Man set foot on the moon in 1969, and since then we’ve been reaching ever deeper into our solar system. Learn about Georgia Tech's space travel and technological innovations happening at the School of Aerospace Engineering with professor Brian Gunter.

Brian Gunter discusses space exploration at Georgia Tech and his small satellite missions that make it possible.

Album art, illustration
Host

Steve W. McLaughlin

College of Engineering
Dean, College of Engineering
Southern Company Chair
Professor, Electrical and Computer Engineering
Steve McLaughlin, headshot
Guest

Brian C Gunter

Guggenheim School of Aerospace Engineering
Associate Professor
Brian Gunter, headshot

Audio

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Transcript

[steam whistle]

[marching band music]

Steve McLaughlin: You're listening to The Uncommon Engineer. I'm your host, Steve McLaughlin, dean of the college.

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Male Speaker: We’re just absolutely pleased as Punch to have you with us. Please say a few words.

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Male Speaker: Sounds like Georgia Tech is kind of a mini NASA.

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Male Speaker: We’re going to plan a [indistinct] run and do this CDH burn. [inaudible] have not heard anything.

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Male Speaker: Now pressurizing and we’re coming up on the power transfer. Making a final check of his computer. 10-9- We have ignition sequence start. Engines on 5-4-3-2- All engines running. Launch commit. Liftoff. We have liftoff, 29 minutes past the hour.

Steve McLaughlin: Man set foot on the moon in 1969. And since then, we've been reaching ever deeper into our solar system. We're discovering evidence of water on Mars. We’ve stepped beyond our stellar neighborhood with Voyager 1, the only Earth object to reach interstellar space. And now, yes, we're exploring commercialized space travel.

[radio transmission]—

Male Speaker: You’re looking beautiful.

Steve McLaughlin: Welcome to The Uncommon Engineer—conversations about the impact Georgia Tech engineers are having on people and society in maybe in ways that you don't expect. I'm Steve McLaughlin, dean of the Georgia Tech College of Engineering. Today we're here to talk to Professor Brian Gunter from the Georgia Tech Guggenheim School of Aerospace Engineering. Brian Gunter, welcome to The Uncommon Engineer.

Brian Gunter: Thank you for having me.

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Male Speaker: Flight crew-OTC-Close and lock your visors, initiate O2 flow.

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Male Speaker: Roger, Hawaii, reading you loud and clear also.

Steve McLaughlin: You know we hear lots in the news about space missions and launches, whether it's a space shuttle, you know, Elon Musk in certainly in the news a lot around SpaceX, and I understand you're involved with SpaceX on a project. Can you talk about that?

Brian Gunter: That's right. We have, in development at Georgia Tech, a small satellite mission. It’s called the Ranging and Nanosatellite Guidance Experiment. And I'll get into some of the details in a second. But it is a small satellite—think of a satellite that's maybe the size of a large coffee cup, and there are two of these together. So together, they're about the size of a loaf of bread. They will be launching on a Falcon 9 rocket which is made by SpaceX. And that should be launching in the fall of 2018. The specifics are you have to be very flexible when you launch satellites because the dates always change. The RANGE mission is—think of these two small satellites and the goal of the mission is all about getting precise, absolute, and relative positioning. So most small satellites only know their position in space to tens of meters, and we want to get that down to centimeters. So we want to know where these satellites are at any point in time down to centimeters. And in addition, we want to know, because there are two of them and they're flying together in this sort of leader-follower formation, we want to know how close they are with respect to each other down to millimeters. And so we have all this instrumentation—we have the laser rangefinder on there. We have a miniaturized atomic clock, which we think is the first one that will fly in space. We're also testing various secondary experiments. A lot of it is—a lot of the operation of the satellites are going to be autonomous. So they're so small, we only contact them maybe five or ten minutes a day. So the rest of the day they have to work on their own. And to maintain their formation—let's say we want them fixed at 10 kilometers apart, they have to do a lot of that themselves. And so there's a lot of interesting development that goes on with that. And there's no propulsion systems on these small satellites, so they have to do what's called “differential drag” where, even though you're in space, there is a small amount of atmosphere, and you're going 7 kilometers per second, so you're really moving fast so even the smallest bit of atmosphere is still interesting or still can create a force on the satellite. So what we do is we'll turn the satellites and given a little bit different area that is heading into the drag forces. So because of that, then we can stretch things back and forth.

Steve McLaughlin: So you have students in your lab that are making these satellites and interacting with SpaceX. What’s it like to interact with SpaceX? You mentioned you got to be patient.

Brian Gunter: So we were—the mission itself was accepted as part of—we got the launch. We had to build a satellite, but we got the launch awarded to us through a proposal, through what was, at the time, the Skybox-CubeSat Partnership. So Skybox was a company; it's now owned by a company called Planet. And for those who maybe follow satellite remote sensing, Planet is now a company who has a number of orbiting imaging satellites that are constantly taking high-resolution images of the Earth. So they—basically we got the launch through them, and they awarded us a launch on one of their following satellites because they have larger satellites, and we go along on what's called a “ride share.”

