The first NASA space mission to return asteroid material: OSIRIS-REx aims to help scientists understand asteroids in the early solar system
The OSIRIS-REx mission is the first time that NASA has brought back a sample from an asteroid, but it is following in the footsteps of the Japanese space agency JAXA, which collected two asteroid samples in its historic Hayabusa and Hayabusa 2 missions. Though the first Hayabusa mission gathered just a tiny amount of material, the second mission managed to return around five grams of material from asteroid Ryugu in 2020.
The asteroid material collected by OSIRIS-REx could help scientists understand the first few months of the solar system.
The landing area for the science capsule was chosen as it is the largest restricted airspace in the U.S. and has been used before for NASA sample return missions like Genesis and Stardust.
The landing area is 36 miles by 8.5 miles, and the entire mission required a very high level of accuracy, particularly for the rendezvous with the asteroid and collection of its sample in 2020.
“The really precise navigation required to orbit Bennu and to touch down and collect our sample, we were under a meter away from our target,” Sandra Freund, OSIRIS-REx program manager, said in a pre-landing briefing. “So that illustrates what kind of navigation precision we’ve had throughout this mission.”
It’s important to be clear that the theory is not that life itself arose elsewhere and was delivered to Earth, but rather that the basic building blocks of life — often referred to as organic compounds — could have arrived here billions of years ago carried by asteroids.
Scientists need access to asteroidal material to test that theory. Going to visit an asteroid and using instruments on a spacecraft to study it is a good start, but to do the kind of detailed analysis scientists want requires a much bigger laboratory, equipped with instruments like a mile-wide type of particle accelerator called a synchrotron which would be impossible to fit onto a spacecraft.
Asteroids represent the primordial building material from our early Solar System, untainted by planetary processes or by the presence of living things. They could show scientists how chemistry can lead to life on our planet.
But there are two problems with this approach. meteorites don’t have a place in the solar system they came from. It is impossible for researchers to know the origin of the data or what other bodies it was close to. If a meteorite passes through Earth’s atmosphere and lands, then it may pick up some trash along the way, and possibly be contaminated with it.
The Asteroid Apophis: From the Beginning of the Solar System to the Very Early Age of the Asteroids, as observed by OSIRIS
“Not all asteroids are the same,” said Lauretta, who is also a member of the Hayabusa 2 team. Both Ryugu and Bennu have a similar spinning-top-like shape, but they look very different. Bennu is blue and smaller than the other one, called Ryugu, which is red in color. Scientists still aren’t sure what that difference in color means, but being able to analyze and compare the samples on Earth should help understand both how the asteroids are similar and how they differ.
That’s clear from looking at other star systems, but there’s also evidence from our own solar system: the planets revolve around the sun in the same direction and in a single plane, supporting the idea they formed from a single disk of material. Some of that material coalesced into planets, and some was swept into the earliest asteroids, a number of which still exist today.
“The asteroids date from about 500 million years earlier in time than the oldest rocks on Earth. So as a geologist, I want to go back all the way to the beginning,” Lauretta said. You go to the very beginning of the solar system when you look at asteroids.
In the capsule should be roughly a coffee mug’s worth of rock and other material collected from the asteroid Bennu, which at the time was more than 200 million miles away.
Now that the OSIRIS-REx spacecraft has dropped off the capsule containing the sample, its initial job is over. But the spacecraft is still in space, and even though it can’t collect another sample it does still have power and a propulsion system, and all its science instruments still operating.
Instead of wasting this craft, OSIRIS-APEX will find a new target, the asteroid Apophis. It will be able to rendezvous with this asteroid, which is one of the most famous in the solar system because it will come close to Earth in the next few years.
The Apophis rocket will fly within 30,000 km of the surface of Earth in 2029, which is about the altitude of our weather satellites. “It’s the biggest, closest flyby of an asteroid for a thousand years,” and it may even be visible to the naked eye from some locations on Earth.
Bennu, the first planetary capsule to be released from the Milky Way: Return to Earth with a clean, safe and pristine sample
Bringing planetary samples back to Earth allows researchers to use cutting-edge laboratory techniques to study what the rocks are made of. The samples of Bennu would be put into an atmosphere of pure nitrogen as soon as the capsule touched down. The asteroid’s chemistry and geology will be preserved all the way back to the creation of the Solar System, which was 4.5 billion years ago. The pristine material is not altered by passing through the Earth’s atmosphere. “The thing that will really be different about this sample is we’ll have that chain of custody of keeping it protected from Earth’s atmosphere,” says Nicole Lunning, the mission’s lead sample curator at the Johnson Space Center.
The results of all the science research are waiting, and the team is excited to get the sample back to Earth.
I am one of the first people to see the capsule, which is in position in the desert. It’s going to be quite an emotional moment for me,” Lauretta said. Over the last 12 years, we have been building and testing this thing. The beginning of the next chapter is the end of a very long journey.
The capsule was tracked as it parachuted and then taken to a lab clean room, after being assessed for safety and given the all-clear.
But for that to happen, that canister had to make the final leg of its journey alone, bearing temperatures hotter than lava. The Osiris-REx spacecraft released the capsule as it flew within 63,000 miles of the planet. The capsule then entered the atmosphere at a screaming 36 times the speed of sound before slowing down enough to land in Utah’s Great Salt Lake Desert.
The first rock and dirt collected from an asteroid: a mission to explore Bennu’s rubbly surface with future generations of scientists
The plan is for future generations of scientists to study the sample with more sophisticated tools than were available when Apollo astronauts first brought it back in the 1960’s.
“I feel like a kid on Christmas Eve who is just too excited to go to sleep,” says Michelle Thompson, a planetary scientist at Purdue University in West Lafayette, Indiana, and a member of the ‘quick look’ team who will have the first chance to study the rocks.
The spacecraft was able to collect a large cup of rocks and dirt, which includes several pieces that are at least one centimetre long. The amount of material that was returned from an asteroid is the largest in history. The Japan Aerospace Exploration Agency (JAXA) had previously collected less than one milligram from the asteroid Itokawa in 2005, and 5.4 grams from the asteroid Ryugu in 2019.
The curators will give the quick-look team up to 100 million in a few days. Thompson thinks that the initial sample will be made up of fine-grained material from the capsule’s outer layers. After that, the team will get a chance to study grains that were picked up by 24 stainless-steel contact pads on the outside of the sample container — which were the first things to actually come into contact with Bennu. The sample container curators will probably not open it for several weeks to get to the bulk of the material inside.
Thompson suggests looking at how the material on the surface of Bennu compares to what’s come from deeper in the asteroid. OSIRIS-REx’s robotic arm might have plunged as deep as 40 centimetres under Bennu’s rubbly surface when executing its fist bump.