OSIRIS-REx will actually need to spend a good deal of time hanging out in orbit around Bennu before it makes its move, so today is just confirmation of the probe's arrival. NASA scientists think the 484-meter-wide rock was once part of a much larger asteroid, which Space.com suggests was as large as the USA state of CT (which is 110 miles wide and 70 miles long), that was blown apart by some colossal collision a billion years ago. Indeed, OSIRIS-REx isn't even in orbit around the 1,650-foot-wide (500 meters) Bennu yet; it's now flying alongside the asteroid, just beginning to take its measure in detail.
NASA's OSIRIS-REx spacecraft has finally arrived at asteroid Bennu more than two years after blasting off from Cape Canaveral Air Force Station.
A live NASA broadcast of the OSIRIS-REx spacecraft's formal arrival begins at 11:45 am (1645 GMT). The spacecraft will spend nearly a year surveying the asteroid with five scientific instruments with the goal of selecting a location that is safe and scientifically interesting to collect the sample. As it does, the feeble gravity will allow scientists on Earth to calculate the mass of Bennu, which will be a big clue to its composition.
This set of 16 images shows the OSIRIS-REx spacecraft's steady approach toward the asteroid Bennu during the last half of October 2018. The new data will help scientists better understand how asteroids form and evolve.
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.
The $800 million probe's mission is monumental in scale and in importance.
Bennu's orbit runs between those of Earth and of Mars instead of in the farther asteroid belt between those of Mars and Jupiter.
The sampler head is stored in the Sample-Return Capsule (SRC) and OSIRIS-REx will return to Earth.
Bennu is relatively close to Earth, and its orbit even crosses that of our planet, making a close approach every six years.
'We have arrived, ' technicians announced, spurring high-fives and clapping around the control room.
Should the probe successfully reach Bennu, it will explore the surface of the space rock for about a year.
Osiris-Rex is the first U.S. mission created to return a piece of an asteroid to Earth. The NASA team is aiming to determine whether the potentially hazardous asteroid is, in fact, on course to impact the Earth and how we might be able to deflect or destroy it if it is.
"Bennu is likely rich in organic molecules, which are made of chains of carbon bonded with atoms of oxygen, hydrogen, and other elements in a chemical recipe that makes all known living things". It is a tool designed pinch the asteroid, take a sample of it and return it back to Earth for study.
Bennu, a diamond-shaped asteroid with 500-meter diameter, is believed to contain organics necessary to form life and retain materials from the beginning of the solar system 4.6 billion years ago.
Osiris-Rex will later fly back to Earth, jettisoning a capsule bearing the asteroid specimen for a parachute descent in the Utah desert, United States in September 2023.
Since the spacecraft's launch in September 2016, the CSIRO-managed, Canberra-based DeepSpace Communication Complex facility has provided two-way communication with the spacecraft.