Primary customer and then our small university satellite go wherever there's space on the rocket and there’s extra mass. And so the way that SpaceX came into be is originally we were supposed to launch on an Orbital ATK rocket. And so it was going to be Skybox, now Planet, that was going to pay for the primary rocket, and we were going to be a ride share on that.

Then, as we've learned, a number of launch delays because you're waiting on the primary customer. So you don't have any choice on when and how you go up. And so things change. So things were rescheduled. Plans changed and so we moved from an Orbital ATK launch to now this launch that's called the Space Flight SSO-A, what they're calling the SmallSat Express, and that is going up on this Falcon 9. And that's a dedicated mission that's operated by a company called Spaceflight Incorporated. So the way it works is we interact with what's called the “launch service provider,” and Spaceflight is that company. And then they interact with the SpaceX, the rocket provider.

Steve McLaughlin: So you talked a little bit about the, you know, the fact that you're going to launch these two satellites, and the goal is to run some experiments that help finally control position or where they're located down to a small scale. Do I have that right as the goal or purpose?

Brian Gunter: That's correct. So the primary mission of the mission is this relative and absolute positioning. So we want to find out how to control or how to position, know where the position of these small satellites are to a level that has never been done before for these small satellites. So that in itself is an enabling technology. It's one of these characteristics about a satellite system that if you know that, then you can enable a number of different other mission concepts. So think of very tightly controlled formations. Think of constellations, or think of—like we talked about earlier—where you have coordinated measurements, and you need to know precisely where things are so that you can take, whether it's images or whether it's ranging data in a very coordinated and precise manner. And so sometimes you need to know that level down to centimeters.

The secondary part of these missions that many of these CubSats are technology demonstration missions. So you are testing out whether new components are going to function in space, whether they do what you think they do. So we have several like I mentioned. One was a miniaturized atomic clock. Another is a laser ranging system. And this laser ranging system also caught the attention of the Navy. So we had a follow-on grant from the Office of Naval Research. And what we're doing with this is for the same laser that we're using to inter-satellite ranging—so think of a range finder that you might get at a hardware store or something like that—except now we're posing this over many hundreds of kilometers possibly. That same laser can be used, if you think about it—pulsing it on and off can be zeroes and ones—so it essentially doubles as a laser communication system. And that's what the Navy was interested in. So we're also demonstrating what we hope to be the first inter-satellite or cross-link laser communication system. And that’ll be a very low rate. It's not going to break any speed records, but it will demonstrate the lengths. It'll demonstrate the technology whether these small components that you can just literally hold in your hand, could they service as a laser communication system.

Steve McLaughlin: So you're living proof of, you know, when NASA goes to Congress every year to kind of justify that, hey you know, what we're doing in space matters.  It's not just the mission, but it's the things that you learn along the way. And you're testing—sounds like you're testing a number of those enabling technologies that even separate from your, you know, the project per se, you're demonstrating new things to even solve your mission, and you're living proof of why we need to support NASA.

[radio transmission]—

Male Speaker: 11-Houston. If you could comply, we’d like to see some smiling faces up there.

[radio transmission]—

Male Speaker: OK, we’ll reconfigure the PB for that.

[radio transmission]—

Male Speaker: Roger.

Steve McLaughlin: Where do you think manned space flight is headed? You keep hearing about possible manned missions to Mars, but what about some of the other planets. Where do you see if you look in your crystal ball for, not just 20 years but 100 years, you know, where is man headed?

Brian Gunter: Well I think in the in the near term most missions are going to be robotic. The reason why is the space environment is extremely harsh. So we know this. It has extremes in temperatures. There's radiation and, of course, there's not this breathable atmosphere or food sources readily available, so you have to build spacecraft that bring all of that along with you to project the astronauts or the humans that are on the trip plus bring all the food and water and air that they need for the journey, not just there, but also coming back as well. So it becomes very expensive. So just to give an example, if you go to the SpaceX website, since we're talking about SpaceX, the Falcon Heavy, which is this next generation of a very heavy lift rocket vehicle, it can carry, according to their website, 37,000 pounds to Mars. And if you think about what a mission would cost—a manned mission anywhere: Mars, even to the moon—you could think of billions of dollars. To put it in perspective, the Cassini mission which was wonderfully successful and just finished up its operations, that was around $3.3 billion for that mission. So you would expect it would be at least as complex and expensive as the Cassini mission if you're sending humans.

And at just 37,000 pounds when you do the math at say a four billion mission cost, you're talking about spending roughly anywhere from 50 to 100 thousand dollars per pound of mass. So it gets really expensive. In addition, there are some very other sort of physiological and psychological challenges that go with manned spaceflight that maybe a lot of people don't know. The human body isn't meant to exist for long periods in zero gravity. We’re meant to be here on Earth. So there's problems with bone densities, muscle mass. There's also been documented cases with problems with eye pressure causing permanent damage. There are interrupted sleep cycles because you're not on this Earth cycle of day and night. And so it's very—there are certain things that have to be overcome before we send somebody off. And a round trip mission to Mars, you can expect to be maybe three years going there and back.

