Scientists study the rugged surface of near-Earth asteroid Bennu — ScienceDaily

As the times count down to NASA’s OSIRIS-REx spacecraft’s Contact-And-Go asteroid sample collection attempt, Southwest Study Institute researchers have aided identify what the spacecraft can be expecting to return from the close to-Earth asteroid Bennu’s surface. 3 papers published on line by Science on Oct. 8 go over the color, reflectivity, age, composition, origin and distribution of products that make up the asteroid’s rough surface.

On Oct twenty, the spacecraft will descend to the asteroid’s boulder-strewn surface, touch the floor with its robotic arm for a few seconds and obtain a sample of rocks and dust — marking the very first time NASA has grabbed pieces of an asteroid for return to Earth. SwRI researchers performed a role in the selection of the sample internet sites. The very first attempt will be built at Nightingale, a rocky place sixty six toes in diameter in Bennu’s northern hemisphere. If this historic attempt is unsuccessful, the spacecraft will attempt again at a secondary site.

Given 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 discovered carbon-bearing compounds on Bennu’s surface, a very first for a close to-Earth asteroid, as nicely as minerals made up of or shaped by water. Experts also examined the distribution of these products, globally and at the sample internet sites

“Our latest experiments exhibit that organics and minerals involved with the presence of water are scattered broadly all-around Bennu’s surface, so any sample returned to Earth really should contain these compounds and minerals,” mentioned SwRI’s Dr. Vicky Hamilton, a coauthor on all 3 papers. “We will assess the sample’s relative abundances of organics, carbonates, silicates and other minerals to these in meteorites to assist identify the situations that ideal describe Bennu’s surface composition.”

Asteroid Bennu is a dim, rubble pile held alongside one another by gravity and considered to be the collisional remnant of a much larger sized primary-belt item. Its rubble-pile nature and seriously cratered surface suggests that it has had a rough-and-tumble life given that currently being liberated from its much larger sized dad or mum asteroid hundreds of thousands or even billions of many years ago.

“Boulders strewn about close to the Nightingale site have vibrant carbonate veins,” Hamilton mentioned. “Bennu shares this compositional trait with aqueously altered meteorites. This correlation indicates that at least some carbonaceous asteroids had been altered by percolating water in the early Solar Program.”

The boulders on Bennu have assorted textures and colours, which might provide information and facts about their variable exposure to micrometeorite bombardment and the photo voltaic wind more than time. Finding out color and reflectance information provide information and facts about the geologic heritage of planetary surfaces.

“Bennu’s assorted surface contains abundant primitive substance most likely from different depths in its dad or mum human body as well as a little proportion of overseas products from another asteroid family members littered about its surface,” mentioned SwRI’s Dr. Kevin Walsh, a coauthor of a person of the papers. “In addition, both of those the primary and again-up sample internet sites, Nightingale and Osprey, are situated within little spectrally reddish craters that are considered to be far more pristine, owning experienced much less house weathering than most of Bennu’s bluish surface.”

The OSIRIS-REx workforce is also comparing Bennu to Ryugu, another close to-Earth asteroid. Both equally asteroids are considered to have originated from primitive asteroid households in the internal primary belt. The Japan Aerospace Exploration Company launched Hayabusa2 in 2014 and rendezvoused with close to-Earth asteroid Ryugu in 2018. Right after surveying the asteroid for a year and a half, the spacecraft collected samples and is envisioned to return to Earth December six, 2020.

The sample returned by OSIRIS-REx, blended with the surface context maps OSIRIS-REx has collected, will enhance interpretations of readily available floor and house telescope information for other primitive dim asteroids. Comparing returned Bennu samples with these of Ryugu will be instrumental for being familiar with the variety within, and heritage of, asteroid households and the complete asteroid belt.

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