Here at CosmoQuest – home of the Daily Space – our citizen scientists were part of mapping the asteroid Bennu to find a suitable site for the OSIRIS-REx mission to grab a rock sample to bring to Earth. We are now one week away from this sampling event! We will be simulcasting any NASA live streams here on CosmoQuestX on Twitch.tv.
According to a suite of journal articles that came out last week, Bennu is considered to be a rubble pile asteroid with material from multiple objects – including a few pieces knocked off Vesta – that are gravitationally held together. According to project scientist Vicki Hamilton: Our recent studies show that organics and minerals associated with the presence of water are scattered broadly around Bennu’s surface, so any sample returned to Earth should contain these compounds and minerals. We will compare the sample’s relative abundances of organics, carbonates, silicates, and other minerals to those in meteorites to help determine the scenarios that best explain Bennu’s surface composition.
Put another way, they are hoping that the few grams of material they’re able to pick up will allow us to work backward to figure out the mineral recipe that makes up Bennu. It appears to be a mixture of rocks that formed in dry and wet environments, but the ratios and details still need reverse engineered.
And next week, the needed material will get picked out of Nightingale Crater to be flown home next year. This mission is following in the path of Hayabusa2, which collected samples from asteroid Ryugu that will be returned to Earth on December 6 of this year.
When that happens, we’ll bring you the science.
“Variations in Color and Reflectance on the Surface of Asteroid (101955) Bennu,” D. N. DellaGiustina et al., 2020 Oct. 8, Science
“Bright Carbonate Veins on Asteroid (101955) Bennu: Implications for Aqueous Alteration History,” H. H. Kaplan et al., 2020 Oct. 8, Science
“Widespread Distribution of Carbon-Bearing Materials on Near-Earth Asteroid (101955) Bennu,” Amy Simon et al., 2020 Oct. 8, Science