Can pulsed ntr be a good torch drive. Atomic rocket says that with some development it can be a low end torch ship. Suppose extraction of hot fission fragment is possible and and also better cooling systems are used, can it be a better torch drive then? If yes what can be the expacted performance and pulse rate.


closed as off-topic by chasly from UK, 011358 smell, Gryphon, F1Krazy, Renan Feb 10 at 19:37

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about worldbuilding, within the scope defined in the help center." – chasly from UK, 011358 smell, Gryphon, F1Krazy, Renan
If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ Hello Samrat Dutta and welcome to Stack Exchange. I believe this question is not about Worldbuilding. I personally think it would be better dealt with on Space Exploration - space.stackexchange.com $\endgroup$ – chasly from UK Feb 10 at 18:07
  • $\begingroup$ Hello Samrat Dutta. They'll potentially be viable, but as chasley sais the question is off topic here. Try taking the tour: worldbuilding.stackexchange.com/tour and read up in our help centre about how we work: worldbuilding.stackexchange.com/help VTC as not about worldbuilding. $\endgroup$ – 011358 smell Feb 10 at 18:16
  • $\begingroup$ Does "ntr" stand for "Nuclear Thermal Rocket?" Also, please be absolutely sure you want the hard-science tag. It is NOT the same as "hard science fiction." I will increase the quality of the answers, but decrease the quantity of answers. You might not get an answer at all. Do you have a need for the hard-core math and all the citations? If not, you'll get more answers via the science-based tag. I'm just making sure. $\endgroup$ – JBH Feb 10 at 18:41
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    $\begingroup$ @FaySuggers, allow me to introduce you to Stack Exchange Magic Links. :-) $\endgroup$ – JBH Feb 10 at 18:43
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    $\begingroup$ @JBH Most kind. I'd played about with BB code and Html to no avail, now it all makes sense, thanks. $\endgroup$ – 011358 smell Feb 10 at 18:58

I am assuming that by 'torch rocket' you mean an inertial mass rocket. That is, one that propels the ship forward by ejecting inertial mass rearword.

You have not specified a time frame, so any answer would be different for today (the technology is not developed enough, and since it is not yet optimized your questions can not be answered), 'tomorrow' (maybe, if there is a breakthrough in development, but again the parameters would be so drastically altered that your questions can not be answered about future technology), or the future (unlikely, except for maybe small ships that are not pressed for time - that is, travel time that is measured in decades, not years). The main issue with these drives will be that very large mass spaceships will require a lot of inertial mass propellant for significant delta-v changes over a short time, even IF the inertial mass is ejected at very high velocities.

Yet I DO see a future for such rockets as maneuvering jets, for minor course corrections and docking steering thrusters at space stations, where large delta-v changes are not required (essentially the same velocity, just a different direction). However, these thrusters would use optimized technology much more advanced than we currently have, and therefore your questions on pulse rate and thrust can not be answered.

However, there is another way to generate forward momentum besides inertial mass ejection propulsion. Consider surfers, sailboats, gliders, and swings. They all generate forward momentum WITHOUT ejecting inertial mass. Surfers use gravitational changes and the energy in the water wave itself. Sailboats use the power in the wind. Gliders use pressure difference between the top and bottom of the wing and control surface. Swings do it by using mechanical energy to utilize gravitational forces and changes in gravitational balance to gain momentum. Methinks the propulsion system of the future will use non-inertial-mass-ejection techniques that haven't been thought of yet, rather than having to carry huge quantities of reaction mass.

I once had a washing machine walk five feet (until the cord pulled out) across the laundry room floor, simply because the load was unbalanced. Yes, these systems still need ENERGY, but they do not require inertial ejection mass.

Also, gravity is a strange beast, and when we humans finally get past the notion of gravity as a 'distortion of the spacetime continuum', or a 'gravity well', we might actually get somewhere that allows us to start harnessing it effectively as a 'delta-momentum system'.

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    $\begingroup$ Hello, @Justin. The question has the tag hard-science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. You can check out a tag's requirement description by hovering your mouse pointer over it. You can then edit your post accordingly. $\endgroup$ – 011358 smell Feb 10 at 20:24
  • $\begingroup$ @Fay Suggers I appreciate the 'hard science' tag, but my answer is that there is not, nor can there be, a hard science answer for the question, and reasons why. I believe that form of answer is allowed. There are just too many unknowns, and not enough equations. There is no where to begin. Any hard science answer would only be conjecture. Even the phrase 'Suppose extraction of hot fission fragment is possible' makes it unanswerable. Hard science based on a supposition? $\endgroup$ – Justin Thyme the Second Feb 10 at 20:38
  • $\begingroup$ Absolutley agree, the whold thing is (from what little I could find on the subject) little more than speculative, and reproducing equations of motion or the wikipedia page on NTR wouldn't have served any usefull purpose. I had to post the comment, the system automaticaly threw your question up for it's quality, probably because of the tag issue - even if you didn't need it pointing out. :) $\endgroup$ – 011358 smell Feb 10 at 20:51
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    $\begingroup$ Yeah, it's a catch-22...you didn't follow the rule for answering questions tagged [hard-science]. But the question shouldn't have had that tag in the first place. It's on hold now anyway. $\endgroup$ – Cyn Feb 10 at 23:46

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