Timescale Abstraction in Gameplay Video (Aug 21, 2017)

[Tavior]

Come on, dude:

Already addressed.

There is currently a kilopower project on paper and testing for providing power to an early Mars colony that would NOT have the necessary water resource for cooling. Heat can be radiated off or converted to electric. Depending on how much heat we are talking about.

You remember that Curiosity tiny nuclear reactor? It has a dedicated radiator for radiating. There is a picture of those radiator and some stat. It generate 2,000 watt of thermal power and 150 watt of electric power. Heck it doesn't use all of that thermal/heat for electric and instead use some of it to keep itself warm. Mars night are pretty darn colder than reasonable.

https://mars.nasa.gov/files/mep/MMRTG_Jan2008.pdf

In space all spacecraft (no matter what their design are) will always need some sort of heat source (either from power source or moving heat from different part of hull that are warmer). Because if a certain part of their spacecraft remain in dark all the time, It would get to -250 F degree. Converse being in sun can go as much + 250 F degree.


I would like to add something to the topic of heat handling. I recently install a new CPU which was a huge upgrade and also generate even more heat than my older CPU.

My older CPU was an phenom II 1075T which did generate a bit of heat. But is pretty darn slow relative to modern CPU and never had problem with a smaller heat air cooler. I have been using that one CPU for more than 3 years. I moved over to AMD Ryzen 1700X. Oh boy it does generate heat like nobody business! I have a liquid cooler to handle that heat. It barely hit 100 F degree while browsing the internet.

The funny part is my GPU is actually running way more hot than my CPU.

Anyway back to topic of heat handling. All I have to say is liquid are great for cooling.


All this heat talking has remind me of something that you can look into. ISS has 10 radiators for heat dissipating (ETCS and PVTCS) and they use liquid ammonia to move heat around. Because radiator work by having lot of surface area to radiate heat. You can scale the system to handle larger load by making larger radiator or add more radiator.

https://space.stackexchange.com/questions/3702/does-the-iss-need-more-heating-or-more-cooling

In additional you can also turn off things that aren't mission critical to reduce heat generation to allow radiator to handle larger load from reactor or vice versa.

TD;LR: Not impossible to handle larger heat load in space.

 

[keynes2.0]

Already addressed.

No, you didn't. What you did was conflate three entirely different designs and act like they are equivalent.

Water turbines dont show things can be done with heatpumps and vice versa.
Heatpumps dont show that things can be done with isotope decay devices and vice versa.
Isotope decay devices dont show that things can be done with heatpumps and vice versa.

Not a single thing you have said has addressed these simple facts. Except for the word "nuclear" and the fact that they generate heat, they share no design principles. Saying that one shows another is possible is like citing the weight of a windup car to say that an internal combustion engine can be made that small or citing the power of an ICE to say that a windup car can be made that powerful.

 

[Tavior]

No, you didn't. What you did was conflate three entirely different designs and act like they are equivalent.

Water turbines dont show things can be done with heatpumps and vice versa.
Heatpumps dont show that things can be done with isotope decay devices and vice versa.
Isotope decay devices dont show that things can be done with heatpumps and vice versa.

Not a single thing you have said has addressed these simple facts. Except for the word "nuclear" and the fact that they generate heat, they share no design principles. Saying that one shows another is possible is like citing the weight of a windup car to say that an internal combustion engine can be made that small or citing the power of an ICE to say that a windup car can be made that powerful.

Heat is still heat no matter what medium it is on or generated by.

In the same principle that electric is still electric in space. Static is still static in space. Light is still light in space. Water well you get the idea. The only difference design constriction are less mass available, lack of air/water that isn't involved with life cycle system, and lack of reliable gravity aside from centrifugal gravity.

I only cited different that one, kilopower, nuclear reactor to show that it IS feasible to build a nuclear reactor without access to plenty of water which you apparently didn't know. You don't get to go back and say I cited the "wrong kind of nuclear" just because. I never said that kilopower would be an "example of a nuclear reactor" on a spacecraft. In fact I will go back and quote exactly what I said earlier.

There is currently a kilopower project on paper and testing for providing power to an early Mars colony that would NOT have the necessary water resource for cooling. Heat can be radiated off or converted to electric. Depending on how much heat we are talking about.

Also most of what you dismissed as unfeasible for some reason or another is pretty much already covered way way earlier in one of my posts.

TL,DR version: No matter how you look at it. There are always "trade-offs".

 

[Herbert West]

An RTG is not a nuclear power plant. The energy generation is on different scales of magnitude. And at those different scales of magnitude, radiate cooling will just not cut it, due to heat flux.

 

[Råttan]

Anyone played Kerbal Space Program?

... No?

Anyway... In that game you learn that fuel-efficiency isnt everything. For lift-off - and sometimes landing - you want thrust. And the more fuelefficient an engine is, the less thrust it tend to give out. (ION-engines being the prime example.)
Also: Diffrent engines work differently in vaccum and in atmosphere. Good in vaccum may be bad in atmo...

Sorry for breaking of the RTG/Nuclear-discussion...

 

[Tavior]

Anyone played Kerbal Space Program?

... No?

Anyway... In that game you learn that fuel-efficiency isnt everything. For lift-off - and sometimes landing - you want thrust. And the more fuelefficient an engine is, the less thrust it tend to give out. (ION-engines being the prime example.)
Also: Diffrent engines work differently in vaccum and in atmosphere. Good in vaccum may be bad in atmo...

Sorry for breaking of the RTG/Nuclear-discussion...

All good.

I also play KSP as well. Not much lately although.

I already mentioned this bit earlier. Vasimr can't be used to launch because of the same reason. Insufficient thrust.

There are also alternative method to achieve orbit while using less fuel (yet more examples of trade-off) but they won't be easy to implement like at all. They range from feasible to lunatic.

To name a few: Elevator, airplane/balloon -> high attitude launch into orbit, blowgun, and other methods that involve negative and/or exotic energy/matter.

An RTG is not a nuclear power plant. The energy generation is on different scales of magnitude. And at those different scales of magnitude, radiate cooling will just not cut it, due to heat flux.

Instead of going over this subject again. I will ask why are you so sure that nuclear power can't be done?

Why not instead of one huge reactor. Split it into smaller unit and spread out to reduce heat flux to something that can be handled? After all spread out heat source in different spot allow you to handle more heat flux load. Even if that isn't enough the vasimr engine will just draw on other source instead of a nuclear reactor.

 

[Herbert West]

I have a degree in reactor (as in nuclear reactor) physics. Trust me, without some sort of fluid to at least feed into a massive, and I do mean massive array of radiating panels, you are not going to deal with any of the waste heat that a reactor (or rather, the heat exchanges driving the steam generators) puts out. And since any such liquid has to have a massive heat capacitance, and since heat capacitance goes, at first approximation, with density, that is several tonnes worth of rocket load you could instead use to deliver solar panels or somesuch.