“Houston We Have a Podcast” is the official podcast of the NASA Johnson Space Center, the home of human spaceflight, stationed in Houston, Texas. We bring space right to you! On this podcast, you’ll learn from some of the brightest minds of America’s space agency as they discuss topics in engineering, science, technology and more. You’ll hear firsthand from astronauts what it’s like to launch atop a rocket, live in space and re-enter the Earth’s atmosphere. And you’ll listen in to the more human side of space as our guests tell stories of behind-the-scenes moments never heard before.
Paul Bookout and David Smith talk about the most powerful rocket since the Saturn V: The Space Launch System. The experts discuss what the rocket is made of, where it will go, and what will be inside. This episode was recorded on March 20, 2018.
Transcript
Gary Jordan (Host): Houston, we have a podcast. Welcome to the official podcast of the NASA Johnson Space Center Episode 41, the Space Launch System part one. I’m Gary Jordan, and I’ll be your host today. On this podcast, we bring in the experts, NASA scientists, engineers, astronauts, all to let you know the coolest information right here at NASA. So, today, we’re talking about the most powerful rocket since the Saturn V moon rocket. It’s called NASA’s Space Launch System. So, we’ve got two guests from Marshall Space Flight Center in Huntsville, Alabama here with us today to tell us a little bit about the rocket, the payloads it will carry. Don’t worry. We’ll define what a payload is. And then, where it’s going to go. Spoiler alert, it will bring people big stuff and little stuff all farther than we’ve ever gone before. Wait. Why did I do that? That totally ruins the, oh wait. Never mind. It doesn’t ruin anything. This is a really good topic, jam packed with information. So much information that we’re going to do this in two parts. This is part one. So, with us today are David Smith and Paul Bookout. David is the Vice President for Advanced Programs at Victory Solutions in Huntsville, Alabama.
He has a long career in aerospace engineering and is a Subject Matter Expert on rocket architecture and how payloads fit inside the rocket. He wrote the SLS mission planner’s guide which gives payload developers a general idea of the capabilities of the rocket and some technical specifications, so they can determine how their payloads might fit inside of it. He looks after some of the big payloads. Our other guest is Dr. Paul Bookout, EM-1 Secondary Payloads Integration Manager who manages integration of five CubeSats in the giant rocket as well as the avionics that will control deployment of the 13 small satellite payloads on the first mission of SLS and Orion called Exploration Mission-1, EM-1. He spends his time managing the little payloads, not much bigger than a shoebox, that goes inside of a skyscraper-sized rocket. So, we’re going to be talking about just how powerful this monster rocket is, its unique capabilities, and what it will be used for, where it is in its development, its first mission with the Orion crew vehicle, and then look ahead to the future to missions to the moon, to Mars, and throughout the solar system.
So, we are go for launch with Mr. David Smith and Dr. Paul Bookout for the Space Launch System Program. T minus five, four, three, two, one, zero, and liftoff of Episode 41 of Houston, We Have a Podcast. Always wanted to do that. Feel like I just ruined it. You know what? Let’s just start.
[ Music ]
Host: All right. Paul and David, thanks so much for coming on the podcast today. We talked about Orion on a few episodes so far but really haven’t had the privilege to talk about he giant rocket that Orion is going to be on, the SLS. And, we have you guys here from Marshall to actually talk to us about this rocket. So, thank you very much for coming on.
David Smith: Sure. Thank you for having us.
Paul Bookout: Our pleasure.
Host: All right. Just to sort of back up, we have Paul Bookout and David Smith, so you guys want to talk a little bit about each one, so we can identify your voices.
Paul Bookout: David, go ahead.
David Smith: Well, sure. I’m just an engineer. My associate Dr. Bookout is a doctor.
Host: Okay.
David Smith: But, we both work together on trying to find innovative ways to associate payloads with the capability of SLS which is going to be the world’s largest rocket. So, I kind of look at the larger payloads, and Dr. Bookout looks at maybe some of the other kind, smaller payloads that can fit in the niches that are left over.
Paul Bookout: Well, thank you Vice President David.
David Smith: Yes.
Paul Bookout: I appreciate you talking about introducing myself. So, what we have is secondary payloads. Again, we’re just trying to understand the whole utilization of SLS since it’s going to be the most powerful rocket built since the Saturn V. It’s going to have a lot more capability, so we want to utilize it to its fullest.
Host: Okay. So, you said there’s going to be, basically, we’re going to utilize the rocket to its maximum potential. We got this big rocket, and we’re going to test it. But, while we test it, let’s put some cool stuff on it.
Paul Bookout: Exactly.
Host: So, let’s back up and talk about just SLS. What is SLS? What is this giant rocket that we’re talking about?
Paul Bookout: SLS is America’s rocket. It’s the next NASA’s launch vehicle that’s going to be able to put humans back to the moon and further out into deep space. Of course, a lot of it’s built on shuttle hardware heritage. The SLS rocket’s made up of the solar rocket boosters, a main core, an upper stage, and then the crew Orion spacecraft with a co-manifest payload or a primary payload. And, David will talk a little bit more about that later. So, of course, this is NASA’s first exploration class launch vehicle since Saturn V, so we’re going to be putting humans back to the moon, out to deep space, and eventually, you know, to Mars systems. It has a very large mass lift capability and also volume, so some of these larger probes that are satellites or probes that are going to outer planets that they’ll be able to arrive at their destination in just a few years instead of maybe eight to ten years.
You’re cutting that trip down to one or two years. So, it’s a lot of savings there.
Host: So, that’s a really important part to kind of hone in on is just the versatility of this rocket. You’re talking about a giant rocket that can take people, giant payloads, faster, farther. That’s pretty much the whole summary of the SLS, right?
Paul Bookout: Yes. Definitely.
Host: So, what’s, what does it take to be human rated? So, I guess the difference between something that’s not a rocket and something that is.
