After travelling more than 1.25 billion miles in 27 months, NASA’s OSIRIS-REx probe has finally reached its destination. On December 3, 2018, the probe reached the diamond-shaped asteroid named Bennu in NASA’s first asteroid-sampling mission. The reason for this $800 million mission is to gather samples from the asteroid and return them to Earth in the year 2023. The name OSIRIS-REx stands for “Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer”.
But the probe isn’t ready to start digging for samples just yet. It is currently flying alongside the asteroid and will continue to do so for the next four weeks. The probe will fly around the 1,650-foot asteroid, even getting as close as 4.4 miles from its surface. The reason for these close flybys is to determine the asteroid’s mass and its exact shape before entering its orbit on December 31st.
Heather Enos, who is from the University of Arizona and is OSIRIS-REx Deputy Principal Investigator, told Space.com, “Manoeuvring around a small body that basically has no gravity is a very challenging endeavor.” She continued by saying, “So, we do have to get a little more information to proceed every step of the way.”
When the probe enters the asteroid’s orbit on December 31st, it will move at just 4 inches per second and get within one mile of its surface which will also set a record for the closest proximity that a spacecraft will have orbited a small body. The probe will then search around the asteroid for the best area to take samples and once an area is picked by July 2020, it will then spiral down to the surface and collect the sample. The entire process of collecting the sample won’t last much longer than about five seconds.
The probe will leave the asteroid in March 2021 and head back to Earth. Then in September 2023, the asteroid sample will land in Utah inside of a special return capsule.
Once the sample is collected, researchers will then study it with high-tech equipment in order to better comprehend the early days of the solar system and the potential role that carbon-rich asteroids could have played in the evolution of life on Earth. And by studying Bennu’s trajectory through space, it could help scientists better understand the non-gravitational forces that determine their paths, therefore helping to predict asteroid-impact forecasts.