• Bringing the Cosmos Down to Earth

    Humanity has been reaching out to the cosmos for decades. We now sit at the dawn of a new era when we will bring the cosmos home.

    Yesterday, NASA selected Osiris-Rex for its next New Frontiers mission. Scheduled for a 2016 lanuch, this mission will travel for four years before entering orbit around the carbonaceous asteroid “1999 RQ36.” (I know… but the naming convention wasn’t designed with casual conversation in mind.) At that point, it will analyze the asteroid’s surface remotely for 6 months, in part to select a sampling site. “Rex” will then descend down towards the surface, where the real magic begins: an arm will shoot liquid nitrogen at the asteroid, stirring up the surface so Rex can collect pieces of the asteroid to bring back to Earth. Read on to find out more about this spectacular mission…

    This particular asteroid is a carbonaceous chondrite, meaning it is carbon-rich and contains amino acids, the building blocks of life. These compounds are essential to life. One of the major sources of amino acids to planets without life is delivery from comets such as 1999 RQ36. To think of it another way, these asteroids provide “grocery delivery” of a major ingredient to prebiotic soup. Because these samples will be brought back to Earth relatively gently, this mission will provide unprecedentedly pristine samples of such an asteroid. In short, Osiris-Rex will reach out to the Cosmos and bring a piece back down to Earth for us to study.

    1999 RQ36 is also one of the most dangerous asteroids known to humanity. Based on current knowledge of its orbit, it has less than a 1-in-1000 chance of hitting the Earth in 2181. However, there is some uncertainty in the orbital projections from something called the Yarkovsky effect: acceleration to an orbit due to differential heating of different sides of the asteroid. Getting more knowledge about this effect for this particular asteroid will give us better orbital projections, and less uncertainty as to whether or not we’re all doomed… or, more accurately, whether or not all our great-great-great grandkids are doomed. Finally – and as part of both of these science goals – Osiris Rex will also get detailed maps of the asteroid’s surface, including altimetry and mineralogy. These measurements will also further increase our general knowledge of this class of asteroids.

    Sample return is clearly at the forefront of robotic space exploration plans all over the world. JAXA’s Hayabusa mission has already returned samples from the stony asteroid Itokawa. NASA has also previously returned samples of comet Wild 2 from Stardust, and samples of the solar wing from the Genesis mission. Looking to the future, the Russian Space Agency plans to return samples from the Martian moon Phobos via the Phobos-Grunt mission. Meanwhile, NASA and ESA are trying to find a way to make sample return from the surface of Mars affordable.

    I, for one, welcome our new saving-us-from-asteroids overlords.