Paul Bookout: Of course, it goes through the whole development process, starts at the beginning. You have to have safety emission assurances involved from the very beginning. Just an overview, you have to have, like redundant systems. If something goes wrong with one system, there’s another system to kick in to back up to still make the vehicle safe. There’s safety reviews throughout the whole process. We do additional testing, a lot more testing than other commercial launch vehicles do just to make sure that the vehicle is safe for humans.
Host: That’s really the main thing, right?
Paul Bookout: Yeah.
Host: The safety. But, then, also the redundancy because I guess redundancy is cost. Redundancy is weight. So, you have to factor that into a rocket where you can just say, “Oh, if it fails, you know, with the primary systems, it fails.” But, at least the only thing we lose is this piece of hardware. And, not to say that that’s not a bad thing, but.
Paul Bookout: Right.
Host: It’s very different from human life. So, I guess, absolutely, you need to be considerate of that.
Paul Bookout: Right. And, there is a tradeoff, as you was saying. Additional systems, more mass, and that’s mass that is being taken away from your primary payloads.
Host: Yeah.
Paul Bookout: And lift capability, but we need that to be safe.
Host: You know what? I actually always wanted to ask this question, but you said primary payloads. I get this question all the time from folks not in NASA, and it’s just, we use this term all the time, but what, to you, is a payload?
[00:07:22]
Paul Bookout: A payload is anything that goes up on top of the rocket that’s lifted into space. It can be a satellite. I can be probes. Of course, the Orion spacecraft, once it’s on the rocket, it can have its own second co-manifested payload along with it. So, just anything, really, that’s launched into space.
Host: Does a person count as a payload.
Paul Bookout: We don’t like to refer to.
[ Laughter ]
Host: It doesn’t humanize it as much, right?
Paul Bookout: No, it doesn’t. No.
Host: So, I guess, for example, going back to that co-manifest thing, the Orion. The Orion would be the payload. That would be the primary thing that you want to bring into orbit.
Paul Bookout: Correct.
Host: But, then, there’s something that is, something called co-manifested which means it’s not the primary thing, but it’s also part of the part that you want to lift the mission.
Paul Bookout: Correct.
Host: Okay.
Paul Bookout: For example, on the second generation of the SLS rocket, it will have capability of launching a co-manifest payload along with Orion, and it could be anywhere from additional probe going out into the moon, or it can be call separation bus, propulsion system that’s launched. And, then, when a habitat is launched, then they can be combined and go to the moon. So, it’s, allows us to build capabilities out in space, too, with co-manifested payloads.
Host: Okay.
Paul Bookout: Along with Orion.
Host: Is that one of the things you’re working on? Or, you’re working on, I guess, secondary payload?
Paul Bookout: Yes. I’m mainly focused in on secondary payloads.
Host: So, what’s secondary payloads?
Paul Bookout: Okay. Secondary payloads, or they call auxiliary payloads.
Host: Okay.
Paul Bookout: They’re payloads that do not drive the primary mission of the, of that launch. For example, on EM-1, we have secondary payloads on that. That’s EM-1, Exploration Mission-1.
Host: Okay.
Paul Bookout: First launch of SLS rocket.
David Smith: Yeah.
Paul Bookout: We have 13 payloads on that, and I’ll talk a little bit more about that later. But, the primary requirements they have is for secondary payloads in general is do no harm to the vehicle and minimal impact. So, the do no harm aspect is that we have to fly safe. The whole system, deployment system and everything, is designed to be safe. Like, all the CubeSats are turned off during launch. They have to have, like, redundant systems, as in two separation switches that allow them to turn on. Because, if one fails while we’re being launched, it could turn on the systems. So, we have two there.
Host: Oh, okay.
Paul Bookout: To back that up, to keep it safe. And then, minimal requirements, of course, if the rocket is ready to launch and the secondary payload’s not ready yet, it’s going to launch. Because it does not affect the primary mission of the payload, of the launch.
Host: Right.
Paul Bookout: Of that.
Host: Well, that puts a lot of constraints on you, then, huh?
Paul Bookout: Yes, yes it does.
Host: Because, not only do you have to worry about these, and I guess we can kind of hone in on the CubeSats a little bit later. But, you have to worry about the CubeSats, but now you have to add something else to it. Now, you have to add these redundant systems. And then, there’s no guarantee that if you’re not ready, that’s okay. We’re going to go without you.
Paul Bookout: Right. Exactly. SLS is, the first rocket’s not going to be the only configuration of SLS. And, of course, SLS is Space Launch System. We, the first launch is going to be called Block 1. Then, we’re going to be stepping up to Block 1B which means we’re going to be adding a different upper stage. Right now, we’re utilizing an existing Boeing ULA upper stage to use on this mission, mainly to save initial money so we can develop the core stage. And, once the core stage has been developed, then we can have additional funds to start developing the new upper stage or exploration upper stage.
Host: Okay.
Paul Bookout: Okay? And, that’s going to be the Block 1B configuration. And, Block 1B will have actually two configurations. It’ll be a crew which was, as we talked about before, the Orion spacecraft with a co-manifested payload. The other configuration will be the Block 1B cargo where that would be your primary payloads. So, the only payload will be that major payload.
Host: Okay. So, when you say “Block”, you’re looking at the entire rocket configuration.
Paul Bookout: Correct.
Host: And, Block 1 is this configuration with the ULE booster, right?
Paul Bookout: Right.
Host: Okay. And then, Block 1B has the NASA booster on top.
Paul Bookout: Correct.
Host: Instead of the ULA, but then you can do crew or cargo on that one.
Paul Bookout: Exactly.
Host: Whereas, EM-1 you don’t, and EM-1, we can get into this later, is, you’re not going to have crew on it, right? That’s not part of the test. That’s for one of the later missions.
Paul Bookout: Correct.
Host: I see. So, really, the blocks are kind of the stages of developing the rocket into its full capability of.
Paul Bookout: Right.
Host: Of this eventual Mars lander. That’s awesome. So, now, you’re using these commercial elements. You’re using ULA in Block 1 and the leftover solid rocket boosters until, eventually, 1B, 1B crew, you get to Block 2. Now, you have the configuration. New boosters. You got the NASA upper stage. You got all of these configurations, and now you can go to, where can you go?
