NGCR Engine

[Boris_Badenov]

Try this;<br /><br /><br /><br />What is the Devil? Well, it's everybody's favorite villain, nuclear power. <br /><br />Oooh, scary, isn't it? <br /><br />Nuclear power has gotten a terribly bad reputation. According to the press you read, it is dangerous, poisonous, pollutes the Earth, kills bunnies, and generally is Bad. Why, oh why, would anyone even consider using such a terrible thing?<br /><br />Because it is very, very powerful, like any terrible thing should be. <br /><br />Remember, chemistry is failing us here. Chemical rockets are just about as powerful right now as they are ever going to get. We have two options for going out into the rich bounty of space. We wait a very, very long time for metastable propellants to finally be developed. Or we use our shiny new technology to tame that nuclear Devil and put it to work. Kind of like fire.<br /><br />A few words about nuclear power and radiation. Despite all the bad press, nuclear power has killed almost no one compared to risks that we take without thought every day.<br /><br />Yes, Chernobyl was a very bad accident. But bad accidents happen all the time, and are often much, much worse than Chernobyl was. <br /><br />For example, Bhopal, India, makes Chernobyl pale in comparison, but we don't stop using all chemicals. According to the UN, burning coal kills 2 million people a year in India. For that matter, burning coal in the United States belches thousands of pounds of Uranium into the air you are breathing right now, millions of times more radiation than nuclear power plants do. <br /><br />As for nuclear power plants: Every nuclear power plant in the United States was designed decades ago. We have put more effort into building better cars than we have into building better nuclear power plants. Compare the safety, comfort, and efficiency of a car today to a car in the 1960's. Air bags? Seat belts? Anti-lock brakes? Traction-control? Engine control computers? Air conditioning? Remember when cars had manual chokes? How about <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

And this;<br /><br />So how good is Nuclear, anyway?<br /><br /><br />VERY good. Fission and fusion and antimatter have the ability, once we build them, to get us anywhere in the Solar System with ease. Chemicals on the other hand can barely get us into orbit.<br /><br />For this discussion, I will stick to nuclear fission. Fusion/antimatter is more complicated, and I like simple. <br /><br />As I mentioned above, way back in the 60's NERVA and ROVER made nuclear powered rockets. These rockets were thoroughly tested and were able to generate as much as 250,000 pounds of thrust, with an Isp of 900 seconds or better. The best chemical fuels in use today are liquid hydrogen and liquid oxygen, the stuff burned by the three Main Engines on the Space Shuttle (SSME's). The SSME's produce a maximum of about 450 Isp. <br /><br />NERVA did this using technology that still used vacuum tubes. And not because they 'sound better' than transistors.<br /><br />Now, technically speaking all rockets that use a reactor to heat up a gas to make thrust are called Nuclear Thermal Rockets (NTR's). An NTR like NERVA is what is called a solid core NTR, since the reactor core was a heavy solid mass of ceramics. <br /><br />The efficiency of any NTR is limited by the difference in temperature between the core and the gas. The bigger the difference, the more efficient the rocket is. I'll repeat that, because it is an important principal: A nuclear rocket is more efficient when the reactor runs hotter. <br /><br />NERVA was pretty hot, basically running just barely under the temperature that would start the core ceramics melting. The smart guys who came up with this concept way back then were not satisfied with that however. They came up with an even more efficient system, in which the core of the rocket was not a huge solid mass of ceramic, but it was a cloud of Uranium HexaFluoride gas. Since the core started out as a cloud of gas, it couldn't melt! Therefore it could get much hotter than a solid core rocket, <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

As for engine size;<br /><br /> <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

And this;<br /><br />In this section I describe a huge nuclear powered rocket launcher. I will repeat and expand upon many of the points I made above, because I don't want to throw cryptic acronyms around. I want people to understand just how powerful we can make this rocket if we decide to do it. <br /><br />The effective use of nuclear power in space transportation allows a paradigm shift in our thinking. All boosters which have been built to date have been shackled by the low efficiency of chemical fuels. Using chemicals it is possible to get off earth, but only barely. Every gram of structure must be trimmed, exotic materials and cutting-edge techniques are a necessity, and safety margins must be as slim as we dare if success is to be achieved. <br /><br />Nuclear power changes all that. Nuclear is VASTLY more energetic than chemical. We no longer must guard every gram of mass. Much more "margin" can be included. Much more safety can be designed into the machine. <br /><br />Let's examine a large heavy lift booster. There are other kinds of nuclear rockets we could build, but we desperately need a heavy lift booster if we are to excite people, catch their dreams, and actually do big stuff in space. <br /><br />The most powerful booster America has built to date was the Saturn V. The size and weight of the Saturn V are easily accommodated by existing infrastructure. <br /><br />Lets use the Saturn V as a "template" for a nuclear powered heavy lift booster. We will make the launcher roughly the same size, weight and power as the Saturn V, and let's see how the performance compares. <br /><br />The most important difference between our new booster and the Saturn V is in the engines. The Saturn V used five massively powerful F1 engines in the first stage, burning kerosene and liquid oxygen. The mighty F1 produced 1.5 million pounds of thrust. Despite its large size and power, the F1 was a very "relaxed" design. It ran well inside the possible performance envelope. The reason it d <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[scottb50]

