Watch videos with subtitles in your language, upload your videos, create your own subtitles! Click here to learn more on "how to Dotsub"

Nuclear Rockets with James Dewar - Live Show 3.25

0 (0 Likes / 0 Dislikes)
♫ Theme Music ♫ In 1969, a group of astronauts changed the world... They walked on the moon. "That's one small step for man and one giant leap for mankind." In 1972, our journey ended. We've never been back. 2010 begins a year of change. Private companies are working on next-generation spaceships, governments are looking to go back to the moon, and on to mars. It's time to look up, and dream again. It's time to push humans into the cosmos. It's time to educate and engage the planet. It's time for SpaceVidCast. ♫ Theme Music ♫ This is SpaceVidCast LIVE 3.25 for Friday, July 30th, 2010 Ben: My name is Benjamin Higginbotham. With me as usual is the beautiful, lovely, wonderful and talented Cariann Higginbotham Cariann: I'm unusual Ben: She is slightly unusual Cariann: I didn't say usual We are your Spacevidcasters. We have got an action-packed EPICsode for you tonight it's gonna be really, really cool, and before we get into our guest I did want to mention a couple really cool things We wanted to thank the Space Frontier Foundation for the New Space 20--uh, ...space...oh no, I forgot what the word is for it. C: Really? B: Yeah, it's the best presentation of space -- there we go -- award. C: And we're doing a really great job right now B: (laughs) we're doing something that we got a new space-- C: No really, they gave us an award for this, people. B: Apparently, for NewSpace 2010 and you can watch almost all of the clips from NewSpace 2010 on spacevidcast.com right now by going to spacevidcast.com/newspace/2010 . With that, as you guys know, we're huge advocates for next-generation space travel and that means we have to do something different than what we've been doing for the last 40 years and that starts with propulsion. One of the things that we've been doing forever and a day is chemical rockets and while chemical rockets are cool, chemical rockets got us to the moon, they're not exactly a sustainable method of space. Tonight's guest is the author of "The Nuclear Rocket" and his name is James Dewar. James, welcome to SpaceVidCast. Let's get the 900-million pound gorilla out of the room here first and that is when you say, "nuclear rocket", the first thing you think of is radiation and the fallout that's going to happen from launching a nuclear rocket. What's the realistic-- what's the realism behind the radiation there? James Dewar: Well, radiation has been, is now, and will be a fact of life for all of us. as you and I sit here, we are getting radiation coming from the depths of space piercing through our body. As you also sit there, you have radiation inside your body which is radiating out. So as you and your wife sleep, you are in essence irradiating each other. It's just a fact of life and we just have to get used to it. Now, in my first book on the nuclear rocket program which was called, "To the End of the Solar System" and there still are some copies with Apogee press, I had an entire annex dealing with radiation and the environment. And the bottom line is there were about 20 tests done with hot systems and 19 of them vented a radioactive plume to the environment. Now, in 1974, after the program was killed by president Nixon, the EPA did a wrap-up study of the effluence and they said -- and I'm paraphrasing here, but the quote is in either of my 2 books -- they said "The program was conducted in a credible manner, and that reflected favorably on both NASA and the AEC", which were the 2 agencies jointly running the program they also noted that all releases of radioactivity were below applicable guidelines. Now, there was 1 test which was not or, which did not give off any radiation and that was the nuclear furnace test that was the last one tested, in 1972. err, 71. And that had what's known as a scrubber. So you had your core here and your nozzle here and at the base of the nozzle, you basically had some very high pressure firehoses and they blasted a stream of water onto that hot plume and cooled it down so that everything condensed. Then all they did was they filtered out the radioactive gases and they trapped those and with the hydrogen gas, that was just vented off to the environment. Now, in terms of using a nuclear rocket in space, you have to bear in mind that there are 2 types of or 2 major types of radiation that come off: neutrons and gamma rays. And these are the most damaging to humans. But the point is, once you are above the Earth's atmosphere, you don't have something called, "air scattering" so that means as the neutrons and the gammas come off the engine they just fly straight off into space. So the bottom line here is you put your engine at the rear and your astronauts as far forward as possible then you just let the tanks absorb whatever radiation there might be coming off. So basically, it's not a problem. It's something that good scientists and engineers can handle. Now, to further back up that point, we have had nuke subs sailing in an equally harsh environment since 1954. Ben: That's a good point. James: And you had seamen living onboard 24/7 and sometimes 365 