Extract from ABC News
A NASA space capsule carrying the largest soil sample ever scooped up from the surface of an asteroid streaked through Earth's atmosphere on Sunday and parachuted into a United States desert, delivering the celestial specimen to scientists.
The gumdrop-shaped capsule, released from the robotic spacecraft OSIRIS-REx as the mothership passed within 108,000km of Earth hours earlier, touched down within a designated landing zone west of Salt Lake City on the US military's vast Utah Test and Training Range.
The final descent and landing, shown on a NASA live stream, capped a six-year joint mission between the US space agency and the University of Arizona.
Associate Professor Nick Timms from Curtin University's School of Earth and Planetary Sciences is one of the hundreds of scientists now involved in the analysis of the sample.
He explains why this mission is significant and how Australia is involved.
What exactly was collected?
Seven years ago, NASA launched a small spacecraft to collect rocky material from sample site Nightingale on the asteroid Bennu — believed to be 4.5 billion years old.
Dr Timms described the asteroid as an ancient, 510-metre-wide object in space between Earth and Mars — "a rubbly rocky relict from the earliest times in our solar system when the planets first formed".
"We anticipate that the sample is a mixture of rocks and dust particles, which will probably be rich in carbon and some of the earliest solid particles to form in our solar system," he said.
"There may even be exotic specs and grains that predate our Sun."
According to NASA, Bennu — first discovered in 1999 by the Lincoln Near-Earth Asteroid Research — comes close to the Earth every six years.
NASA scientists estimate the asteroid has a one in 2,700 chance of hitting the Earth during one of its close approaches in the late 22nd century.
Why is it significant?
While it's not the first time an asteroid sample has been collected, the size is comparatively significant. Scientists estimate the capsule holds at least a cup — about 250 grams — of rubble, but won’t know for sure until the container is opened in a day or two.
Japan has twice returned asteroid samples through its space agency, JAXA, however the largest of those two was 5.4 grams.
"With each mission we [scientists] learn more and more from the pristine samples recovered from different types of asteroid," Dr Timms said.
"The JAXA missions paved the way for NASA's OSIRIS-REx mission."
How is Australia involved in the mission?
Experts from 38 different universities across the globe are now involved in the analysis of the samples.
Dr Timms, along with five other colleagues at Curtin University and a researcher in the eastern states, form the Australian sample analysis team.
"We will receive a small fraction of the asteroid material to characterise it using a range of state-of-the-art analytical instruments with capabilities of measuring the structure and chemistry of even the tiniest particles with exceptional precision, right down to the nanoscale," he said.
He said the Australian team would be collaborating with the 200-strong mission scientists around the globe to try to answer some of the mission questions:
- What types of organic molecules and compounds are preserved on Bennu – the ancient building blocks of life?
- How and when did asteroids such as Bennu form and why are they still around?
- Is there water or other resources on these kinds of asteroids?
"I was so filled with anticipation and excitement watching the NASA live feed of the sample return capsule arriving to Earth last night," Dr Timms said.
"I cheered when I saw the red and white striped parachute had deployed, gently touching the capsule down in the Utah desert. To think that minutes before it was hurtling towards Earth at over 44,000 kilometres per hour.
"Being involved in planetary science and space missions is both mind-boggling and humbling."
What is NASA hoping to discover?
Like other asteroids, Bennu is a relic of the early solar system.
Because its present-day chemistry and mineralogy are virtually unchanged since forming some 4.5 billion years ago, it holds valuable clues to the origins and development of rocky planets such as Earth.
It may even contain organic molecules similar to those necessary for the emergence of microbes.
Samples returned three years ago by the Japanese mission Hayabusa2 from Ryugu, another near-Earth asteroid, were found to contain two organic compounds, supporting the theory celestial objects such as comets, asteroids and meteorites that bombarded early Earth seeded the young planet with the primordial ingredients for life.
What does it mean for future space research?
Dr Timms says we are currently in a "renaissance of space and planetary science and exploration".
"The success of missions such as this one comes with so many benefits to future research," he said.
He said the OSIRIS-REx spacecraft had spent time mapping the surface of Bennu before collecting a sample, leading to a new understanding of the character of these space objects and their orbital dynamics.
"Then there is the wealth of knowledge and experience gained from successfully completing such a complex mission," he said.
"The OSIRIS-REx spacecraft is now heading to rendezvous with and map another near-Earth asteroid. And we haven't even started examining the Bennu sample yet.
"These are certainly very exciting times, not just for the scientists and engineers involved directly in missions, but for everyone."
NASA is planning to hold a public show and tell of the samples next month.
ABC/wires
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