Long before it came out on its own, a remote little asteroid called Bennu had a wet, watery start, according to new evidence just announced by NASA.
NASA's OSIRIS-REX spacecraft, arrived at Bennu on December 3 after a two-year trip, is currently located about 12 miles above the asteroid's surface. It recently sent data back indicating that the surface of the asteroid is filled with clay-like minerals, indicating that parts of this rumrock had a floating water at some point in its distant past.
"Bennu seems to be a very watery goal and water is the most interesting and perhaps the most lucrative item you would like from an asteroid," said Dante Lauretta, chief researcher of OSIRIS REX mission, at a press conference today .
Water is considered valuable for future space tasks because it is a potential source of fuel. Remembering asteroids for water would mean that future missions should not rely on Earth for fuel, and could potentially explore further into the Solar System.
It is important to note that while Bennu may be watery, it does not mean that it has floating water on the surface now. Just over 1600 feet in diameter, Bennu is currently so small that the surface can not support liquid water. Scientists hypothesize that between 800 million and one billion years ago, the rocky rubble we know as Bennu, probably a part of a larger asteroid, was more than 62 miles in diameter, which would have been large enough to support water. Planetaric scientists believe that the larger body was broken in a huge collision, leaving behind smaller pieces like Bennu, flowing through space in accumulations resembling massive bunker piles of rubble.
People who work on the project have long suspected that Bennu might have such terrific laughs. "Bennu turns out to be just the asteroid we hoped it would be," said Jeff Grossman, program researcher for OSIRIS-REx mission, at today's press conference.
The spacecraft got its very first glimpse of its target in August this year when Bennu was still a distant speck, 1.4 million miles away. Over the last couple of months, the surface of the asteroid has come into focus, and researchers now have a much better idea of what it's made of. During the approximation, the spacecraft's instruments picked up readings that showed that there was watery clay on the Bennus surface.
"This is really great news and it's a big surprise," said Amy Simon, a deputy instrument researcher at OSIRIS-REx Mission at the press conference.
In addition to the presence of once wet material, researchers also announced that they had gathered enough data to create a new, more precise 3D model of the asteroid's surface.
The model looks solid, but Bennu has hidden depths. Based on data collected so far, researchers estimate that as much as 40 percent of Bennus's interior can simply be cavities.
OSIRIS-REX will go around Bennu on December 31st and will eventually map the surface in detail. The spacecraft will stay close to Bennu for the next couple of years and stick to 2020 when it comes into contact with the asteroid surface, hopefully to collect a test before it takes its vacation in 2021. It is planned to return – regardless of What it collects – back to earth in 2023.