David Smith: Well.
Host: Is it just to Mars?
David Smith: Well, you really need Block 2, ultimately, to fulfill a human settlement on the lunar surface as well.
Host: Really?
David Smith: You need a kind of lift capability. But, if you want to assemble an architecture, because it’ll take multiple flights of a Block 2 to assemble a human architecture capable of transiting to Mars, you’ll need four to five Block 2 flights at a time to assemble that stack that can go to Mars.
Host: So, what’s, I guess, how much more power does Block 2 provide you that, I guess, Block 1B would not?
David Smith: Well, it nominally, you’re talking another 25 tons or so. So, it could bring a second Orion vehicle in comparison because Orion weighs about 25 tons. So, it, really, from a lift standpoint, is maybe a fifth more powerful than the Block 1B, and it gives you that extra diameter, potentially for the payload ferrying that would allow, you know, the smaller the diameter of the ferrying, the taller a lander needs to be. And, think about a lander on the surface of the moon or Mars, if it’s three or four stories, that’s a lot of vertical height an astronaut has to overcome every time they’re taking stuff back and forth.
Host: That’s right.
David Smith: So, we’re, the larger the diameter, the shorter can be the squatter, can be the easier it is to manipulate items on and off a lander. Whether it’s on the moon or Mars.
Host: Okay. Wow. So, then, you’re talking about once this Block 2 configuration is done with the new solid rocket boosters, you can actually have a wider payload go on top of the rocket.
David Smith: Right. Well, there’s a nuclear thermal propulsion that’s out there that has the potential of getting people to Mars a lot sooner. It needs a much larger diameter because it used hydrogen as a fuel. Hydrogen is very bulky because it isn’t very dense. And so, if we were ever to use a new kind of propulsion that would lower the time to get to Mars, you need a Block 2 vehicle. A smaller rocket will never allow you to do nuclear thermal propulsion.
Host: Okay. Let’s go back to some of these other configurations. I kind of want to get a sense of the look and feel of this rocket. We sort of talked about it, but to just sort of go into detail. If I was looking at let’s just say the Block 1 configuration, the one that’s actually going to go for EM-1, what does that look like? How tall is it? What’s the weight of it? How much power?
David Smith: Right. So, roughly Block 1 and 1B are somewhat similar.
Host: Okay.
David Smith: They’re going to be about the same height as the Saturn V.
Host: Oh.
David Smith: Which means it’s a big rocket, but part of that’s because we can’t really exceed the vehicle assembly building limitations that are at the Cape. So, you want to make it as big as you can, so you can put as much fuel in it as you can. Basically, the thrust of the Block 1 vehicle which is similar to the Block 1B for the solid rocket motors is about 3.6 million pounds each. Those only fly for about two minutes. Then, you have the core engines. There’s four space shuttle era type SSMEs that each have about 512,000 pounds of thrust. You multiply that by four. They operate for about eight minutes. Together, you get about a total thrust of about 8.8 million pounds which gives you an escape velocity of over 22,000 miles an hour. The core stage itself is about 2/3 the length of a football field which is pretty tremendous. One single stage of this vehicle’s about 2/3 of a football stadium. And, which is around 212 feet, and the Block 1B ferrying that we talked about, the 8.4-meter diameter ferrying, could accommodate up to three school buses inside its volume. So, that’s pretty incredible when you think about the size of what can be lofted in a single vehicle like that.
In comparison, the Block 1 vehicle, you know, can throw 70 tons to lower earth orbit where the shuttle can only do 28 tons to low earth orbit. So, it’s about three times more powerful than the shuttle.
Host: Wow. So, you’re talking, you’re comparing it to the Saturn V in terms of its size but talking about these efficient engines. What makes, what is it about the engines that’s more efficient that’s giving you this extra power?
David Smith: Well, they, you know, the shuttle engines were rated at 100% thrust originally, and I think they got them up to 109%. So, they actually got them to work 9% more efficiently at the end of the shuttle program. We’re taking these up to 11% more thrust, and maybe even 13% more thrust. So, you’re really pushing these engines to their limit, and the, it’s really coupling their efficiency now at 113% thrust with the reliability of the shuttle system.
Host: Unbelievable. The engine itself is called an RS25, right?
Paul Bookout: Yes.
Host: That’s what it’s called. And, these are the engines that were on the shuttle. Now, you’re pretty much just putting it on the SLS, but it sounds like there’s a good reason for that. It’s because you’ve flown the shuttle so many times, improved the capability of it past its, like, total 100% thrust ratio. Now, you’re going, you’re going past the 100%. So, basically, is like why would we, why would we do something else? We worked so hard on this one. This one is, like, extremely efficient. Why would we, and we can make it even more efficient. That’s the logic behind it?
Paul Bookout: Well, right. Initially, of course, we have about, I believe, 16 space shuttle main engines or these RS25s left over from the shuttle program. So, we’re utilizing the existing hardware to save cost while we’re developing the core stage. You know, the first part of the SLS.
Host: Yeah.
Paul Bookout: And, as you mentioned, we are updating the engines, getting more capability out of them. So, to that point, we can do four per, so we can do about four launches, four rocket, or four engines on each launch. So, we can do about four launches with the current RS25s.
Host: Okay. And, that, is that for one of the later configurations?
Paul Bookout:That’s correct.
Host: Okay.
Paul Bookout:Yeah.
Host: Is it the Block 2?
Paul Bookout:The Block 2.
Host: Block 2?
Paul Bookout:Block 2 and beyond.
Host: Oh, okay. I see. I see where the whole idea of staging this whole thing comes from, right?
Paul Bookout:Correct.
Host: You’ve got, you’re using the leftover solid rocket boosters, and you’re using this commercial upper stage. And, it’s just basically getting to this point where you’re going to maximize the efficiency of the rocket.
Paul Bookout: Right.
Host: Unbelievable. So, three school buses inside of the 1B configuration, right? That’s, is it about the weight of three school buses? Is like taking three school buses to space?
