NASA's OSIRIS-REx sample from the asteroid Bennu has exceeded expectations in terms of the amount of material, leading to slow progress in sorting it out. Advanced analytical methods are currently being used, with more detailed examinations planned in the coming weeks.

NASA's OSIRIS-REx initial work on sorting out samples from the asteroid Bennu is going slower than expected, but for the best reason: There are just too many samples. A large amount of material was discovered when the lid of the scientific canister was lifted earlier this week, which means the beginning of the process of dismantling TAGSAM (Touch-and-GoSampleAcquisitionMechanism).

After conducting a collection campaign on the Bennu asteroid three years ago, scientists saw particles slowly leaking out of the TAGSAM head before it was stored, so they expected they might find some asteroid material in the canister outside the TAGSAM head. However, the actual amount of dark particles covering the inside of the lid and base surrounding TAGSAM was higher than they expected.

"The best 'problem' was that there was so much material that it took longer than we expected to collect it," said Christopher Snead, OSIRIS-REx associate curator at NASA's Johnson Space Center. "There's a lot of rich material beyond the TAGSAM head that's interesting in its own right. It's just spectacular to have all that material there."

An animation of NASA's OSIRIS-REx spacecraft leaving the surface of asteroid Bennu after collecting samples. Image source: NASA Goddard Space Flight Center/CILab/SVS

The first sample taken from the avionics deck outside TAGSAM's head is now in the hands of scientists, who are conducting rapid analysis that will give us a first look at Bennu's material and what we can expect to find when the bulk sample is revealed.

"We have all the microscopic analysis techniques to really, really take it apart, almost down to the atomic scale," said Lindsay Keller, a member of the OSIRIS-REx sample analysis team at Johnson & Johnson.

Rapid observation studies will utilize a variety of instruments, including scanning electron microscopy (SEM), infrared measurements and X-ray diffraction (XRD), to better understand the sample.

Taken on October 20, 2020, during the Touch-And-Go (TAG) sample collection event of the OSIRIS-REx mission, these two sets of images show the SamCam imager's field of view before and after the NASA spacecraft touched the surface of asteroid Bennu. Image credit: NASA/Goddard/University of Arizona

Scanning electron microscopy will provide chemical and morphological analysis, while infrared measurements will provide information on whether the sample contains hydrated minerals and organic-rich particles. X-ray diffraction is sensitive to the different minerals in the sample and will provide a list of minerals and perhaps show their proportions.

This rapid observational science tool will provide researchers with more data as they get closer to bulk samples for subsequent analysis.

Over the next few weeks, the finishing team will move the TAGSAM head to another specialized glovebox, where they will perform a complex disassembly process that will ultimately reveal the bulk of the sample within.