And there are some also some psychological challenges. Basically in a solitary confinement for three years as an individual, and that's very difficult to overcome. When they screen people to be astronauts, their psychological makeup is just as important as what their technical skills might be. So that said, I think the challenges for human exploration are not insurmountable. And I believe the technology is there to do that, or can be developed in the near term to put humans on Mars or other celestial bodies. We don't have to go to Mars—we could go to asteroids and comets—these are also been proposed. And sometimes they are a lot easier because, if you go to Mars, you go to a very large planet that has a large gravity that you have to overcome to return flight. But if you were to land on an asteroid that there is no large, you know, gravity, getting off of it is much easier. But I think it just needs the investment and the support behind it. So I think we can do it; it's just very expensive.

Steve McLaughlin: You know, missions to other planets, what are the other kinds of things that you see out there either that you're working on or that Georgia Tech is working on or things that maybe our listeners haven't heard about?

Brian Gunter: Well, I would say, since we're talking about, you know, manned and robotic missions, I would I would also argue that there are still a tremendous amount of things that robotic missions can do, and some of them that they should be doing instead of humans. So not everything is something that we should do with manned exploration. And one of them, for example is, let's say, an orbiting imager like we've talked about, that you're just gathering real-time information that's up there for decades at a time gathering 24/7 data 365 days a year. That information is best done by robotic missions. And so, sort of the link to that is some of the work that maybe is not so known where we use remote sensing. So I am part of also, yes, I build satellites and we have this whole CubeSat and small satellite program, but another aspect of what I do is actually using the data from those missions. And because they’re launch for a reason, and a couple of good examples are some NASA missions that I've been involved with in the past—the GRACE mission and the ICESat mission. GRACE was a mission that was designed to observe the time-variable gravity of the Earth. And that's important because anything that moves on the surface of the Earth—water, snow, ice, oceans—it's all mass, and mass and gravity are linked. So when you observe the time-variable nature of Earth—the time-variability of it—you are also understanding what are the processes that are causing that change in the gravity.

And so we use that remote sensing data from these NASA missions to observe all sorts of things that people may not know about. One of them is I study the motion of the ice mass and solid-earth changes in Antarctica. And you may ask, “Why are we interested in, you know, the changes in ice and the solid-earth in Antarctica?” And the answer is that it has a direct influence on the rest of the world in terms of sea level change because it's so like a cup and Antarctica is, if you were to put a ping pong ball in a glass of water and you push it down, the water would rise; pull it up, and it would it would lower. And Antarctica is a very large continent. It has 70 percent of the world's freshwater on it. And so observing the changes in Antarctica directly influence our understanding of the water cycle, sea level change, climate change—all of this.

So we've been using that data and, for time, variable gravity. We can use it to observe. And gravity is an interesting observation because it doesn't—it's not limited by a camera like a camera is limited by its line of vision. So if it's something underneath a tree you're not necessarily going to see it. But gravity is insensitive to that. So we can observe changes in underground aquifers. So we can monitor let's say large, the behavior of large river basins or large aquifers that we depend on for agriculture, for food production. And so this type of remote sensing data, looking at the data that comes from these major NASA missions is also another one of our major objectives. And I’ll also say that the ICESat and GRACE missions that I've been working with, they have now follow-on missions. So Grace follow-on just launched a few months ago or a couple of months ago in early 2018, and ICESat 2 is set to launch later this fall in 2018. So these two missions will continue to, not just look at Antarctica, but do global mapping and global—and ICESat, I didn't mention, but it measures the topography. It's using LIDAR systems to measure the changes in the surface and the volume of the Earth, and the GRACE mission measures the change in mass. So these are fundamental properties that we are observing, and will continue to observe now for many, many years to come. But that's something that I'd like to throw out too is that we're not—or at least I'm not—just focused on just the hardware and just the, you know, the satellite components, but I'm also very much interested in what the satellites do and interpreting the data that they generate.

Steve McLaughlin: So you know all the things that you've talked about your expertise your interests, you know, span a huge range of things. And what I'm really curious is, you know, your path to becoming an aerospace engineer, you know, even as a kid or whether it's in high school or college. Can you talk about how you found your way to doing all these interesting things? I think there's so many young people that might be out there trying to understand. I mean, done a pretty good job I think of saying what engineers do, but how’d you find your way there?

Brian Gunter: Well I've always been sort of interested in designing things. So as an engineer your job is to build something to complete a particular task—and that's a very big umbrella. And so my particular task is the exploration of space.

