NASA on Wednesday gave the public the first glimpse of what scientists found inside a sealed capsule returned to Earth last month containing a carbon-rich soil sample scooped from the surface of an asteroid, including hydrous clay minerals.
A small sample of the material collected from the near-Earth asteroid Bennu three years ago by the OSIRIS-REx spacecraft was unveiled in an auditorium at NASA’s Johnson Space Center in Houston, just over two weeks after it was dropped in the Utah desert. .
The return capsule landing capped a seven-year joint mission between the U.S. Space Agency and the University of Arizona. It was only the third asteroid sample, and by far the largest, to return to Earth for analysis, following two similar missions by the Japanese Space Agency that ended in 2010 and 2020.
“It’s days like these that never cease to amaze me,” NASA chief Bill Nelson said from the podium as he introduced the first photo of material retrieved from Bennu, a celestial artifact about 4.5 billion years old, onto a display .
The image showed a loose cluster of small charcoal-colored rocks, pebbles and dust left in the outer portion of the sample collection assembly when the asteroid’s soil was sucked through a filter in the spacecraft’s storage canister.
Technicians are still methodically disassembling the hardware surrounding the inner science canister that holds the bulk of the sample, a process expected to take another two weeks.
But the “bonus sample” of spillover material was immediately examined with electron microscopes and X-ray instruments, said Dante Lauretta, the mission’s principal investigator at the University of Arizona.
What they found was material with a high carbon content, nearly 5% by weight of an element essential to all life on Earth, as well as water molecules locked in the crystallized structure of clay fibers, Lauretta said.
Scientists also discovered iron minerals in the form of iron sulfides and iron oxides, “which in themselves are indicative of formation in a water-rich environment,” Lauretta told a later news briefing.
Daniel Glavin, a senior sample scientist at NASA’s Goddard Space Flight Center, said early analyzes showed the material appears to be “full of organics.”
The preliminary findings point to the likelihood of further discoveries that could support the hypothesis that early Earth was seeded with the primordial ingredients for life by celestial bodies such as comets, asteroids and meteorites that bombarded the young planet.
Old dump
Discovered in 1999, Bennu is described by scientists as a relatively loose clump of rocky material, like a rubble pile, held together by gravity. It measures about 500 meters in diameter, making it slightly wider than the Empire State Building is tall, but small compared to the Chicxulub asteroid that hit Earth some 66 million years ago and wiped out the dinosaurs.
Like other asteroids, Bennu is a remnant of the early solar system. Because its current chemistry and mineralogy have remained virtually unchanged since its creation, it holds clues to the origin and development of rocky planets like Earth, and could play a central role in studies of astrobiology.
The capsule was initially inspected at the Utah Test and Training Range near the landing site and then flown to Houston for further examination in a purpose-built “clean room” at an astromaterials curation facility at the Johnson Space Center.
In the coming months, the entire asteroid sample will be broken down into smaller specimens, promised to some 200 scientists in 60 laboratories around the world.
At the time it landed, the Bennu sample was estimated to weigh about 250 grams (8.8 ounces), well above the minimum amount of 60 grams (2 ounces) that scientists had hoped to collect. A more accurate measurement will take place in a few weeks, once the can has been fully opened and all contents have been weighed.
OSIRIS-REx was launched in 2016 and reached Bennu in 2018, orbiting it for almost two years before venturing close enough to grab a sample of the loose surface material with its robotic arm on October 20, 2020.
Lauretta said preliminary analysis of the first pieces of the sample showed that orbital observations of the asteroid “predicted the mineralogy very accurately.”
NASA will launch a separate mission Thursday to a more distant asteroid called Psyche, a metal-rich body believed to be the remnant core of a protoplanet and the largest known metallic object in the solar system.
© Thomson Reuters 2023