NASA’s Robotic Explorer OSIRIS-REx Arrived At Asteroid Bennu

MessageToEagle.com – NASA’s robotic spacecraft OSIRIS-Rex arrived at the asteroid Bennu Monday. The spacecraft executed a maneuver that transitioned it from flying toward Bennu to operating around the asteroid.

Now, at about 11.8 miles (19 kilometers) from Bennu’s Sun-facing surface, OSIRIS-REx will begin a preliminary survey of the asteroid. The spacecraft will commence flyovers of Bennu’s north pole, equatorial region, and south pole, getting as close as nearly 4 miles (7 kilometers) above Bennu during each flyover.

The primary science goals of this survey are to refine estimates of Bennu’s mass and spin rate, and to generate a more precise model of its shape. The data will help determine potential sites for later sample collection. The mission’s navigation team will use the preliminary survey of Bennu to practice the delicate task of navigating around the asteroid.

The spacecraft will enter orbit around Bennu on Dec. 31 — thus making Bennu, which is only about 1,600 feet (492 meters) across — or about the length of five football fields — the smallest object ever orbited by a spacecraft.

It’s a critical step in OSIRIS-REx’s years-long quest to collect and eventually deliver at least two ounces (60 grams) of regolith — dirt and rocks — from Bennu to Earth.

“The OSIRIS-REx team is proud to cross another major milestone off our list — asteroid arrival,” Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson, said in a press release.

“Initial data from the approach phase show this object to have exceptional scientific value. We can’t wait to start our exploration of Bennu in earnest. We’ve been preparing for this moment for years, and we’re ready.”

OSIRIS-REx mission is the first U.S. mission to carry samples from an asteroid back to Earth and the largest sample returned from space since the Apollo era. It’s the first to study a primitive B-type asteroid, which is an asteroid that’s rich in carbon and organic molecules that make up life on Earth.

When OSIRIS-REx begins to orbit Bennu at the end of this month, it will come close to approximately three quarters of a mile (1.25 kilometers) to its surface. In February 2019, the spacecraft begins efforts to globally map Bennu to determine the best site for sample collection.

After the collection site is selected, the spacecraft will briefly touch the surface of Bennu to retrieve a sample. OSIRIS-REx is scheduled to return the sample to Earth in September 2023.

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