Additional content about Georgia Tech's space travel and technological innovations happening at the School of Aerospace Engineering with professor Brian Gunter.
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Steve McLaughlin: It sounds incredibly complex—it sounds like—to build these that span—I’m really geeking out here.
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>> 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.
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>> 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.
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>> 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—
>> 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.
>> 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.
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