A handful of asteroid dust collected by a Nasa spacecraft that could offer key clues about the formation of Earth and the origin of life successfully landed in the Utah desert on Sunday.
Around 250 grams from the Bennu asteroid, the largest sample ever returned to Earth, re-entered the atmosphere at about 27,650mph protected by a capsule from the Osiris-Rex spacecraft, the culmination of a seven-year journey across the solar system.
The sample-carrying capsule glowed red hot as it hit the upper atmosphere and plunged towards the Earth, with temperatures inside expected to peak at 2,800°C.
Nasa senior scientist James Garvin said he was “literally tingling all over with exhilaration” as the sample landed at the US military’s vast Utah Test and Training Range, to the west of Salt Lake City, its descent arrested by a parachute.
“This is a small step for a capsule but a giant leap for science,” he said.
The sample has been whisked to a “clean room” and will on Monday head onwards to Nasa’s Johnson Space Centre in Houston – but parts will soon be studied by researchers across the globe, who are hopeful it could hold secrets crucial to understanding the formation of planets like Earth.
Scientists believe that many of the key components on Earth were delivered to our planet early in its history through a series of asteroid collisions, many of which could well have been like Bennu, which is older than Earth.
The dust from this asteroid could be of huge significance as it has been collected directly from the asteroid in space – meaning there has been almost zero contamination.
By contrast, meteorites that fall to Earth are quickly contaminated from the second they make contact with our atmosphere.
Bennu is thought to be rich in organic molecules, which are made of chains of carbon bonded with atoms of oxygen, hydrogen, and other elements in a chemical mix that makes all known living things. Scientists expect it to also contain water and minerals and possibly precious metals.
Scientists believe that asteroids like Bennu could have delivered these molecules and water through collisions with Earth, explaining why our planet now has an abundance of both.
Bennu’s rocks are unlike any found on Earth because factors such as weather and erosion have changed the planet.
Although the Japanese Hayabusa mission has previously brought samples back from an asteroid in space, known as Ryugu, this is the first asteroid sample Nasa has collected and will be the largest amount ever collected in space.
Comparing the two samples of asteroid dust will be a key part of research to understand the history of the solar system.
The sample will be studied by more than 200 people from 38 globally distributed institutions, including a team of scientists from the University of Manchester and the Natural History Museum.
Ashley King, of the Natural History Museum, said: “These are crucial ingredients for understanding the formation of planets like Earth. We think the Bennu samples might be similar in composition to the recent Winchcombe meteorite fall, but largely uncontaminated by the terrestrial environment and even more pristine.
“Osiris-Rex spent over two years studying asteroid Bennu, finding evidence for organics and minerals chemically altered by water.”
Dr Sarah Crowther, of the University of Manchester, said: “We’re excited to receive samples in the coming weeks and months, and to begin analysing them and see what secrets asteroid Bennu holds.
“A lot of our research focuses on meteorites and we can learn a lot about the history of the solar system from them.
“Meteorites get hot coming through Earth’s atmosphere and can sit on Earth for many years before they are found, so the local environment and weather can alter or even erase important information about their composition and history.
“Sample return missions like Osiris-Rex are vitally important because the returned samples are pristine, we know exactly which asteroid they come from and can be certain that they are never exposed to the atmosphere so that important information is retained.”
At 11.42am UK time, the Osiris-Rex spacecraft released a capsule carrying the sample about 63,000 miles from the Earth’s surface.
The capsule pierced the Earth’s atmosphere traveling at about 27,650mph (44,500kph). At this pace, the compression of Earth’s atmosphere produced enough energy to envelop the capsule in a superheated ball of fire.
A heat shield helped to regulate the temperature inside the capsule, keeping the sample safe at a temperature similar to that of Bennu’s surface, Nasa said.
Parachutes brought the capsule’s descent to a safe landing speed and at touchdown, slowing its speed to about 11mph (18kph).
The capsule touched down at 3.52pm UK time, three minutes earlier than expected.
The Bennu asteroid was in the news this week after scientists warned there was a very slight chance – around 0.05 per cent – that it may slam into Earth in the next 150 to 200 years – though Sunday’s news was more positive.
Queen guitarist Brian May, a keen astrophysicist who has published a book on Bennu that informed the mission, said: “What an incredibly exciting day.”
“Today is the day, the long awaited day, when the sample of a piece of material from Bennu is recovered to Earth. This box, when it is opened, of material from the surface of Bennu can tell us untold secrets of the origins of the universe, the origins or our planet and the origins of life itself.”
“It’s only recently we have begun to understand the enormous significance of asteroids in the fortunes of Planet Earth. It’s long been recognised that some of them have the power to destroy our planet by collision,” Dr May said.
“But it’s now becoming evident that previous asteroid (and cometary) impacts supplied all the material from which our entire Biosphere is made – and as such are responsible for our very existence. This, together with the possible benefits to humanity from mining asteroids for minerals, gives us vital reasons for making close studies of near-Earth asteroids,” he said.
Dr May’s book, Bennu 3-D: Anatomy of an Asteroid, contains 3D images of the asteroid that were derived from images of the asteroid collected by Nasa.
