if only the ISS were nuke powered

NUKE ROCKY44 · Senior Member

if only the ISS were nuke powered

GoogleNaut · Guru

One interesting problem that I know they must contend with even on a normal orbital day-night cycle is continously cycling the batteries--those things must get a real workout--charging and discharging in 45 minute cycles. The situation gets worse once the load sizes exceed 75 KW--one wonders if you can capture enough energy and store it in a usable form to keep the power on 24/7. A small nuke would even the load out quite a bit--keep some solar panels for emergencies of course, but for larger stations, I really don't see anyother way about it...

Even a solar dynamic system--which can come online pretty quick, will not be able to perform as efficiently as a smaller, nuclear unit that can run 24/7...

The other thing, is that NASA's budget is so constrained that they literally can't do anything else but 'put all of their eggs in one basket' technologically speaking. The station was supposed to be a platform to test new technologies--and one of those technologies was power generation and energy storage. If they can't test a variety of different ones, how can they work the bugs out of technologies let alone find one or several that will actually work...

Yet another reason for expanding the budget--give NASA the freedom to make mistakes--how else are you going to operationally search the 'parameter space' of technical possibilities...

-- Edited by GoogleNaut at 19:22, 2007-11-03

john fraz · Veteran Member

Don't know if I could get too enthusiastic about this. It's not really needed, and it's another way to spend more on the Incredible Shrinking Station before getting anything from it.
What the ISS needs (besides going over to private operation) is ED tether, possibly with an eye to testing a hypersonic shyhook application. The tether could boost it while it's in the Sun, and charge/upkeep batteries even while in shadow.

What nuke needs R&D now, is for Lunar and Mars applications, and tri-modal NTR/power plants.

GoogleNaut · Guru

...well a nuclear powered station of the size of the ISS is silly--granted. But I was thinking it terms of a much larger station--the problems of creating a pulse mode power supply that can produce 2x needed line power to charge batteries for the 45 minutes of sunshine in LEO--provide adequate power for utilities and then storing atleast that much in battery banks--so that the banks can supply power during dark cycle...

Also, most high performance NiMH battery packs are only capable of a few thousand charge-discharge cycles before they begin to fail--In the ISS case this starts to sound like swapping batteries about once every other year assuming 10,000+ Charge/Discharge cycles as a lifetime...

And those things are not small--several hundred pounds for each one and there are I think about 10 of these things in On Orbit Replacement Modules...

And the problem only gets worse if the station gets bigger. Imagine the scale of the problem for a station where the utility power demands are a steady 1 MWe--the on orbit energy infrastructure will not be trivial.

If we get really good at utilizing lunar and asteroid resources, it may be possible to create a solar furnace with a fairly large thermal mass (possibly something like molten regolith in an insulated retort) that can store enough thermal energy to continuously supply the heat needed for 1 MWe production, but the needed mass is very considerable--several hundred tons atleast I should think...