You're built with basically taking a problem that needs a solution, and you build something to either solve that problem and that can also encompass programming and coding and analysis. And so I was sort of drawn—I've always sort of drawn to that. If you have some sort of unknown problem that you'd like to fix, and you know that there's a technology that maybe if you just design it right, could solve that problem. And that's always appealing to me. And then there's an additional appeal to space because there's just so much we don't know about space. We don't know about working in the space environment or the origins of life and, even, you know, every new mission that NASA sends out, especially the planetary ones, comes back with this host of just amazing images and new insights about things. And so that's also a very big draw that you have the opportunity to start tackling and answering some of these big unknown questions. So that was a big draw for me. And how I got into specifically this particular field, it started, of course, with graduate school, undergraduate and graduate. It was always—I started first as a mechanical engineer and then I transitioned into aerospace engineering because of this appeal to work with space.

But initially I thought, you know, I was going to work as a mission control guy at Johnson Space Center. That was what in most people's, I think, vision you are either going to be an astronaut or you're going to work at mission control because you see this in popular media, in the movies, and things like that. And the reality is when you get into it and I started working with the original GRACE mission when I was at University of Texas at Austin, so my advisor was the PI on the GRACE mission. And I got this other insight into, wow, there's this whole science aspect to the engineering that we do. So the science and the engineering was a really big appeal for me. And so that's what I continue doing. So I started blending more and more the remote sensing and the science and the engineering. And the more I understood more about the purpose of these missions, the more I enjoyed that.

But I also wanted to also bring my engineering knowledge to say, “A ha! I think we could do this or I think we could do this” or “If we analyzed the data this way, we'll get some new insights.”

And so it just sort of fed on that and I've built out over the years and I was able to bring that to Georgia Tech, but now realize it a little bit different way with all of the small satellite missions that we have in development.

Steve McLaughlin: You kind of touched on it—did you think you wanted to be an astronaut at one point?

Brian Gunter: I did. There was a time, and I did apply to several rounds of the astronaut program. It's extremely challenging. You got 20,000 people applying for six positions and which three will go to civilians, so if, you know, I wasn't an Air Force pilot or Navy pilot. And so it's extremely competitive. But ultimately, I tried but I wasn't disappointed, of course, because there's so many other things that so many other contributions you can make. Who knows, depending on how things go with some of these new ventures with space tourism, maybe even before my life, I'll still be in space.

Steve McLaughlin: Yeah. Is that something you think you'd like to do, if you know—right now it seems to be for billionaires and—

Brian Gunter: I’m going to hold out to make sure that—I worry less that, while the money is a factor, because like, you know, I don't have $10 million to do some of these really specialized trips. But I would like to wait for the—just to make sure that it's demonstrated to be safe, and make sure that these are reliably—before you trust your life strapping yourself onto a rocket and orbiting Earth, you want to make sure that it's going to be a safe experience.

Steve McLaughlin: Do you think, you know, in the next 20-30 years do you think that will be a possibility.

Brian Gunter: I do. I think you'll see it won't be—I think it's something that you just book up online—it won't be that popular, but I do think that in the next 20 years, you're going to see at least suborbital flights. Maybe you just get weightlessness for an hour and a half or two hours, possibly even full orbits where you're actually orbiting for maybe some days, and then you return. I think that that there are certainly companies who are pushing very hard to achieve that. And I would very much like to do that. That would be a great thing to do.

[radio transmission]—

Male Speaker: Hello, Houston. the Endeavor is on station with cargo, and what a fantastic sight!

[radio transmission]—

Male Speaker: Beautiful news!  Romantic, isn't it?

[radio transmission]—

Male Speaker: Aw, this is really profound, I’ll tell you. Fantastic!

Steve McLaughlin: You know, at the high level, it makes sense that an aerospace engineer is designing a satellite. But, like, when we get down to it and all the pieces that need to work together tens of thousands of miles, if you will, is that—what's the orbit?

Brian Gunter: About 600 kilometers.

Steve McLaughlin: 600 kilometers. OK. So to do that 600 kilometers away requires incredible skills. So can you say a little bit about—you know, this is, I think, the work of yourself and your students—can you say a little bit about the kinds of students that might make their way to your lab?

Brian Gunter: And I'll say that we rely heavily on our talented students that we've got here at Tech to do all of this work because these missions are very complex. So at any one time—and I'll throw out that at Georgia Tech in the aerospace program, we have six active satellites in development right now. And so I'm a principal investigator for three of them, RANGE is just one of them. There are colleagues within the space systems design lab, and in aerospace they manage some others. So we have six missions currently in development at different stages. Some are going to launch soon; some are going to launch in a couple of years from now.

