If an asteroid the size of a
small village were headed straight toward Earth, there isn’t much we could do
on short notice to prevent a major disaster – except blow it up, that is. Scientists
are investigating the possibility of using a specially designed spacecraft to
nuke approaching cosmic objects, in hopes that doing so could deflect the
threat.
While it could be possible
to divert a near-Earth object by slamming into it with a so-called impactor,
experts say a nuclear explosion may be the best bet when time is running out. In
a new paper, scientists from NASA and the National Nuclear Security
Administration have laid out a plan for the Hypervelocity Asteroid Mitigation
Mission for Emergency Response (HAMMER).
The 8.8-ton HAMMER
spacecraft could be used to steer itself directly into a small asteroid, or
blow the space rock up using a nuclear device, according to BuzzFeed News. The
team has devised a proposal around a potential impact with the 1,600-foot-wide
asteroid Bennu, which is currently the destination for NASA’s Osiris-Rex sample
return mission.
While Earth isn’t at risk of
a collision with Bennu any time soon, there’s a 1 in 2,700 chance it will slam
into our planet sometime next century.
Bennu is also the
best-studied asteroid of all the known NEOs, the researchers note. ‘The two
realistic responses considered are the use of a spacecraft functioning as
either a kinetic impactor or a nuclear explosive carrier to deflect the
approaching NEO,’ the authors wrote in the study, published to the journal Acta
Astronautica.
But, there are several
factors that would determine the best approach. The asteroid’s size and mass
must be taken into consideration, along with the amount of time available
before it hits Earth. Plus, there are always ‘various uncertainties.’ ‘Whenever
practical, the kinetic impactor is the preferred approach, but various factors,
such as large uncertainties or short available response time, reduce the
kinetic impactor’s suitability and, ultimately, eliminate its sufficiency,’ the
authors wrote.
By driving multiple
spacecraft into the asteroid’s path, it could be possible to slow the object
down and throw it off course to avoid a collision with Earth.
If the conditions aren’t
right to use the kinetic impactor, however, nuking it might be the only option.
‘If the asteroid is small
enough, and we detect it early enough, we can do it with the impactor,’
physicist David Dearborn of the Lawrence Livermore National Laboratory told
BuzzFeed News. ‘The impactor is not as flexible as the nuclear option when we
really want to change the speed of the body in a hurry.’
Despite ongoing efforts to
catalog potential hazards in Earth’s vicinity, scientists have increasingly
warned that there are countless large objects that remain undetected. Given the
risk of an inevitable impact sometime in the future, the experts say it’s necessary
to plan for the worst. The researchers will present their proposal at a
conference in Japan this coming May.
For now, however, whether or
not the HAMMER plan will ever come to fruition remains up in the air.