NASA’s plan to nudge an asteroid

In the sci-fi movie Armageddon, astronauts intercept a killer asteroid heading for Earth, saving mankind. NASA is taking the first step to develop the technology to do just that, by planning a mission to slightly alter an asteroid’s orbit. The mission will also serve as an initial test of a solar-electric propulsion system and other technologies essential for a manned flight to Mars.

The newly announced Asteroid Redirect Mission (ARM) is scheduled to begin in 2020 with the launch of an unmanned spacecraft that will travel to one of three asteroids under consideration. After touching down, the craft will use its robotic arms to capture a boulder about 12 feet wide, and then return to orbit with the rock. Scientists will try to use the combined mass of the craft and the boulder as a “gravity tractor” to slightly alter the asteroid’s trajectory, a process that could last up to 400 days. “You are talking about a very large mass [that] you are trying to influence with a very small mass,” says ARM director Robert Lightfoot. “It takes a while.”

The craft will then move toward a stable orbit around the moon, where astronauts will collect samples from the boulder while also testing new spacesuits and other technologies for deep-space missions. “The systems we are going to bring into play,” says Lightfoot, “are the kinds of things we know we are going to need when we go to another planetary body.”