And each one of these has upwards of 10 to 20 plus undergraduate and graduate students working on them. And they have the whole skill spectrum because you need someone who is knowledgeable in programming; you need circuit board design; you need CAD; you need structural design; you need to understand thermal properties. We have lots of mechanisms, so we have mechanical engineers, and we have computer scientists, and we have electrical engineers. We have a whole team, and I recruit from across the campus. Yes, there are certainly aerospace engineers because we need them to do the orbit analysis and the mission design, but we need everybody because, if you think about what the mission encompasses, it's everything from design to electronics to programming to science analysis—ultimately we want to do some analysis after the mission launches. There’s radio signals that we need to interpret. That's how we communicate with the satellite. So the full spectrum of skill sets need to go in to these missions.

[radio transmission]—

Male Speaker: OK, loud and clear, Dave, and you’re Go for liftoff, and I assume you’ve taken your explorer hats off and put on your pilots’ hats.

Steve McLaughlin: It seems like we maybe have a mini NASA here at Georgia Tech. Can you talk about, I mean, could somebody come to Georgia Tech and kind of do the whole thing as if you think that only NASA could do?

Brian Gunter: Yes, in many ways, I would say. We have the capability here, and I think we're fairly unique or just one of a handful of universities that could even offer this, we have the ability to handle every single phase of a small satellite mission.

This includes the mission design—so the early concept work to the fabrication of it. So at Georgia Tech’s aerospace, we have a fantastic machine shop within the SSDL, the Space Systems Design Lab. Amongst the shared facilities that we have, of all the professors there, we have thermal vacuum chambers. We have vibration tables that are we use out at Georgia Tech Research Institute, so we can do all of the testing and analysis. We have the setups to do hardware in the loop testing where we’re evaluating attitude control systems and the communication systems. We have multiple ground stations. We have an S-band station and we have multiple, what are UHF radio stations, and those were used during mission operations.

So after the satellites launch, we can download the data here. All of our mission control is here at Georgia Tech. So we don't delegate any of that other than the actual launch itself to any other party. And so that's a pretty unique feature. And the number of satellite missions that we have in the works—like I mentioned, we have six active flight projects in the works—enables a student, if they have the interest, if they want to go beyond just what they learn in the classroom, the opportunity is there to come to Georgia Tech and actually get involved in a mission that is going to launch in space. And that's a pretty—I certainly didn't have that when I was an undergraduate, so I enjoy that that we have that opportunity here at Georgia Tech. And the students really enjoy it too. They love the challenge of it. They love knowing that what they are working on is going to go into space.

[radio transmission]—

Male Speaker: Apollo 15-Houston, over.

[radio transmission]—

Male Speaker: Hello, Houston. Endeavor’s on the way home with a burn status report for you.

[radio transmission]—

Male Speaker: Roger. Sounds good. Standing by.

Steve McLaughlin: One of the questions we always ask is what makes you an uncommon engineer because I think, you know, a lot of the things that you talked about, I don't think people necessary think about it as engineers, but so, Brian, what makes you an uncommon engineer?

Brian Gunter: So I would say I'm uncommon in the sense that I am as excited as much by the science and the discovery behind some of these space missions that we work on as about the process of building the systems and the satellites that are required to achieve those goals. So I think many engineers are very content to just work on a particular subsystem, whether it's an attitude control or a propulsion system or power system, flight software or what have you, but those people tend to be relatively disconnected with the larger objective of the mission. And so I'm fortunate to have this opportunity to work on all aspects of a satellite mission. So all of these satellite missions that I've talked about—the RANGE mission, the target mission—we have taken those from a mission concepts from a PowerPoint presentation all the way to gathering data from an orbiting satellite and actually executing that. So we get the full spectrum from fabrication to testing to the analysis and interpretation. And so I'm just as excited by the science return and the data that we're going to get back by these missions, as I am in the engineering processes. So in this sense, I think I'm a little bit—I'm a little bit uncommon for most engineers in that I am a true sort of—I love the science and the engineering. I like how they interact.

Steve McLaughlin: Well, we're really lucky to have you here today to talk about your project. But I think, just as much, really lucky to have you here Georgia Tech because that kind of expertise, that kind of interest, really benefits so many students. And we just really want to thank you for today and for everything you’re doing at Georgia Tech. So thanks so much, Brian. We appreciate it.

Brian Gunter Thank you.

Steve McLaughlin: Next time on the Uncommon Engineer, we'll meet Dr. Annabelle Singer and her work on memory cognition and possible therapies for Alzheimer's disease.

[radio transmission]—

Male Speaker: Apollo 15. this is Recovery, over.

[radio transmission]—

Male Speaker: Apollo 15, everybody’s in good shape.

[archival recording]—

Male Speaker: We had a lot of support from a lot of people and I just like to say that we appreciate every bit of it and we could not have done the mission, we couldn't have gone one step without the support of the many, many thousands of people involved. Thank you very much.

[applause]

[marching band music]

Geekout

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[radio dial scanning, static]

[big band swing]

Steve McLaughlin:  It sounds incredibly complex—it sounds like—to build these that span—I’m really geeking out here.

[big band music]

[two-way radio transmission]

>> It so happens there are two vials of 500 eggs each. Diapause refers to the hibernation.