and they are not glowing in the dark. So the bottom line here is if you have a well run program with good people doing the managing, you can make your radiation exposers virtually nil. Now I want to further emphasize this point that there were 3 deaths that you can link to the nuclear rocket program or that I was able to link. The first one happened in 1957 or 58 when one of the founders of the program was driving from Camp Mercury at the test site out to Jackass Flats where they did the testing and he crashed and was killed. Now, there was no traffic and it was in bright daylight and all the people could say is he just fell asleep at the wheel. The second death occurred at Jackass Flats where a worker was told to go burn some classified tapes so he took them out to a gulley and he poured 5 gallons of gas on them then he says, "well, geez, I don't have enough gas" and he went and got another 5 gallons and poured that on it. Then he struck a match. (laughter) Cariann: Awesome. James: And the third casualty was at Westinghouse where a worker on the nuclear rocket program for some reason entered a tank that was filled with nitrogen and he was asphyxiated. No-one knows why he did it and it had nothing to do with the program, but since he was listed as a worker on the nuclear rocket his death was labeled as caused by it. Cariann: Of course. Ben: Now when, I guess part of where the fear comes in is when people hear "nuclear rocket" they think something like Project Orion where you're taking a nuke and blowing it up underneath the vehicle over and over and over again. You know, there are going to be a tremendous amount of fallout that's going to happen and in that scenario, that happens, of course, inside our atmosphere so you do have backscattering. So what do you propose in your plan? James: Well, what my second book argues is that you use a nuclear rocket engine to take payloads to low earth orbit and then you bring that engine back and reuse the non-nuclear components such as the turbopump and the nozzle and the pressure vessel and you take the old core out and send it for recycling. Now, the way I see doing it is you start off with a small engine, not these very large systems that people were thinking about during the 1960s but something small and you build it so it can be carried in the cargo bay of let's say a C-5A or maybe a 747, or maybe you build a special plane for it. Well, you take it there, then you fly it out several thousand miles out to an isolated ocean area, and you push it out then you have 2 solid rocket boosters that take this stage up from roughly 30, 40, 50 thousand feet... I mean, this is just a concept that I am setting on the table for people to think about. The stage takes it up to over 100,000 feet and then the nuclear engine fires and takes the payload up to low earth orbit. Now, if there are no people and there are no people several thousand miles out in an isolated ocean area, there is very few people to get hurt. Second, the use of the solid rocket boosters does this: is it gives the aircraft time to get out of the way while the nuclear engine is coming up to power. And a nuclear rocket engine is different from a chemical rocket engine in that it takes 30-60 seconds for it to come up to full power. So while these 2 or 3 solids are carrying the stage up the nuclear engine is coming up to power it's going to reach full power somewhere above 100,000 feet and above 100,000 feet you are basically above the Earth's atmosphere, so all the neutrons and the gammas coming off are just going to go straight into space or straight into the atmosphere where they will be treated like the gammas and neutrons that are coming from the deep solar system they're all blocked by our atmosphere. Ben: Can we compare that to, because that's actually a good point... There is a ton of radiation that doesn't make it down to Earth because of our atmosphere and when you look at this was actually mentioned in new space, and I forgot the exact formula but it's something along the lines of, if you're on Earth and that's 100% protection, when you're up on the ISS, that would only be 2% protection based on the amount of atmosphere that's around you. Cariann: That's fascinating. Ben: So, when you're up there, how much radiation would we be giving off as compared to what's just naturally-- because radiation is just a natural occurance there's nothing-- just because we're making it doesn't mean that it's not something that is just naturally occurring. Cariann: Right James: Uhh, I'm not quite certain I follow your question. Ben: What-- how much more radiation would we be putting up above the atmosphere than is naturally there already? James: That's like-- (laughs) well, not much. Ben: (laughs) So, in reality, we wouldn't be able to perceive it at all here on Earth. In fact, it would be a controlled reaction, so we would know where it is as opposed to space where we just don't know. The naturally occurring radiation, we just don't know as much about that as opposed to the radiation that we create ourselves. Cariann: Right. James: Well, the engine would run for 10, 12, maybe 15 minutes to reach low earth orbit. Then it's shut off, so we're talking about a gamma and a neutron burden from, let's say, a very small