The spacecraft will nominally collect a sample on 4 July 2020 and return it to Earth in 2023. McMahon explained that as OSIRIS-REx brushes past Bennu this time, the asteroid will exert a minute gravitational pull on the spacecraft. To that end, the College of Optical Sciences, which helped design some of OSIRIS-REx's cameras in conjunction with the Lunar and Planetary Laboratory and Steward Observatory, recently received a $20 million endowment. Bennu orbits the sun between the Earth and Mars.
"This does look a challenging surface", said Lauretta, gesturing to a blown-up image of Bennu.
The Touch-and-Go Sample Acquisition Mechanism (TAGSAM) will suck up the regolith, kicked up by its nitrogen gas thrusters, and hopefully collect enough to study back at home.
The arm has a full range of motion, with joints capable of movement comparable to shoulder, elbow and wrist joints. It will spend a year in orbit, surveying the surface of the Potentially Hazardous Object (PHO) before settling on a location for the key phase of its mission: a sample return to Earth. As such, it's an astronomical time capsule. Today's milestone marks the end of a two-year journey to Bennu, and the start of a 1.5-year study period. Expect to hear lots of cheering when confirmation comes that OSIRIS-REx finally found its new home around Bennu. "So that's over two-and-a-half years of operations at the asteroid". Here, scientists will be able to study it with an array of instruments that will provide a huge leap in our understanding of asteroids. Only five asteroids met all criteria. The rapid rotation also sends small rocks on the asteroid's surface flying into space, meaning there's nothing there for the spacecraft to collect. Bennu's nearly 500 meters in diameter, and rotates only once every 4.3 hours. Both Bennu and Ryugu are near-earth asteroids, with a diameter of about 500 meters and 900 meters respectively.
"OSIRIS-REx seeks answers to the questions that are central to the human experience: Where did we come from?"
"But this is all dependent on the outcome of a very close approach that Bennu has with Earth in September 2135", Johnson said. It is not impossible that asteroids like it delivered the building blocks of life to the early Earth - the mission could help us investigate this theory.
'Besides carbon, Bennu also might have another component important to life: water, which is trapped in the minerals that make up the asteroid'.
'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. If it collided with Earth, Bennu would probably cause a crater. Such work could improve asteroid-impact forecasts, NASA officials have said. "You have a pristine sample of what the solar system was like billions of years ago", said Michelle Thaller, a spokeswoman for NASA's Goddard Space Flight Center. It orbits the sun at roughly the same distance as Earth. And Bennu is believed to be a grouping of rocks held together by gravity rather than a single object.
Starting in October, OSIRIS-REx performed a series of braking maneuvers to slow the spacecraft down as it approached Bennu. When will asteroid hit Earth? It will spend the next 505 days circling the asteroid and scanning it with cameras, LIDAR and spectrographs to try and find out as much information as possible about its composition.