Four tablespoons worth of real estate from a nearby asteroid could help to explain how life began.
- A sample from a pristine asteroid may explain whether the chemistry for life on Earth exists in space.
- The targeted asteroid, RQ36, is a rare, carbon-rich rock.
- RQ36 is on the list of potentially dangerous asteroids, with a slim chance of striking Earth in 160 years.
Some of the answers to how life began on Earth may be sitting on the surface of an asteroid circling in our backyard.
The asteroid, known as RQ36, is no ordinary rock. Scientists believe it is covered in organic materials and relatively unchanged since its formation in the early days of the solar system.
That's the primary driver behind OSIRIS-Rex, an asteroid sample return mission that is one of three robotic space expeditions vying for NASA funds.
If selected, the spacecraft would fly to RQ36, survey it extensively, then ease down to the asteroid's surface to collect four tablespoons worth of real estate to return to Earth.
"If you want to know something about the origin of life -- whether the chemicals that were necessary for the evolution of life came from space -- this is a really good place to look," project scientist Joseph Nuth, with NASA's Goddard Space Flight Center in Greenbelt, Md., told Discovery News.
Though scientists have an extensive collection of asteroid chunks that have landed on Earth as meteorites, there are no samples in the collections of the RQ36 variety, which officially is categorized as a "B-class" carbonaceous asteroid. These asteroids are believed to have escaped extensive heating and therefore retain relatively pristine materials from the early days of the solar system.
"We have many meteorites, but not that many organic-rich ones, and we have nothing that's pristine, uncontaminated by the Earth," said Michael Drake, director of the University of Arizona's Lunar and Planetary Laboratory and the lead scientist of the OSIRIS-REx team.
Scientists have no idea if RQ36 contains one or dozens of amino acids, or whether any of its organic molecules are structured with the same chirality, or symmetry, as amino acids on Earth.
"There is a tiny bias in the galaxy toward left-handed structures. Whether that's something that characterizes all living things, or whether it's an accident, nobody knows," Drake told Discovery News.
Whatever chirality RQ36 organics may show "would be very, very interesting," he added.
Aside from its composition, RQ36 is of special interest because it has a 1-in-1,800 chance of striking Earth 160 years from now.
"If we've got to go move it, it'd be nice to have been there and seen what it looks like," Nuth said.
The OSIRIS-Rex team has a $3.3 million NASA study contract, as do two competing missions. One of those two missions would return samples from a water-rich area on the moon's south pole. The other would head to Venus to search for clues about its early history.
NASA expects to select one of the projects for a $650-million New Frontiers mission by next spring.