engine lasting for that short a time then it shuts off. Now, I further posit that you put this engine into what I call a cocoon or it could be any number of structures it could be, you know, just something that you wrap around it because you want to bring it back. And not leave it up in orbit. You would leave it up in orbit for a couple months for it to cool down, and then after it's cooled down, then you'd bring it back to Earth. And if it's in this protective cocoon, that is going to dampen much of the gammas and the neutrons that are still coming off from it. Ben: Someone in the chatroom would like to know, and this is a really good question What's the cost difference between this system and traditional um, just chemical rockets? Why, basically, why would we want to do this system as opposed to chemical rockets? James: Well, first off you have much higher thrusting power you are talking about a system that starts off at roughly 825 seconds, and I argue in my book, that it looks like 1200 is the ceiling for the solid core. That's roughly 3 times better than your best chemical system. Also, at one time very early on, in the old roll removal program there were some speculating sixteen hundred seconds out of the solid core, and I have had some people speculate to me. I mean really putting on, their you know their crystal balls, sort of glasses and saying well seventeen, eighteen hundred seconds is the ceiling. So the bottom line with those two things is no-one knows what the ceiling is, but it is certainly much higher than a chemical rocket which reached its ceiling back in the nineteen sixties with liquid oxygen and hydrogen. Ben: Well it sounds to me your entry level rocket just where you begin already starts three times more efficient, or three times greater I guess than the chemical rockets we have today. Would that be a fair statement? James: Yes Ben: So why aren't we doing this then? James: Well I think NASA, or certain parts of NASA have a fair - well in nineteen sixty the first head of NASA got into a big argument with the AEC, over the scope and pace of the program. And in nineteen sixty, T. Keith Glennan said that NASA was only going to use a nuclear rocket engine from low earth orbit going out into deep space. Which would "pose no harm toward earth." The reason they did this was basically for PR, because back in nineteen sixty you had mass of world wide protest against atmospheric testing. With hundreds of thousands of people marching here in the US and in Europe. So they were sensitive, I mean NASA was an agency just a couple years old, so he didn't want to have any of that bad PR. So he just said, we are only going to use it from low earth orbit outward. Now as a consequence, all of the mission studies that had been done basically since then have been focusing on using a nuclear rocket engine, to take payloads from low earth orbit going somewhere into the solar system where it would "pose no harm to earth." I think that's wrong and at the time the AEC thought it was wrong. Now in my book there is a quote by John Simpson. And for the audience who doesn't know who John Simpson is well in the atomic energy area John Simpson is of equal stature to Wernher von Braun in the space field. So he was a very name person and you took what he said back then seriously. and I have a quote from him which basically said "We don't see any insurmountable technical problems in using a nucleur rocket engine to take payloads up into low earth orbit." Now from 1955 through 1960 there were any number of studies done on using a nucleur rocket engine in that mode and I have them all in my 2nd book. But what I'm postulating here is look, we need to re-examine this because if you do follow this launch sequence you have a revolution in the economics of space and as you lower your cost down to lets say $800 per pound or even lower then you are changing the space program from something that is government run, into a private sector program. Where each one of you can now have personal access to space. Now Ben you look like you weigh couple hundred pounds well add $100 per pound they would cost you maybe $20,000 to go into space. That's still quite high. Ben: A lot lower than what we have got today though! Cariann: Exactly James: Yes, the Russians are I think in my book I said they were 30 Million and someone said no they are 50 million now. Ben: They are. James: 50 million is beyond what most people have to spend on a shot into space. $20,000 I could even do that. Ben: That's absolutely do-able but how realistic is it? Lets just say someone had a blank check and just said you know what, lets build this thing. Lets make this go, with all the regulations in place and just the fear in the hearts and minds of everyone in the world. whether founded or unfounded is it a realistic plan will they actually let something like this get built? And if they did how long would it take? James: Well from a technical point of view the only thing that had to be done was to test out the stage, because you had any number of reactor tests. You had a couple of prototype engine tests, but there was no real stage testing done. Where you had the engine and the hydrogen tank to test the oh I'm having a senior moment, I've got to think of it. Ben: