Osiris-Rex: NASA's Asteroid Mission Gathers Smaller Sample

NASA/R.MARKOWITZ

NASA's asteroid sample-return mission appears to have brought back a slightly smaller amount of material than initially estimated

Scientists initially speculated that the Osiris-Rex capsule, which landed in Utah in September, might contain approximately 250 grams of rock from the asteroid Bennu. This projected quantity was likened to the weight of a large hamster by a U.S. space agency official. However, researchers have now revised their estimate downward. Despite the adjustment, they still expect the final amount of collected material to be significant.

NASA targeted the 500-meter-wide asteroid Bennu because its composition is expected to provide valuable insights into the formation of the Solar System around 4.6 billion years ago, and potentially shed light on the origins of life on Earth.

The uncertainty regarding the exact amount of material collected from Bennu during NASA's Osiris-Rex mission has a straightforward explanation: the mission team has been unable to fully open the mechanism used to capture and store the material taken from the asteroid. Although scientists have collected 70.32 grams of dust that spilled from the mechanism, called the TagSam, two fasteners holding down an enclosing plate are resisting unscrewing.

As a result, the majority of the collected extraterrestrial material remains inaccessible. Despite this setback, researchers have managed to weigh the TagSam. By comparing its mass before and after collecting the sample, they estimate that the hidden contents from Bennu likely amount to approximately 120 grams, with a margin of error of around 20 grams. This suggests that the total material collected may be around 170 grams instead of the initially estimated 250 grams.

NASA/Erika Blumenfeld & Joseph Aebersold

Principal investigator Dante Lauretta emphasizes that the 70 grams of material collected is still a substantial achievement, exceeding the mission's requirement of 60 grams. Lauretta, a professor at the University of Arizona, expressed his excitement, stating, "We're ecstatic; sixty grams was the requirement before the mission, and we've already got 70. So, I couldn't be happier."

To access the remaining material, a part of the team is working on designing new tools to open the TagSam, and this process is expected to take place next year. Nasa's director of planetary science, Dr. Lori Glaze, noted that while the samples are billions of years old, they can wait a few more weeks for the necessary tools to be fabricated and tested.

The largest piece of Bennu extracted from the TagSam so far measures 3.5 centimeters across, but a significant portion of the 70 grams comprises tiny fragments that are sub-millimeter in size. Scientists around the world are receiving portions of these samples for analysis, and early findings suggest that Bennu was an excellent choice for study.

Preliminary analysis indicates that the asteroid contains abundant water in the form of hydrated minerals and a substantial amount of organic, carbon-rich compounds. This is significant, as it aligns with the theory that carbon-rich, water-rich asteroids, similar to Bennu, may have played a role in delivering essential components to the young Earth, contributing to the formation of oceans and the chemistry needed for life's beginnings.

The global collaboration of scientists is specifically examining the samples for amino acids (building blocks of biological proteins), base chemicals forming the "letters" in the genetic code, lipids used in cell membranes, and types of sugars essential to the structure of DNA.

"There will be some exciting, detailed organic molecular results coming soon. But the team needs a bit more time to think about them because we need to make sure all the results are correct. This is so important; we don't want to make a mistake," explained Professor Lauretta, speaking at the American Geophysical Union Fall Meeting in San Francisco.