>> Stay cool, [indistinct]

>> I knew I couldn’t do it.

>> I knew I could only get you once, though.

>> If I could get Procedures to quit laughing over here. Hibernation cycle of a larva.

Steve McLaughlin: I think our audience is familiar with GPS, right? We use satellites to determine our position here on Earth. They send us signals, you know, we have a GPS receiver on our phone or in our car. And it sounds like, in your case, you're doing something a little different, but it’s still with positioning, and you're saying the positioning of the satellites themselves in space relative to each other is super important. Can you say why that's important?

Brian Gunter: The reason why the positioning is important is if you're going to have, let's say for example, a formation of satellites and they're going to coordinate measurements, for us we have several applications that we want to know. We want to know, without getting into too much detail, information about Earth’s time-variable gravity or we want to know its shape, so we're going to send maybe laser measurements from the satellite to the surface, and those measurements are only as accurate as you know where your satellites are. And so we are using GPS to track our satellites, but we're using additional information to try to get it as precise as possible.

Steve McLaughlin: Yeah, makes tons of sense. We see these you very high-precision photographs from space, but you have other things that you want to get high-precision and that only is as good as the precision.

[two-way radio transmission]

>> Roger, Hank. You remember about two weeks ago when we were talking about the clunkety-clunk noise down in the command module?

>> Yes, it’s not back is it?

>> Yeah, it’s back. Wasn’t as severe; you couldn’t feel as much as you could just hear it.

Steve McLaughlin: Your saying is actually satellites can be small things and people out there might be saying, “Hey, can I get can I come up with something and put it on a rocket?” And it sounds like kind of, but not really.

Brian Gunter: You can. And there is a tremendous amount of work that needs to get done because the satellites, even though they're small, they are still a fully functional spacecraft, and they have all of the systems that a major spacecraft would have—So they have a power system; they have communications; they have computing; they have a structure; and it all needs to survive the environment of space, and they also need to go through some regulatory hurdles as well—You can't just throw up something that is going to beacon things or take images of things; you need approvals for a lot of that.

And so, yes, they are small, but they have to go through almost the same process as a major mission. But I do want to mention that this SmallSat Express is interesting in that it is a satellite that's being managed by this company, Spaceflight, but 70 other small satellites are going up at the same time. So it is one of the larger single launches of satellites to go up on an individual rocket.

Steve McLaughlin: Are those mostly other universities that are doing the small satellites or is it all kinds of—

Brian Gunter: If you go and you look at the list, I think the division—they’re from all over the world, so a lot of universities a lot of small companies. There are other larger companies, so it's a full mixture from satellites from all across the world. But I think maybe two thirds of them are university and small companies, startup companies that are looking to demonstrate a technology.

Steve McLaughlin: When you were describing the two satellites that are going to be, that are going to be launched, it sounds incredibly complex. It sounds like you need to have skills, you need have students, you need to have abilities that span a huge array of things. Can you talk about that? Can you talk about a little bit about your research group?

Brian Gunter: The experience of actually designing, building, and assembling the satellite has been, for me, extremely educational. It’s been very enriching both for myself and for the students. And it's easy when you just talk about it and you see them, you'll see the satellites. On the outside it looks relatively simple—it's a box—but it's very easy to underestimate the effort that goes into all of that because it is an extremely complex and challenging thing to build, especially because it's so small. And the integration phase, in particular—and that's where, you know, the students at Georgia Tech—they're very well trained for the design aspects of it. They'll take a, you know, a computer-aided design course, and they know about the dynamics or maybe the orbital mechanics, so they know the theory and the mathematics about it all. But they've often never had the chance to actually implement this in real life on a satellite mission that needs to work. There's no there's no room for failure on a satellite because, once it goes up in orbit, if it fails you can't bring it down and fix it, and there's no servicing mission that's going to save your small satellites. So it has to work 100 percent.

And so the students working on these small satellite projects, they really get to enrich their experience here because they get to apply this knowledge that they learn in the classrooms to real-world problems and hardware. So they're working on—it's an actual satellite, and it's a hands-on environment.

So they need to develop a lot of other skills that they don't have they need to learn to work together. They need management skills. We have deadlines to meet. We have reporting to do. We have licenses to apply for. So they need to develop their writing skills, public speaking, in addition to just the pure technical skills of finally building something. And when you finally go to build something, for everyone who's done that before, who have actually had an idea, designed it, and then actually went to build it, you find out all of the things that you didn't find, that you didn’t design in advance. And everything just comes out of the woodwork for these things. We've had components fail at the last. We've had to make last-minute design changes, and so many little things. Many all-nighters we're had building these satellites. But at the end, you really get an understanding of what it takes to build the satellites and get them ready.

And that's only part of the story, right? Only building is just part of it—we still have to launch it, do mission operations, process the data. These missions have a goal and a purpose, so that's really the end goal of all this. So this is only part of this whole experience.

[two-way radio transmission]

>> Hey, did you find them?