But the staging process its self? Correct? James: yes, so all of the plans are there and if you go back to what was proven and what has plenty of room for technological growth, you could probably do it in 5 or 6 years. But if you've got some scientist and engineers come in a say well I've got this great idea and you know we are going to do this and that, Well then you can probably talk 10, 12, 15 years. One of the hardest problems they had was the nuclear rocket back then is what would face anyone now. And that is how do you keep the core inside the pressure vessel. And the reason why is simple. If this is your pressure vessel here and your core is here, you have hydrogen gas that comes on the top of the core and then in 52 inches - it comes through at very high pressure and at 0 centigrade, and then 52 inches later it leaves the core at very low pressure and 2 or 3 thousand centigrade. Well this pressure difference - from high to low. In essence creates a force which is trying to blow the core out the nozzle. Cariann: hmm Ben: Yes that makes sense. James: And it took Los Alamos from 1955 - 1964 to come up with a core design that they knew that was going to stay inside the core and that was the key we before core design. And they went through dozens of these. I have some of them in my first book. On the nuclear rocket program there were old black Joe and erm gosh I cant think of the other ones now but they all had colorful names. The did any number of studies. How do you keep the core inside the pressure vessel? First step. Ben: Well the core seems to be the issue with nuclear in general isn't it? I mean that where you have things melting down and just creating massive amounts of pressure and blowing the tops off of things. I mean that seems like a logical problem and you have to deal with the 0G right? So you have got this object that could float around anywhere if it wasn't totally stabilized and then you have got this massive pressure difference, trying to force it out of the back. That doesn't seem easy? James: Well first lets deal with the fear of an explosion. In both of my books I talk about what's known as the Kiwi TNT test. The TNT stands for Transit Nuclear Test. And here they purposely rigged a full scale 1,000 mega watt, 35inch core by 52 inches long. They rigged it to explode, and it was especially designed to do so. And I have pictures. And you can see it prior to the test, you can see the explosion coming from the test and they you can see the aftermath. Where they split the area up into six sectors, then they went and picked up the pieces. But they first measured how far they were from ground zero and how much they weighed. From that they were able to calculate that the force of the explosion was equal to 2-3 hundred pounds of black gunpowder. Now the principal damage that was done is a trailer of about 600-700 hundred feet from ground zero, suffered a couple of broken windows. Stan Gunn, who's still living and I hope he's watching, Stan helped to found the program and Stan went and picked up the pieces. He said he got 10 hour from doing it, which is double the dose on it now but Stan is 87. Cariann: Nice James: And he's still going strong and if Stan is going to die, Stan is going to die in his 1960 Corvette, which he ramped up the horsepower. So he's getting something like 560 or 580 horsepower out of it. Stan is a turbo pump man, so he puts all these things on his engine. (B&C Laugh) Ben: So lets just say we had done this in the 60s and rather than continuing with chemical rockets we decided, "You know what, we are going to explore this. We are going to start to build it." Where do you in your opinion think we would be technologically today when it comes to space? James: Well at some point, even assuming the ban. If you had people using it starting in the late 1970s. You would probably have the fear of nukes in space drastically downgraded. You would probably now have any number of systems using a nuclear rocket engine to push payloads into space. So I think you would have probably very large space stations. Much larger than the 440ton ISS. I mentioned earlier, the study that Rocketdyne did in 1968 that said if you take first generation NERVA and you put it on the Saturn V as the third stage, you've doubled the boosting power from 250,000 to 500,000lbs. Well that's 250 tons! The Space Station weighs 440. Ben: What about to the moon? Would we be able to go back to the moon and onto Mars? Would we be able to do more human space flight from using this technology? Or would we still be kind of stuck? Basically will it lower the costs and make space travel that much easier to do? James: Well what it would do is it would force, in my view and this is what I write in my second book it would force a restructuring of the space program. So you would have a much broader and much deeper private sector space program. And they would come up with the funding, and so you would have this shift. So NASA would still have certain types of duties, but it would sort of change into be something like the FAA, where it does airline safety and you have different groups that regulate the airline industry. I mean NASA is now an operational entity. Plus doing research in other areas, so you know, you would find