#58 Resident space rock expert Greg Brennecka is back to preview the return to Earth of NASA’s OSIRIS-REx spacecraft with a sample of asteroid Bennu.

Cosmic Coffee Time’s resident space rock expert and NASA mission scientist Greg Brennecka is back again to preview the return to Earth of NASA’s incredible OSIRIS-REx mission. OSIRIS-REx is coming to the end of an epic seven year journey to collect a rock and soil sample from asteroid Bennu. Greg is a mission scientist on OSIRIS-REx and will be doing analysis on the Bennu sample in his own lab. It’s breathtakingly rare to get a pristine sample from an asteroid in another part of the solar system, and Greg shares with us the plans for this sample and what this 60 gram sample of asteroid could teach us. 

• If you want to learn more about rocks from space, check out Greg's book 'Impact' at Harper Collins here

 
 
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Transcript

 This is Cosmic Coffee Time, the place where we take a look at what's happening somewhere in the universe in about the time it takes to have a coffee. It's cosmology in a cup. I'm Andrew Prestage, and join me for a coffee and see where in the universe we're going this time. Cosmic Coffee Time's resident space rock expert Greg Brennecka is back with us to preview the return to Earth of NASA's OSIRIS-REx mission. It's scheduled to return a sample of asteroid Bennu back to Earth in late September 2023. Greg's involved with a couple of these sample return missions, where a robotic spacecraft is launched from Earth, travels to another body in the solar system, like an asteroid, collects a rock or soil sample and returns it back to Earth.

Because of the huge distances in space, these missions typically take several years. But when they do return, it's people like Greg who analyze the sample and tell us what it all means. Let's check it out. Friend of Cosmic Coffee Time, Greg Brennecka joins me again, this time to talk about NASA's OSIRIS-REx asteroid Bennu sample return mission.

It's always great to talk with you, Greg, and I hope you're enjoying the summer in the Northern Hemisphere. 

Absolutely. Hope you're enjoying the winter in the Southern Hemisphere, Andrew. 

I've, well, I am, in a way. And, I called you a friend of Cosmic Coffee Time, Greg, but I'll have to change that to a regular.

So you're now officially a regular on Cosmic Coffee Time



 I feel honored. I feel honored.



 You are a mission scientist on Osiris Rex, that sample return mission. And congratulations again on that. Can you remind us how you got that gig? And what does a mission scientist do on a project like this? 

So missions like this, uh, you know, they were planned.

So a long time in advance. Uh, so there's a lot of scientists that joined the team initially, and this was planned probably 10 to 15 years ago. And then what happens is that when, you know, the mission, you know, continues and things look like it's successful, they opened it up to current scientists that are doing kind of newer or different types of analyses.

They Want a broad group of scientists involved in a mission like this that has you know, a sample return. So the people that were selected for the initial, I wasn't one of the people that was selected for the initial part of the mission cause I was still in graduate school or before. But when they opened it up to a lot of scientists, uh, you know, currently this was about a year and a half ago.

Uh, I was lucky enough in my group was lucky enough to be selected as one of the, um, participating scientists in the mission. Uh, so that's, we get, we get, uh, part of the sample when it comes back to do some analysis on it and, and make some measurements 

and the mission's getting close to a very significant moment later this month, as we speak, after seven years in space, it's going to parachute back to earth on the 24th of September, 2023, are you feeling nervous about the landing confident?

A 

little of both, I guess. Yeah, confident. Uh, definitely a little nervous. I mean, there's been a lot of space missions that have been successful, but there's also been a lot of space missions that have not been successful, um, including the Utah desert. So that, uh, that is, you know, the Genesis mission was a success, uh, overall, but the landing was a pretty hard landing.

So we're hoping to avoid that one. 

And these sample return missions are really something you and your colleagues have been analyzing a sample from asteroid Ryugu, which we spoke about. a little while back and that episode's in the library if listeners want to check it out. But what does it mean to get these pristine samples uncontaminated by anything on earth or any superheating from an entry through the atmosphere?

It's really exciting because, you know, it's, it's great to have meteorites and that gives us a nice window into, you know, what was going on in the early solar system. But like you said, they do have some interaction with the atmosphere. They have interaction with earth. Uh, even if we collect them very quickly, they still, you know, landed somewhere that had life.

