The National Aeronautics and Space Administration (NASA) successfully collected 70 grams of samples from the asteroid Bennu, exceeding the previous target of 60 grams. Despite the challenges encountered during the extraction process, more material awaits collection as the team ensures the purity of the sample.
The exterior view of the OSIRIS-REx sample collector. Sample material from asteroid Bennu can be seen at center right. Scientists found evidence of carbon and water in preliminary analyzes of the materials. Most of the specimens are located inside. Image source: NASA/Erika Blumenfeld & Joseph Aebersold
The sample processing team has removed and collected 2.48 ounces (70.3 grams) of rock and dust from the sampler hardware - exceeding the agency's goal of bringing at least 60 grams of samples to Earth. The good news is that NASA's OSIRIS-REx (Origin, Spectral Interpretation, Resource Identification and Security - Rock Explorer) sample has more to collect.
The samples currently being processed include rocks and dust from the outside of the sampler head, as well as some bulk samples from the inside of the sampler head, which can be accessed through the tape baffle of the sampler head. Additional material remaining inside the sampler head, known as the Touch and Move Sample Acquisition Mechanism (TAGSAM), will be removed later, adding to the overall mass.
Members of the OSIRIS-REx cleanup team at NASA's Johnson Space Center begin removing and turning over the TAGSAM (Touch-and-Go Sample Acquisition Mechanism) from the science canister's avionics deck. Image source: NASA/James Blair
Last week, a team at NASA's Johnson Space Center in Houston changed the method of opening TAGSAM's head. After multiple disassembly attempts, the team discovered that two of the 35 fasteners on the TAGSAM head could not be removed with tools currently approved for use in the OSIRIS-REx glove box. The research team has been working hard to develop and implement new methods to extract materials from inside the head while continuing to keep the sample safe and pristine.
As a first step, the team successfully obtained part of the material by holding down the tape baffle on the head and removing the sample inside with tweezers or a spoon, depending on the size of the material. By collecting and controlling the material in this way, plus the previously collected material located on the outside of the head, the total mass exceeds the required 60 grams.
This imaging sequence, captured on October 27, 2020, shows NASA's OSIRIS-REx spacecraft successfully placing the sample collection head into the sample return capsule (SRC). The sequence begins with the collection head hovering over the SRC behind the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) arm and moving it into position for collection. At the end of the procedure, the collection head is fixed on the capture ring of the SRC. Some particles can also be seen escaping from the capsule. This image sequence was captured by a StowCam camera. StowCam is a color imager, one of three cameras that make up TAGCAMS (Touch-and-Go Camera System), which is part of the OSIRIS-REx guidance, navigation and control system. Source: NASA/Goddard/University of Arizona/Lockheed Martin
The team will spend the next few weeks developing and practicing a new procedure to remove the remaining asteroid samples from the TAGSAM sampling head while processing the material collected this week. The OSIRIS-REx science team will also continue its plans to characterize the extracted material and begin analysis of the large number of samples obtained so far.
All preservation of samples and TAGSAM heads is carried out in a special glove box filled with nitrogen to prevent the samples from being exposed to the earth's atmosphere, thus maintaining the original state of the samples for subsequent scientific analysis. Tools for any proposed solution to extract remaining material from the head must fit inside a glove box without compromising the scientific integrity of the collection, and any procedures must meet cleanroom standards.
While the team develops procedures to extract the final portion of the material, the team has removed the TAGSAM head from the active nitrogen flow inside the glove box and stored it in a transfer container, sealed with an O-ring and surrounded by a sealed Teflon bag to ensure the sample is kept safe in a stable, nitrogen-rich environment.