/sci/ - Science & Math

>>9540608 allows the fuel to melt, and loosens the temperature limits, but the rest of the engine still has to be cooled. Note "to radiator" caption. Performance is improved, at the cost of losing tremendous amounts of expensive fissionable material -- quite a lot of which has yet to undergo fission. No one ever solved that problem, not even "lightbulb" designs.

>>9540617 is halfway to being an "Orion" and shares some of that concepts advantages and disadvantages. Zubrin's original plan had the reaction just BEHIND the vehicle. Your diagram looks like it's INSIDE, but additional water is injected. Either alternative "dilutes" the thrust, just as Orion does. The NSWR still has excellent performance (though 10,000 sec is "just" 100 km/sec exhaust). See image. With an assumed R of 20, initial acceleration is much less than 1 gee, and a coast period is required. No one at NASA would object to a 5 day trip to Mars! (No one except the accountants!!) Not The Expanse though.

>>9540613 is new to me. The Wikipedia article really doesn't explain how all the desirable characteristics are achieved without overheating the engine (though gamma and neutron absorption, if nothing else.) It also concedes "technical challenges remain". Any additional references?
"Dusty plasma" reminds me of '50s concepts where radioisotopes are thinly plated on a backing sheet and allowed to decay naturally.