The idea with Falcon 1 is they pump them out them out by the gross. You could put a 1200 pound Module into LEO and dock it to another 1200 pound Module. Eventually you have a functioning Station.<br /><br />For people I would rather have a smaller number of more powerful engines. I really don't see a Falcon nine being such a great idea. Five even seems to be a stretch to me.<br /><br />Mass producing the engines on an assembly line needs to be the next step. From what I've seen that wouldn't be that hard, they seem like fairly simple straight forward engines. <div class="Discussion_UserSignature"> </div>

 

[qso1]

stevemick:<br />NTR's(and solar thermal rockets) are a little faster than you think and all beat the Hohman ellipse transfer which is a specific trajectory BTW. Admittedly they are hard pressed to cut the time in half vs. chemical, but that is still signifigantly faster.<br /><br />Me:<br />Can you provide the link to this? The initial NTR designs were for use in Hohmann transfer type orbits because althought they were designed with ISPs of around 900 in mind, they weight of the reactor almost eliminated the ISP advantage. End result, somewhat more powerful than chemical rockets but not enough to overcome utilization of Hohmann transfer orbits. The Von Braun Mars mission plan was based on this and those were generally 500-600 day mars missions in part because upon reaching Mars, this limited the stay time at mars to around a month. For return, they had to wait until the next favorable earth return alignment occured or utilize a gravity assist flyby Venus in or outbound.<br /><br />The nuclear electric system I referred to was based on the VASIMR program which is actually better known and widely publicised as plasma propulsion but the technical classification VASIMR fell under was nuclear electric propulsion. I recall seeing that somewhere but apparently not on the web. Maybe nuclear electric is a stretch in VASIMRs case but in the excerpt below, VASIMR is compared to Hall thrusters etc.<br /><br />Links to VASIMR:<br />http://www.nasatech.com/Briefs/Sep01/MSC23041.html<br />http://www.nasa.gov/vision/space/travelinginspace/future_propulsion.html<br /><br />The excerpt below explains the difference in VASIMR and other nuclear electric designs such as Hall thrusters.<br /><br />Excerpt start:<br />Because the VASIMR uses plasma to produce thrust, it is related to several previously developed thrusters; nam <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

You have covered the tech end well enough, now the cost and public concern end.<br /><br />Boris1961:<br />Its exhaust is completely clean: It is very difficult to make hydrogen radioactive in a fission reactor. It basically can't happen.<br /><br />Me:<br />Is there some data, a link to back this up? <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[tap_sa]

It's a credible claim for closed cycle GCR (aka nuclear light bulb). In that design the gaseous core is contained in transparent 'bulb' which allows the core to radiate and heat the propellant outside it. The problem is associated radiation and heatfluxes are so high it is questionable that any known material would survive in this environment very long. It's just a concept.

 

[qso1]

GCR I haven't really addressed that much but from what I could gather, it appeared less close to being practical in the near future than NTR or plasma. My view is that plasma offers the best choice for sending humans to mars or unmanned probes to mars and beyond. For one thing, like NTR, plasma has been taken well into the testing stage. Although at this point I'm not sure if its still being developed. Last I heard, private industry was supposed to be taking it over with Franklin Chang Diazs cooperation. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[tap_sa]

GCR concepts come in two form, open and closed cycle. Open has the gaseous core with direct contact to the propellant, meaning some of the core gets always vented too. Closed cycle has the core isolated from propellant.<br /><br />Solid cores vent radioactivity because ~3000K temp cause inevitable erosion of the core into the propellant flow.

 

[qso1]

Thanks for the info. Did they ever get to the point of being tested? <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[tap_sa]

GCRs? AFAIK no. Only solid core NTR has been tested. There's also intermediate step of liquid cores where the core is mixed into the propellant fluid. You may have heard of Zubrin's nuclear salt water engine, that's one example. These have hideous amounts of radioactive contaminants in the exhaust.<br /><br />IMO NTR of anykind makes sense only beyond Mars where solar thermal becomes unpractical. And even there nuclear-electric might be more suitable.