David Smith: No, it would be, it would be more than that.
Host: More than that?
David Smith: I mean, nominally, if you went to the moon, we’re going to take, the Block 1B could take roughly 40 tons to lunar vicinity which is, which is pretty incredible.
Host: Wow, and just in terms of not only, like, quantity, you’re talking three school buses. But, also size.
David Smith: Yeah, and mass.
Host: Also weight.
David Smith: Right.
Host: You know, you got all of these, all these different components. So, I guess we can kind of focus in on now that we kind of understand the rocket and the evolution of the rocket, let’s go to that first, that first test flight, EM-1. We’ve talked about EM-1 on the podcast before, especially from testing Orion and that. But, really haven’t focused in on what is it about, what is it about EM-1 that we’re testing SLS for? So, let’s start with that. What are we going to test, and I guess we can kind of start with the overview of EM-1 for those who haven’t listened to it before.
Paul Bookout: Right. So, EM-1 is, of course, going to be the first launch of the SLS rocket. Its primary segments are, of course, solid rocket motors which are a heritage from shuttle hardware. Shuttle had four segments, where EM-1 is going to have five segment motors. Then, of course, the core stage which is heritage off the shuttle external tank but made longer for additional capability of fuel. And, we’re also using the main engines from the shuttle program with updated technology and ratings to get more power out of those four rockets on there. So, that makes up the primary lift capability of the SLS rocket. On top of that, we have an interim cryogenic propulsion stage, which, or second stage, upper stage, that we’re utilizing from Boeing, existing hardware for EM-1 mission. And then, of course, in addition to adaptors, then there will be the Orion spacecraft, which is the primary mission of EM-1 is to test out the SLS rocket.
Then, also, to test out the Orion spacecraft with its trajectory and telemetries and communications. It’s going to be on about a 25 1/2 day mission to distant retrograde orbit. That really means just go way past the moon and come back.
Host: Yeah.
Paul Bookout: You know, a 25 1/2 day trip. Of course, and, you know, we’re doing all this because, again, for the safety aspects. We want to test the vehicle out and Orion spacecraft before we put humans in it.
Host: Right.
Paul Bookout: So, we want to make sure it’s safe, make sure everything works. And, that’s that safety aspect, that human rated part of a launch vehicle.
Host: So, the human rated part is the Orion can go to 25.5 days, or is this going past what it’s expected to possibly operate at?
David Smith: I think that’s a nominal timeframe for the Orion with crew. So, this is pretty much, I think, its extreme capability.
Host: Yeah.
David Smith: But, you know, part of it is testing just the systems period. You always, for human rating, you always want to test it far in, you know, far from what the humans will actually experience so that you have a safety factor that’s sufficient for human use.
Host: Oh, yeah. Because if you’re going to be operating on, say, 16 day missions, you don’t really want to, okay. Well, let’s just test 16.
Paul Bookout: Exactly.
Host: You really want to go kind of further out and see, all right. Let’s see how far this puppy can go.
David Smith: And, I think part of this mission’s objective is to bring it in at a lunar return velocity to test that heat shield.
Host: Yeah.
David Smith: You can’t do it from low earth orbit. You got to kind of go out and bring it in fast, so.
Host: So, what’s the difference with EFT-1? That was one of the first test flights we did where we didn’t go all the way out to the moon, but we did kind of a, this large apogee so that we can get up to, I think it was some, like 25,000 miles. Or, maybe it was a little slower than that. The difference is between EFT-1 and EM-1.
David Smith: I think, I think it was very close to what they would experience in a lunar return, but it’s not the actual lunar return.
Host: I see.
David Smith: Right, so you want to be able to stage it. You want to go out in orbit. You want to test the time that you’re out in orbit. That was a very short mission, maybe five or six hours. Now, we’re talking 25 days. Well, all the equipment still work when it’s, you know, soaked in a cold temperature, hot temperature, all those days. And, now, you’re coming in. Will it all work when it comes to the right moment. So, this really puts the pedal to the metal.
Host: That’s right. So, what is it? I guess the relationship between what are you guys looking at for SLS versus Orion on this particular mission, EM-1?
Paul Bookout: So, for SLS, again, we want to test all the systems, make sure they’re fully functional. We’ll be checking out redundant systems indirectly, of course. And, communications with the vehicle, since it’s the first time the vehicle’s being launched. We’re all, we’re talking with the vehicle all the way up.
Host: Yeah.
Paul Bookout: So, we want to make sure all those ground systems are ready to support, actually, human flight mission. So, it’s just not the vehicle. It’s the overall architecture of everything that goes into supporting a launch that we want to verify and check out.
Host: Oh, that’s right. Now, we’re preparing to go into fly deep space missions. So, not only is it, all right, let’s test the hardware, but let’s test to operational aspect.
Paul Bookout: Exactly.
Host: Let’s test what it’s going to take to actually do these missions from the broadest perspective possible.
David Smith: And, that includes, even, just bringing the, you know, the pieces are being built all over the place.
Host: Yeah.
David Smith: And, tested all over the place. So, just bringing them together at the cape and making sure they can be integrated in a safe and timely fashion for launch. That, in itself, is a really important objective. We’re talking about such a large rocket.
Paul Bookout: Yeah, so this is the first time all those components going to be coming together, and there’s going to be hiccups along the way. And, we just need to understand how this vehicle goes together and make sure we do it correctly.
Host: So, you say the vehicle’s going to be talking to you guys throughout its flight. What is it going to be telling you? What kinds of data are you really looking for that’s really going to tell you that this thing is working how we’re expecting it to work?
David Smith: Well, remember, you’re talking to payload guys, so, you know, we’re more interested in seeing what the payload’s going to experience.
Host: Yeah.
David Smith: But, think about this. When it launches on the pad, it has an incredible noise issue coming off that mobile launch platform. That’s why, if you remember, they had these things called rainbirds, the big sprinklers that start spraying as soon as the engines go to try to mitigate that noise.
Host: Right.
