TRANSCRIPT – Bio-Essential Sugars Discovered in Samples from Asteroid Bennu

Interview conducted on August 21, 2025 at NASA's Goddard Space Flight Center

DANIEL GLAVIN

Co-Investigator on the OSIRIS-REx asteroid sample return mission

00;00;00;00 - 00;00;08;23

My name is Danny Glavin. I'm an astrobiologist at NASA's Goddard Space Flight Center. And I'm leading the sample organics analysis team for the OSIRIS-REx mission.

00;00;09;10 - 00;00;38;25

So, OSIRIS-REx is NASA's first asteroid sample return mission. It launched in 2016, rendezvoused with asteroid Bennu in 2018, collected a sample from the surface of the asteroid in 2020, and then brought it back to Earth, where it landed in Utah in 2023. And now this sample is available for scientists to study around the world to look for chemicals, including the building blocks of life, which is what our team is interested in.

00;00;38;25 - 00;01;30;26

So, our team, which included an international group of scientists led by our colleagues in Japan at Tohoku University, discovered evidence for bio-essential sugars, sugar molecules essential for life in the samples returned from asteroid Bennu. We actually found six different sugars, including two - ribose and glucose - that are fundamental for life as we know it. The reason that this discovery of ribose and glucose is so exciting is ribose is actually a fundamental component of nucleic acids, it forms the sugar phosphate backbone of RNA. Glucose is an important source of energy for all living organisms, and this is the first discovery of glucose in any astromaterial. So, this is this is truly exciting, a very big surprise. We weren't expecting to find this in the samples.

00;01;30;26 - 00;02;09;14

So, in order to detect these sugars essential for life, we actually had to take some of the Bennu chips and crush them up. We made a powder. Kind of like making flour. We used about 600 milligrams, so a fair amount of sample, and then we basically extracted it in water at cool temperatures, kind of like making a cold, cold brew, a cold tea, and then extracted the sugars into that water. Then we analyzed the water by a technique called gas chromatography mass spectrometry. Kind of a mouthful, but basically it allows you to separate the individual sugars and measure them and identify them by their masses.

00;02;09;14 - 00;02;48;18

This discovery of these bio-essential sugars was led by our colleagues in Japan on the OSIRIS-REx mission from Tohoku University, Hokkaido University, and JAMSTEC. We helped them at NASA crush the samples to provide them with the powder, where they did the extractions in Japan and were able to detect these sugars including ribose and glucose, using these gas chromatography mass spectrometry techniques. So, this is really exciting. This is truly a joint effort to make these really important discoveries, and I'm proud to say that this is really an international team that made this happen.

00;02;48;18 - 00;03;36;02

Yeah. So, this discovery really builds on some of the earlier findings of the mission. When we first started the sample analysis, we discovered amino acids. In fact, 14 of the 20 protein amino acids found in life. And we also found the nucleobases. These are the components of the genetic code in DNA and RNA. All five, in fact, and phosphates. So, we had all the components that we needed to make proteins and enzymes and almost all of the components we needed to make RNA. We have the phosphate and the nucleobases, but not the sugar. And so, this discovery of ribose was actually really critical. It filled in that missing component of this nucleic acid that some believe was really needed for the origin of life on Earth.

00;03;36;02 - 00;04;15;03

Yeah. So, what we're learning now with the discovery of all the three main components, the building blocks of life and the samples from Bennu, is that these actually formed very early on in the outer part of the solar system, 4.5 billion years ago. You had chemical reactions inside the asteroid Bennu parent body. This icy body with melting and fluid, salty brines that actually formed the sugars and some of these other building blocks of life. And then the parent body was flung into the inner solar system, into the asteroid belt, where it was eventually disrupted and reaccreted to have what we now have, asteroid Bennu, a rubble pile.

00;04;15;12 - 00;04;41;16

What this means is that these building blocks of life were distributed from the outer solar system all the way into the inner solar system. They were everywhere, ubiquitous, which really makes me more optimistic that not only could these building blocks have enabled life on Earth, but potentially elsewhere, Mars, Europa, the outer solar system. I'm becoming much more optimistic that we may be able to find life beyond Earth, even in our own solar system.

00;04;41;16 - 00;05;25;28

So, I just want to make it clear that even though we found all of the chemical building blocks to make proteins and nucleic acids, we haven't found evidence for life itself in Bennu. We don't see nucleic acids or large polymers. And this actually opens up a whole new area of research. And the question is why? Why didn't we have more chemistry leading to the origin of life happening inside this giant parent body? Did we not have enough time to form them? Or were the temperatures too cold? What is the answer to that question? I think this is going to open up a lot of new areas of research for folks to try to figure out, why didn't these building blocks advance to something more complex inside this giant asteroid parent body?

