While we celebrated a new year, NASA had other reasons to celebrate on December 31. That was the date when the OSIRIS-REx spacecraft managed to go into orbit around Bennu. For those who do not know, Bennu is an asteroid close to Earth.
The spacecraft managed to break a record, Bennu being the smallest object that was ever orbited by a spacecraft. OSIRIS-REx reached Bennu on December 31, 2018, at 18:43 UTC (2:43 p.m. EST). The object is located 70 million miles away from our planet.
“The team [performed] the orbit-insertion maneuver perfectly. With the navigation campaign coming to an end, we are looking forward to the scientific mapping and sample site selection phase of the mission,” explained Dante Lauretta, the OSIRIS-REx principal investigator at the University of Arizona Tucson. “Our orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field, which we didn’t know before we arrived,” he added.
Bennu is definitely smaller than you’d imagine, and scientists explained that its gravity is barely enough to keep a vehicle in a stable orbit. Thermal pressure and solar radiation are also stronger there. The OSIRIS-REx is about a mile away from the center of Bennu. The spacecraft should orbit the asteroid through February.
“Our orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field, which we didn’t know before we arrived. Up until now, we had to account for a wide variety of possible scenarios in our computer simulations to make sure we could safely navigate the spacecraft so close to Bennu. As the team learned more about the asteroid, we incorporated new information to hone in on the final orbit design,” explained Mike Moreau, OSIRIS-REx’s flight dynamics system manager.
Brad is a former Senior Fellow at the Schuster Institute for Investigative Journalism at Brandeis University, is an award-winning travel, culture, and parenting writer. His writing has appeared in many of the Canada’s most respected and credible publications, including the Toronto Star, CBC News and on the cover of Smithsonian Magazine. A meticulous researcher who’s not afraid to be controversial, he is nationally known as a journalist who opens people’s eyes to the realities behind accepted practices in the care of children. Brad is a contributing journalist to Advocator.ca