There's, they landed somewhere that had oxygen, um, and they've changed the chemicals. They've changed, uh, some of the. Um, you know, amino acids and things that might be in those, uh, meteorites, uh, when we do these sample collections, uh, in deep space like this, uh, in outer space, they come back to us entirely pristine, just like they were found.

Uh, these things are sealed, uh, in the spacecraft. So it really does give us the opportunity to study what our solar system is made from without having any contamination from earth. And 

Osiris Rex. Is that sample return mission that was launched seven years ago as we mentioned in September 2016 to get to that near earth asteroid Bennu.

Now near earth is a relative term in astronomy. It's still a mind blowing distance and OSIRIS REx, the name, it's an acronym, I guess, or a backronym that NASA sometimes uses for Origins Spectral Interpretation Resource Identification Security Regolith Explorer. We said earlier that it's a sample return project.

So the primary objective is to collect and return around about 60 grams of material from Bennu and then return it to Earth. How long is it until you get your hands on that 

sample? Well, like you said, it lands in September, uh, 24th, and there's going to be some processing at Johnson Space Center. Um, and I'm lucky enough to be part of the team that will be doing some of the, some of the processing.

So I'm excited about that. We'll probably not get our sample in, uh, our lab until probably a month after somewhere around there. Um, but things move pretty quickly once the sample is landed. Um, so I would say, you know, late October, we should, we should get our hands on some of the sample here in Livermore.

And I'm very excited about it. 

And the mission, it's a really cool timeline. If you don't mind, Greg, I'll just quickly sketch it out for our listeners. So OSIRIS REx was launched in September 2016. It was in cruise mode for a bit over two years. I mean, we said it was a near Earth asteroid, but it still takes two years to get there.

It arrived in December 2018 and orbited Bennu for just over 500 days, mapping the surface to select a touchdown sample site. October 2020, OSIRIS REx had collected that sample, which was a complex process. That sample head was opened up and only the sample head made contact with the surface of Bennu, and as it did, There was a blast of nitrogen gas that stirred up that gravelly surface and it seems a good sample was collected and then that sample was sealed in that sample return capsule.

April 2021, it started that long journey home and that would take another two and a half years, which brings us to 2023. The 24th of September. We're expecting re entry and parachute landing of the sample return capsule in the Utah test and training range. It's about 46 kilos. I understand about a hundred pounds.

So a couple of cement bags there. And Greg, a little while ago, I saw the recovery crew. They did a full rehearsal in the Utah desert, had a dummy sample return capsule and transported it away in a cargo net suspended underneath a helicopter. As mission scientists. Are you rehearsing your processes too? 

Uh, yes, absolutely.

This is, uh, not something you want to be doing for the first time when you get the sample, of course. Uh, so we do a lot of practicing, um, you know, in, in as realistic scenarios as possible. So as, uh, scientists that are going to be analyzing this material, we've actually practiced, uh, you know, kind of three rehearsals, uh, where we have.

You know, sometimes, uh, meteorite material that has been ground up, uh, and kind of sprinkled into the sample container. And then we do the holes, the whole pouring, uh, separating the whole process that will happen when OSIRIS REx, uh, is returned to Johnson Space Center. Uh, this has all been practiced using.

kind of proxy materials. Um, so it's, it's really thrilling to be, be part of that stuff and kind of see how it's going to be done. You know, there'll be a lot of curators, uh, that'll be involved actually pouring the sample out, moving the sample around. Uh, and there's a lot of scientists that are involved, uh, as well.

Tell us a bit about asteroid Bennu. What type of asteroid is it? And, and why was Bennu chosen for this mission? 

What's it's what's called the C type asteroid and C type asteroids, uh, they are, they have a lot of carbon. They're, they're known to be very, um, you know, kind of volatile rich, uh, and their spectral, uh, their, their spectral signatures basically tell us that they're very primitive.

Uh, they haven't been melted. They're very pristine, uh, materials that Uh, really lend themselves well to studying the early solar system. And this is the same type of asteroid that Ryugu was, the Japanese space agency collected, uh, from. And, and that turned out to be an extremely important, um, sample that came back.

