I hope you're not all partied out after the InSight lander's successful touchdown on Mars this week, because there's another big spaceflight event just around the corner.
NASA's OSIRIS-REx probe will officially arrive at the near-Earth asteroid Bennu at about 12 p.m. EST (1700 GMT) on Monday (Dec. 3), ending a 27-month deep-space chase. NASA will mark the occasion with a special webcast event from 11:45 a.m. to 12:15 p.m. EST (1645 to 1715 GMT), which you can watch live here at Space.com, courtesy of NASA TV.
The space agency will also air an "arrival preview program" at 11:15 a.m. EST (1615 GMT). You can catch that here at Space.com as well. [OSIRIS-REx: NASA's Asteroid Sample-Return Mission in Pictures]
The $800 million OSIRIS-REx mission launched on Sept. 8, 2016, embarking on a looping trek toward the 1,640-foot-wide (500 meters) Bennu. Upon arrival, the probe will take up a position about 12 miles (20 kilometers) from the space rock, NASA officials said.
OSIRIS-REx will then fly by Bennu repeatedly over the next four weeks, gathering data that will help mission team members establish the asteroid's mass. With this information in hand, OSIRIS-REx will slide into orbit around the space rock on Dec. 31 — just hours before NASA's New Horizons probe cruises past the distant object Ultima Thule, billions of miles from Earth.
The diamond-shaped Bennu will then become the smallest object ever to be orbited by a spacecraft.
OSIRIS-REx will study the rock from orbit for the next 18 months or so and then make its way down to Bennu's surface to grab a sizeable sample of material in mid-2020. The spacecraft will depart the asteroid in March 2021, and the sample will come down to Earth in a special return capsule in September 2023.
Scientists around the world will study this material, looking for clues about the role that carbon-rich asteroids such as Bennu may have played in bringing the building blocks of life to Earth.
OSIRIS-REx — which is short for "Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer" — will also make significant contributions in other ways, mission team members have said. For example, the probe's measurements should help researchers better understand the resource potential of Bennu-like space rocks. And other data will increase knowledge of how asteroids move through space, which in turn should improve predictions of where hazardous rocks are headed.
Bennu is itself a potentially dangerous asteroid; there's a very small probability that it could hit Earth in the late 22nd century.
OSIRIS-REx isn't the only active asteroid-sampling mission. Japan's Hayabusa2 spacecraft is currently orbiting the 3,000-foot-wide (900 m) Ryugu, which shares Bennu's diamond shape. Hayabusa2 will grab a Ryugu sample next year and return it to Earth in late 2020, if all goes according to plan.