‘Bonkers’ excitement for Aussie scientists getting Bennu dust

For planetary scientist Phil Bland, who has spent most of his career analysing the primordial dust contained in meteorites to better understand the history of the universe, there is one word that sums up his feeling of being involved with NASA’s OSIRIS-REx mission: “Bonkers”.

“I mean, I’m part of a once in a lifetime space mission,” the John Curtin Distinguished Professor in the School of Earth and Planetary Sciences at Curtin University says.

“It’s a giant thrill. As a scientist, I’m really fascinated about the chemistry of the material that was the starting point for all of the planets in the Solar System – and I’ve got a hunch that we’re going to learn an awful lot about that from this material.”

The material Bland is referring to is the estimated 250-gram sample of rock and dust collected from the near-Earth asteroid known as ‘Bennu’ by the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer – or OSIRIS-REx. As Bland explains, one of the reasons why the material is so special is because, unlike the meteorites he usually studies, it has not been contaminated by Earth’s atmosphere.

“It’s really primitive, really pristine stuff,” Bland says.    

Launched in 2016, the OSIRIS-REx spacecraft took two years to travel to Bennu, and nearly two more years orbiting the spinning-top shaped asteroid, studying its rocky terrain, before plunging its arm into the loose surface of a crater located in the northern hemisphere. It stored this sample in a sealed capsule, known as TAGSAM, which in late September it released roughly 100,000 kilometres from Earth.

The capsule plummeted through Earth’s atmosphere, glowing with heat, before deploying its parachutes to stabilise its landing in the Utah Desert, where scientists from NASA rushed to collect it. They immediately transported it to a temporary cleanroom and connected it to a continuous flow of nitrogen to protect it from earthly contaminants, before transferring it to NASA’s Johnson Space Center in Houston, Texas.

Exactly the kinds of material that we wanted to find.

NASA Administrator Bill Nelson

It was there that they discovered a delightful surprise before they even opened the canister containing the main sample: a portion of rock and dust on the lid. Preliminary testing of this “bonus sample” found that it contained abundant water in the form of hydrated clay minerals and was nearly 5 percent carbon by weight.

According to NASA Administrator Bill Nelson, this was “exactly the kinds of material that we wanted to find” – chiefly because this might explain how Earth got all of its water and all of its life.

Analysis of the main sample will shed much more light on this – and Bland is one of the key members of a consortium of Australian scientists who will be involved with it. In the wee hours of the morning, he has been dialling into the live video feed from the Johnson Space Centre to watch his colleagues at NASA carefully working on the sample.

“I can’t put salt on my chips with as much care as the guys in there have when handling tiny amounts of material with these giant rubber gloves on – all while being watched by dozens of scientists from around the world. It’s amazing to see.”

It’s lovely to be part of a mission from the beginning to the end.

Professor Phil Bland

In a few weeks’ time, once the material has been completely extracted, weighed and carefully catalogued, Bland will travel to the Johnson Space Center to view the rocks and decide which ones he wants to bring back to Australia for analysis.

This will mark the beginning of the final chapter of many years of work on this project, which Bland became involved with shortly before the OSIRIS-REx spacecraft launched.  

“I’ve been part of it now for a very long time,” he says, “and it’s lovely to be part of a mission from the beginning to the end.”

Bland is still unsure if the samples will be shipped to his laboratory in Perth or if he will be able to bring them back with him. The first step of his analysis will involve using microscopy techniques such as electron backscatter diffraction to “characterise” the material.

“When I say characterise, I mean making as high-resolution a map as possible for either the chemistry or mineralogy of the material,” he explains. “If there’s a grain in there that’s a hundred nanometres, we can extract that and get its entire chemistry and isotopic composition in three dimensions. It’s just crazy.”

Once that stage of the analysis has been completed, Bland will forward the samples onto Professor Trevor Ireland from the School of Earth and Environmental Sciences at The University of Queensland.

Ireland became involved with the OSIRIS-REx mission a few years ago, after his work on the Japanese space agency (JAXA) Hayabusa 1 and Hayabusa 2 missions, which delivered asteroid material to Earth in 2010 and 2020. His study of the samples collected from Bennu will entail geochronology and oxygen isotope analysis, which will offer more insight into the age of the asteroid and its chemical composition – and thus help answer what he calls the “primary question” of how it relates to the meteorites that have been found on Earth.

However, this stage of the analysis is quite destructive, hence why it is happening last. “There’s a protocol for maximising the use of material from the sample,” Ireland says.

There is an avenue in Australia in terms of actually doing science.

Professor Trevor Ireland

Ireland is indebted to the many people who have been involved in the OSIRIS-REx mission and have helped it succeed so far. “It’s great to be standing on the shoulders of all these engineers and scientists and technicians as we try to figure out what happened in the early Solar System and how that’s impacted what we see now on Earth.”

One of the benefits Ireland identifies of his involvement in the mission is that it enables him to develop key instrumentation. “Every time we are involved in one of these missions, we have to develop new techniques to help us analyse the new materials that are inevitably going to be in these samples. And once we’ve done that, we can apply those same techniques to any number of samples, including all the samples we have on Earth – and in Australia for that matter.”

Ireland says his involvement and that of his Australian colleagues is also “great for kids who are thinking of getting involved in science and technology. They can see that there is an avenue in Australia in terms of actually doing science.”

Bland echoes this sentiment, adding that hopefully the consortium of Australian scientists involved with the OSIRIS-REx mission serves as a reminder of the quality of science that is done in this country with limited resources – and the respect it commands internationally.

“You know, there is a really strong tradition of Australian scientists being involved with world-class planetary science. We have a great track record globally. But at the moment in Australia we aren’t really funding space and planetary science very much at all, and I hope that me doing this kind of work can help change that.”