What the capturing portion of an asteroid capturing mission might look like. Image credit: Rick Sternbach / Keck Institute for Space Studies.
There’s a lot of interest in space rocks these days. Mining asteroids robotically, exploring an asteroid with a manned mission, and preparing for the worst if a big one were to smash into us—each is a need scientists are actively exploring. A few months ago a group of scientists from the Keck Institute for Space Studies in California published a proposal that would address all three by grabbing an asteroid and anchoring it in space to one of the Earth-Moon Lagrange points—points in space where the gravitational balance is just right for a spacecraft or an asteroid to stay put.
It’s a wild idea but NASA’s officially taken an interest in it. The agency’s budget request for the fiscal year 2014 will include $100 million to at least begin an asteroid capture mission.
Motherboard's "Spaced Out" episode about NEEMO, an undersea mission to practice asteroid-harnessing
The Keck team’s idea is, on the surface, pretty great: Send a robotic spacecraft to an asteroid using solar-electric propulsion, capture it with a deployable bag, and bring it closer to home for scientific study. The proposal calls for the captured asteroid to be anchored by gravity at Lagrange point 2, which lies slightly beyond the Moon. Sending men to an asteroid would suddenly be as obtainable as going to the Moon—which isn’t easy, but is still easier than flying out to some distant and moving rock in space. And all for a cool (estimated) $2.65 billion.
What’s more, the Keck team maintains it wouldn’t be dangerous. The ideal asteroid to capture would weigh about 1.1 million pounds, measure less than 25 feet across, and have a density similar to dried mud. If an asteroid like that came close enough to the Earth to enter our atmosphere, it would be less damaging than the meteorite that landed in Chelyabinsk, Russia, in February.
There are other possible benefits from an asteroid capture mission. The technology and know-how NASA scientists would have to develop to pull this off would help in locating and dealing with threatening asteroids in the future, something we should all be at least a little worried about.
The Earth-Moon Lagrange points. The proposed captured asteroid would end up anchored at L2. Image credit: David A. Kring, LPI-JSC Center for Lunar Science and Exploration, via Space.com
There are, of course, a number of hurdles to overcome. This wild plan is contingent on NASA's completing the Orion spacecraft and the SLS heavy lift rocket. Finding a suitable target asteroid is another matter; a good candidate would be much smaller than the threatening near-Earth objects already being sought, which means it would be harder to find. The target asteroid would also have to have the right composition, spin, and be in a heliocentric orbit that will return to Earth’s vicinity in the 2020s. It wouldn’t help to find the right rock in the right place right now. NASA will need some time to develop and test all the pieces of this mission.
In spite of obvious challenges, there are murmurs around the Internet that this mission could happen sooner rather than later. If NASA gets the funding it needs and starts right away, it could take advantage of a good launch opportunity in 2018. It could even fly as early as 2016 if there are no major setbacks. Which would, in turn, make President Obama’s stated goal of landing a manned mission on an asteroid by 2025 much easier to accomplish. That timeframe doesn’t look so bad when the goal is in our backyard.
Perhaps the best thing about this mission is that it would give NASA a clear and exciting goal, the likes of which we haven't seen since the Kennedy era. It would also be an amazing demonstration of how we can use space resources on our home turf. Private companies like Planetary Resources could also benefit from this mission run under NASA’s umbrella; it would help develop realistic plans to mine and use space resources on Earth.
There could be a lot of positive offshoots if NASA does get the requisitioned funding and pursues this idea. But there are still a lot of “if”s. It’s another awesome, almost sci-fi mission plan that I’d say is worth taking with a grain of salt. At least for now.