 

[qso1]

Thats what I kind of thought. I didn't recall ever hearing about any GCR tests. There had been quite a bit of testing on the NTR design through projects Rover, Kiwi, Nerva, but they are long gone. VASIMR is about the closest I can think of to a system in recent years that has reached a significant level of testing though not quite to the NERVA level.<br /><br />NTR was the main propulsion choice for manned mars under the 1969 Von Braun proposal. In recent years, I considered the plasma approach to be better suited for at least two reasons, quicker transits and very high ISPs. It also has the potential to lead to nuclear fusion propulsion. Keeping the crew weightless as short a time as possible so they won't have to endure difficulties in adjusting to martian gravity once on Mars. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[SteveMick]

I completely understand Isp and was talking about specific power because as I stated, the mass of the electric power generation sys. is a limiting factor in electric propulsion in that it limits potential acceleration rate. <br /> I sat in on many conference paper sessions in which the proponents of NTR claimed 3 month or less transfers to Mars and even claimed greater than 1 g acceleration. I don't know if they were "blowing smoke" or not, but I do know that solar thermal IS capable of transfers in this range, although only 1/10g acceleration or less. Isp for solar thermal is at least 800sec. with hydrogen and even at Mar's distance a L'Garde type concentrator produces about 10KW/lb. which at 33%(conservative) efficiency, means 3.3KW turning into enthalpy in the exhaust for every lb. of concentrator at Mars. At Earth this is about 8.5 KW/lb. although if the radiator mass is factored in this drops although this can be mitigated by using the radiator as part of the concentrator structure.The point being that STR's do not suffer from specific power limitations that would preclude faster than Hohman transfers.<br /> Solar power at extreme distance from the Sun still works and provided the concentrator mass is kept down to solar sail type levels(which reduces concentration as the mirror cannot hold a perfect shape) it can still produce the 150suns for concentrator cells. 10KW/lb. at earth will be only about 1/160KW/lb. or 6w/lb. thermal at Pluto and about 2w/lb. electric. 500lb./KW elec. is better than current radioisotope based generators. <br /> If VASIMIR(which might not work BTW) is so capable, then why isn't NTR tech? Vasimir cannot produce as much thrust per lb. mass of the system vs. NTR since the nuclear energy must first be converted to elec. just to run the thing. NTR's lower Isp vs. VASIMIR isn't really relevant since the acceleration of VASIMIR is necessarily so much lower that there is simply not enough distance involved for this advantage to matter.<br />Thank

 

[Boris_Badenov]

qso1 You have covered the tech end well enough, now the cost and public concern end.<br />NASA's post Columbia accident period (2004) has so far revealed itself to be largely introspective and self correcting. It finds itself defining a role within its mandate toward a new vision.<br />This comes amid a backdrop of war in Iraq entering a phase of self determination by its people, domestic corporate scandal, a less than stellar economy, international security concerns, a contentious U.S. presidential election this fall. A flurry of investigative and advisory commissions all designed to right the agencies' "Ship of space". Some major structural changes and events have occurred namely its "Slim fast" approach to bureaucracy, leaning toward public transparency with regards to groups expressing concern over its nuclear space efforts. <br />Recent major "Robo Space Exploration" success, its ongoing Shuttle return to flight program, present and future projects development and its continued International cooperative work on the ISS all guarantee the agency still holds the leading position on the space technology front.<br />Recently nuclearspace.com conducted an informal survey to pulse the merit of public support with regards to the use in space of power and propulsion systems that require the extended use of nuclear fission reactors. During the early part of 2004 almost half of all responding claimed to be U.S. nationals while the other half claim to be from other mostly European countries. The poll was conducted by Ron Godlewski of Sofiaron Inc. Some conclusions were drawn namely the desire for those responsible for implementation of space systems in the future to "think outside the box" in their approach. The need for a vibrant diverse use of nuclear fission reactor power in space. And the overwhelming desire to see heavy lift capacity launch services as a key component in any future space venture.<br />Convincing a skeptical U.S. public will be difficult in part due the pub <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[qso1]

I should point out that I'm no expert on this, I can only reference that which I have seen published and it seems everything I reference ends up wrong as soon as I flap my yap about it, especially tech stuff. All I can say at this point is that I will have to wait and see what works and what doesn't work.<br /><br />Sorry if anything I said offended you or was wrong. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

Looks to me like you got a handle on the public concern side of it as well. I on the other hand, must find some new way to discuss tech stuff. I always say something that ends up being wrong even if I have a stack of written works a mile high.<br /><br />Much of what little I know came from research I did writing failed books. Least I know now why they failed. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[Boris_Badenov]

