After a careful survey of Bennu to characterise the asteroid and locate the most promising sample sites, Osiris-Rex will collect between 2 and 70 ounces (about 60 to 2,000 grams) of surface material with its robotic arm and return the sample to Earth via a detachable capsule in 2023. The agency says its OSIRIS-REx spacecraft has reached its hunk-of-rock target after a trip lasting two years and two billion miles.
In January, the probe will get closer to the asteroid - between 1.4 and 1.9 kilometres - before starting to orbit it.
Coverage of the event will be streamed live starting 11:45 a.m. ET.
There is also the possibility the asteroid sample could be rich in a valuable material that could be extracted for use on earth.More news: Australia coach Langer fears history-chasing India are 'smelling blood'
Among OSIRIS-REx's instruments are a tools to measure visible and near-infrared light, temperature, mineral and chemical content, X-rays (to explore its composition), a three-camera suite to help map the asteroid an an altimeter that will help scan the surface to create 3D models.
Scientists believe that asteroids may have delivered the ingredients for life to the young Earth - and hope to analyse samples from Bennu to prove the theory.
Scientists contend the more they learn about asteroids, the better equipped Earth will be in heading off a truly catastrophic strike. NASA's Goddard Space Flight Center in Maryland manages the overall mission. OSIRIS-REx was finally at the doorstep of its new home. The spacecraft executed a maneuver that transitioned it from flying toward Bennu to operating around the asteroid.
Bennu is a carbonaceous asteroid - a primitive, carbon-rich piece of debris left over from the process that formed the solar system 4.6 billion years ago.
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. It is theorized from the study of the orbit of Bennu that the gravity interaction between the two bodies during a close approach to Earth in 2060 (466,000 miles) will slightly alter its course.More news: Montana health officials confirm first influenza death this season
"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.
Scientists estimate there is a one-in-2,700 chance of the asteroid crashing into Earth 166 years from now.
"OSIRIS-REx will spend almost 2.5 years performing a detailed study of the asteroid with every instrument it has available". 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.
"When we understand Bennu, we will understand something fundamental about our solar system". 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.More news: One Marine rescued, 6 missing after planes collide off Japan