REx Spacecraft Arrives at Asteroid Bennu


Yesterday (Dec. 3), NASA's OSIRIS-REx probe sidled up to its diamond-shaped target, the near-Earth asteroid Bennu, ending a deep-space chase that lasted 27 months and covered more than 1.25 billion miles (2 billion kilometers).

The long-awaited rendezvous officially kicks off the start of the ambitious mission to study a near-Earth object that could hold the key to understanding the origins of our solar system, and life itself.

But to dive into that past, OSIRIS-REx will first need to get close enough to Bennu to snag a sample of the loose, rocky material from its surface in 2020.

A special webcast is scheduled for just before the spacecraft reaches Bennu, at 11:45 a.m. EST. "But while the spacecraft might tell us some things about where we have been and where we are headed, it also can remind us of where we are right now", NASA officials said in a statement. The spacecraft has been traveling through the solar system en route to its target Bennu for almost 27 months now and will stay about 12 miles away from the asteroid.

But there's still a lot to learn about the object, said University of Arizona Planetary Scientist Bashar Rizk, who oversees three of OSIRIS-REx's cameras. NASA's Jet Propulsion Laboratory gives Bennu a cumulative 1-in-2,700 chance of impacting Earth between 2175 and 2199. Once the team knows how heavy Bennu is, OSIRIS-REx researcher Andrew French said, they can begin to guess at what it's made of on the inside-past the reach of OSIRIS-REx's arm.

In August, the craft snapped its first image of asteroid Bennu. Current theories suggest that the diamond-shaped space rock was once part of a much larger asteroid, one perhaps the size of CT.

This meeting will provide scientists with a rare window to look back at the beginnings of Earth's solar system, said Jay McMahon, an assistant professor in aerospace engineering at CU Boulder.

NASA's Osiris-Rex spacecraft is now just a few miles from a skyscraper-sized asteroid, Bennu, which has the potential to hit Earth in just over 150 years time.

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Why Did NASA Send OSIRIS-REx to Bennu?

It is the first USA attempt to gather asteroid samples for return to Earth, something only Japan has accomplished so far.

The $800m Osiris-Rex mission began with a 2016 launch from Cape Canaveral, Florida.

OSIRIS-REx's approach to Bennu This video shows the OSIRIS-REx spacecraft's view of Bennu during the final phase of its journey to the asteroid. The third spectrometer, known as REXIS, is an X-ray spectrometer that will map out the individual elements present on Bennu's surface. Its orbit switches between those of Earth and Mars, making it what's officially called a "near-Earth asteroid".

The asteroid Bennu is of interest to Earth for another reason. Carbon is the key to the organic molecules needed for life, so finding organic molecules on a sample from Bennu would help to answer a big question about the origin of life. Water, another vital component to the evolution of life, may also be trapped in the asteroid's minerals. After the collection site is selected, the spacecraft will briefly touch the surface of Bennu to retrieve a sample.

The craft will obtain somewhere between 2 ounces and 4.4 pounds of soil sample from the surface of Bennu using a robotic arm that will blast the surface with a puff of nitrogen gas and collect the pieces that fly off. With two years of flying already under its belt, expectations are high for the probe, but first NASA has to make sure it arrives safe and sound, and that's what today is all about.

'Bennu is a leftover fragment from the tumultuous formation of the solar system, ' NASA says.