NASA officially concluded the OSIRIS‑REx mission on Sept. 30, marking the end of the first United States effort to collect a pristine piece of an asteroid and bring it safely back to Earth. The van‑sized spacecraft, whose acronym stands for Origins, Spectral Interpretation, Resource Identification, Security‑Regolith Explorer, spent a decade traveling to and sampling the carbon‑rich near‑Earth asteroid Bennu.
Mission milestones and challenges
OSIRIS‑REx launched on Sept. 8, 2016, after a $1 billion New Frontiers Program approval in 2011 that followed two earlier rejections. The probe’s journey across the inner solar system culminated in a 2018 arrival at Bennu, which turned out to be a loosely bound collection of jagged boulders rather than the smooth, sandy sphere scientists had anticipated. “Our expectations about the asteroid’s surface were completely wrong,” Principal Investigator Dante Lauretta said in an Oct. 7 statement.
When the spacecraft touched down in the Nightingale crater, the surface offered little resistance, behaving more like a fluid than solid rock. The sampling head sank 20 inches (51 cm) before thrusters pulled it back, securing a sample. A subsequent jam of the collector lid threatened loss of material, but the team quickly stowed the head inside the return capsule, preserving the cargo.
The return phase was equally tense. The capsule’s parachute malfunctioned during re‑entry on Sept. 24, 2023, yet the vehicle landed safely in the Utah desert. Lauretta reflected that successful missions are those designed to adapt to surprise, noting that OSIRIS‑REx repeatedly faced unexpected circumstances and still found a way forward.
Scientific returns
The mission delivered 4.29 ounces (121.6 grams) of asteroid material, more than twice the mission’s original requirement and the largest sample ever retrieved from an asteroid. Remote‑sensing observations confirmed Bennu’s surface is coated in carbon‑bearing compounds and revealed that the rock originated from a larger, water‑rich parent body that shattered in the main asteroid belt.
Laboratory analysis has already identified amino acids and sugars—molecules essential for life on Earth—as well as evidence of past exposure to liquid water that could have acted as a “broth” for chemical interactions. Over 200 research papers are now in press, piecing together the composition and history of the ancient rock.
In addition to the scientific haul, OSIRIS‑REx set a Guinness World Record by entering orbit around Bennu, a 1,610‑foot‑wide (490 m) body that became the smallest object ever circled by a spacecraft.
Future of the spacecraft
Although the OSIRIS‑REx chapter is closed, the probe itself continues under the new name OSIRIS‑APEX (OSIRIS‑Apophis Explorer). Using remaining propellant, the spacecraft will travel to the near‑Earth asteroid Apophis, a different type of space rock, with an expected arrival in 2029.
Most of the Bennu sample will be preserved for future generations of scientists, who will study it with instruments and questions that have not yet been imagined, according to Lauretta. The mission’s legacy therefore extends beyond its immediate discoveries, offering a lasting resource for planetary science.
Steve Lopez is a Senior Editorial Columnist and Health & Public Policy reporter for News Raise. Steve focuses on healthcare advancements, medical technologies, and public health policies.
