NASA Podcasts

NASA EDGE: Space Launch System
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NASA's New Space Launch System
- Todd May
- Katherine Van Hooser
- Barry Howell
- The Co-Host SLS


ANNOUNCER: The Space Launch System. NASA's new and powerful heavy launch vehicle designed to take astronauts and payloads beyond low Earth orbit into deep space. Is this the most powerful rocket NASA has ever made? Will the Co-Host gather enough technology and materials to launch his own rocket? Find out next on NASA EDGE!

CHRIS: Welcome to NASA EDGE…

BLAIR: …an inside and outside look…

FRANKLIN: …at all things NASA.

CHRIS: I can’t believe this is our 100th episode.

BLAIR: I’m amazed actually. I’m very excited that we’re still doing this and still having fun at the same time.

FRANKLIN: Six years doing the show I wouldn’t rather be here with anybody other than you guys.

CHRIS: What about our fans? Without the fans’ support this wouldn’t be happening.

BLAIR: That’s right. And in honor of our fans, everyone, go out there and download each episode a hundred times. It will be a little celebratory activity.

FRANKLIN: Tell a friend.

CHRIS: That’s right. On today’s show, we have a jam-packed show. We’re going to be talking about SLS or NASA’s Space Launch System. The SLS will be taking astronauts and science experiments farther into space then ever before.

FRANKLIN: On this show, we’re going to be bringing you a lot of information about the SLS and how it was made, its rockets and we’ll even talk to a model maker who is making models of SLS.

BLAIR: Don’t forget NASA EDGE’s own contribution to the program, which we’ll hear about later.

CHRIS: First, let’s go and talk with Todd May who is the SLS Program Manager. He can fill us in with what SLS is all about.

CHRIS: So Todd, we’re celebrating our 100th episode and what better way to celebrate it than with SLS.

TODD: Well, thank you for that honor and congratulations on a hundred episodes. That speaks well of your program. SLS is the Space Launch System. It’s the nation’s next heavy lift launch vehicle designed to take humans beyond the bounds that have constrained us for the last 40+ years.

CHRIS: The Space Launch System involves a pretty big rocket, doesn’t it?

TODD: Even in the initial configuration it’s as tall as the Statue of Liberty to put it in perspective.

CHRIS: Wow! How does that compare to a Saturn V back during the Apollo program?

TODD: It’s a little smaller than the Saturn V in terms of initial configuration. When we get to the ultimate Block II capability, it will actually be taller than the Saturn V. Even in the first launch it will have 10% more thrust off the pad than the Saturn V did.

CHRIS: It seems if you have to go beyond low-Earth orbit, if you want to go to the moon, you want to go the asteroids, to Lagrange points or to Mars, you need a pretty big rocket just to get up there, don’t you?

TODD: You do if you want to take humans to those places…

CHRIS: Okay.

TODD: …because us, humans, are fairly needy people. We need water and our food and our clothes and our laundry and our teddy bears for those long trips.

CHRIS: We were talking offline earlier and you talked about the difference of the 1969 Stingray and the 2014 Stingray. Talk about that analogy comparing it to rockets.

TODD: We saw an old picture of the Apollo astronauts next to a bunch of Stingrays that Allen Bean had evidently designed the color scheme for and we happened to also hear the other day on the radio about the new Stingray they’re coming out with in 2014. In some ways, we like to think it as this is not your grandfather’s Stingray. This is not your grandfather’s rocket.

CHRIS: Right.

TODD: The new Stingrays have completely new designs on the inside. The outside has roughly the same dimensions but it has computer health monitoring, nanocomposites, it actually gets better gas mileage than we had in the past.

CHRIS: Right.

TODD: In the same way, we used a lot of the same components we had on the Saturn V, like the J-2X engines, or on the Shuttle, the RS-25 main engines or the boosters.

CHRIS: Some people might think you’re using old technology from the Shuttle days and before but you’re actually not because you’ve improved that technology over the past 30 years.

TODD: That’s right. Just for example, the RS-25 engines have actually been through seven different evolutions over the time of the Shuttle flights, and, even today, it is the state of the art in terms of stage combustion. As an example, one of those engines has as much power as eight Hoover Dams.


