The technology used could also help NASA defend the planet from
future asteroid impacts. During the mission, the agency will try out the
techniques that it could use to throw an asteroid off course if it were
coming towards Earth.
NASA refers to the robotic arm plan as “option B”, and was selected
over another plan that would see an entire asteroid redirected. In the
successful plan, a robotic arm will land on an asteroid big enough to
have suitable boulders on it, and then throw one of those into orbit
around the moon.
NASA said that it will pick an asteroid no earlier than 2019, and
will launch the spacecraft carrying the throwing robot about a year
later. NASA has identified three candidates already — and expects to
find one or two more per year — all of which will be examined for their
shape, size, orbit and other characteristics before they are chosen.
When the asteroid is chosen, and the craft landed on it, robot arms
will be deployed to grab a boulder. The unmanned ship will then send the
boulder into orbit over a number of years.
The same technology could be used in future to save us from asteroids
that are headed towards the earth. The robot could eventually defend
the planet by using a technique called a “gravity tractor” — if it heads
towards the asteroid, the robot’s gravity can throw off the course of
an asteroid without touching it. That will work even better if the robot
can successfully grab a boulder, giving it more mass and more
gravitational pull.
The mission will also be testing out technologies for future missions into deep space.
The plan will make use of Solar Electric Propulsion, for instance,
which allows spacecraft to convert sunlight into electric power and use
that to move through space. Using that technique is less efficient than
burning fuel, but means that space missions will need much less fuel and
fewer launches, bringing down costs.
That technology could eventually be used to send out cargo or vehicles
to be picked up by astronauts on their way to Mars. Objects could be
sent out into space to work as a waypoint, or be ready for humans when
they arrive on the red planet.
It will also give a chance to use new systems, as astronauts head out
to the asteroid to study it. They will be able to jump out of the Orion space capsule, wearing new space suits designed for deep space missions, and collect samples that could then be returned to Earth for study.
"Asteroids are a hot topic," said Jim Green, director of NASA
Planetary Science. "Not just because they could pose a threat to Earth,
but also for their scientific value and NASA's planned mission to one as
a stepping stone to Mars."
NASA has been receiving more and more money from the US Congress to
fund its asteroid observations work, known as the Near-Earth Object
Observations Program. It has been finding an increasing number of
near-Earth objects, helping find rocks that could pose a threat to life
on Earth.
Recently, the program spotted asteroid 2014-YB35, which will skim past the Earth this Friday.
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