NASA Planetary Scientist Noah Petro dishes on what it took plan the impressive touch-and-go return mission, why much of the sample will be preserved for future generations of humanity, the best-case scenario for what we find in these rocks — and the worst.
Credit: Space.com | NASA Goddard Space Flight Center
Credit: Space.com | NASA Goddard Space Flight Center
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00:00NASA sent a spacecraft toward an asteroid named Bennu with the goal of collecting samples
00:06from the space rock without actually landing on it.
00:09In 2020 that sample collection happened, quite dramatically I might add, and in just a few
00:15days the spacecraft is returning to Earth, sample in hand.
00:19And so we're very excited about the OSIRIS-REx mission and today we have NASA expert Noah
00:25Petra here with us to discuss the ends and outs of the mission and you know what this
00:28endeavor might mean for the future of space studies.
00:32Thank you for joining us Noah.
00:33Oh my pleasure, thank you for having me, what an exciting time.
00:36Oh of course.
00:38And so to begin, I guess the question everyone has is, you know we've collected moon rocks
00:42and we're looking at Mars sample return, well what can we learn from asteroid sample collection
00:46that we can't with planetary or moon samples?
00:49Well the first thing is really that we think, we think that asteroids reflect the very earliest
00:56parts of our solar system's history, that they are effectively pristine fragments left
01:01over from the first few hundred million years of solar system evolution and as such, as
01:07they hurtle through space, remain relatively unchanged.
01:11And so what we hope to learn through the samples from Bennu is what this particular type of
01:15asteroid, this carbon-rich asteroid, how it reflects what happened four and a half billion
01:20years ago and compare it to what we learned from samples from Apollo, through other meteorite
01:25and asteroid sample studies, and really, you know again, use this to inform how we
01:30construct the family tree that is our solar system and maybe challenge some assumptions
01:35that we've had, change our interpretations of early solar system history, and then guide
01:40us on future studies of our solar system.
01:43Yeah, absolutely.
01:44And more specifically, why was Bennu selected as the asteroid for this project and I guess
01:50in particular, why was the northern crater from which the sample was collected, why was
01:54that the site?
01:56So for multiple reasons, Bennu was an excellent target.
01:59One, it's a near-Earth asteroid, it will pass close to the Earth in the future.
02:04So we want to understand what these potentially future Earth-intercepting asteroids are like.
02:08And so by going and studying it, orbiting and mapping the asteroid, we get a greater
02:14insight into the properties of this wonderful rock in space.
02:19Collecting the samples, again these carbon-rich samples, may inform our understanding of what
02:24were the things that seeded Earth with the chemistry that led to life.
02:29There's a possibility that we'll find amino acids, chemistries within these rock fragments
02:35that may have helped introduce the compounds that lead to multicellular life on the Earth.
02:42The other thing is, again, understanding how these samples relate to fragments from other
02:48asteroids that have been brought back by the Japanese Space Agency from meteorites.
02:53For me, one of the exciting things is by shepherding these materials through the Earth's atmosphere
02:57in the sample return container, we're able to understand how different pristine samples
03:02are from those meteorites that we've been studying for well over 50 years.
03:06And so the encapsulation and preservation of those fragments from the surface of Bennu
03:12will help us understand meteorite history, whether it's from Bennu or other objects that
03:18reside in our labs.
03:19Now, the interesting thing about the spot that these samples were collected from goes
03:24back to our interpretations of the Earth-based data that we had of Bennu before OSIRIS-REx
03:29was launched.
03:30It was assumed that the surface of Bennu would be relatively beach-like, very fine-grained
03:35material covering the entire surface.
03:37Of course, when we get there, we see that the surface of Bennu is covered in rocks.
03:41Almost every inch of the surface has a rock fragment.
03:45I'm holding a small piece from my personal collection of a rock fragment.
03:49The entire surface was covered in these rocks.
03:52And so the spot that we ended up collecting these samples from was one of the few places
03:57that was not completely covered by rocks.