David Smith: The payload is particularly sensitive to it. Obviously, the vehicle itself is sensitive to that noise as well. So, acoustic mitigation is one of the most important things at launch. Then, we have a thermal issue, right? We go up to max Q, max dynamic pressure. We have a certain heating that is, occurs on the outside of the vehicle. And, before, we got to get through all that heating before we can make sure that the crew is going to be safe, that we can take the shielding off the Orion and so forth. So, we’re going to be testing all those environmental concerns as we go forward, and of course, the jettisoning of, you know, the SRBs off the core stage. Then, the ICPS in Orion off the core stage. And then, of course, then, the Orion off the ICPS. All these jettison events, and there’s quite a few of them, are extremely important, and we need to test those. Each one has its associated thermal and acoustic issues. So, we’re going to test each one of those as it goes forward.
Paul Bookout: Since this is the first launch of SLS rocket, we don’t really understand the full environments that it’s going to be launched in. As David mentioned, the thermal, interior thermal, acoustic, vibration. It’s the first time we’re going to launch it. So, what we’re also have is a lot of instrumentation on this vehicle to be able to measure the actual vibration levels and everything else. So, we can, once we go back to designing and looking at what we call safety factors, reducing those so we can have more margin on the vehicle and means that goes into more mass lift capabilities. So, we’re trying to understand the overall characteristics of the vehicle itself. So, in addition, for secondary payload, or payloads in general, we can give them more of an accurate environment that they will see during launch. As in, how much vibration they’ll feel, how much thermal environments that they’ll see. So, when they start designing their payloads for, to run the ride on this vehicle, they can have more of an accurate environment.
And, maybe not have, make it a lot more efficient design.
Host: Okay. So, then, what data are you going off of now based on, you guess you haven’t launched the SLS. So, what are you assuming, or where are you getting the data from?
David Smith: We have, we started off with assuming, at least for the payloads, that we would provide an ELV, and expendable launch vehicle class environment.
Host: Okay.
David Smith: So, if you’ve flown on Atlas or Delta, you should expect nothing worse than that.
Host: Okay.
David Smith: That’s our starting point.
Host: Oh, okay.
David Smith: Now, what Paul’s going into is we’re going to try to characterize is that really true? So, the first flight’s important. Are we in? Are we out? What do we have to do? Is there more foam that you got to put in the payload section to mitigate the noise? That’s what we’re trying to figure out. But, we should be within an ELV class is what we’re projecting right now.
Host: Okay. So, then, I’m assuming you’re going to have some actual science on board EM-1, right? Because you’re testing, you’re testing the structure of EM-1. You’re testing the rocket. But then, you have this mission. Why not take advantage of it? Is there anything else going on the EM-1?
Paul Bookout: Oh, definitely.
Host: Okay, good.
Paul Bookout: Yes. We have, we’ll have 13 secondary payloads that we’re going to be launching on EM-1.
Host: Wow.
Paul Bookout: That’ll, that is located in the Orion stage adapter. That’s the segment that connects the SLS rocket to the Orion spacecraft. So, it’s a small ring about five feet high. About 18 or so feet in diameter. And, along the inner circumference of that is where we are mounting these 13 secondary payloads.
Host: Oh, so I guess they have to be kind of small, right? That’s not a lot of space compared to the, what’s in the ferrying.
Paul Bookout: Correct. So, on EM-1, we have 13 CubeSats. CubeSats are defined as a, we call a 1U, which is about ten by ten by ten-centimeter cube.
Host: Okay.
Paul Bookout: So, what we’re having on EM-1 is allowing them to go up to what we call a 6U. So, it’s a CubeSat that’s about the, a little bit larger than the size of a shoebox, a large shoebox.
Host: Okay.
Paul Bookout: And, that’s kind of the dimensions of these 6U CubeSats that we’re having on EM-1.
David Smith: Which is the most common CubeSat, really, today, right?
Paul Bookout: Correct. Exactly. So, we have multiple missions that these payloads are going to be doing. So, we’ve got one destination is to the moon. We have Lunar Flashlight which is out of Jet Propulsion Laboratory, and their primary mission is to search for ice deposits and resources on the moon using a laser.
Host: Ooh.
Paul Bookout: Okay. And, the second one is Lunar IceCube which is Morehead State University up in Kentucky. And, they’re going to also be searching for water of all forms and volatiles on the moon using infrared spectrometer. These are some big words that I can’t even define, so.
[ Laughter ] LunaH-Map is from Arizona State University, and they’re going to be creating high fidelity map of near surface hydrogen in craters on the moon. Lunar IR is from Lockheed Martin in Colorado, and they’re going to be performing advanced infrared imagery of lunar surface. We’ve got one that’s going to the sun facility, and it’s called CuSP. It’s from Southwest Research Institute here in Texas, and it’s going to be measuring particles and magnetic fields of space weather between us and the sun. We have one that’s going around the Earth. It’s called EQUULEUS. It’s a Japanese payload, and we actually have three international payloads on this mission. And, I’ll touch on those others.
Host: Awesome.
Paul Bookout: So, again, EQUULEUS is from JAXA. It’s the University of Tokyo supporting that. I mean, it’s imaging the Earth’s plasma sphere for a better understanding of Earth radiation environment. And also, it’s going to be initially on the far side of the moon and detecting any meteor crater flashes that may impact the far side of the moon.
Host: Wow.
Paul Bookout: So, they’ll be out there for about two months or so and just hopefully they’ll be able to catch something. Some of the other missions are BioSentinel. It’s from Ames Research Center, and they’re going to be using baker’s yeast to see the effects of radiation on actual live items, you know, live yeast. And, then, ArgoMoon, which is the European Space Agency, is built in Italy. It’s going to be observing the interim cryogenic propulsion stage. That’s upper stage is going to be deployed. Look at that upper stage, and then it’s going to go on some additional missions. And, it’s going to look at the upper stage to see what kind of effects the environment has during liftoff on the upper stage. Because, until now, we, once the upper stage is launched, we usually don’t get a chance to look the conditions of that. This will give us some feedback and see what the upper stage has went through, if there’s any damage or anything.
