Comets and asteroids are all the rage these days. Late last year, the European Space Agency gave the world a historic hold-your-breath moment when it landed a small probe on a comet, and late last week NASA reported on its upcoming plans for the Asteroid Redirect Mission (ARM). A priority of ARM is to develop and test the means for putting astronauts on Mars, but the mission also hopes to yield discoveries that will improve navigation and trajectory techniques and even develop new possibilities for planetary defense.
First an asteroid boulder, and then to Mars
According to the NASA press release describing ARM’s ambitious plan, “a robotic spacecraft will capture an [asteroid]boulder from the surface of a near-Earth asteroid and move it into a stable orbit around the moon for exploration by astronauts, all in support of advancing the nation’s journey to Mars.”
Don’t try and hold your breath for this one, though: Once the spacecraft obtains the asteroid boulder, it will take roughly six years to move the boulder into lunar orbit. So what is the connection between Mars missions and moving asteroid boulders around?
One of the important new technologies the mission will help develop is Solar Electric Propulsion, described in the press release as “a valuable capability that converts sunlight to electrical power through solar arrays and then uses the resulting power to propel charged atoms to move a spacecraft.” While SEP-powered spacecraft would be slower than those powered by rocket propellant, they would be cheaper and more energy-efficient, allowing scientists to position supplies in deep space locations to await astronauts.
Scientists working on the ARM also hope to develop planetary defense techniques that, perhaps to the chagrin of some, will not involve detonation devices or spacecraft slamming into incoming celestial bodies. In the event that an asteroid appeared to be on a crash course with earth, scientists could use a technique called a “gravity tractor.” With this technique, a spacecraft may be able to affect an asteroid’s trajectory simply by staying very close to it, and the chances of success improve if the spacecraft is carrying some of the asteroid’s mass.
ARM will also test new sensor technologies, docking techniques, and sample collection methods. Asteroids even provide clues to the origins of the solar system.
NASA is aiming to retrieve an asteroid boulder sometime in 2020, with manned spaceflight missions commencing a few years later. Check out this great video on ARM from NASA’s YouTube channel, complete with requisite heart palpitation-inducing music: