Free Astronomy Magazine January-February 2021

13 JANUARY-FEBRUARY 2021 ASTRO PUBLISHING O SIRIS-REx collector head on the TAGSAM arm being stowed in the Sample Return Capsule (SRC). [NASA/Goddard/University of Ari- zona/Lockheed Martin] N ASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Oct. 20, 2020, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023. [NASA’s Goddard Space Flight Center] warded on October 20, 2020, when the talon-like TAGSAM (Touch-and- Go Sample Acquisition Mechanism) arm collected somewhere between half and just-over a kilogram of re- golith to safely stow and return to Earth on 24 September 2023 for ex- haustive chemical and mineralogi- cal analyses. The regolith sampling from the “Nightingale” collection site was nearly flawless – flaps on the collec- tor meant to keep the material con- tained were instead blocked open by a few too many large particles, resulting in a steady release of small particulates. The secure stowing process of the remaining collection into the Sam- ple Return Capsule (SRC) was com- pleted on October 28 th , with a heralding confirmation taking 18.5 light minutes to reach Earth from the mission’s currently location. Our knowledge of chemistry and geology, when combined with spec- troscopic measurements of its sur- face, reveal a more complicated his- tory for Bennu than simply an aster- oid in near-Earth orbit. Certain min- erals can only be formed under certain combinations of pressure, heat, and, in some cases, water. When we observe certain minerals on asteroids, such as the carbona- ceous materials detected on Bennu, for which that body’s mass and composition are simply incapable of forming those minerals alone, we know that those minerals must have formed in some other environ- ment. Bennu is a large, undisturbed body today, but it very likely origi- nated from a catastrophic event for some much larger protoplanet very early in the formation of the solar system. By its composition and loca- tion, we can even estimate its ori- gin – there is a very high probability that Bennu originated from a body that now constitutes either the Polana or Eulania families of aster- oids in the inner asteroid belt. A key motivator for OSIRIS-REx was