04:00And so the fascinating thing will be understanding what we got and how the samples we collected
04:05relate to other parts of the asteroid.
04:07And again, we have this wonderful collection of data from the orbital phase of the mission.
04:13Understanding what we have compared to what we think exists elsewhere on the asteroid
04:17is going to be, I think, a very exciting field of study as we unlock these samples.
04:21Yeah, absolutely.
04:22One of the most interesting things about the sample collection to me was when the spacecraft
04:27reached out and it went sort of poof instead of, you know, having like a solid surface
04:31as we might expect with an asteroid.
04:33Was there any reason that you, that the team decided to not land and actually just do a
04:39touch and go?
04:40Yeah.
04:41I mean, the idea that a touch and go was baked into the mission from its, you know, from
04:46its very earliest stages, because, you know, to actually stop the spacecraft and touch
04:51for more than a few seconds takes fuel and time.
04:56So this idea that we touch and go to make it this cosmic kiss really simplifies things.
05:02You know, as we touch the spacecraft, there's a blast of gas to kick up material that then
05:06gets collected into the sample collection system and we leave.
05:12The assumption was, and again, remember, Bennu is a very small object.
05:16So it's a microgravity environment.
05:18So there was a thought that when we touched the surface of Bennu, they would kick up abundant
05:23dust, that it could become this dust cloud around the spacecraft.
05:26So we wanted to get the spacecraft away from this dust cloud as quickly as possible.
05:31So through this touch and go, we minimize the chance for contaminating the entire spacecraft,
05:36but maximize the opportunity for collecting these precious fragments that will be returning
05:40to Earth on Sunday.
05:42Yeah, absolutely.
05:43And one of the things that I was really awestruck by is reading about how, like what it took,
05:48like the maneuvers it took to bring this spacecraft, not just back to Earth, but to a very specific
05:53spot in Utah.
05:55So what does it take to accomplish such a feat?
05:58It takes practice, high-level math, engineering, but also an understanding of exactly where
06:03the spacecraft is in the solar system, right?
06:05So this is one of the wonderful things about tracking spacecraft, is we know where OSIRIS-REx
06:12is within a few meters of its location as it hurtles towards the Earth, and it will
06:17drop off the sample return canister, and that sample return canister has to find a particular
06:22spot above the Earth.
06:24Parachutes have to deploy and it will gently touch down in the Utah desert.
06:29So this takes, you know, a team of people.
06:31I hope people don't think that, you know, missions are one or two folks locked in an
06:35office somewhere, punching numbers.
06:37This takes expertise across NASA and really around the world.
06:41This is a global effort to return these fragments to us here on Earth.
06:47And, you know, we've had an opportunity to do this type of thing before.
06:51There was the Genesis sample return mission from many, many decades ago that was effectively
06:57a test run for this.
06:58So as much as everything is new with OSIRIS-REx, we've learned from previous missions how
07:03to do this.
07:04So we have great confidence that, you know, come Sunday morning, we'll all be glued
07:08to our televisions and see parachutes deploy and a gently rocking spacecraft touchdown
07:14in the Utah desert and make its way to the Johnson Space Center, where those samples
07:18can be curated so that not only scientists today, but scientists for decades and centuries
07:24to come can benefit from the samples that come back from asteroid Bennu.
07:28I'm certainly very excited.
07:29And I know the whole space.com team, as we've been covering it very, very detailedly, detailedly.
07:34I don't know if that's a word.
07:37It is today.
07:38It is today.
07:39On something you said about how these samples will be used for generations to come or studied
07:43for generations to come, I was really impressed by one of the points in the mission overview,
07:48which said that 70% of the sample is going to be preserved at, I believe, Johnson Space
07:52Center.
07:53And I wrote the quote down because I really loved it.
07:56It was for a study by scientists not yet born using technologies not yet invented.
08:02So what do you think is the importance of that approach?
08:04And if you can think of any, what are some gaps that we currently have in these studies
08:09that like future technologies can help fill?