Host: It sounds like these CubeSats are all over the place.
Paul Bookout: Yes. Yeah. I’ve got a couple more here.
Host: Oh, really.
Paul Bookout: I haven’t got to my two favorite yet. So.
Host: Oh, we’re standing by.
Paul Bookout: Okay. Centennial Challenge. That was a challenge that NASA set up called Cube Quest, and it’s to help develop communications for these smaller CubeSats. There’s two challenges. One was a lunar challenge to around the lunar surface and for longevity. And, the other one was a deep space mission which was a CubeSat, as it says, going out into deep space to see how far and long and what burst rates and clarity that you can have in your signals. So, there’s total prizes for everything through all the development and final missions. It’s up to $5 million.
Host: Wow.
Paul Bookout: So, that’s a lot of money.
Host: Yeah.
Paul Bookout: Spread out over those. So, you did, you asked what my two favorite payloads are.
Host: Oh, yeah.
Paul Bookout: Let me tell you. One of them is NEA Scout. That’s developed at Marshall Spaceflight Center. What’s unique about that is NEA Scout means Near Earth Asteroid. So, they’re going to be going to a near earth asteroid. But, the exciting thing about it is that they’re going to be using solar cell to get there for their propulsion system. So, this is the first time a solar cell will be used to, for propulsion out into deep space. There have been other missions in low earth orbit to check out the technology and feasibility of solar cells, but this is the first time going out to deep space. And, for a CubeSat that’s a little bit larger than a shoebox, it will be deploying the cell that will be 40 by 40 feet.
Host: Whoa.
Paul Bookout: So, that’s huge.
Host: Wait, and a little CubeSat.
Paul Bookout: In a little CubeSat.
Host: And, it deploys a 40 foot.
Paul Bookout: Yes.
Host: Oh, wow.
Paul Bookout: Yeah, so that solar cell is very thin material.
Host: Yeah. It must be to fold up into, like, this ten-centimeter cube thing.
Paul Bookout: Exactly.
Host: So, so, the solar.
Paul Bookout: You said ten centimeters. 6U CubeSat is 10 by 20 by 30.
Host: Oh, because this is 6U.
Paul Bookout: 6U, correct.
Host: Oh, okay. Okay. Okay. So, solar sails, though, this is, it basically unfurls this 40-foot sail, and is it the one where the high-power laser that pushes it?
Paul Bookout: No.
Paul Bookout: That’s different.
Paul Bookout: This is going to ride the solar winds.
Paul Bookout: Ride the solar winds.
Paul Bookout: Solar particles will be pushing it along. It’ll do actually a fly by the near-earth asteroid as it comes up. It’ll be taking images all the way around as it passes.
Host: Okay. Wow.
Paul Bookout: So, and my ultimate favorite one is.
Host: Yeah, we didn’t get the last one.
Paul Bookout: Is actually the one that I’m the Secondary Payload Integration Manager for.
Host: Oh.
Paul Bookout: So, it’s one of my CubeSats.
Host: So, it’s an unbiased favorite, then.
Paul Bookout: Yes.
Host: Okay.
Paul Bookout: Yeah, still. It’s called OMOTENASHI. It’s another Japanese CubeSat.
Host: Okay.
Paul Bookout: And, their mission is to land on the moon.
Host: Oh.
Paul Bookout: Can you imagine a small little CubeSat, you know, a little bit larger than a shoebox, land on the moon? Of course, and the big thing about it is that they’re going to be using a solid rocket motor to slow down to be able to land on the moon. So, that’s one of the things on EM-1 that we’re offering that previous commercial launch vehicles and that don’t offer propulsion systems for secondary payload to be able to utilize that. That’s one thing EM-1 and SLS is allowing. So, that’s a huge deal.
Host: Yeah.
Paul Bookout: For those. So, if OMOTENASHI is successful at landing on the moon, they’ll be the fourth nation in the world to have actually land and do some science on the moon.
Host: Wow.
Paul Bookout: You know.
Host: So, what kind of science?
Paul Bookout: Well, because, again, they’re still a small payload, so they can’t get large science instruments to the moon, when they land, actually land on the moon, all that will be left is about the size of a sandwich box. Because they have to get rid of all the extra weight to be able to slow down enough to be able to land. And, they’ll probably so some soil impact measurements, as in how soft vibration, shock, as it’s landing on the moon. And, I, so, and they’re only going to be able to do it for about 30 minutes or so. Again, because of the size, what we’re limiting them to.
Host: Yeah.
Paul Bookout: They can’t get the mechanics, orbital mechanics and velocities and everything. I’m sorry.
Host: So, it’s, it’s kind of general on where you can land, then? It’s just like, it’s just going to land. It’s not going to land in a targeted spot, I guess?
Paul Bookout: Correct. They know the general vicinity where it’s going to land.
Host: Okay.
Paul Bookout: But, they can’t have ultimate control, like any of the other landers that have larger systems, propulsion systems, to slow them down. So, they would be actually, once the solar motor fires, they’ll still be traveling at about 60 miles an hour when they impact the moon. So, they’re going to inflate these impact balloons to actually bounce, similar to what they’ve done on Mars, some of the Mars Rovers.
Host: Okay.
Paul Bookout: So, it’ll come and impact moon and bounce and then finally rest on the moon.
Host: Okay.
Paul Bookout: And, do about 30 minutes of impact soil measurements.
Host: Wow. How would that be, though? I’m imagining, I mean, landing at 60 miles an hour. That’s, you know.
Paul Bookout: Well.
Host: That’s not slow, but at the same time, it’s the moon, right? It’s.
Paul Bookout: Right. Yes, but then again, you’re not going directly into it. You know, you’re coming in at an angle, too.
Host: At an angle.
Paul Bookout: So, it’s not a fully impact.
Host: Okay. Great.
Paul Bookout: Direct impact, so.
Host: So, you got all these CubeSats going around the Earth, around the upper stage, around the moon, on the moon, to deep space. Where do you deploy, how does that work? Where do you deploy everything? It’s not just like you just let everything go at all. It has to be pretty controlled because each one has a very specific mission.
