NASA's OSIRIS-REx asteroid sample return mission has achieved extraordinary results, yielding findings about the asteroid 101955 Bennu, which significantly illuminate our knowledge of the origins of life. The mission, which started with the spacecraft's launch in 2016, culminated with the successful collection of samples during its touch-and-go operation on October 20, 2020, and the return of these samples to Earth on September 24, 2023.
Located around 300 million kilometers from Earth, Bennu was initially targeted because it is considered to be a remnant from the early Solar System, and researchers aimed to analyze its composition for insights about the building blocks of life. Following its collection, scientists analyzing the 120 grams of material from Bennu, which is roughly the weight of a banana, observed remarkable findings published recently.
A highlight of the research involves the detection of organic compounds and minerals found to be fundamental to life. Among the notable discoveries, 14 of the 20 amino acids—essential components for proteins found on Earth—were identified within the Bennu samples. This discovery has exciting implications. Dr. Daniel P. Glavin, the lead author and senior scientist at NASA's Goddard Space Flight Center, remarked, "This is all very exciting because it suggests asteroids like Bennu once acted like giant chemical factories in space and could have also delivered the raw ingredients for life to Earth and other bodies in our solar system."
During detailed analysis, researchers noted not just amino acids but also various briny salts and minerals, typically associated with the chemical pathways leading to life. Tim McCoy, curator of meteorites at the Smithsonian's National Museum of Natural History, co-leading one of the studies, explained, "We have discovered the next step on a pathway to life," referring to the remarkable insights gathered from this pristine extraterrestrial material.
The unique nature of the Bennu samples, shielded from Earth's atmospheric conditions, provides scientists with heightened confidence about their conclusions. Traditional meteorites, often altered during atmospheric entry, can obscure organic matter's true nature. Glavin asserted, "These organic molecules have all been found previously in meteorites, but the Bennu samples are pristine and were protected from heating during atmospheric entry and exposure to terrestrial contamination. So we have much higher confidence now." This comparison elevates the significance of the findings surrounding Bennu as unique and unaltered data about the origins of life.
The samples also reveal significant insights about the presence of salty minerals formed after water evaporated on Bennu's parent body, evidenced by finding compounds previously unobserved in asteroid samples. Yasuhito Sekine, from the Institute of Science Tokyo, emphasized the ramifications of these observations, explaining, "The salts would otherwise have rapidly absorbed moisture in the Earth's humid atmosphere." For researchers, these minerals imply Bennu's ancient environmental conditions may have supported the basic building blocks of life, potentially hinting at the broader processes of the Solar System's formation.
Additional findings about the structure of the amino acids—specifically their chirality—add another layer to our exploration of life's origins. Curiously, the samples exhibited equal distributions of left-handed and right-handed amino acids, starkly contrasting with the typical dominance of left-handed forms found within terrestrial life. "Even though asteroid Bennu has no life, the question is could other icy bodies harbor life?" queried Nick Timms, of Curtin University's School of Earth and Planetary Sciences, pondering the broader questions raised by Bennu's analysis.
This collection of findings draws attention to the significant role asteroids may play as conduits for life's building blocks — factors potentially influencing the conditions of early Earth and other celestial bodies. The OSIRIS-REx mission has provided a credible foundation for future explorations and studies about the origins of life, as researchers look to analyze samples from future missions beyond Bennu.
Such studies not only deepen our knowledge of life’s beginnings but also broaden our perspective on potential life-harboring celestial objects. The research emphasizes the importance of continued examination of various extraterrestrial bodies, promoting the idea of asteroids acting as life’s messengers. The mission's legacy could very well reshape our grasp on how life traversed from the cosmos to Earth, establishing pathways to support life.
NASA's successful endeavors with OSIRIS-REx demonstrate how space missions can yield fundamental discoveries about our existence and surroundings. The findings from Bennu are paving the way for future research, addressing the complex questions surrounding life’s origins and our wider solar system.