Cosmic shenanigans seem to be waiting on the cosmic horizon. And in order to ward off some future cosmic threats, NASA plans to crash a robotic spacecraft into an asteroid.
That’s right. The space agency intends to smash an unmanned space probe, named Bennu, against the relatively small space rock in 2020, wrapping it up with a controlled crash.
Here’s how it will work: Bennu will get hit by a car-sized spacecraft, and then the crash will be controlled with a tether, ensuring no one gets hurt.
Why does it matter?
That information, specifically its impact speed, could help scientists learn how best to deflect a space rock if it was ever on a collision course with Earth.
“We may get a deeper understanding of how our planet is built, or have we built ourselves to the point that it becomes a danger,” said study co-author Lars-Johan Larssen, a planetary scientist at the National Center for Scientific Research in Toulouse, France.
This upcoming crash will be the fourth attempt to crash a spacecraft into a near-Earth asteroid. The first was made in 1999 in a test, when a spacecraft launched in 1996 ultimately crashed into a comet to demonstrate the feasibility of such a maneuver. (The comet it crashed into ended up being no threat to Earth and a debris field was seen.)
The second, more successful collision took place in 1999, when NASA test-launched the OSIRIS-REx spacecraft toward the asteroid Bennu in a dive through Earth’s atmosphere.
It’s no coincidence that Bennu and OSIRIS-REx are headed in the same direction: Bennu’s orbit, traveling at an orbit that takes it close to Earth on Dec. 31, 2135, is about 13,200 miles away – or as close as 94 percent of the distance between Earth and the moon.
NASA has several other opportunities in the year 2020 to put a spacecraft into the vicinity of Bennu.
The third and final attempt, however, is planned as part of a study. This one, backed by the U.S. Department of Defense, will focus on the feasibility of a “buddy” spacecraft that will follow up the first and second collisions. (Bennu is, after all, traveling close to the planet. Some scientists have dubbed it “T’Woloshan” because it looks a bit like Russia.)
That’s due to reports that asteroids are as plentiful as the word “paradise” on vacations, and it’s important to be able to deflect a potentially dangerous object quickly in a live emergency.
Of course, there’s a price to be paid. NASA’s calculations say the two spacecraft that collide – one sending the second hurtling into the atmosphere – are likely to have a considerable amount of dust and debris, and the effect could be a slight release of gravitational stress that could take a bite out of the vehicle.
Scientists and engineers have studied the notion of a collision for decades, and have worked to develop new techniques. More than a decade ago, for example, a team at the California Institute of Technology tried out a strategy in which they squeezed a rock closer to a target asteroid with a spacecraft using an extra-compact heat shield. The team also employed inertial mass counterweights to exert an extra gravitational tug. That experiment ended without any observations of an asteroid after the nuclear-powered craft bumped against the rock.
The next field study of space rock impacts will be from NASA’s Stratospheric Observatory for Infrared Astronomy, set to release an infrared flight of Bennu in 2020. Astronomers will look for the presence of whatever burning glowing material is spewing up after impacts.
But NASA says the two spacecraft most likely to make impact with Bennu, as well as an asteroid’s orbit, are also set to get test runs between now and the end of the decade.