The National Aeronautics and Space Administration (NASA) is intent on deflecting Armageddon or anything that resembles the catastrophic Earth-asteroid collision that led to the extinction of the dinosaurs. And it plans to do so by capturing an asteroid and placing it in orbit around the moon for astronauts to explore in the future.
NASA's $1.25 billion Asteroid Retrieval Mission (ARM) is still in the early stages of planning and isn't poised to launch until 10 years from now, but officials have already identified nine asteroids as potential targets. Three of these, the asteroids 2013 EC, 2011 MD and 2009 DD, are closely monitored, but only one of them is considered an early favorite.
Asteroid 2011 MD, which was discovered whizzing just 12,000 kilometers past the Earth in 2011, is likely the best candidate for asteroid capture, agency officials said in a televised news conference Thursday. Paul Chodas, an astronomer at NASA's Jet Propulsion Laboratory, says the space rock could be captured once it comes in close contact with the Earth once again in 2024.
The asteroid is said to have unusually low density, only around one-third the density of a similar-sized chunk of rock, which suggests that 2011 MD may actually be a hunk of smaller boulders bound together due to gravity. And although one may harbor ideas that the asteroid is about the size of a small town, it's not. NASA's Spitzer infrared space telescope has just completed a survey of 2011 MD, and it shows that the asteroid is just about 6 meters in diameter. It's not much larger than a medium-sized delivery truck.
"You might actually be able to put this asteroid into your garage at home," says David Trilling, astronomer at Northern Arizona University and co-author of a published study on 2011 MD.
The plan, according to NASA, involves launching a solar-powered robotic spacecraft that would deploy a giant inflatable airbag around the truck-sized asteroid and park it around 75,000 kilometers above the surface of the moon. Another option would be to pluck off a piece of rock from a larger asteroid and drag it into orbit around the moon. NASA is looking at three larger space rocks for the second option. These are 2008 EV5, Itokawa and Bennu.
It is also looking into using the electric ion propulsion system on the spacecraft to blast ion thrusters against the asteroid and see how much force and time is needed to displace an object of a certain mass.
If all goes according to plan, NASA can then use the same procedure to capture asteroids seen to be travelling on a collision course with the Earth. But it isn't just saving the planet that the scientists at NASA are concerned about. It also wants to create a deep-space testing bed where it can gear up for a planned mission to Mars in the 2030s and plans to send astronauts via the Onion capsule and Space Launch System to the asteroid once it is positioned safely in orbit around the moon.
"We're supporting the ARM mission with our observation program, and in turn the ARM mission can support our planetary defense objectives," said Lindley Johnson, head of NASA's Near Earth Objects Program.
NASA announced that it has not made its final decision yet but will conduct a concept review for ARM next year. The robotic spacecraft is scheduled for launch in 2019 and the asteroid captures anywhere between 2021 and 2024, depending on the target selected.
