NASA Mulls Waking WISE for Three-year Asteroid Hunt
WASHINGTON — NASA will soon decide whether to wake the Wide-field Infrared Survey Explorer (WISE) space telescope from a two-year hibernation to resume its NEOWISE asteroid hunting mission for another three years, the head of the agency’s Near-Earth Object Observations Program said.
WISE launched in December 2009 and scanned for faraway comets, asteroids and galaxies for about 10 months before it depleted its hydrogen coolant in October 2010, rendering two of its four infrared detectors unusable. Rather than shut the telescope down right away, NASA approved the NEOWISE extended mission, which kept the observatory operating for another four months looking for asteroids in our solar system.
Now, NASA’s Planetary Science Division is hoping for a much longer extension, which might be affordable even if Congress does not double the Near-Earth Object Observation Program’s $20 million budget in 2014, as the Obama administration requested in April.
“We are in the final stages of evaluating the proposal and expect to announce its potential for award in a few days,” Lindley Johnson, program executive for the Near-Earth Object Observations Program, wrote in an Aug. 1 email.
The extended NEOWISE mission would cost 10 times as much as the original four-month mission, or about $18 million, Johnson said.
The Jet Propulsion Laboratory (JPL) in Pasadena, Calif., has been trying to get an extended NEOWISE mission approved since January, according to Amy Mainzer, principal investigator for the original mission.
“NASA asked us for the proposal ... and we turned it in in late January, per their direction,” Mainzer said in an Aug. 1 email.
That proposal, submitted to the Advanced Exploration Systems division of NASA’s Human Exploration and Operations Mission Directorate, was rejected, only to be picked up in mid-June by the Science Mission Directorate, Johnson said.
The proposed NEOWISE extension would focus on near-Earth object (NEO) detection and characterization — the determination of an asteroid’s size, composition and orbital peculiarities. WISE, a $320 million observatory built by Ball Aerospace & Technologies Corp. of Boulder, Colo., around an infrared telescope supplied by Space Dynamics Laboratory of Logan, Utah, detected more than 30,000 asteroids during the four-month NEOWISE phase.
NASA officials have mentioned the possibility of a WISE restart before, most recently during the Small Bodies Assessment Group and the Ball-hosted Target NEO-2 workshop, both of which took place here in early July. At the Small Bodies meeting, Johnson spoke for the group in urging a WISE restart, noting that “some urgency” was required. By 2017, Johnson said, the telescope’s sun-synchronous Earth orbit will decay past the point of being useful for asteroid spotting.
Should NASA decide to fund JPL’s proposal and awaken WISE, “the mission will be staffed with a small team of scientists and engineers who have worked on it before,” said Mainzer, who would again be principal investigator.
There would not be very much in a NEOWISE restart for Ball Aerospace. If NASA decides to go ahead with JPL’s proposed three-year mission, Ball would dedicate only one full-time employee to the project, spokeswoman Roz Brown said in a July 31 email.
WISE Choice for Asteroid Redirect Mission?
Although WISE is not the ideal tool for the job, Johnson said, it is capable of spotting asteroids of the size desired for NASA’s proposed Asteroid Redirect Mission. In a plan that has gotten a cool reception in Congress, NASA in April proposed building a small robotic spacecraft capable of nudging an asteroid about 10 meters in diameter into lunar orbit, where it could be visited by astronauts in the early 2020s.
“The smallest asteroid NEOWISE has detected so far is about eight meters in size,” Johnson wrote in an Aug. 1 email. The small space rock, well within the target size for the proposed redirect mission, was about 1 million kilometers from the Earth when it was spotted, Johnson said.
Having infrared detectors in space is a key part of NASA’s effort to find an asteroid that is not only the right size, but also in the right place at the right time for the proposed redirect mission. A WISE restart is a relatively cheap option, but not NASA’s only option.
The agency is also considering building an infrared asteroid-spotting telescope that could be hosted aboard a commercial geosynchronous communications satellite. Last August, NASA solicited ideas for the instrument, which it said should weigh no more than 75 kilograms, be no larger than 0.5 cubic meters, draw no more than 500 watts of power, and cost no more than $50 million.
Now the agency is close to soliciting proposals for such an instrument. Johnson said competition will move forward if the Near-Earth Object Observation Program gets the $40 million the White House requested for it this year.
“Reactivating NEOWISE is much cheaper to do, but it is also not as capable for detecting [near-Earth asteroids] as we envision the geo-hosted instruments can be,” Johnson said. “If sufficient funding is make available, we plan to first reactivate NEOWISE [then] develop the geo-hosted instruments and have them available for launch.”
It is not certain that the program will get that $40 million any time soon as Congress is widely expected to pass a stop-gap funding measure that would freeze federal spending at 2013 levels for at least part of the 2014 budget year, which begins Oct. 1.
Meanwhile, both WISE and the proposed hosted infrared telescope would also watch for asteroids that might collide with the Earth, Johnson said.
That type of lookout activity is more popular among the lawmakers who set NASA’s budget each year than the proposed Asteroid Redirect Mission.