This week, NASA officials announced that NASA’s Osiris Rex spacecraft will leave the near-Earth asteroid Bennu and begin a nearly three-year journey to Earth.
The spacecraft, formally known as Origins, Spectroscopy, Resource Identification, Security and Regolith Explorer, is carrying a massive sample that it collected from the asteroid’s surface in October. The goal of the mission was to collect 60 grams or 2 ounces of material – and although scientists won’t know for sure until they open it, the collection event appears to have exceeded this goal. The regolith is a layer of dust and broken rocks on the surface of asteroids and planets.
A sample taken from the asteroid could shed more light on the formation of the solar system and how elements such as water may have reached Earth earlier through the effects of these rock remnants.
When Osiris Rex departs Benno in May, it will begin a 200-million-mile journey back to Earth. The sample is expected to be delivered to Earth on September 24, 2023.
The spacecraft first arrived to take a closer look at Bennu in 2018 and has been orbiting the asteroid since then. We will take a final look at the asteroid before the spacecraft bid farewell to its only companion in space over the past few years.
In April, the spacecraft will make a final flyby of the asteroid to see how the spacecraft’s contact with the Bennu surface may have altered the sample collection location.
Originally, Osiris was scheduled to leave Rex Pino in March.
“Leaving neighboring Benno in May puts us in the” perfect spot, “when the departure maneuver consumes the least amount of fuel on board the spacecraft, said Michael Morrow, deputy project director for OSIRIS-REx at NASA’s Goddard Space Flight Center in Greenbelt. Maryland in a statement.
“However, with speed changing by more than 593 mph (265 meters per second), this will be the largest propulsion maneuver by OSIRIS-REx since approaching Bennu in October 2018.”
Flying in early April wasn’t part of the mission at first, so departing in May allows more time for that last look.
If all goes according to plan, OSIRIS-REx will fly over the sample site, called Nightingale, from two miles away.
When the sample collection head on the spacecraft arm descended to the surface of the asteroid in October, it actually sank about 1.6 feet below the material on the asteroid. This event was called TAG, or Touch and Go.
The spacecraft also launched its propellers to safely away from the asteroid.
It is possible that these two events caused material to form on the asteroid’s surface and altered the appearance of the Nightingale’s site.
This flight will be similar to the one Osiris Rex made in Benno for about a year before the mission team decided on a suitable location to land and collect a sample.
The spacecraft will observe the full rotation of Pino, including the northern and southern hemispheres and the equator, and those images can be compared to the images it collected in 2019.
The flyby also serves as a good test for the scientific instruments on OSIRIS-REx, which may have been covered in dust during sample collection. The spacecraft may have a future that goes beyond this mission if everything is going well because it will simply drop the sample back to Earth, and it will never land on the planet again.
Once OSIRIS-REx approaches Earth in 2023, it will dispose of the capsule containing the sample, which will shoot through Earth’s atmosphere and parachute into the Utah desert.
The team will be on hand to retrieve the sample from the hangar that will serve as a temporary cleanroom. The sample will then be transported to laboratories currently under construction at the Johnson Space Center in Houston.
“Osiris-Rex has indeed presented incredible science,” said Lori Glaze, NASA’s director of planetary science, in a statement. “We are really excited that the mission is planning another observational flight of asteroid Bennu to provide new information about how the asteroid is responding to TAG and to make an appropriate farewell.”