Two recent investigations reveal new features regarding the composition of Bennu. The samples captured by the OSIRIS-REx space probe will arrive on Earth in 2023 to be studied in a laboratory.
Those responsible for The OSIRIS-REx space mission have revealed that the probe managed to collect 250 grams of samples from the asteroid Bennu. This helps to reveal new details regarding the formation of the rocky body, as published this Thursday (07.07.2022) by two articles in the journal Science.
The return of the National Aeronautics and Space Administration (NASA) probe, scheduled for next year, is now expected. Scientists have been investigating the physical properties that lie up to ten centimeters below the surface of the asteroid.
The analysis of data from the probe indicates that the surface of (101955) Bennu -its official name- is made up of low-cohesion debris and the underground material it possesses is darker and finer..
Data gathered during the sampling of asteroid #Deciding by the #OSIRISREx mission shows that the asteroid’s surface consists of low-cohesion rubble, according to two new studies—one each in Science and @ScienceAdvances. ???? pic.twitter.com/Trz34aBbww
— Science Magazine (@ScienceMagazine) July 7, 2022
More details on the characteristics of the asteroid Bennu
one of the studies, led by the Southwest Research Institute (USA), analyzed the forces experienced by the spacecraft. There they found that Bennu’s low gravity has given rise to a granular surface bed with weak inter-particle cohesion.
The researchers recreated the forces exerted on the spacecraft when it drove the sample collection mechanism once morest Bennu’s surface. This provided direct evidence of the near-surface physical properties of debris asteroids or rock fragments in microgravity. Little known so far.
The team found that the near-surface material is loosely packed and less dense than the average for the asteroid as a whole, with very low cohesion. The material’s high porosity and low resistance allow dust and other small particles to move to the asteroid’s subsurface.
Also, spectral and thermal data collected during the mission suggest that these results apply to the entire asteroid and are not unique to the sampling site.
Surprises during the extraction of the samples
the second jobled by the University of Arizona (USA), presents the spectral and image data from the probe collected during and following the collection of a sample from Bennu’s surface.
“Our expectations regarding the surface of the asteroid were completely wrong. There was no obvious place to collect a sample anywhere,” said lead author Dante Lauretta.
When extracting the samples, pieces of rock and dust broke off, excavating an elliptical crater 9 meters long.: “What we saw was a huge wall of debris coming out of the sample site,” Lauretta recounted. The exposed material was darker and more abundant in fine particles than the original surface.
Why is the asteroid Bennu studied?
The particles that fell onto the instrument’s optics spectrally resemble water-altered carbonaceous meteorites, according to the researchers.
The OSIRIS-REx mission ship arrived in 2018 to where Bennu is located. After two years of observation and exploration, The probe took 250 grams of samples that are currently heading to Earth to be analyzed in a laboratory.
Although there are more than a million known asteroids in the Solar System, Bennu, a rocky body regarding 500 meters in diameter that might impact the Earth in just over 100 years, it is the ideal candidate for a study due to its size, composition and its proximity to Earth, according to NASA.
