Houston, Texas - A sample collected from the 4.5-billion-year-old asteroid Bennu contains abundant water and carbon, both vital materials for the formation of our planet, NASA revealed on Wednesday.

The finding offers yet more evidence for the theory that the foundations for life on Earth were seeded from outer space.

"The first analysis shows samples that contain abundant water in the form of hydrated clay minerals," Bill Nelson said in a press event.

"This is the biggest carbon rich asteroid sample ever returned to Earth," he said, with the carbon contained in the form of both minerals and organic molecules.

The OSIRIS-REx mission collected rock and dust from Bennu in 2020, and a capsule containing the precious cargo successfully returned to Earth on September 24, landing in the Utah desert.

It is now being painstakingly analyzed in a specialized clean room at NASA's Johnson Space Center in Houston.

NASA chose Bennu because they think similar asteroids could have delivered organic building blocks to Earth along with water through collisions billions of years ago.

Bennu's orbit, which intersects that of our planet, also made the roundtrip journey easier than going to the Asteroid Belt, which lies between Mars and Jupiter.

Researchers have so far focused their efforts not on the main sample itself but on "bonus particles," described as black dust and debris coating the sample collector.

"The very best 'problem' to have is that there is so much material, it's taking longer than we expected to collect it," said deputy OSIRIS-REx curation lead Christopher Snead, in a statement.

An inspection of the remainder of the sample will follow later.

It's thought that Bennu formed from pieces of a larger asteroid in the asteroid belt, following a massive collision between one and two billion years ago.

Data gathered by the spacecraft revealed the particles making up its exterior were so loosely packed that if a person were to step onto the surface, they might sink in, much like stepping into a pit of plastic balls.

In addition to scientific insights, better understanding of Bennu's composition could prove useful if humanity ever needs to steer it away.

While it has no chance of hitting Earth through the mid 2100s, the chances rise to around 1 in 1,750 between then and the year 2300, NASA says.