Uh, and, and we're hoping for something similar that's, that's very pristine. And we should, we should get something, uh, you know, very good as well, because we do have a pretty good idea that this is very pristine, pristine asteroid. 

And when you get the sample, well, when you got the Ryugu sample, you said that that arrived by FedEx in a cardboard box.

Uh, you're expecting something different this time? Well, uh, I 

don't know about that. Um, like I said, I'm, I'm lucky enough to, to go down to Johnson Space Center and, and be part of, uh, you know, kind of manipulating the sample after it arrives. So I'll bring mine back on the plane with me. So in my carry on luggage, I guess.

Um, but I think a lot of other scientists are involved. We'll be getting it in a FedEx box, probably. 

And so you will be able to do the, the analysis in your own lab. You won't have to go to, to Johnson in, in, Oh 

yeah, absolutely. Uh, so the beauty, the beauty of, of science is that it's all over the world. Uh, that can also be a pain in the butt, but, uh, you know, it's, it's great because certain machines cannot be really moved and certain labs specialize in certain type of, uh, instrumentation, so it really does need to get.

To get proper study, it really does need to be shipped all around the planet. We're 

expecting about 60 grams of material. It might be more than that, but how much of that sample will, will you get to analyze? Is there a plan to save some of it for years to come when there might be different techniques and maybe even different, um, different priorities?

Absolutely. And that's one of the big things about curation of material like this. And certainly it was, uh, you know, with the Apollo collection, a lot of it obviously still exists, uh, and is available for study now and for future generations. And that's really critical when you do sample returns like this.

Uh, it's great to, to be able to analyze the material, but you also realize that things will improve in the future. So a lot of it. A significant percentage of the material is going to be archived for later use, but also a significant material is going to be able to be studied right now by current scientists.

And we hope, I think, you know, based on what we get, uh, you know, back in the sample capsule will probably get somewhere on the order of a half gram in my lab. And that allows us to do an awful lot of science. A half gram doesn't sound like much. It doesn't sound a lot. No, but it, it, it is a lot of rock. Uh, you know, we don't need a lot to do some of the science that we, we do.

So it's, it's actually a considerable amount of 

material. And what testing do you have planned for that sample? Is, is there like a targeted plan? for maybe some specific objectives or do you have, are you going to run every test you can think of? 

Well, it's a little bit, a little bit of both actually. So we do have targeted areas that we want to, you know, questions that we want to answer with, with certain, certain experiments.

Uh, our lab specializes in what are called isotopic and chemical signatures. So it's kind of your, your fingerprint. Uh, I like to think of it as, uh, of the rock or the DNA of the rock, uh, you know, in, in a genetic sense of a rock. Uh, so it, it kind of tells us where it formed in the solar system, how old it is.

So we're going to be trying to answering those types of questions with the analysis that we're doing. Uh, and of course, you know, you don't, uh, pass up a good opportunity to answer extra questions. So we'll obviously be, be doing everything we possibly can with those samples and not waste anything. 

And you have an idea of what you, what you might expect to find?

Um, are there any particular elements or characteristics you're looking for? And what, what would be really meaningful for you if you, if you did find it? 

Well, uh, you know, good scientists try not to expect anything, of course. Uh, but, uh, we were expecting to answer kind of where in the solar system it formed.

Uh, and, and there are certain. Uh, signatures that tell us that, like, uh, titanium isotopes, chromium isotopes, we can measure these, uh, and they can kind of tell us how far out from the sun, uh, this particular body formed. So that gives us an idea about where in the solar system, uh, all this material agglomerated.

And 

you know, I can't resist, Greg, I always have to ask you the question, will it help explain how non living elements came to life and ended up with two specimens like us recording a podcast about it? I have to ask you that every 

time. Well, absolutely. We'll answer that question. I think there's no doubt.

No, but there's a large, there's a large group of people, uh, and one of the main focuses of this mission is looking at the organics that are present in, uh, in this asteroid. And uh, while that's not my expertise, there's a lot of people, uh, in the community that do organic research. Uh, so they will looking at the, kind of the building blocks of, of podcasters, I guess, uh, if you 

will.

And earlier on, we touched on that, uh, Ryugu sample from the Hayabusa2 mission. Have there been some developments or any, any findings from that sample? 