Paul Bookout: Right. We’ve created what we call bus stops.
Host: Oh.
Paul Bookout: They’re basically different aspects of the trajectory of the upper stage. So, the first bus stop is when you’re in between the two radiation belts or Van Allen belts. Bus stop two is when you’ve passed all the radiation belts. Bus stop three is half way between the Earth and the moon. Bus stop four is the closest proximity to the moon, and bus stop five is when you’re going into a heliosynchronous or sun orbit. And, that’s where the upper stage will be disposed into the sun orbit. So, when a payload says, “Hey, I want to get off at 200,000 miles away from the Earth.” Well, okay, where is that exactly? So, that’s why we kind of created these bus stops.
Host: I see.
Paul Bookout: They can get off anywhere they want to, but it helps us relate to the areas where they want off. So, most of them are wanting off at stop one. About seven or eight of them. Because they need to get out and start changing their trajectory as soon as possible. Again, we’re offering propulsion systems, but they’re not large enough to have really change their directions further on. So, a little change at first makes a big change later.
Host: Yeah.
Paul Bookout: So, they want to get off to be able to do that, make those little changes. Most of the payloads that are going to lunar orbit, what they’re wanting to do is slow down because the ICPS, you know, is launching Orion into this distant retrograde orbit. And, you know, way past the moon.
Host: Yeah.
Paul Bookout: So, it has a lot of velocity heading that way, and if the payloads don’t slow down, they’ll just go flying past the moon. The moon can’t, doesn’t have enough gravity to pull them back into an orbit. And, some of them, even though they are going to the moon, they’ll actually fly past the moon, and it may take a month or so for them to come back, to slow down enough to come back and get hooked into the moon’s gravity and start orbiting the moon.
Host: Oh, wow.
Paul Bookout: So, it’s not a direct flight into the moon orbit, just because they don’t have the propulsion systems large enough to be able to do that.
Host: So, is it fair to say they’re all going to be in a very similar orbit, or are they all going to kind of go their respective directions?
Paul Bookout: They’re going to do their respective ways.
Host: Okay.
Paul Bookout: Some of them wants to do in the crater, so they’re going to be going to the pole system, up to the poles to look see if there’s ice up in there. And, some of them will just be doing a regular geosynchronous type of orbit.
Host: Okay.
Paul Bookout: Type thing.
Host: All right.
Paul Bookout: We talked about where these, what the payloads are and where they’re going to want to get off. To be able to allow them to get off, again, we have to have a deployment system where, again, some of the primary requirements for EM-1 was or SLS is to do no harm and to have minimal impact to the vehicle.
Host: Yes.
Paul Bookout: Well, to do that latter one, what we’ve come up with a system is that we will receive an energy, the avionics unit for deploying the secondary payloads will receive an energy pulse for, from Orion. Or, I’m sorry. Will receive an energy pulse from the upper stage once Orion has already left and the upper stage has gone through its disposal maneuvers. That means burning off extra fuel and everything making it safe. Right before it shuts down, it will turn on the avionics unit for deploying the secondary payloads. Then, the upper stage turns off. So, we wake up, and we’ve got our own internal battery system. And, each payload is inside of a dispenser, and so, the dispenser operates as the, has a spring-loaded lid. And, the payloads inside are installed by compressing the spring. So, when the, when it’s time for that particular payload to be deployed, we get an energy pulse from the avionics unit sent to the dispenser to open the door.
The door flings open, and then the secondary payload is pushed out by springs. So, that’s how they’re deployed.
Host: Okay. So, like a, so, like an SLS jack in the box. [laughter]
Paul Bookout: If you will.
Host: That’s what I’m imagining. Obviously, it’s going to shoot out.
Paul Bookout: We have pulled those analogies before, but I’ll let you state it.
Host: And then, I guess there’s, you get this power pulse that’s going to, I guess, be directed to whatever seven is going to be part of bus stop one, and whatever the next ones for bus stop two.
Paul Bookout: Correct.
Host: Okay.
Paul Bookout: And, they’ll be deployed, if there’s multiple at a particular bus stop, they’ll be deployed a minute or two away from each other, after each other because we don’t want to be able to deploy one and then deploy another one right behind it.
Host: Yeah.
Paul Bookout: And then, they have recontact.
Host: So, I’m trying to imagine the way everything is situated in my head, and at this part of the flight when you’re starting to deploy these secondary payloads, what does, what does the rocket, I guess, or what does the piece that’s actually flying, what does it look like? I guess you have Orion and then there’s this deployment system, and then there’s, is it the upper stage behind it?
Paul Bookout: Okay. So, once we’ve launched.
Host: Yeah.
Paul Bookout: After about two minutes, the solar rocket motors are.
David Smith: Jettisoned.
Paul Bookout: Jettisoned. And then, the core stage lifts the rest of the vehicle up into orbit. And, after that time, when the core stage is spent, then it’ll be jettisoned. And then, you’ll have your upper stage and your Orion spacecraft which of course the secondary payloads are still in part of that. And then, then, it’ll go into what they call a translunar injection that’s basically the upper stage will ignite and put Orion into its mission profile going past the moon.
Host: So, at this point, right before it ignites, it’s still in, I guess, Earth orbit, and the translunar injection gets it to the moon.
Paul Bookout: Correct.
Host: Okay.
Paul Bookout: Okay. So, once the upper stage has spent its fuel, the Orion spacecraft will separate, okay? From the upper stage. So, it’ll go through on to its mission. And then, about 30 minutes later, 20, 30 minutes later, the secondary payloads will start their deployment.
Host: I see. Okay.
Paul Bookout: So, Orion is well away and actually speeding faster away from the upper stage.
Host: Yeah.
Paul Bookout: The upper stage, once it goes through its disposal maneuver, is actually flying kind of, you would say, backwards, engine first, towards the moon.
Host: Oh.
Paul Bookout: So, the secondary payloads will be ejected out the other direction. So.
