i suppose if you want to be picky about what a fusion reactor is. think of it as the convertible of the reactor world. a fusion reaction does occur inside it and energy is produced in the form of heat. just cause it has a hole to let the boom out doesn't mean its not a reactor.
Yes, but Sharkfinn's criticism was on fusion reactors not yet being able to produce electrical energy on a large scale without net loss. This is completely different from using fusion reactors to produce thrust.
look up reactor in the dictionary pls. for an apparatus to be called a reactor, there is no specific requirement that it be enclosed, nor does it specifically require the output to be electricity. its still a reactor. (hint that was irt to what battuta said, not sharkfin)
you still need to use solar panels, lots of them,
Not really. It only needs 200KW -- about the same power produced by the ISS solar panels.
those panels are huge. there are a lot of them. and the structures that support them are heavy. the iss wasnt exactly a single launch affair either.
seems you need some kind of plasma
...? It uses deuterium-tritium pellets.
where do you think you get the plasma? out of the aether? im actually much more concerned over the metal "liners" i believe is what the article called them. if the metal has a low enough meltim point you might stick those in tankage, of course you would need some kind of process for shaping them to the required geometry.
these are likely not as easy to extract from mars has hydrogen or oxygen, so you need to carry your entire fuel supply on one ship. a ship weighed down by a lot of engine and structural mass
The required fuel mass fraction is significantly smaller than for conventional propulsion methods.
Seriously, nuke, did you even read the article? All of the points you've raised were addressed in it. Your first question on specific impulse could have been answered just by skimming it.
yes i read the article, and was rather unimpressed. i read about every kind of propulsion technology and power systems. i also look at their technological readiness level. fdr hasn't even seen a vacuum chamber test. countless engines with better isp have, and they work. only problem is they are rather hungry beats. vasimir can pull off a higher isp, and is ready to fly, and uses plain old hydrogen. we know we can make nuclear (fission) reactors that work in space (there are some up there btw thanks to soviet russia). so looking at other technologies, id say were better off using those.
that does not mean screw fdr, that means we have engines closer to flying that could pull off a mars mission. fdr might be the revolutionary engine that they say it is, or it can end up in the queue with the other engines waiting for their trl to rise.