TODD: It can empty a family size swimming pool in 25 seconds.

CHRIS: Whew!

TODD: It has over 100-horse power per pound, so if you think of a Corvette as 600-horse power, that’s like designing a Corvette that weighs only 6 pounds.

CHRIS: Is this technically going to be the workhorse for NASA for the next 5, 10, 20, 30 years?

TODD: We have a couple of different paths. The Shuttle actually used to take people to and from low-Earth orbit. The agency and the nation has decided that we want to enable commercial crew and cargo to and from low-Earth orbit while we, NASA, focus on the longer strides. This will be the workhorse for heavy cargo and humans out beyond things like the moon, Mars, and asteroids.

CHRIS: It really essentially is not going to make any sense to use a SLS cargo version, let’s say 130 metric ton, to go to low-Earth orbit.

TODD: Unless you wanted to put something very big in low-Earth orbit.

CHRIS: Maybe a hotel.

TODD: We could, yeah. We have a friend in Mr. Bigelow out in Las Vegas and he designs inflatable habitation modules. One of his concepts is the Bigelow 2100, which is about 45 feet long and can fit 16 people inside of it. We can actually launch that thing in one launch on a Space Launch System.

CHRIS: You take all the Shuttle launches it took to build Space Station, now you’re saying with just a few launches with SLS you could put a huge hotel in space or a huge complex.

TODD: It’s really a great enabler on a number of fronts; mass to orbit is one, volume to orbit is another, and the ability to take humans in very long-reach capability.

CHRIS: What do you see the technology currently today in terms of the materials and structure of the SLS compared to the Saturn V?

TODD: Sure. A couple of major things in terms of just the basic structure, things like we used to use simply aluminum as part of the super light-weight external tank on the Shuttle. We learned about super lightweight aluminum lithium.

CHRIS: Okay.

TODD: We intend to use some of that on the SLS. We also went from old historical welding techniques like variable polarity of plasma arc welding to friction stir welding and self-reacting friction stir welding. So, in our welding techniques we have much more efficient ways of welding things up, much more stable ways.

CHRIS: Is that sort of a seamless weld?

TODD: Sure, you butt the pieces up together and you start to stir and you actually semi-melt the two materials together and it forms a very clean weld line. It actually improves manufacture’s ability and performance in terms of the weld itself.

CHRIS: Okay. What are some of the advances in technology that you might see in the near future or what you’re working on today?

TODD: We’ve got a couple of areas where we’re working on some really interesting things. One is called selective laser melting. You may have heard of 3-deminsional printing where you build up complex structures with a laser printer. Now we can actually do the same thing with high performance materials like those that would make engine components. We’re actually testing that out today so that one day we can actually make engine components for a tenth of the normal cost.

CHRIS: This particular rocket is really a game changer for NASA and for the world.

TODD: In terms of the capability, it really does open up the frontier. It, also, allows us to press forward out into the solar system in ways we haven’t done in over forty years.

FRANKLIN: You know, I wonder for the 100th episode we can get three Stingrays?

CHRIS: 2014 models?

FRANKLIN: 2014 models.

BLAIR: That’s appropriate. I mean really if you think about it we’re medianauts. We should be honored in the same way the astronauts are honored. We should get Stingrays.

CHRIS: That’s right. There are three of us, three astronauts for Apollo 12. Yeah.

FRANKLIN: As a medianaut, I can actually put the Blair medianaut bobble head on my dashboard.

CHRIS: Speaking of fun facts, I’ve got a fun fact for you. All right?

BLAIR: All right.

CHRIS: We talked about Corvettes and Stingrays.


CHRIS: The SLS, the first version that we talked about that’s going to have Orion on top, in terms of power, it’s going to 8.4 million pounds of thrust. How many Corvettes would that be equivalent to?

BLAIR: 486,000.

FRANKLIN: I’ll say 486,001.

CHRIS: Da-da-dada. It’s 160,000 Corvettes.

BLAIR: Well, that’s still quite a bit.

CHRIS: That’s a lot of Corvettes.

