Life after asteroid Bennu

Last fall, a NASA spacecraft called OSIRIS-REx dropped a capsule containing more than 120 grams of space dust into the Utah desert. That material came from Bennu, an asteroid that broke away a billion years ago from a larger world that may have contained liquid water. Studying this material will clarify the role asteroids may have played in bringing the ingredients for life to Earth.

For Dante Lauretta, a planetary scientist at the University of Arizona and the mission leader, retrieving the sample marked the end of an era. Since the mission began in 2016, Dr. Lauretta immersed in everything related to OSIRIS-REx. Frames on the wall of his office show covers of the journals Nature and Science describing the journey to Bennu and back. Next to it is an oversized 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 on Bennu, one entangled in Dr. Lauretta – finding each other again.

After delivering the sample, the OSIRIS-REx spacecraft continued its journey through the solar systemand Dr. Lauretta handed over the keys. He recently spoke with 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 up to since the final act of OSIRIS-REx?

The weeks after returning from Earth were all Houston, all day. The disassembly of the asteroid sample collector was slower than we expected, but it was fun and historic. I was allowed to go to the cleanroom and be there when we first saw the sample. In early November I had part of the sample in my laboratory in Arizona.

Students in my astrobiology class received live lectures from the Johnson Space Center in Houston. I took them with my phone, and the sample processors came over and danced around in their bunny suits. It was amazing.

Why did the disassembly take so long?

There were a few screws stuck and we had no tools to keep the sample pristine. Hard tools contain carbon steel, and we didn’t want those tools in the cleanroom because of the contamination. Carbon is important to astrobiology, the origin of life, and all the fun science we do. So the tools we use are soft. And you could see the head of the screwdriver starting to deform as it tried to remove the fasteners.

In the end we decided to just go through a flap on the head of the sample collector and get about 70 grams of stuff out. That was already more than we promised NASA would bring back. Then we spent some time building a screwdriver that we could use, and finally cracked the thing open in January.

Are there any surprises with the monster so far?

In 2020 we wrote one paper across large white veins – about a meter long and 10 centimeters thick – on the rocks and boulders of Bennu. We thought these were carbonates that formed in water, which is exciting. Carbonaceous minerals are found in biological systems.

When we got the stones back, some of the stones had white, crusty material all over them. I was so excited because I thought we had gotten the carbonates. But when I got some grains into the lab, they were phosphate, a compound containing the element phosphorus. And it was high in sodium.

We had a student look at one grain under an electron microscope, and it was cracked and dried out. After the water evaporates, it looks like a mudflat, when it completely cracks and shrinks.

Did we get the asteroid wrong? Don’t know. Were those veins actually phosphates? We are still working on that.

What would it mean if those veins were made of phosphorus instead of carbon?

Phosphorus has a special place in my heart because of the astrobiology work I did as a graduate student. It is one of the “big six” elements of life, along with hydrogen, carbon, nitrogen, oxygen and sulfur. Because phosphorus is the least abundant, it provides important clues about how the element became involved in biology.

I read one paper about sodium-rich phosphates coming from the plumes of Enceladus, one of Saturn’s moons. And then one study came out about soda lakes in Canada, the most phosphate-rich lakes known on earth. 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 could be evidence that liquid water evaporates with high concentrations of phosphorus, a key ingredient for the origin of life. And other groups are finding similar chemistry in biologically important environments, one around Saturn and one on Earth. This is a dream come true.

How did your book come about?

In 2018 I came up with the idea to write a more personalized version of OSIRIS-REx, even before the mission had reached Bennu. We collected the sample in 2020 and had two and a half years before it landed on Earth, so I spent those years writing.

The book ends with the return of the example in Utah, so the two epilogues were not written until the following week. On the flight from Utah to Houston, I put in a pair of earbuds and recounted everything that had happened in the past 24 hours. And then I wrote the finale of The Two Carbons, the universal thread underlying the story, later in my hotel room.

Your book is about OSIRIS-REx, but 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 twelve, it was just my mother raising the three of us. I was much older than my two brothers. We had no television. There was nothing but the desert for entertainment. So I spent a lot of time exploring it, discovering all kinds of amazing little secrets.

I had come across Native American structures and petroglyph walls and truly felt a connection in time with those who had come before me. And I started thinking about: who was there before them? And how far back can you take that question? I remember the first time I found a trilobite – it was amazing. I wondered why it wasn’t there anymore. What happened to it? Could that happen to us?

Then I started to appreciate geology. There are stories in the rocks. Since then I have always been an explorer. As I got older I went backpacking, camping, hiking and so on. I just loved going somewhere, and I wanted to go where no one had gone before.

When I did an expedition in Antarctica I felt like that was it, I would never get further remote than that. Then came OSIRIS-REx, and that was just another level: the final frontier.

What’s next for you?

I am the first director of the new one Arizona Astrobiology Center. And it’s a blast! It really is a community center because people come to us. The bachelor students are arriving. Primary school teachers and administrators want to know how they can get involved.

I love interacting with students, which I did a lot of during OSIRIS-REx. It is very accessible for them to participate. We can train students within a few days and have them look at material from Bennu on an electron microscope. It’s great to be in this new environment that puts the student and community first.

I think this is the culmination of what people can do when we unite with a common vision. OSIRIS-REx is so much bigger than me. People tell me how inspiring what we did was, and how proud they are of me, this team and this nation. I feel like I’m part of something incredible, amazing and powerful.