>> Yeah, that rascal left us some goodies.

>> How about that!

>> All gaily wrapped in Christmas paper and ribbon and the whole bit.

>> Yeah, I was a little puzzled the other night when you called down and said you had one present to put under the tree.

Brian Gunter: I should mention also that this particular mission will be tracked by ground-based laser-ranging systems. So there are systems. There's a whole network of—think of telescopes with lasers on them that track precisely where the satellites are. We have these mirrors, or these retro reflectors on the bottom side, so we're able to really precisely track the location of these satellites to verify the positions that we hope to get. And there's all sorts of secondary experiments because you could almost treat these satellites as a piece of space debris—it’s a space debris that we just happened to know precisely where it is, but let's model that or let's say well, what if we only got a few images of it and we wanted to predict in time, and maybe we needed better atmospheric models or better, you know, orbit trajectory analysis? We could test these theories out and use our satellites because we know where they are to validate those models. So there's a lot of secondary science and other aspects of this mission.

Steve McLaughlin: You know, as you were describing a little bit earlier some of the aspects of your satellites, the one that caught my eye—I’m an electrical engineer—I think you said there's no power source on these?

Brian Gunter:  No propulsion system.

Steve McLaughlin: No propulsion system.

Brian Gunter: So there are plenty of electronics. In fact, that's one of the things that we've learned a lot doing our custom electronics. We try to buy as many just off-the-shelf components as we can, but we've also learned that there is just some instances where you just have to make—

Steve McLaughlin: Not having a propulsion system asks to me my mind says, OK, well then, you know how do you—you're going to want to move the satellite either relative to each other or in place. And then I think you talked about atmosphere. I’m really geeking out here. So you're able to you're able to, even though you don't need propulsion, you can, because of the atmosphere, the thin atmosphere around the satellites, be able to adjust?

Brian Gunter: You think of two satellites, even the simplified case where it's one edge is a big, flat plate and if you turn it 90 degrees, it would be very well, let’s say, much less surface area. And now think about once both of them being in the same orientation and you just turn one, now the drag force on one is different than the drag force on the other. And that's where this term “differential drag” comes in. So then they're going to change position. And it's a little counterintuitive how you actually change the inter-satellite position of each other, but that's the basic concept of it—that you're changing the drag force on each satellite but one at a time out and you can control their inter-satellite—

[radio transmission]

>> Good morning. At 8:35 Central Standard Time the crew will reach the halfway point in the scheduled 84-day mission.

Steve McLaughlin: Flying through my brain. I mean if you’re really—your experiment is to try to measure down to a centimeter or millimeter scale, the ability—I keep going through this. He's not an aerospace engineer; he's like about 10 different kinds of engineers.

Brian Gunter: Exactly and an Earth scientist as well and a planetary scientist all mixed together.

Steve McLaughlin: Yeah because, yeah, I mean at the high level, it’d make sense that an aerospace engineer is designing a satellite. But like when we get down to it and all the pieces that need to work together tens of thousands of miles, and you started to talk a little bit about some of these other projects. Can you share some information about the other projects that are going on?

Brian Gunter: And one of the other missions that I have in the works is a NASA-sponsored mission so, nice that we're talking about NASA because it is sort of a mini NASA. This was a mission called the Tethering and Ranging Mission of the Georgia Institute of Technology, or TARGET for short when you do the acronym. So TARGET is a mission that is also very exciting. It's a little bit larger than the Range mission and it's just I'll say its goal is to test what we call an imaging LIDAR. So a LIDAR system is, again, this ranging system. So think of a system that could generate a three dimensional map of a surface, and that's what this LIDAR system can do. And what we want to do is create a compact imaging LIDAR for planetary applications.

Steve McLaughlin: I see.

Brian Gunter: So the goal is we—if we build this system, we can now—next time let's say NASA goes to Mars or to Saturn or Jupiter that we have a small satellite, a CubeSat, as a rideshare in the similar concept that we have on Earth that we spin off, and we get to go explore maybe other aspects other celestial bodies that we don't know about moons or comments or asteroids and we can do this in this very small compact satellite. And so this target mission, it is NASA-sponsored. So again, it's a whole team of students. We have 25 students currently working on it, developing all sorts of things. And it's a really interesting mission concept because we're going to test, again, a lot of new technologies. So the LIDAR system itself is a new instrument. We're hoping to do this for very low cost and make it very robust and high precision. But the way we're going to test this LIDAR system is we're going to tether out—so think of like a fishing wire on us on a very thin tether—we're going to tether out what we call an inflatable. If you looked at it you might look at it as a balloon. So we're going to tether out something about 10 meters, so 30 feet. We're going to inflate it. And that is going to be our, let's say, sample moon. So we're going to validate our imaging LIDAR on this inflated target, hence the name “TARGET,” and the challenging part is going to be, you know, the nice thing is we'll know everything about it because we build the target, so we'll be able to verify that the images, the 3-D maps that we're getting from imaging this small target are correct.

