NASA pressed to avert catastrophic Deep Impact
By Jitendra Joshi
Agence France-Presse
Last updated 08:22am (Mla time) 11/09/2007
WASHINGTON -- NASA penny-pinching risks exposing humankind to a planetary catastrophe if a big enough asteroid evades detection and slams into Earth, US lawmakers warned Thursday.
But the US space agency said the chances of a new "Near-Earth Object" (NEO), like the one that is believed to have wiped out the dinosaurs 65 million years ago, were too remote to divert scarce resources.
Scott Pace, head of program analysis and evaluation at NASA, said the agency could not do more to detect NEOs "given the constrained resources and the strategic objectives NASA already has been tasked with."
Critics say NASA has imposed big cuts on many research programs in a bid to meet President George W. Bush's goal of returning astronauts to the Moon by 2020 and use it as a stepping stone for manned missions to Mars and beyond.
Pace and other NASA officials were grilled at a House of Representatives hearing on the NEO program, which seized the public imagination in the late 1990s through the movies "Armageddon" and "Deep Impact."
The hearing of the House of Representatives space and aeronautics subcommittee highlighted one small asteroid named Apophis, which some scientists say could come perilously close to Earth in 2029.
NASA now only tracks NEOs larger than one kilometer (0.62 miles) in diameter, which come near Earth only once every few hundred thousand years.
Objects of that size can cause global disaster through their immediate surface impact and by triggering rapid climate change.
"Extinction-class" objects measuring at least 10 kilometers, such as the object that crashed into Mexico's Yucatan peninsula about 65 million years ago, would be rarer still.
Lawmakers complained that NASA had failed to come up with a budget in line with a 2005 act of Congress that mandated an expanded search for NEOs that are at least 140 meters (153 yards) in diameter.
There are about 20,000 objects of this size with the potential to hit home, according to NASA, and Republican Representative Tom Feeney said "they could still inflict large regional impacts if they struck the Earth."
The subcommittee's Democratic chairman, Mark Udall, said he was "disappointed and concerned" that NASA had neglected to abide by the act's recommendations.
Apophis is about 250 meters in diameter and is on track to approach Earth on Friday the 13th, April 2029. NASA says there is a one in 45,000 chance that it could pass through a "gravitational keyhole" and hit the planet in 2036.
"It's a very unlikely situation and one we can drive to zero, probably," said Donald Yeomans, who manages the NEO program at NASA's Jet Propulsion Laboratory.
Options to divert space rocks on collision course with Earth include slamming nuclear missiles into them, although scientists believes that in most cases involving smaller debris, conventional rockets would do the job.
Yeomans said also that while the European and Japanese space agencies are stepping up their own NEO programs, more than 98 percent of the work is now done by NASA.
The 2005 act mandated NASA, by 2020, to survey 90 percent of smaller NEOs measuring at least 140 meters that could strike the planet.
The agency's annual NEO budget of 4.1 million dollars was attacked as being too meager to cover this goal, while lawmakers also decried the threatened closure of a giant radio telescope in Puerto Rico that tracks space objects.
The National Science Foundation has earmarked the Arecibo Observatory, which featured in science-fiction movie "Contact" and the James Bond installment "Goldeneye," to shut down after 2011 if new private-sector money is not found.
The NASA officials said a new network of four telescopes being built in Hawaii by the US Air Force would be able to do much of Arecibo's work.
But Republican Congressman Dana Rohrabacher said the Puerto Rico facility cost little to run.
"We're talking about minimal expense compared to the cost of having to absorb this type of damage," he said. "After all, it may be the entire planet that is destroyed!"