Last fall, a NASA spacecraft called OSIRIS-REx dropped a capsule containing more than 120 grams of space dust in the Utah desert. The material came from Bennu, an asteroid that broke off a billion years ago from a larger world that may have liquid water. Studying this data provides a clear picture of the role asteroids played in bringing the ingredients for life to Earth.
For mission leader Dante Lauretta, a planetary scientist at the University of Arizona, recovering the samples marked the end of an era. Since the mission began in 2016, Dr. Lauretta has been immersed in all things OSIRIS-REx. On his office wall hangs framed covers of the journals Nature and Science about the trip to Bennu. Next to it is the large cover of his new book, “The Asteroid Hunter: A Scientist's Journey to the Dawn of Our Solar System.” Part mission report, part memoir, the book tells the story of how two ancient carbon atoms – one from Bennu and one entangled in Dr. Lauretta's genetic code – find each other again.
After dropping the sample, the OSIRIS-REx spacecraft continued its journey through the solar system, and Dr. Lauretta delivered the key. He recently spoke to The New York Times about life after OSIRIS-REx and how the mission's impact continues. The following conversation has been edited for brevity and clarity.
What have you been doing since OSIRIS-REx's last action?
In the weeks following Earth's return, it was Houston all day long. The teardown of the asteroid sample collector went slower than expected, but it was fun and historic. I had to go to the clean room and be there for the moment we first saw the samples. In early November, I had some of the samples in my lab in Arizona.
Students in my astrobiology class attended live lectures at the Johnson Space Center in Houston. As I carried them around on my phone, the sample handlers came up dressed as rabbits and started dancing. It was great.
Why did it take so long to take it apart?
There were a few screws stuck and no tools to keep the sample clean. The hard tools contain carbon steel and we did not want to keep these tools in the clean room because of contamination. Carbon is of interest to astrobiology, the origins of life, and all the fun science we do. So the tools we use are soft. And as I tried to remove the fastener, I could see the screwdriver's head starting to distort.
In the end we decided to take out about 70g of material by passing it through a flap on the sample collector head. That was already more money than we promised to bring back to NASA. We then spent time creating a usable driver, and finally released the product in January.
Anything surprising about the samples so far?
In 2020, we wrote a paper about large white veins about a meter long and 10 centimeters thick in the rocks and boulders of Bennu. We thought it was carbonate formed in water, which is really interesting. Carbon-containing minerals are found in biological systems.
When we got the rocks back, some of them were completely covered in a white, hard substance. I was very excited because I thought we got carbonate. But when the grain was sampled in the laboratory, it turned out to be phosphate, a compound containing the element phosphorus. And it was rich in sodium.
We had a student look at one grain under an electron microscope, and it was cracked and dry. After the water evaporated, it all broke down and shriveled, looking like a mudflat.
So did we get it wrong on the asteroid? I do not know. Were those veins actually phosphates? We're still tracking it.
What does it mean that the veins are made of phosphorus rather than carbon?
Phosphorus holds a special place in my heart thanks to the astrobiology research I did as a graduate student. It is one of the “six” elements of life, along with hydrogen, carbon, nitrogen, oxygen, and sulfur. Phosphorus, which is the least abundant, provides important clues about how this element may have been involved in biology.
I read a paper about sodium-rich phosphates coming from the plumes of Enceladus, one of Saturn's moons. And then a study came out about Canada's Soda Lake, which is the most phosphate-rich lake on Earth that we know of. And it had exactly the same chemistry.
I don't know if Bennu is an exact analog, but this kind of fluid chemistry is important. This may be evidence that liquid water evaporated as the concentration of phosphorus, a key ingredient for the origin of life, increased. And other groups are discovering similar chemistry in biologically important environments: around Saturn and on Earth. This is a dream come true.
How did your book come about?
I came up with the idea of writing a more personal version of OSIRIS-REx in 2018, before the mission reached Bennu. We collected the samples in 2020 and it had to cruise for two and a half years before it landed on Earth, so we spent that time writing about it.
Because the book ends with the return of the samples from Utah, the two epilogues were not written until the following week. On the flight from Utah to Houston, I plugged in my earphones and told them everything that had happened in the last 24 hours. I then wrote the finale of Two Carbon Atoms, the universal thread that underlies the story, later in my hotel room.
Your book is about OSIRIS-REx, but it's also about you. How did your childhood prepare you for exploring the solar system?
I grew up in Arizona, and by the time I was 12, my mom was the only one raising the three of us. I was much older than my two brothers. We didn't have a TV. The only place for entertainment was the desert. So I spent a lot of time exploring it, finding all kinds of surprising little secrets.
I came across Native American structures and petroglyph walls, and really felt a connection in time to people who came before me. And I started thinking about who came before them. And how far back can you trace that question? I remember when I first discovered trilobites. It was really amazing. I wondered why it wasn't around anymore. What happened? Could something like that happen to us?
From then on, I began to understand geology. Rocks have stories. Since then I have always been an explorer. As I got older, I used to go backpacking, camping, and hiking. I just liked going somewhere, somewhere no one had been before.
When I did my Antarctic expedition, I felt like that was it, I couldn't go any further than that. Then OSIRIS-REx came along and it was another level, the final frontier.
What's next for you?
I am the first director of the new Arizona Astrobiology Center. And it's pounding! This is a real community center because people come to us. College students are flocking here. Teachers and administrators in K-12 schools want to know how to get involved.
Although I gave up a lot of work during OSIRIS-REx, I love hanging out with my students. It's very easy for them to get involved. In just a few days, we can train students to observe Bennu's material under an electron microscope. It's great to be in a new environment focused on students and the community.
I think this is the pinnacle of what people can do when we come together around a common vision. OSIRIS-REx is much bigger than me. People tell us how inspiring they are about what we did and how proud they are of me, this team and this country. I feel like I am a part of something incredibly amazing and powerful.