BLAIR: Yeah.

CHRIS: Now, if you have the 130-metric-ton rocket, which is later down the road, that’s 208,000 Corvettes.

BLAIR: Dude, I was doing the math!

CHRIS: Oh, okay.

BLAIR: That’s what I would have said.

FRANKLIN: Speaking of propulsion and rockets, Blair, you did an interview.

BLAIR: Actually I did and it’s good we’re talking about that because, really, a lot of the externals on SLS look the same as the old Apollo but it’s the inside where you can start to see all the difference. I learned about that when we talked to Katherine Van Hooser down at Marshall.

CHRIS: This was your 100th episode interview too.

BLAIR: Yes. I’m going to preface everything with that from now on.

CHRIS: Let’s check it out.

BLAIR: So Katherine, I understand that you’re very involved in the overall propulsion system for the SLS, which we’re very excited about by the way. I’m just wondering how do you design a propulsion system for a new space vehicle?

KATHERINE: Well, a lot goes into that. It takes a long time and a lot of people. We work very closely with the people who design the vehicle. That’s the first thing you have to do, figure out where you want your vehicle to go; how big is it; how much propulsion do you need. Then, there are lots of trades that go on trying to size the engine; what type of engine; what kind of propellants. A lot of work goes back and forth between the engine and the stage.

BLAIR: Now, we’re not developing a new engine for the SLS. We’re using the Space Shuttle’s engine. Is that correct?

KATHERINE: That’s exactly right. At the end of the Space Shuttle program we were lucky enough to be able to manipulate our assets in such a way that we saved several flights on 15 engines and we have enough parts to build a 16th engine. So there were 16 usable, main engines at the end of the program. SLS decided to use those engines as part of its vehicle. We’re going to use those sixteen first and after that if we have to make more, we’ll do that. That will give us some opportunities to put in some cost savings mechanisms because SLS is not a reusable vehicle like the Space Shuttle was. We’ll be able to improve some manufacturing techniques and do things a little more simply and a little more cost effective because the engines won’t have to be reused.

BLAIR: You have these sixteen motors and they’re sort of legacy motors from the Shuttle program.


BLAIR: You’ve been using those motors for a while so they’re not new. Have we made some improvements or upgrades on those motors over the years?

KATHERINE: Of course, SSME was continually upgraded over the years. The contract was awarded in 1971 and we first built hardware in ‘72. The first Space Shuttle mission was in 1981. At the end of the program, we were still flying hardware that had flown as part of the engines on STS-1.


KATHERINE: Some of the hardware is 30 years old. The design itself, much of it, 40 years old but it has been continually improved. The engines at the end of the Space Shuttle program were 4 times more reliable than they were at the beginning of the program and took 57% less time to maintain than they did early in the program. We’ve updated a lot of the major components; turbo pumps, nozzles, chambers. A lot of the major components have gone over upgrades over the years. One of the reasons that SSME was so successful with the Shuttle program is that it was a very well understood engine. We have over a million seconds of hot fire time. That’s ground tests and flight time on that engine.

BLAIR: Hot fire. Hot fire time.

KATHERINE: Hot fire time.

BLAIR: Wow, that’s a lot of seconds.

KATHERINE: Because that includes ground test and flight that is a lot of time. We have a bulk of data, a lot of data to analyze and help us understand how the engine works, and what it’s doing that’s not ideal; what we can do to make it better. We use all of that data to do our upgrades. Another big benefit of the Space Shuttle program is that because the engines were reusable, when they came home, we would do inspections, periodically take components apart and see how the hardware performed. That let us know what areas we needed to improve the most.

BLAIR: What’s the difference between the F-1 that was used on the Saturn rockets and what’s now being developed for SLS?

KATHERINE: That’s a good question. The F-1 developed a long time ago actually has more thrust. It’s a larger engine. It uses RP-1, which is like kerosene and liquid oxygen. So, the stuff coming out of it is a black, sooty residue. That’s what’s left on the hardware. The RS-25 being used for the SLS uses liquid hydrogen and liquid oxygen. It’s roughly a third the thrust but it’s a much more efficient engine. The way the engine operates itself causes it to be much more efficient. You get a lot more thrust for the amount of propellant you consume. The exhaust from a Space Shuttle main engine or the RS-25 is a hydrogen rich steam. When you take our hardware apart it all looks steam cleaned. It looks just like it did when it went in.

