
NASA’s first asteroid sample mission arrived at its destination. However, there is still a lot of preparatory work ahead before the spacecraft will disturb the heavenly body.
On December 3, NASA's OSIRIS-REx spacecraft reached its long-awaited target, the near-Earth asteroid Bennu. Thus, he managed to complete the journey of 27 months and pass 2 billion km.
The mission cost $ 800 million. Its main goal is to get asteroid material and deliver it to Earth in 2023. But the spacecraft is not going to take any stones. Moreover, OSIRIS-REx is not currently located in the orbit of the 500-meter Bennu. He flies near the asteroid, evaluates it and only plans to approach.
OSIRIS-REx will continue to fly over the asteroid for the next 4 weeks, exploring the north and south poles, as well as the equator, which will allow a distance of 7.1 km from the surface.

Photos of the asteroid Bennu from the OSIRIS-REx spacecraft at a distance of 80 km
Members of the mission team want to make sure that they were able to accurately determine the shape and mass of Bennu before the spacecraft goes into orbit on December 31. Although scientists have studied the object well, it is extremely difficult to maneuver around a small body that has virtually no gravity. OSIRIS-REx will move 10 cm per second relative to the asteroid when it goes into orbit. The device will be able to set a record for the nearest distance of rotation around a small body. On December 31, it will reach a distance of 1.6 km from the surface. After fixing in orbit the tempo is not going to increase. The distance will be shortened by July 2020, when they choose two sites for the extraction of samples.
The spacecraft uses a special capture mechanism, extracting (sucking) 60 grams of material (at a minimum). The maneuver will take no more than 5 seconds. OSIRIS-REx will stay near Bennu until March 2021, after which it will go to Earth. Scientists are expected to receive samples in September 2023.
Researchers around the world will be able to study the material obtained with the help of expensive and advanced equipment that could not be contained in the apparatus. Analyzes will help to better understand the early period of the solar system and the role that carbon-rich asteroids played in the life of the earth.
Probe measurements will also determine asteroid potential, such as Bennu. Accurate tracking of the object will help to better understand the non-gravitational forces that form the trajectories of asteroids.