Wanted: man to land on killer asteroid and gently nudge it from path to Earth
Pastor Dale Morgan
Wanted: man to land on killer asteroid and gently nudge it from path to
Earth*
· Nasa evokes Hollywood in effort to avoid catastrophe
· Mission would bridge gap between moon and Mars
David Adam
Friday November 17, 2006
The Guardian
It is the stuff of nightmares and, until now, Hollywood thrillers. A
huge asteroid is on a catastrophic collision course with Earth and
mankind is poised to go the way of the dinosaurs.
To save the day, Nasa now plans to go where only Bruce Willis has gone
before. The US space agency is drawing up plans to land an astronaut on
an asteroid hurtling through space at more than 30,000 mph. It wants to
know whether humans could master techniques needed to deflect such a
doomsday object when it is eventually identified. The proposals are at
an early stage, and a spacecraft needed just to send an astronaut that
far into space exists only on the drawing board, but they are deadly
serious. A smallish asteroid called Apophis has already been identified
as a possible threat to Earth in 2036.
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Chris McKay of the Nasa Johnson Space Centre in Houston told the website
Space.com: "There's a lot of public resonance with the notion that Nasa
ought to be doing something about killer asteroids ... to be able to
send serious equipment to an asteroid.
"The public wants us to have mastered the problem of dealing with
asteroids. So being able to have astronauts go out there and sort of
poke one with a stick would be scientifically valuable as well as
demonstrate human capabilities."
A 1bn tonne asteroid just 1km across striking the Earth at a 45 degree
angle could generate the equivalent of a 50,000 megatonne thermonuclear
explosion. Attempting to break it up with an atomic warhead might only
generate thousands of smaller objects on a similar course, which could
have time to reform. Scientists agree the best approach, given enough
warning, would be to gently nudge the object into a safer orbit.
"A human mission to a near Earth asteroid would be scientifically
worthwhile," Dr McKay said. "There could be testing of various
approaches. We don't know enough about asteroids right now to know the
best strategy for mitigation."
Matt Genge, a space researcher at Imperial College, London, has
calculated that something with the mass, acceleration and thrust of a
small car could push an asteroid weighing a billion tonnes out of the
path of Earth in just 75 days.
Gianmarco Radice, an asteroid expert at Glasgow University, said the
best approach would be to land a device to dig into the object. "You
could place something on the surface to eject material that would push
the asteroid in the other direction."
Mirrors, lights and even paint could change the way the object absorbed
light and heat enough to shift its direction over 20 years or so. With
less notice, mankind could be forced to take more drastic measures, such
as setting off a massive explosion on or near the object to change its
course. In 2005, Nasa's Deep Impact mission tested a different technique
when it placed an object into the path of a comet.
Dr Radice said robots could do the job just as well, doing away with the
need for a risky and expensive manned mission. Last year Japan showed
with its Hayabusa probe that a remote spacecraft can land on an asteroid.
But with manned missions to the moon and possibly Mars on its to-do list
again, Nasa is keen to extend the reach of its astronauts.
Dan Durda, a senior research scientist in the Department of Space
Studies at the Southwest Research Institute in Boulder, Colorado said an
asteroid landing mission would be a good way test the new Constellation
programme spacecraft, the Apollo-style planned replacements for the
space shuttle with which Nasa hopes to return to the moon.
He told Space.com: "A very natural, early extension of the exploration
capabilities of this new vehicle's architecture would be a "quick-dash"
near-Earth asteroid rendezvous mission."
Tom Jones, a former shuttle astronaut, said: "After a lunar visit, we
face a long interval in Earth-Moon space while we build up experience
and technology for a Mars mission. An asteroid mission could take us
immediately into deep space, sustaining programme momentum, adding
public excitement and reducing the risk of a later Mars mission."
Europe has its own efforts to tackle asteroids. Its planned Don Quijote
mission will launch two robot spacecraft, one to tilt at a harmless
passing space rock, and a second to film the collision and watch for any
deviation in the asteroid's path.
'Not if, but when...' Hits and near misses
At Nasa's Jet Propulsion Laboratory, in California, scientists monitor
all "potentially hazardous asteroids" that might one day end up on a
collision course with Earth. So far they number 831. The next close-ish
shave - at a mere 17 times the distance from the Sun to the Earth - will
be asteroid 2004QD14 on November 29.
The Earth has a long history of asteroid strikes. Thirty five million
years ago, a 5km-wide asteroid ploughed into what is now Chesapeake Bay,
in the US, leaving an 80km crater. In 1908, an asteroid devastated
swaths of Siberia when it exploded mid-air with the force of 1,000
Hiroshimas. The theory that the dinosaurs were wiped out by a huge
asteroid striking Mexico 65m years ago is controversial since scientists
uncovered rocks from the crater predating the extinction of the
dinosaurs by 300,000 years.
A near miss, when asteroid QW7 came within 4m km of Earth in September
2000, led Liberal Democrat MP Lembit Opik to declare: "It's not a case
of if we will be hit, it is a question of when. Each of us is 750 times
more likely to be killed by an asteroid than to win this weekend's lottery."
In January 2002, the former science minister, David Sainsbury, announced
the government's response to the threat from hurtling asteroids: a new
information centre based in Leicester.