Osiris-Rex: Nasa reveals first look at ‘beautiful’ asteroid sample
“It’s beautiful, it really is – certainly what we’ve seen of it so far,” said Dr Ashley King.
The UK scientist was in a select group to put first eyes and instruments on the rocky samples that have just been brought back from asteroid Bennu.
The materials, scooped up by a US space agency (Nasa) mission and returned to Earth 17 days ago, are currently being examined in a special lab in Texas.
“We’ve confirmed we went to the right asteroid,” Dr King told BBC News.
The three-day analysis by the Natural History Museum (NHM) expert and five others on the “Quick Look” team showed the black, extraterrestrial powder to be rich in carbon and water-laden minerals.
It’s a good sign the samples taken from the 500m-wide asteroid will be able to reveal new information about the formation of the Solar System some 4.6 billion years ago.
However, scientists on the Osiris-Rex mission are still not sure precisely how much of Bennu they actually have in their possession.
The sample canister which landed in the Utah desert on 24 September has been opened but the inner chamber used by the Osiris-Rex spacecraft to store the asteroid fragments has yet to be fully emptied of its contents and weighed.
The mission team thinks it has about 250 grams (9oz) in total. It will take a few more days careful disassembly to corroborate this estimate.
To perform their initial experiments, Dr King and colleagues used particles that had been spilled from the inner chamber – or Tag-Sam (Touch And Go Sample Acquisition Mechanism) as it’s known. This fine Bennu dust coats the surrounding canister’s surfaces.
“When they took the lid off the sample canister, it just revealed this black powder everywhere. It was incredible; it was so exciting,” Dr King recalled.
“We were sitting at the time and everybody just stood up and started pointing at the screen. It meant we had lots to play with for the quick look. It made our job easier.”
The dust was put in an electron microscope, subjected to X-ray diffraction and infrared spectroscopy techniques and scanned by a computed tomography (CT) machine.
Once the full sample is extracted, a portion of it will be shared with researchers worldwide. About 100 milligrams is expected to come to the UK to be further worked on by Dr King’s department at the NHM, and by collaborators at the Open, Oxford and Manchester universities.
The Osiris-Rex spacecraft picked up the Bennu materials in October 2020, using a daring manoeuvre to approach and then “high-five” the asteroid – an operation performed while 330 million km (205 million miles) from Earth.
It then took almost three years, for the Nasa probe to come home and drop off its precious cargo at a restricted military test range a couple of hours’ drive west of Salt Lake City.
Bennu interests scientists because it likely retains the chemistry that existed when the planets began forming around the nascent Sun.
There’s a theory that carbon-rich (organic), water-rich asteroids similar to Bennu may have been involved in delivering key components to the Earth system, such as the water in our oceans and some of the compounds that had a role in kick-starting life.
The researchers, when they examine the returned samples in detail, will be looking for indications that might support or counter these ideas.
“We’re going to get a lot of new information from Bennu to really understand exactly just how complex are these organic molecules that we find,” explained Dr Lori Glaze, the director of planetary science at Nasa.
“The samples will feed our understanding of how the earliest organic building blocks might have come together to form life on Earth and perhaps elsewhere in the Solar System, too. I think that’s going to be incredibly valuable,” she told BBC News.
The Osiris-Rex teams aim to have a raft of studies completed in time to report at the Lunar and Planetary Science Conference (LPSC) in March. Two major overview papers are also expected to be published at the same time in the journal Meteoritics & Planetary Science.