08:12The valuable lesson comes from Apollo, Apollo samples, because we learned in 2008 that by
08:17studying previously studied samples, we could find water in them because we had instrumentation
08:22that measure smaller fragments.
08:24And so the valuable thing for OSIRIS-REx is to preserve everything from fragments the
08:28size of a walnut down to things that are microscopic, because future studies of those microscopic
08:34samples will find things that we miss in the next years to come.
08:38So the study of smaller and smaller fragments, I think, is where the bonanza will be, because
08:42we expect that there's going to be many, many microscopic samples that we'll have.
08:47And so, you know, my children and their children and their children's children will develop
08:50those technologies and unlock the secrets that are held in those tiniest of fragments.
08:55Absolutely.
08:56And just the second part of my question was sort of, you know, what are there any gaps
09:00that we currently have when studying these types of samples that you know of that you
09:04hope will be filled with future technologies?
09:06You know, I don't know.
09:07I mean, that's the joy is that I think the questions that we want to ask haven't even
09:11been raised yet.
09:12Right.
09:13So for me, it's perhaps about what might have, you know, where in the solar system to those
09:17fragments form.
09:18And so on extracting every piece of atomic information from them using technologies that
09:24have not yet been developed to answer questions that that actually might get raised by other
09:28sample return missions.
09:29We're going to be surprised by Artemis, we're going to be surprised by bringing in fragments
09:32from across the solar system.
09:33And so those missions will help inform things that we ask of OSIRIS-REx and we know that
09:39we'll be surprised.
09:40So for me, the joy is finding out where the surprises come from that lead to future questions.
09:45Definitely.
09:46I guess sort of related, I think a lot of a lot of the time, the public questions, whether
09:52it's worth, you know, funneling money into space missions in general, and more specifically,
09:57very science forward space missions like OSIRIS-REx, what would you say in response to that?
10:02Why is this important for humanity?
10:04Again, I think it becomes, again, the fodder for future science.
10:09And in my limited amount of time that I have left, I want to say, you know, we've learned
10:12that missions not only fulfill science questions today, but then allow us to raise and answer
10:18other questions.
10:19We have data from Bennu, we have the samples, and those are going to be used for decades
10:24to come, centuries to come.
10:25And so, yes, it takes money, but those fund scientists to ask important questions, to
10:31educate the public, and then hopefully inform people and excite people to become the future
10:36scientists.
10:37So I think that the kids that watch the sample come back on Sunday will be those future researchers
10:42who are in laboratories around the globe, studying those fragments and unlocking the
10:46history of the solar system.
10:47Wonderful.
10:48I know you have to leave soon, but I guess I'll just leave you with one final question
10:52on a very personal, like in your opinion, what would be the best thing we find from
10:57these samples?
10:58And what would be the worst?
10:59Do you think?
11:00I mean, I think that the best thing that we'll find are fragments, potentially water of amino
11:06acids that may have been the precursors to seeding life here on the planet, as well as
11:10the ages of these samples.
11:12How old are they?
11:13Are they 4.8 billion years old?
11:15Are they 4.4 billion years old?
11:16Are they 3.8 billion years old?
11:18Bennu will hold secrets.
11:20Some of them will surprise us, and that's what I'm most excited about.
11:23I think the worst case scenario is that we get a suitcase and all of the rocks are very
11:28similar.
11:29I'm looking for the diversity of fragments as well, because we know that there are different
11:32types of material on Bennu, and I expect that these samples will all reflect the diversity
11:37of that asteroid and have other surprises as well.
11:40Other fragments of other asteroids that have found their way onto the surface.
11:44But even said, if everything is identical, you will then have material that is the feedstock
11:50for future scientists and for understanding this earliest history of the solar system.
11:54Wonderful.
11:55Thank you so much for your time, Noah.
11:56This was really insightful, and I really enjoy our conversation.
11:59My pleasure.
12:00Enjoy the show on Sunday.