Scientists study the rugged surface of near-Earth asteroid Bennu

As the days rely down to NASA’s OSIRIS-REx spacecraft’s Contact-And-Go asteroid sample collection attempt, Southwest Analysis Institute researchers have served ascertain what the spacecraft can assume to return from the near-Earth asteroid Bennu’s floor. Three papers released on-line by Science on Oct. 8 focus on the color, reflectivity, age, composition, origin and distribution of products that make up the asteroid’s tough floor.

On October 20, the spacecraft will descend to the asteroid’s boulder-strewn floor, touch the ground with its robotic arm for a couple seconds and acquire a sample of rocks and dust — marking the to start with time NASA has grabbed items of an asteroid for return to Earth. SwRI researchers played a function in the choice of the sample websites. The to start with attempt will be designed at Nightingale, a rocky location sixty six toes in diameter in Bennu’s northern hemisphere. If this historic attempt is unsuccessful, the spacecraft will consider once more at a secondary website.

Considering the fact that the spacecraft arrived at Bennu in 2018, researchers have been characterizing the asteroid’s composition and comparing it to other asteroids and meteorites. The mission found carbon-bearing compounds on Bennu’s floor, a to start with for a near-Earth asteroid, as very well as minerals made up of or shaped by h2o. Scientists also researched the distribution of these products, globally and at the sample websites

“Our modern reports demonstrate that organics and minerals linked with the existence of h2o are scattered broadly close to Bennu’s floor, so any sample returned to Earth need to contain these compounds and minerals,” claimed SwRI’s Dr. Vicky Hamilton, a coauthor on all a few papers. “We will examine the sample’s relative abundances of organics, carbonates, silicates and other minerals to all those in meteorites to help ascertain the scenarios that very best make clear Bennu’s floor composition.”

Asteroid Bennu is a darkish, rubble pile held together by gravity and imagined to be the collisional remnant of a considerably more substantial principal-belt item. Its rubble-pile mother nature and closely cratered floor implies that it has had a tough-and-tumble existence considering that becoming liberated from its considerably more substantial mother or father asteroid tens of millions or even billions of years in the past.

“Boulders strewn about near the Nightingale website have bright carbonate veins,” Hamilton claimed. “Bennu shares this compositional trait with aqueously altered meteorites. This correlation implies that at least some carbonaceous asteroids have been altered by percolating h2o in the early Photo voltaic Program.”

The boulders on Bennu have numerous textures and hues, which might offer information and facts about their variable publicity to micrometeorite bombardment and the photo voltaic wind above time. Researching color and reflectance info offer information and facts about the geologic history of planetary surfaces.

“Bennu’s numerous floor incorporates ample primitive material probably from different depths in its mother or father entire body plus a small proportion of overseas products from a different asteroid spouse and children littered about its floor,” claimed SwRI’s Dr. Kevin Walsh, a coauthor of a person of the papers. “In addition, equally the main and back-up sample websites, Nightingale and Osprey, are situated in just small spectrally reddish craters that are imagined to be much more pristine, possessing experienced fewer place weathering than most of Bennu’s bluish floor.”

The OSIRIS-REx workforce is also comparing Bennu to Ryugu, a different near-Earth asteroid. Each asteroids are imagined to have originated from primitive asteroid family members in the internal principal belt. The Japan Aerospace Exploration Company introduced Hayabusa2 in 2014 and rendezvoused with near-Earth asteroid Ryugu in 2018. Right after surveying the asteroid for a year and a 50 %, the spacecraft gathered samples and is anticipated to return to Earth December six, 2020.

The sample returned by OSIRIS-REx, merged with the floor context maps OSIRIS-REx has gathered, will enhance interpretations of offered ground and place telescope info for other primitive darkish asteroids. Comparing returned Bennu samples with all those of Ryugu will be instrumental for being familiar with the range in just, and history of, asteroid family members and the whole asteroid belt.

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