NASA finds proof of carbon, water in asteroid Bennu samples

Material collected from the asteroid acts as a time capsule from the earliest days of our solar system

By Nandita Banerji
Published: Thursday 12 October 2023
The sample return capsule from NASA's OSIRIS-REx mission is seen shortly after touching down in Utah, September 24, 2023. The sample was collected from the asteroid Bennu in October 2020. Photo: NASA / Keegan Barber

Samples collected from 4.5-billion-year-old asteroid Bennu could indicate the building blocks of life on Earth. Initial studies on the samples collected in space and recently brought back on earth have shown evidence of high-carbon content and water-bearing clay minerals, according to a statement by National Aeronautics and Space Administration (NASA) released October 11, 2023.

Bennu is a small near-Earth asteroid that passes close to Earth every six years. A 4.5 billion-year-old relic of our solar system's early days, asteroid Bennu has seen it all. Bennu’s current composition, according to scientists, was established within 10 million years of the formation of our solar system.

The material collected from the asteroid acts as a time capsule from the earliest days of our solar system and can help us answer big questions about the origins of life and the nature of asteroids.

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer, better known as OSIRIS-REx, is the first United States mission to collect a sample from an asteroid. The spacecraft was launched on September 8, 2016 and the sample was collected three years ago.

An illustration of OSIRIS-REx dropping off its sample return capsule at Earth. Photo: NASA

OSIRIS-REx returned to Earth on September 24, 2023 to drop off material from asteroid Bennu. After dropping off the sample, it continued on to a new mission to explore the asteroid Apophis. 

“The OSIRIS-REx sample is the biggest carbon-rich asteroid sample ever delivered to Earth and will help scientists investigate the origins of life on our own planet for generations to come,” said NASA Administrator Bill Nelson in a release. 

NASA missions like OSIRIS-REx will improve our understanding of asteroids that could threaten Earth while giving us a glimpse into what lies beyond, Nelson added.

The mission has provided an “abundance” of samples — the goal of the OSIRIS-REx sample collection was to collect 60 grams of asteroid material. But scientists disassembling the sample return hardware found bonus particles covering the outside of the collector head, canister lid and base. The total sample weight has been estimated at around 250 gms.  

The abundance of sample threw off the scientists, as it was even more than they’d anticipated

Scientists have performed “quick-look” analyses of that initial material until now by collecting images from a scanning electron microscope, infrared measurements, X-ray diffraction, and chemical element analysis. Computed topography helped the team create a three-dimensional computer model of one of the particles, highlighting its diverse interior, which provided an early glimpse of evidence of abundant carbon and water.

For the next two years, the mission’s science team will continue characterising the samples and conduct the analysis needed to meet the mission’s science goals. NASA will preserve at least 70 per cent of the sample at Johnson Space Center in Houston for further research by scientists globally, including future generations, the agency stated. 

The practice of retrieving samples from space began in 1969 with NASA’s Apollo 11 mission, the first to land astronauts on the Moon. Many more sample-gathering missions to the Moon and beyond followed, growing in ambition with each passing decade.

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