Rather than try to bag an entire small asteroid with an unmanned probe and bring that back to Earth, NASA has decided to send an unmanned probe into orbit around an asteroid and use it to grab one of the asteroid’s boulders.
The $1.25 billion mission, which is planned to launch in December 2020, would send a robotic spacecraft for a rendezvous with an asteroid in 2022. After touching down on the asteroid’s surface, the spacecraft would snatch a boulder several meters across. The spacecraft would then orbit the asteroid for up to 400 days, testing out an idea for defending Earth from a catastrophic asteroid impact: using the spacecraft’s own gravitational field to subtly alter the asteroid’s orbit. Next, the spacecraft would bring the snatched rock back to Earth’s vicinity in 2025. Finally, as part of preparations for a possible mission to Mars, astronauts would visit and examine the rock for some 25 days, using the planned Orion spacecraft to make the trip.
From both a science perspective as well as a manned space perspective, the unmanned part of this plan is a very good idea. Whether it will get funded depends upon Congress, since its roots go back to President Obama’s April 2010 commitment to send astronauts to an asteroid by 2025. Such a commitment was never really realistic, so it has devolved to capturing a rock and sending astronauts to visit it, thus meeting Obama’s commitment in a Potemkin Village sort of way.
Much better to bring the rock back to Earth orbit where it can be captured and brought to ISS by any number of vehicles and studied there. Whether Congress will fund this in the manner proposed in order to help Obama meet his commitment however remains very doubtful.
Posted from Santa Barbara, California.