NASA said the "building blocks of life on Earth" could be present in a 4.5-billion-year-old asteroid as the agency showed off samples collected from it in space.
The US space agency said on Wednesday that early tests of materials collected from the Bennu asteroid as part of the Osiris-Rex mission showed evidence of high-carbon content and water.
Scientists and space agency leaders gave a first glimpse of the asteroid material – returned to Earth last month – at a live streamed event at the Johnson Space Centre in Houston, Texas.
The display came after a capsule containing about 250 grams of rocks and dust collected from asteroid Bennu touched down in the Utah desert near Salt Lake City on September 24.
NASA has said it was "the biggest, carbon-rich asteroid sample ever delivered to Earth", and its contents have now been hailed as "scientific treasure."
NASA administrator Bill Nelson said the sample will "help scientists investigate the origins of life on our own planet for generations to come."
He added: "Almost everything we do at NASA seeks to answer questions about who we are and where we come from.
"NASA missions like Osiris-Rex will improve our understanding of asteroids that could threaten Earth while giving us a glimpse into what lies beyond.
"The sample has made it back to Earth, but there is still so much science to come – science like we've never seen before."
Asteroid Bennu is a 4.5-billion-year-old remnant of our early solar system and scientists believe it can help shed light on how planets formed and evolved.
The spacecraft launched on September 8 2016 and arrived at Bennu in December 2018.
It dropped the samples off sealed in a capsule last month.
"Already this is scientific treasure," said the mission's lead scientist, Professor Dante Lauretta, of the University of Arizona on Wednesday.
In a statement, he added: "As we peer into the ancient secrets preserved within the dust and rocks of asteroid Bennu, we are unlocking a time capsule that offers us profound insights into the origins of our solar system.
"The bounty of carbon-rich material and the abundant presence of water-bearing clay minerals are just the tip of the cosmic iceberg.
"These discoveries, made possible through years of dedicated collaboration and cutting-edge science, propel us on a journey to understand not only our celestial neighbourhood but also the potential for life's beginnings.
"With each revelation from Bennu, we draw closer to unravelling the mysteries of our cosmic heritage."
NASA's mission goal was to collect was 60 grams of asteroid sample.
But when the canister lid was opened, NASA said scientists discovered "bonus material" covering the outside of the collector head, canister lid, and base.
There was so much extra material it slowed down the process of collecting and containing the primary sample, NASA said.