BLAIR: As far as propellants are concerned, and these are important questions, you can choose between whether you are going to use solid or you’re going to use liquid. What goes into the decision when you’re trying to figure out which propellant you want to use?

KATHERINE: I’ve worked on liquid engines my whole life so, obviously, that’s the better choice.

BLAIR: Tried and true, in your case.

KATHERINE: Tried and true. They both have important places in rocketry. Solid rockets tend to give you a lot more thrust but for a shorter amount of time and they’re less efficient. You use those to get off the ground where you need the most thrust at that point in your launch. So, SLS will use, just like Shuttle did, a combination at lift off and then the solids will fall away and the liquids will continue to burn for the rest of the mission.

BLAIR: Now, you’ve got these extra Shuttle motors that you’re using but I can think of about four locations around the country where there might be some in existence that aren’t being used. Maybe I could borrow those or at least look into them being accessed.

KATHERINE: I think you might mean the museums where we’ve put the orbiters around the country?

BLAIR: Uh, I might be thinking of the museums.

KATHERINE: Well, good luck. Those, since we finished the Shuttle program with flights remaining on all of our engines, we did save for SLS. We knew SLS was coming along. What are in the orbiters around the country for viewing are not SSMEs. They are RSMEs. They’re replica shuttle main engines. They have development or older nozzles that you see. Everything you see is a real part of a SSME but the part that is inside the orbiter that is hidden from view is just support structure. We needed the engines for future use.

BLAIR: Now, did the museums know they were getting replicas?

KATHERINE: They do. They absolutely know and they know why. And as good Americans, they completely support it.

BLAIR: With all do respect, I really appreciate what Katherine had to say but I need some verification that the museums don’t have actual rocket motors in the Shuttles around the county.

FRANKLIN: You know you could actually go to these museums on your own and do a little bit of…

BLAIR: I’m going to have to do that.

FRANKLIN: …snooping.

BLAIR: Oh yeah, I’m good at that.

CHRIS: Would you like another 100th episode fun fact real quick?

BLAIR: Yeah, sure. Why not? Fun facts.

CHRIS: Okay, how much will SLS weigh in terms of 747 jumbo jets? So, let’s take the 70-metric-ton rocket. How many jumbo jets?

BLAIR: One hundred jumbo jets.

CHRIS: One hundred jumbo jets. What do you think?


CHRIS: He’s much closer. 7.5 747 jumbo jets is equivalent to the weight of the SLS, 7-metric-ton version.

BLAIR: But it’s our 100th episode.

FRANKLIN: You were thinking of a scaled down model version.

CHRIS: Yeah.

BLAIR: Speaking of scaled down model versions. And Franklin with his 100th episode segue.

CHRIS: Yes. [Laughing]

FRANKLIN: Who knew? I had an opportunity to talk to Barry Howell at the Marshall Space Flight Center about making models and the SLS.

BLAIR: Super models.

CHRIS: Yeah, super models.



FRANKLIN: So Barry, when you first started, you had 30 to 40 people working in the shop. Now, you’re down to about three model makers.

BARRY: Yeah.

FRANKLIN: Has technology enabled you guys to do more with less?

BARRY: It certainly has. In the past, the way we use to do things was we had to machine each part or piece.

FRANKLIN: Now, back in the day, you used to use blue prints.

BARRY: We use to have blue prints, yes.

FRANKLIN: And now?

BARRY: It’s computer-generated drawings, not a lot of detail to what we’ve got. We take that. We scale it down and try to pick out what we think the customer will want as far as detail. Some customers want a lot of detail, and there are some of them that just want something that looks like the SLS. Of course, with more detail, it costs a little more to do it.

FRANKLIN: When you first walked in the door as a 19-year old, you started working on the Saturn 1B.

BARRY: Saturn 1B, Saturn V, all the Saturn vehicles, the old Block 1, the 2 but the Saturn V and the 1B were the most that we built.