00;05;25;28 - 00;05;52;23

So life, of course, requires the right environment, liquid water, energy sources, but it also requires these fundamental chemical building blocks. And we've already talked about the amino acids needed for proteins, the nucleobases, the genetic components of DNA and RNA, but also sugars, which can act as an energy source for life. We found all three of those in Bennu, and we've been looking for them in other asteroids and meteorites as well.

00;05;52;24 - 00;06;30;01

So asteroid Ryugu, we have samples returned from that asteroid from the Japanese Hayabusa2 mission, and we're looking for sugars in those samples right now. One of the challenges is that you need a lot more sample to analyze sugars. They're present at much lower concentrations than the amino acids and the nucleobases. And so with the Bennu samples, we've had the luxury of having more sample to work with to actually target these compounds. But right now, scientists are actively looking for these sugars in the Ryugu samples as well. And I wouldn't be surprised if we found them there as well.

00;06;30;01 - 00;07;17;08

It's absolutely crucial that we return and bring back samples of pristine asteroid materials. We've got plenty of meteorites that we know are fragments of asteroids littered all over the Earth, but they get contaminated. The first thing that happens is a meteorite will come through the atmosphere and it'll be heated by atmospheric entry heating, potentially thermally destroying some of these fragile organic compounds. And then the meteorite hits the Earth, and immediately it's contaminated by the soil. Bacteria in the soil, organics, water, which can make it really hard to be able to discriminate between an organic compound that's a terrestrial contaminant versus an organic molecule that was actually formed in space. So having these pristine materials from asteroid Bennu and asteroid Ryugu is really a precious opportunity.

00;07;17;11 - 00;07;44;02

We have these samples that were protected from the atmospheric entry heating by the shield. They were contained in containers to protect them from the terrestrial environment. And so we know that these samples are clean from contamination. Bottom line is, with these pristine asteroid materials, we can trust the results when we detect these sugars and other molecules. We know that they were formed in space and came from these samples and weren't a product of terrestrial contaminants from the Earth.

00;07;44;02 - 00;08;29;02

So, one of the biggest scientific mysteries is how we all came to be. How did life start on the Earth? In order to answer that question, we go to these asteroids like asteroid Bennu and bring back samples to look for the chemical building blocks of life, to try to get clues into how life may have started on the Earth. Of course, with this new research, we've now found sugars, the missing component of the three that we need for life. So, we have the amino acids, the nucleobases, and the sugars needed for proteins and nucleic acids. But I think what's really key here is that we're showing that these compounds were widespread throughout the early solar system, formed in the outer solar system and then delivered to the inner planets, such as Earth and Mars.

00;08;29;05 - 00;08;52;16

And so, I think we're really beginning to understand that these chemical building blocks were not only ubiquitous, but were also delivered to environments on the early Earth and potentially other planets that would have enabled the origin of life. And for me, this is really exciting. It really makes me more optimistic that if life started elsewhere in the solar system, the building blocks were available to do it, and I think we're going to find it.

00;08;52;16 - 00;09;17;20

So we found ribose in the Bennu samples, which is a really important finding because ribose is an important component of RNA as the sugar phosphate backbone. RNA, some have argued, was actually the first genetic material that started at the origin of life. It's called the RNA world hypothesis. And that DNA and the protein world followed subsequently.

00;09;17;23 - 00;09;51;23

One of the interesting findings, actually, with the Bennu samples isn't what we found, but what we didn't find. We didn't find deoxyribose, which is the equivalent sugar in DNA that forms the backbone of DNA. Deoxyribose, we didn't see it above our detection limits, but ribose was present. So I think this supports this idea that maybe RNA did come first because there was more ribose available as its building block very early on, and perhaps DNA and deoxyribose did come later on in biological evolution.

00;09;51;23 - 00;10;16;13

Some people consider the origin of life just a simple nucleic acid like RNA that could make copies of itself and transfer information that way. Didn't even require DNA or proteins or even a cell membrane. So this discovery of ribose, in fact, is really important and adds more credibility to that hypothesis that maybe the origin of life was just a single strand of RNA.

00;10;16;13 - 00;11;10;26

One of the goals of the OREX mission was actually to study asteroid Bennu, which has been classified as a potentially hazardous asteroid because its orbit crosses Earth's orbit every now and again. And so the mission actually determined that the threat of impact of Bennu on Earth is very low: 0.037%, 1 in 2700 chance of hitting the Earth in September of 2182. So, well in the future. In fact, there's zero probability that Bennu will hit the Earth in the next 150 years. But the other aspect of this mission that was important, it was actually able to touch the asteroid to see what it feels like. During the sampling we actually sunk in to asteroid Bennu, which was quite an unexpected. We thought we were going to kind of springboard off the asteroid. So we learned just by touching it kind of how it was made up, but we also returned the samples.

00;11;10;26 - 00;11;27;02

We have the samples in our lab to understand their physical and chemical properties, and all of this information is going to be really important for designing a mission if we ever have to deflect an asteroid like Bennu in the future so that, you know, [it will] avoid colliding with the Earth.

END OF INTERVIEW