a basic shift from a public sector space program to a private sector space program. Once you have the private sector funding it well it's going to fund what it wants to fund. Ben: Alright. I'm just checking the chat room, just to see if there is any final comments. Where can people get more information about you and your projects online? I got you with that one. Cariann: Well there is www.nuclearspace.com is my understanding. James: Pardon? Cariann: www.nuclearspace.com James: That is a website and they have very active people who talk about various types of nuke issues. But I don't have a website, I've got too many irons in the fire. Ben: But people can pick your book, the nuclear rocket through Apogee Books. We actually do have a copy to give away, and we will do that at the end of the show. If you are able to stick around for a little bit I would like to ask you a few questions that were brought up in the chat room. Comparing it to other technologies, but for now we will wrap up this show and I want to thank you for joining us. Like I said this is a one of those things we need to explore if we really truly want to go out to the stars. We can't continue to rely on chemical rockets, we have hit the maximum we can do with those. Unless we are going to build another Saturn V or Ares V, they are these towering monstrosities that are nothing but fuel. Cariann: Right. James: That's right I mean you talking about 80-90% of a chemical rocket on the launch pad is just fuel and oxidizer. The rest is your weight of your tanks, your engine and your nozzles. After you take all of that out what's left is your payload. And as a general rule or as a general rule, from a practical point of view it is around 1-2%. Ben: So, James stay with us we will come back to you in just a few minutes. For everyone else joining us live, lets see here. What are we doing? I forgot what the contest was. We were doing er Cariann: The pre-tweet Ben: Someone who had pre-tweeted the show is the winner so we have already got a winner. By the way, this is isn't just a copy of James' book. It is actually a signed copy. Unlike last week, it is already signed. So we are set on that one. So how do you want to do this? I will go like that. Cariann: Ok. Ben: Bethejustin? Cariann: Bethejustin! Ben: Bethejustin congratulations. You have won a copy of James Dewars' The Nuclear Rocket. So we will get that out to you. For everyone else we are going to go into post-show in just a minute. If you don't have a copy of Spacevidcast EPIC Pick that up, you can watch the post-show on demand. If you don't have a copy of Spacevidcast EPIC, you are going to want to grab that because we have videos going up from the new space confrence Of the lunches and dinners that were not made available. You had to actually be at the lunch or dinner, there was no live stream of it. The only other way you can watch it is through Spacevidcast EPIC. It is the entire lunch or dinner in fact we have even got the SEDS ISU video going up a little bit later on tonight. That is like over 2hours! That one video alone is over 2hours, thats 2 ½ GB Cariann: That was a crazy dinner, it was very very fun. Ben: It was really cool it had DJ Dr P. in it, it had Bob Richards and then it had from er, hold hold hold! From the National Space Society, er name is blank in here. Anybody? Cariann: I cant remember to save my life. Ben: Well i'm not going to delay the whole thing anyhow, but it was an awesome presentation. We have also got LaserMotive's speech online right now. If you are Spacevidcast EPIC and we got two more going online that are EPIC only. Of course you get the ad-free experience and you help us to go to other conferences such as Spaceup DC. We are about 85% go on that one right now, and other stuff like that because we like to bring you coverage. Again I did want to thank the Space Frontier Foundation for the awesome award. It is pretty epic, it is heavy. Cariann: It is like 4 ½lbs Ben: It is, this has got some weight. Cariann: They said "We can send it to you." We said no no no, its ok we will pack it. We were like oh, hey we're over. Ben: So we packed it in our luggage and then we went to leave and they were like you are going to need to move some stuff out of this. We were like WHAT! What are you talking about? OH!! it's the big heavy award. Cariann: The big heavy thing Ben: Yeah. Alright guys thank you so much for watching we will see you next week.

Video Details

Duration: 35 minutes and 32 seconds
Year: 2010
Country: United States
Language: English
Producer: Benjamin Higginbotham
Director: Adam Jochum
Views: 113
Posted by: spacevidcast on Aug 4, 2010

Author of "The Nuclear Rocket", James Dewar joins us to discuss why we should consider moving away from chemical rockets and re-start development of nuclear rockets. Think radiation would be a huge issue? Think again! This is a completely different way of looking at space travel and a very fascinating interview. ;If you want even MORE technical information, pick up both of James' books at http://www.apogeebooks.com and check out our post-show interview that continued for another hour! Post shows are made available exclusively on Spacevidcast epic!

Caption and Translate

    Sign In/Register for Dotsub to translate this video.