FRANKLIN: The materials that you are using to build the SLS models are way different than what you used to build your Saturn.

BARRY: Absolutely. Use to be the old Saturn parts you used the aluminum tubing. You used Plexiglas but now days we use the two-part mixture that you just add together. It dries in 15 minutes and you’ve got your parts. So, instead of standing at a machine, turning a piece of Plexiglas down for an hour, you can take this liquid, mix it together and in 15 minutes you’ve got a part.

FRANKLIN: When I first walked into your shop, I walked over to your area and you had a crawler on the desk.

BARRY: Yeah.

FRANKLIN: It was huge. What are you actually working on right now?

BARRY: Actually, right now, I am building a 1 to 50-scale crawler and launch tower for the SLS. The tower is going to be 88 inches tall.


BARRY: Eighty-eight. I think it’s going to be a floor model versus a 1 to 100. Crawler and all, it’s going to be tall.

FRANKLIN: Tall. I’m only 73 inches so, I’m assuming you’re working on some step ladders.

BARRY: Yeah, I’ll be working off a flat. Actually, I’m building it in such a way that it comes in sections.


BARRY: So you cut it down on your shipping of it. It will be easier just to assemble.

FRANKLIN: In forty-four years, you’ve got to be honest with me, Barry. Have you ever taken an exacto knife and carved your initials somewhere on the inside?

BARRY: I probably have in the past. I wouldn’t know what model it went to. You know, you got to put your mark somewhere. Yeah, probably I have.

FRANKLIN: Do you get the information like we’re making this model that’s going to go to the White House. Have you ever received any information like that?

BARRY: I can’t say that we have. Most of the time we don’t know where the models are going. We have models at the White House but at the time when we were building them we didn’t know where they were going.

FRANKLIN: There’s a BH somewhere on one of those.

BARRY: I’d like to think so… [Franklin laughing]

BARRY: …but I wouldn’t know that.

FRANKLIN: When you finally leave Marshall, they’ll probably make a mode of you.

BARRY: It would be a short one. [Laughing]

CHRIS: Tell you what Franklin, did you by chance put any NASA EDGE stickers or signage on the models?

FRANKLIN: Well, like Barry, I can neither confirm nor deny whether or not there is a NASA EDGE sticker on anything over in the model shop.

BLAIR: If you find it there, don’t be surprised.

FRANKLIN: Yeah, I like that right there.

CHRIS: We learned quite a bit today.

BLAIR: Absolutely.

CHRIS: And, in fact, in 2017 when we have the first flight test for SLS down at Kennedy, hopefully we will be there in person with a live show.

BLAIR: I tell you what guys, that will be great when were there, probably episode 168.

CHRIS: No, it could be episode 200.

BLAIR: Or 200. If we’re down there watching that launch, you can reflect on what I’m about to show you on this 100th episode of NASA EDGE. Care to venture a guess?

FRANKLIN: Um, you have your own model?

BLAIR: Okay, you know the surprise but I have constructed…

CHRIS: Well, you have it on your desk.

BLAIR: Well, that’s the initial box. That’s not the completed thing.

CHRIS: Okay.

BLAIR: But for you guys, for this 100th episode, I am going to show you now footage of the very first maiden flight of NASA EDGE SLS-X, the first flyable demonstration of technology that will eventually take Co-rion into space.

CHRIS: Do you have Co-rion on this model?

BLAIR: I have a test flight article of Co-rion. It’s not the full-scale version. It’s obviously been scaled down for safety reasons but it’s a legitimate flight.

CHRIS: We knew about Co-rion but didn’t know anything about this.

BLAIR: I mean progress is progress. You guys sit around and conduct your meetings but it’s time to launch.

CHRIS: All right, let’s go check out this 100th episode flight test.

FRANKLIN: Show me whatcha got. [Music]

BLAIR: Go ahead, and 5, 4, [Rocket noise]

BLAIR: Oh, oh, oh. Success! [People gasping and laughing]

BLAIR: Now, if we can just find the capsule. Anyone seen Co-rion?

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