The spacecraft's round-trip journey to asteroid Bennu concluded with an almost perfect landing of its sample return capsule on Sunday morning in Utah. The OSIRIS-REx mothership, which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, released the capsule to descend into the atmosphere while utilizing its thrusters to maneuver onto a trajectory for its extended mission to another asteroid within the Solar System.
Following a swift retrieval by ground teams, the capsule was transported from Utah to NASA's Johnson Space Center in Houston on Monday via a US Air Force cargo plane. Subsequently, it was sent to a meticulously constructed super-clean curation facility located at the space center. This facility is renowned for housing Moon rocks collected during NASA's Apollo missions, over half a century ago.
The sample canister was then carefully placed inside a glovebox, allowing scientists to manipulate the hardware through gloved ports. On Tuesday, a pivotal moment occurred when the scientists finally opened the lid.
"Today, we opened up the canister and visually observed some visible black dust-like material," shared Lauretta on Tuesday. "We are hopeful that this material is from Bennu. We anticipate collecting a portion of it tomorrow morning, which will then be sent directly to laboratories."
Lauretta, the principal investigator of the OSIRIS-REx mission, added, "This is our initial glimpse of what we might have. There are positive indications that we have obtained a sample."
When the spacecraft departed from the roughly 1,600-foot-wide (500-meter) asteroid Bennu in 2020, engineers estimated that it had collected approximately 250 grams (8.8 ounces) of specimens from the asteroid's porous surface. To obtain these samples, the spacecraft employed a robotic arm, extending it in front of Bennu, and briefly making contact with the asteroid's surface. Upon contact, the spacecraft released gas to facilitate the capture of loose rocks into a collection chamber cleverly designed like an air filter at the end of the robot arm. This instrument is known as the Touch-and-Go Sample Acquisition Mechanism (TAGSAM).
Upon analysis, scientists discovered that the collection chamber's door was blocked open by larger rocky material, leading to some fragments escaping into space. Consequently, they promptly secured the sampling device inside the return capsule to prevent further material loss. This raised the possibility among some scientists on the OSIRIS-REx team that the spacecraft may have returned with an even greater quantity of material than the estimated 250 grams, which already surpassed the mission's minimum requirement by fourfold.
Until next month, researchers will likely remain uncertain about the exact amount of material that OSIRIS-REx has brought back. To determine this, the laboratory team in Houston must remove the TAGSAM sampling mechanism from its protective restraint inside the canister, akin to nested dolls, which safeguarded it during the journey back to Earth. Subsequently, the device will be opened, and it is hoped that larger rock fragments will be discovered. All of these tasks are expected to occur within the following couple of weeks.
Despite the limited information available, the preliminary examination of the sample canister reveals promising signs.
"By Friday, we should have gained significant insights from the quick-look analysis," Lauretta stated. "Firstly, we need to ascertain whether we have actual asteroid dust. This is the primary consideration. Additionally, we will determine if the material aligns with our prior remote sensing observations of the asteroid. This information will also contribute to our detailed sample analysis plan, which has been under development over the past two years.
"However, we must note that, at present, we can only visually observe the dust. The true treasure lies within TAGSAM, an area yet to be accessed and likely to occur towards the end of next week. This process will be executed with utmost care to ascertain the nature of the collection, distribute it fairly among our international partners and the OSIRIS-REx science team, and preserve its long-term integrity for future researchers."
Approximately 70 percent of the asteroid sample will be reserved by NASA for future analysis by scientists armed with advanced laboratory technologies and techniques. On October 11, NASA has scheduled a press conference to divulge additional details about the nature of the sample obtained from Bennu.
Lauretta expressed his excitement, stating, "I am thrilled because this marks the moment we have long dreamed of. The object that made contact with Bennu has now arrived in our laboratories. Naturally, we are eager to access it. However, there is still much work ahead. We must gain access to TAGSAM. That is where the true treasure lies, and we are fully prepared and enthusiastic to proceed."