Yeah, actually, it's been really exciting. Uh, you know, we've had the chance a couple years now to study that sample. And, and even though, you know, it sounds like there's, comparatively, uh, it's, it's about five grams.

So there's not as much material to study. Uh, as I mentioned, we don't need a lot of material. Uh, in the type of stuff that we do, there's been a lot of cool research and it looks like we're finding out, uh, you know, most recently the meeting I was at last week, actually, there's a lot of people talking about how we're able to use that sample, uh, to look and see that there's kind of three main groups of, uh, kind of planetary building material.

There's kind of inside Jupiter, outside of Jupiter, and then stuff even further out beyond that. So what we're learning from that Ryugu sample is that kind of the structure of the early solar system, uh, and, and how it was built, uh, and, and because it's such a pristine sample, it gives us a really good window into that information.

The Ryugu sample that was shared with labs all over the world, or at least with, with yours, is there a plan for the, for the Bennu sample to be shared? Among, well, to be shared with JAXA, the Japanese space agency or any others? 

Yeah, absolutely. And this is one of the things I think is really great about space, uh, and, and collaborations that go on with space research.

Um, so of course we were able to get, get samples. A lot of, uh, teams around the world were able to get samples of the Ryugu. asteroid. And then we're doing the same with with Bennu. So we're sharing a significant portion with JAXA. Uh, they shared, uh, some with, with U. S. scientists. Uh, and it's a, it's a great collaboration.

Uh, and also other scientists around the world are able to kind of apply for, uh, making measurements on the material once it's here. 

And Greg, what are some of the little nuggets in this project? Is there, is there anything about it that you found just weirdly interesting? Something that just really, something that was really 

exciting to you?

It's pretty cool because you think about, you know, we're not able to see this asteroid at all with the naked eye, of course. It's, it's extremely black. It's extremely small comparatively. Uh, but this is an asteroid that, you know, was found by people with telescopes and, you know, it's, it's a tiny little dot even from an earth telescope.

We're able to shoot something up there, hit it, grab a sample and come back. I mean, it's just mind blowing the engineering that goes into that and the math and the science that goes into that. I thought, I mean, that's just absolutely remarkable to me. Uh, and then to bring it back to earth and then to be able to study it in our labs, uh, you know, it really is incredible.

And one thing that was really interesting to me was this is considered a potentially hazardous object. There is a chance some point in the future. that Bennu might collide with Earth. I mean, it's, we're all safe. There's nothing, uh, nothing in the next couple of hundred years, but the biggest risk is on the 24th of September, 2182.

Weirdly, that'll be the 159th anniversary. of the sample arriving. It seems on the 24th of September, we've got to look up 

for Benedict. Exactly. Keep your eyes open. No, it is, it is pretty a funny coincidence. Uh, that is the, the highest, uh, you know, danger, but, uh, one of the, the S in OSIRIS REx is security.

And, uh, that is one of the things that is important about this mission is that it's not just about bringing a sample back. It's about understanding what asteroids are. Um, while they're out there, we can look at them through telescopes, uh, and we can get spectral information about them, understanding exactly how they're constructed, how hard they are, uh, you know, what would happen if one was coming at earth, how we deflect it.

Uh, these are all also parts of the mission, um, that I, I can't speak as intelligently to as I can the sample analysis, but they're, they're all part of that acronym for a reason, uh, because they're all important aspects of space science. 

It's an incredibly cool thing you're doing, Greg. It's been great to hear about what's planned for the Bennu sample.

And I know I can't wait to hear what you discover when it arrives. And will you come back and tell us all about what you find? 

Absolutely. Well, it sounds like I'm a regular now. Uh, so I think, I think I'd love to, I'd love to come back, Andrew. 

Well, we're hoping the landing goes well later this month. And fingers crossed, fingers and toes for a, for a safe landing.

And thanks again, Greg. As always, it's been great to talk with you on Cosmic Coffee 

Time. All right. Thanks a lot. Take care. Check out 

Greg's book, Impact. It's a cracking read. If you want to know more about rocks from space, there's a link in the show notes. Remember, if there's something in the universe that you want us to take a closer look at, send us an email at cosmiccoffeetime at gmail.

com. Thanks for joining me. I'm Andrew Prestidge, and I'll see you again soon for another Cosmic Coffee Time.