And then the challenging part at the end is the very last part of the mission. And the reason we have the tether is because as soon as you cut that tether, the target is only within the vicinity of the main spacecraft for a few hours. But that's exactly what we're going to do at the very end of the mission. We're going to cut the tether and this thing is going to free-float away, and we're going to use all of our satellite systems to continue to track this and continue to range to it and gather data on it as it goes 10, 20 kilometers away. And this is representative of a scenario where you had a CubeSat and you're flying it by—you know, deep space navigation can get you within 10, 20 kilometers of an object pretty reliably, and so this is why we want to target this. If we can demonstrate that we can track this object as it goes 10 kilometers away, that's pretty representative of us being able to fly by a comet or an asteroid or maybe a particular surface feature on a moon.

And there are a lot of applications for this. So you could think of going to a moon and doing some reconnaissance. There are a lot of destinations that NASA is considering for a future manned flight, Europa or Phobos, these are moons of planets. And it would be great to send this small imaging system there to map out to make sure that the area is safe, make sure there's not any large features, make sure there's not going to be something terrible that happens if you send a manned lander down.

But it's also, if you think about what the systems that are involved—lasers very similar to what we're doing with the intersatellite ranging systems on range except we also want to demonstrate laser communications. So then you could think about using the same LIDAR system as a way to either gather mapping data or reconnaissance data. You can actually use it as you approach the satellite or the moon as ranging information, so you could use it for your guidance. And then you could, conceivably, after you gather all this information, turn the whole spacecraft back towards Earth and use high-speed laser communications to transmit all that data back to Earth at a very high data rate.

And so this ties into another theme another project that we have that we recently got over the summer that involves just that very thing—developing yet another space-borne high data rate—and this is gigabit per second time data streams—from space to ground. And so this is working. This other project that I'm just talking about that was just started over the summer, we hope to demonstrate that on the space station. So the objective is to develop this laser communication terminal that was originally developed at JPL, but we're going to take it, we're going to miniaturize it, and we're going to demonstrate, you know, gigabit, up to 10 gigabits per second from space to ground. And that's a pretty enabling technology. You can think about even sending 10 gigabits of data or a network of think tens or hundreds of these satellites that can all communicate at 10 gigabits per second or a planetary mission that could live stream high HD video from wherever they are. It's really enabling. So these are the types of things that we're working on.

Steve McLaughlin: Wow. As a taxpayer, you know, the kind of just—the idea of letting robots—and as you know, I think people know robots are becoming more and more human-like. But the idea of multiple missions of robots to go and explore someplace before we put humans does make a bunch of sense because for all the risk factors you talk about well, maybe even just purely from a cost standpoint, that makes sense. But I mean I know we're learning so much. We have learned so much through the space programs that, you know, whether we're sending robots or humans, we're going to continue to learn, you know, a huge, huge amount.

What a fantastic opportunity for students to study undergrad or grad because of that that whole system. And at the end of the day, it's really teamwork, and I think that that’s the thing you and emphasize over and over again, you know, our students develop you know good solid skills, engineering skills. But, you know, even more than ever that doesn't mean a lot unless you really know how to work with a team. And it seems like these projects, dare I use the word, are just perfect scenarios for students and others to just, you know, use their skills but, more importantly, learn about teams. And so talk about how you help the students build teams.

Brian Gunter: A lot of is just done by learn by doing. When we take in students, we try to take them as freshmen and sophomore because we know that that development process takes many years before they're ready to take on more complicated tasks. And it also gives them this exposure to decide whether they enjoy this type of work or not. Many of them don't, and that's fine. Many of them really embrace it, and they absorb things. And they may not come in with necessarily good programming skills, but they realize that's important and then they develop those skills over the next couple of years, and now they're working on some particular component or an embedded system. Or, somebody who comes in, for example, with some of the laser projects, they're not necessarily—you don't get that training to become an optics expert or to work with laser communication systems, that's not part of the undergraduate curriculum, so you have to learn on the job. So much of what we look for in the students that are really successful are just those students who are just really ready to be open minded, to give it their all, to learn new skills and, as part of that, they learn how to coordinate with other teams because you have to coordinate with the power subsystem; you have to talk with the—there’s the main onboard computing system, and if you have your payload which is the laser system, all of that has to be integrated together; they can work on things on an island. And so we have these regular weekly meetings. We have formal reviews with NASA that we have to pass. And these are all big occasions to finally get everything together, to coordinate with each other, and so it is important. And I think it's also very representative of what you will find when you actually go into the workplace, that you have to work along with other people; you have to solve problems. It's not about, necessarily, your individual subsystem, but it's about the whole mission being successful, and that's the overriding goal. And I think most of the students embrace that.

[piano concerto]

[radio transmission]

>> It’s just that being up here and being able to see the stars that you can, and look back at the Earth, you can see your own sun as a star, makes you much more conscious of that.

[marching band music]