BY IAN O'NEILL
Your mission, should you choose to accept it: Refine an asteroid deflection plan that will attempt to bring a little piece of Armageddon to a space rock in 2022. This is the message from the European Space Agency (ESA) when details of a joint US/Europe plan were announced last week.
The idea is simple. In 2022, a binary asteroid called Didymos will be minding its own business, gliding past Earth at a safe distance of 6.5 million miles. But the two-spacecraft Asteroid Impact and Deflection (AIDA) mission will be on an intercept course to give one of the asteroids a very bad day. The reason? To understand how we might deal with a hypothetical asteroid that’s on a collision course with Earth in the future.
65803 Didymos consists of a primary asteroid measuring 800 meters across and a smaller asteroid satellite measuring 150 meters across. The smaller satellite orbits the primary every 11.9 hours. The plan, according to ESA, is to smash one of the AIDA spacecraft — called the Double Asteroid Redirection Test (DART) impactor, developed by the U.S. Johns Hopkins Applied Physics Laboratory — into the 150 meter-wide satellite asteroid. The second AIDA spacecraft — called the Asteroid Impact Monitor (AIM), developed by ESA — will observe the interplanetary collision from afar.
As noted by Ars Technica, the 150 meter-wide target asteroid has an estimated mass of 3×109kg (3 million metric tons). The kinetic impactor will likely have a mass of around 300 kilograms (a little smaller than the NASA Deep Impact spacecraft that collided with Comet Tempel 1 in 2005). A hypervelocity impact between the DART impactor and asteroid certainly wont “blow up” the target, but it should generate a big flash — impactor and impact zone will be instantly vaporized, generating a very hot plasma and, undoubtedly, a whopping crater.
As the impact will be within the observational capabilities of ground based and space based telescopes, it is hoped valuable science can be done. The AIM spacecraft will remain close to Didymos before and after the impact so we can better understand whether or not a kinetic impactor can have a significant effect on changing the binary asteroid’s orbital period.
“The advantage is that the spacecraft are simple and independent,” said Andy Cheng of Johns Hopkins, AIDA project leader. “They can both complete their primary investigation without the other one.”
Also, by combining the efforts of two independent spacecraft, the quality of the mission will be greatly increased. “Both missions become better when put together — getting much more out of the overall investment,” said Andrés Gálvez, ESA AIDA mission manager. “And the vast amounts of data coming from the joint mission should help to validate various theories, such as our impact modelling.”
However, the details of the mission have yet to be finalized, so AIDA scientists are asking for suggestions as to how to better develop the mission. A formal call for AIDA experiment proposals will be made via the ESA’s Near Earth Objects website on Feb 1, 2013.
If I didn’t know better, I’d suggest strapping a nuclear warhead to the DART impactor… but that would breach some pretty heavy space treaties, so I won’t be submitting a formal proposal. What would you suggest to the AIDA team?
Image: Artist impression of the AIDA mission. Credit: ESA