What To Know
- The mission OSIRIS-REx was launched with the goal of collecting samples from Bennu, a small B-type asteroid known for its carbon-rich composition and proximity to Earth.
- Magnesium-containing phyllosilicates, identified as the main constituents of the regolith samples, also offer clues about the geological conditions in which Bennu formed and evolved over time.
- These findings open new avenues for space research, providing crucial insights into the processes of solar system formation and the prebiotic chemistry that may have contributed to the conditions for life on Earth.
On September 24, 2023, a landmark event in space exploration occurred when NASA successfully returned asteroid samples collected by the OSIRIS-REx spacecraft to Earth. After a seven-year journey through the Solar System, the historic mission recovered approximately 120 grams of pristine carbonaceous regolith from the near-Earth asteroid Bennu.
Collecting samples from the asteroid Bennu
The mission OSIRIS-REx was launched with the goal of collecting samples from Bennu, a small B-type asteroid known for its carbon-rich composition and proximity to Earth. After several years of observations and preparation, the spacecraft used its Touch-and-Go Sample Acquisition Mechanism (TAGSAM) to collect regolith from a particularly promising site, Bennu’s Hokioi Crater, also known as the Nightingale site. The recovered samples were then carefully packed into a special capsule and returned to Earth on September 24, 2023. They now represent the largest reservoir of unaltered asteroid material ever recovered, providing scientists with a unique opportunity to study materials that have not been altered by Earth’s atmosphere or other processes.
Illustration of the Osiris-Rex probe flying over the surface of the asteroid Bennu. Credits: NASA / Goddard / University of Arizona
Scientific findings and implications
The first analyzes Samples revealed expected components such as carbon and water, confirming hypotheses about Bennu’s composition based on previous observations. However, one unexpected discovery caught the attention of researchers: the presence of magnesium sodium phosphatean ionic compound often associated with vital biochemical processes on Earth. The presence of this phosphate on Bennu suggests potentially aqueous origins for the asteroid, raising questions about its history and evolution. Magnesium-containing phyllosilicates, identified as the main constituents of the regolith samples, also offer clues about the geological conditions in which Bennu formed and evolved over time. This discovery thus suggests that Bennu’s parent body was a water-filled objectwhich opens new perspectives on the geological and chemical processes that shaped this distant asteroid. This body could have been a primitive celestial object, probably made of material from the cloud of gas and dust from which our Solar System was formed.
