NASA needs
more cash in order to meet its goal of finding nearby space rocks that could
hit Earth in a devastating impact, a new report says.
Congress
ordered NASA in 2005 to find and track 90 percent of the large
asteroids near Earth by 2020, but did not set aside the necessary funds
required to do the job, according to a report released Wednesday by the
National Academy of Sciences.
Without
that funding, NASA will not be able to build the new facilities and telescopes required
to track potentially threatening asteroids down to the size of about 460 feet
(140 meters) across, according to the interim report.
"I think
they're pretty much right on," said Lindley Johnson, NASA's manager of the
Near-Earth Objects program at the agency's headquarters in Washington.
Johnson told
SPACE.com Wednesday that NASA has estimated it needs between $800
million and $1 billion over the course of 12 to 15 years to build and support
the more sensitive telescopes required to meet its goal of tracking most of the
near-Earth objects.
Astronomer
Donald Yeomans, manager of NASA's Near-Earth Object program office at the Jet
Propulsion Laboratory in Pasadena, Calif., has said that about 15 percent of
the objects 460 feet
wide and larger have been found, and only 5 percent of objects down to about 164
feet (50 meters) in size.
One of the
top space rocks under observation is 2007 VK184, a 425-foot-wide
(130 meters) asteroid that has a 1-in-2,940 chance of hitting Earth sometime
between 2048 and 2057. An impact, if it occurred, would cause an explosion
roughly equivalent to 150 million tons of TNT, or more than 10,000 times that
of the atom bomb dropped
on Hiroshima.
NASA is
just about 85 percent complete with tracking asteroids about a half-mile (1 km)
in size, Johnson said.
Hunting
asteroids near Earth
Scientists
estimate there are about 100,000 asteroids and comets near Earth, but only
about 20,000 are expected to pose any risk of impact. As of Monday, NASA has
found 6,330 of those objects, 1,000 of them flying in orbits that could potentially
threaten the Earth in the future, Johnson said.
Aside from
efforts to launch space-based missions to track incoming asteroids by Germany
and Canada, the United States is carrying the bulk of the asteroid watch work,
the new report stated. NASA currently has three separate search teams running
five different telescopes to hunt for potentially threatening objects near
Earth.
The recent impact
on Jupiter last month of a previously unknown object has brought Earth's risk
of a similar hit back to the forefront. If such an impact occurred on Earth, the
results would
be catastrophic, scientists have said.
"It caught
us a little bit by surprise," Johnson said of the Jupiter impact, which
scientists believe was caused by an asteroid or comet.
Johnson
said that scientists plan to use data from NASA's new Wide-field Infrared Survey Explorer
spacecraft, which is slated to launch in late 2009 to map the night sky in more
detail than ever before, to expand their search for near-Earth objects. He and
his team are looking forward to the final version of the National Academy of
Sciences report.
A final
version of the report is slated to be completed by the end of the year.
In the
meantime, NASA recently launched a new "Asteroid Watch" Web site (http://www.jpl.nasa.gov/asteroidwatch/)
to keep the public current on its work to track near-Earth objects. The Web
site launched July 29 to post updates and alert the public to new research and
findings via updates, Twitter and an asteroid tracking widget.
Johnson
said the Web site was in development long before the Jupiter
impact, which occurred just over a week earlier.
"We had
actually started work to bring up that Web site a couple of months ago," Johnson
said. "That was just another event out of the blue."
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