Nasa has gathered a large piece of a distant asteroid. What now?


Scientists have gathered a significant chunk of a distant asteroid, which has made its way to Earth after a mission taking millions of miles. But the really useful work will begin now.

Nasa’s Osiris-Rex mission flew to the distant Asteroid Bennu, scooped up a piece of the object into a canister, and then flew back to Earth to drop it off. On Sunday, Nasa picked up that canister in the Utah desert and is now working to secure it.

It will then send those samples to a variety of scientists around the world, with a chunk of it being sent to more than 200 people at 38 different institutions across the world. They hope that they can use them as a “time capsule” to peer into the early universe, telling us about where we came from.

“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 of our planet and the origins of life itself,” said Queen musician Brian May, who helped with the research by mapping out the asteroid to find a landing spot. “What an incredibly exciting day.”

Sample return missions are particularly exciting to scientists because they offer a look at a pristine piece of a distant world that has been undisturbed by the environment on Earth. While some pieces of asteroids and other objects can fall down to Earth, they have to make their way through the atmosphere and can be damaged and changed in the process.

They also mean that researchers are able to use all of the Earth’s latest technology to study the sample. Other pieces of distant worlds have of course been studied by spacecraft and landers, but they are only able to do so with the limited instruments they take to those planets.

Another advantage of sample return missions over studying the objects at their home is that scientists can look back at those samples with new sensors and equipment invented long after the sample was actually taken. Many space missions continue for years – Curiosity is still examining Mars after arriving there in 2012, and the Voyager probes are still providing information almost 50 years after they were launched – but they are only able to do so with the technology that was available when they set off.

The analysis done in sample return missions really begins when the spacecraft arrives at its target: then, it starts looking at the context of the sample, gathering information about the world from which it came that should prove useful to scientists later. Osiris-Rex arrived at Bennu in 2018, and spent two years mapping the asteroid before it set off back home with its delivery.

All of that information in addition to the samples could help answer a variety of questions about our planet, scientists hope.

“The asteroids in our solar system contain the raw building blocks from which the Earth was made, so working out their composition will tell us a lot of how our planet formed,” said Boris Gansicke from the department of physics at the University of Warwick.

“There are many open questions, for instance, where did the water that we have on Earth come from? And where did the ingredients that made life possible to develop come from?

“To answer those questions, ie measure the composition of an asteroid, you need to get your ‘hands’ on them (or in this case the arm of a space mission), and this is what Osiris-Rex achieved.

“In a nutshell, it’s similar to sitting in front of a delicious dinner and wanting to have the list of ingredients.”

Sample return missions are almost as old as space travel itself, and the first of them were the early Apollo missions, which brought back pieces of the Moon. Those continue to be useful to scientists.

Since then, as human travel into space has declined, most of the work has been done by robots. In the early 1970s, the Soviet Union’s Luna missions gathered pieces of the Moon and brought them back, and in 2020 Japan’s Hayabusa2 mission brought back pieces of the asteroid Ryugu.

Scientists have high hopes for future missions: perhaps the most discussed is a mission to Mars, which would bring back the first ever pieces of that planet. Engineers have suggested that for decades, and a number of plans have been formed, but none are likely to launch any time soon.