are merely assessing what it would take to build a complete telescope, and contemplating exactly what the telescope could do. He said the super-Hubble could conceivably be launched in 2024 "with a plausible budget."
The telescope could be finished even earlier, in the 2019-2020 time frame, "if money is no object," Hertz said. However, he added,?"We have no reason to believe that that would happen."
He made clear that there was no thought of using the theoretical super-Hubble as a cheaper substitute for the controversial James Webb Space Telescope, which is now slated to launch in 2018 with a mission cost of $8.8 billion. The JWST, which has been portrayed as Hubble's successor, is a much larger telescope with a much narrower field of view than the super-Hubble would have. Hertz said he could imagine an eventual scenario in which the super-Hubble spots something in a wide-field image that would merit follow-up with observations using the narrow-field, deep-viewing JWST'.
Hertz said NASA was considering the development of only one space mission using the transferred hardware, even though the NRO gave the space agency two virtually identical sets of space telescope parts.?
"We don't, at this point in time, anticipate ever being rich enough to use both of them," he told reporters. "But it sure would be fun to think about, wouldn't it?"
More about future space telescopes:
Dressler discussed what he called the "NRO-1 2.4-meter telescope" today during a meeting of the National Academies' Committee on Astronomy and Astrophysics. Here are the PDF slides that he presented during his talk.
Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the?Cosmic Log page?to your Google+ presence. You can also check out?"The Case for Pluto,"?my book about the controversial dwarf planet and the search for new worlds.
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