I found this;<br />Gas core nuclear engine worked on by Glushko 1962-1970. For use in second stage of two-stage interplanetary rockets. This gas phase nuclear reactor was designed by Energomash for a Venus station/Mars flight. It would be launched from orbit. Work stopped in the USSR (and in the US) but it would have worked well in principle. This was one of the 'B' category engines developed by OKB-456 Filial 1 because it was too dangerous to test at Khimki. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

This is a NASA study<br /><br />1<br />REDUCING THE RISK TO MARS:<br />THE GAS CORE NUCLEAR ROCKET<br />S. D. Howe·<br />P.O. Box 1663<br />Los Alamos National Laboratory<br />Los Alamos, NM 87545<br />INTRODUCTION<br />The next giant leap for mankind will be the human exploration of Mars. Almost certainly within<br />the next thirty years, a human crew will brave the isolation, the radiation, and the lack of gravity to<br />walk on and explore the Red planet. However, because the mission distances and duration will be<br />hundreds of times greater than the lunar missions, a human crew will face much greater obstacles<br />and a higher risk than those experienced during the Apollo program. A single solution to many of<br />these obstacles is to dramatically decrease the mission duration by developing a high performance<br />propulsion system. The gas-core nuclear rocket (GCNR) has the potential to be such a system.<br />Several studies over the past decade have identified the difficulties of sending manned missions<br />beyond the moon. Most prominent of these obstacles are the radiation from galactic Cosmic Rays<br />(CR) and the substantial decalcification of bone that occurs in a zero gravity environment. In<br />addition, anecdotal stories have circulated for years about psychological problems associated with<br />living in confined quarters for long periods of time on board the Russian space station, MIR. The<br />effects of all of these threats can be reduced substantially by reducing the total mission time to eight<br />to ten months. To accomplish this and maintain a reasonably sized ship in Low Earth Orbit (LEO),<br />· - This paper is declared a work of the US government<br />and is not subject to copyright protection in the<br />United States<br />2<br />a high thrust system with a specific impulse greater than 2000 seconds will be required. The gascore<br />fission rocket is the most likely candidate to achieve this performance in the near future.<br />Because of the high specific <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

Here's another one.<br /><br />Gas core reactor rocket <br />Gas core reactor rockets' are a conceptual type of rocket that is propelled by <br />the exhausted coolant of a gaseous fission reactor. The nuclear fission reactor <br />core may be either a vapor, gas, or plasma. They may be capable of creating <br />specific impulses of 3 000 - 5 000 s (30 to 50 kN•s/kg) and thrust which is <br />enough for relatively fast interplanetary travel. Heat transfer to the working <br />fluid (propellant) is by thermal radiation, mostly in the ultraviolet, given off <br />by the fission gas at a working temperature of around 25 000°C.<br />Theory of operation<br />Nuclear gas-core-reactor rockets can provide much higher specific impulse than <br />solid core nuclear rockets because their temperature limitations are in the <br />nozzle and core wall structural temperatures, which are distanced from the <br />hottest regions of the gas core. Consequently, nuclear gas core reactors can <br />provide much higher temperatures to the propellant. Solid core nuclear thermal <br />rockets can develop higher specific impulse than conventional chemical rockets <br />due to the extreme power density of the reactor core, but their operating <br />temperatures are limited by the maximum temperature of the solid core because <br />the reactors temperatures cannot rise above its component’s lowest melting <br />temperature.<br />Due to the much higher temperatures achievable by the gaseous core design, it <br />can deliver higher specific impulse and thrust than most other conventional <br />nuclear designs. This translates into shorter mission transit times for future <br />astronauts or larger payload fractions. It may also be possible to use partially <br />ionized plasma from the gas core to generate magnetohydrodynamically <br />electricity, subsequently negating the need for an additional power supply.<br />General features of the nuclear reactor<br />All gas-core reactor rocket designs share several properties i <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[Boris_Badenov]

WOW!! Check out this page.<br /><br />http://www.inspi.ufl.edu/research/ntp/nuclear/index.html <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[webtaz99]

Another white paper based on another computer model. {yawns} <div class="Discussion_UserSignature"> </div>

 

[Boris_Badenov]

Check out this White Paper!!!<br /><br />http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720015242_1972015242.pdf <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[webtaz99]

Just a few things missing. Investment, people and hardware. <div class="Discussion_UserSignature"> </div>

 

[nexium]

Nuclear engines shorten the life expectancy of humans, if operated or tested in Earth's atmosphere or surface. Shortly after we have tiny colonies in small asteroids, someone can test such an engine at considerable personal risk. The researh done 40 years ago, indicates several advantages over rockets for travel throughout the solar system including the Oort cloud, but intersteller missions would take thousands of years = too long to expect the technology to be repairable, even if we have the patience. Neil