Host: Okay. So, so.
Paul Bookout: So, when they’re deployed, the ICPS won’t run back into them.
Host: That’s right.
Paul Bookout: Okay. So, they’ll be deployed in the other direction.
Host: But, now, Orion is going in, it’s doing its own thing.
Paul Bookout: Correct.
Host: Because it did its job. It delivered Orion. That’s the primary payload. Now, it’s off. But, the secondary payloads are still part of this upper stage. They haven’t gone with Orion. They’re totally separate.
Paul Bookout: Correct. They have their own.
Host: So, it’s like, they’re kind of doing, they’re going.
Paul Bookout: Yeah.
Host: Different ways. Interesting.
Paul Bookout: Yeah, they have their own mission profiles going in all different directions.
Host: Okay. Okay. I don’t know why that wasn’t clear to me before but thank you. All right. So, I guess kind of backing up from there, you’re talking about the solid rocket boosters are disposed. The core stage is disposed. Where are all these pieces going?
Paul Bookout: Okay. Depending on their mission profile, all the secondary payloads are going to end of missions at different places. Some of them will be actually crashing into the moon, and that’s common where the other countries and their lunar missions depositing on the moon. Some will, one or two will burn up in Earth’s atmosphere as it comes back. Some of the other ones that are going out into deep space, of course, just keep going. The CuSP, which is going to solar. I’m sorry. CuSP, which is going to the sun’s vicinity will just stay out there and eventually be pulled into the sun.
Host: Okay.
Host: So, that’s all the secondary payloads.
Paul Bookout: Correct. And, for each mission, each payload that’s launched on U.S. rockets, they all have to have an end of mission plan. What are they going to do to end their mission, not just to be left out there as space junk. Because that’s, we’re having, sorry. We’re starting to have a lot of problems with, as you know, there’s a lot of space junk around Earth.
Host: Oh, yeah.
Paul Bookout: And, you don’t want that same situation around other planets, too.
Host: That’s fair. That’s fair. And, that’s why, that’s part of the, I mean, this is going back, but Cassini, right? That was the whole. It did its thing, and instead of just letting it be. It had a controlled entry into Saturn so that it didn’t contaminate any other.
Paul Bookout: Exactly. Yes.
Host: Any other bodies. Yes, yes, of course.
Paul Bookout: And, it doesn’t matter what size you are.
Host: Yeah.
Paul Bookout: Even these small CubeSats have to have an end of mission.
Host: Have to have an end of mission.
Paul Bookout: Yes.
Host: Awesome. But, I did want to go back to some of the earlier parts of the mission, right after launch. You know, you’re talking about solid rocket boosters separating being.
David Smith: Those go into the ocean.
Host: Ocean? Okay.
David Smith: Still, but they’re not recovered this time.
Host: Oh, okay.
David Smith: You know, for shuttle, they were recovered. This time, it’s too difficult. They’re too large. So, they’re just going to sink.
Host: Okay.
David Smith: The external tank is, it can’t go into orbit, so it’s kind of lofted in such a way that it’ll break up over the Indian Ocean safely.
Host: Ah.
David Smith: So, it’s a very large tank. You know, this is much larger than the external tank of shuttle, so it’s very important that it break up safely. So, that’s, that’s why you need the upper stage to actually bring the payload up into a circular orbit around the Earth. Otherwise, the payload would go down with the core module as well.
Host: Okay. Okay. And, what about the, I guess, the upper stage. You said it’s going to be doing this deployment, but then, after it deploys [inaudible].
David Smith: It’s heliocentric. It goes into a sun, heliocentric disposal.
Host: Sun heliocentric disposal.
David Smith: So, it kind of goes away, and we should, hopefully, not see it again.
Host: Okay. All right. That’s a very nice summary of EM-1, and I feel like there’s so much more to talk about. I kind of wanted to get into, you know, where are we now with SLS, all the history of it. So, I think we should take a break and just sort of let this one be Episode 41. We’ll come back, and we’ll do Episode 42 and just sort of get into the process behind building the SLS and then the journeys of where it’s going to go and beyond. So, guys, thank you so much for coming on. We’ll take a break. I’ll see you in a few minutes. And, for everyone else, I guess we’ll see you for the next episode.
David Smith: All right.
David Smith: Great, thank you. Look forward to it.
Paul Bookout: Thank you.
[ Music ]
Host: Hey, thanks for sticking around. So, the best places to follow development and delivery of the rocket as we test the major components and deliver it piece by piece to the Kennedy Space Center are on the social media channels on the web for the Space Launch System. So, first the website. You can go to www.nasa.gov/ guess what? SLS. That’s where you can get the latest, the greatest on the Space Launch System. On Twitter, it’s @nasa underscore SLS. On Facebook, it’s NASASLS, that’s one word. Or, this is one of the things that actually David Smith wrote. You can actually search SLS Mission Planner’s Guide. And, it’s a document that you can find on the web. You can download it, and it actually has a lot of great information on just the whole scope of the Space Launch System. We’re really looking forward to the first launch of SLS and Orion from the Kennedy in a couple years. Sounds like we’re well on our way to the pad, and we’ll be launching astronauts back to the moon in just a few short years. If you have questions on SLS and its development, use the hashtag asknasa on your favorite platform. Just go to the Johnson accounts. Those are the ones we look at.
The NASA Johnson Space Center accounts on Facebook, Twitter, and Instagram. You can send an idea or a question, and we’ll make sure to mention it’s for, or just make sure to mention it’s for Houston, We Have a Podcast, and we’ll bring it up in a later episode. Or, maybe address it in an entire episode. The whole episode will be dedicated to the question. Who knows? So, this podcast was recorded on March 20, 2018. Thanks to Alex Perryman, Rachel Craft, Laura Reshawn [assumed spelling], Kelly Humphries, Pat Ryan, Tyler Martin, Bev Perry, and all the folks at the Marshall Spaceflight Center for coming on to help to put this together. Thanks again to Dr. Paul Bookout and Mr. David Smith for coming on the show. We’ll be back next week with part two.