One sci-fi trope I like is finding an old ship, or an old station/facility, with minimal power, but which you can power once more and explore. And another trope - finding long-frozen people in still-functioning cryoberths. But if I recall correctly, Traveller power plants usually have limited fuel which lasts for a few weeks and then they power down. Or is there a way without deviating too much from the basic CT/MGT rules and technological assumptions, for such long-term power? This need not be long-term power for power-hungry systems such as M-Drives and energy weapons, but rather for minimal life support, emergency lighting and low berth survival.
Long-Term Backup Power
- Thread starter Golan2072
- Start date
epicenter00
SOC-13
Apparently low berths, particularly emergency low berths have their own power supply - there's multiple references to low berths functioning for long periods of time. It makes sense - an emergency low berth that shuts off when the ship's main power shuts off isn't very useful as an emergency survival method.
I'd imagine the power would probably be supported by some sort of radioisotope battery (like modern satellites) using some isotope that is a good compromise between long-lasting and sufficiently energetic to deliver the "trickle" (the term used in TNE) of electrical power necessary to keep the low berths going.
The term trickle also suggests that low berths have very low energy requirements.
Lifeboats in TNE instead of radioisotopes utilize solar power - it's a reasonable compromise, since it can be assumed that solar power collection is much more efficient and panels more durable than it is in our barbaric 21st century. In addition, ships in Traveller appear to spend most of their time in the more inner parts of a solar system where sunlight is reasonably abundant.
I'd imagine the power would probably be supported by some sort of radioisotope battery (like modern satellites) using some isotope that is a good compromise between long-lasting and sufficiently energetic to deliver the "trickle" (the term used in TNE) of electrical power necessary to keep the low berths going.
The term trickle also suggests that low berths have very low energy requirements.
Lifeboats in TNE instead of radioisotopes utilize solar power - it's a reasonable compromise, since it can be assumed that solar power collection is much more efficient and panels more durable than it is in our barbaric 21st century. In addition, ships in Traveller appear to spend most of their time in the more inner parts of a solar system where sunlight is reasonably abundant.
kilemall
SOC-14 5K
Jump drives in CT HG have a set capacity of capacitor for a percentage tonnage set aside for jump capacitors. Each ton of capacitor is 36EP, which translates to 9 GW. In an emergency, perhaps these can be charged, the reactor shut down, and the capacitors drawn upon in a trickle to life/cryo support.
I always figured the life support per person charge was filter/waste processing/air scrubbing chemicals/bio supplies for conventional life support. Prudent captains would lay in a several month capacity for both emergency and economic lean times. Others may be caught short.
Don't forget to add in fun things like artificial gravity being a power luxury you can't afford, and having to power budget between cryo and say an emergency radio broadcast once you make it back to somewhere people can pick you up.
And of course, what are you going to do to prevent piracy.
I always figured the life support per person charge was filter/waste processing/air scrubbing chemicals/bio supplies for conventional life support. Prudent captains would lay in a several month capacity for both emergency and economic lean times. Others may be caught short.
Don't forget to add in fun things like artificial gravity being a power luxury you can't afford, and having to power budget between cryo and say an emergency radio broadcast once you make it back to somewhere people can pick you up.
And of course, what are you going to do to prevent piracy.
mike wightman
SOC-14 10K
Looking at the trade tables radioactives are still incredibly valuable - a bit odd since fusion power is so cheap and at TL12+ you can use damper technology to fiddle about with decay rates...
Which makes me think that ships could well have some sort of small fission plant capable of providing a few MW as back up power...
Which makes me think that ships could well have some sort of small fission plant capable of providing a few MW as back up power...
Radiothermal generator (RTG), like the one powering the Pioneer spacecraft now leaving our solar system, are capable of providing a good power output for a very long time. One capable of supplying 50kW when new will still be supplying around 25kW even a century later. And that's without any nuclear damper assistance.
For your very long term power needs, a nuclear damper moderated fission RTG ought to be able to provide modest (10s of kW) amounts of power for centuries.
While the classic CT/Striker fusion plants have very short power supply lifetimes, the fuel supply requirements for these plants makes no real sense. The output of a hydrogen bomb comes from fusing a few micrograms of Hydrogen. Assuming the rest of the plant will not fall apart lacking maintenance, a Kg of hydrogen should provide a good amount (order of a Megawatt) for centuries if not millennia.
My problem isn't the power requirements, its how the rest of the equipment stays functional after long periods unattended. Left in a vacuum, metals begin to vacuum weld together, plastics erode and break down. Left in extreme cold, everything becomes brittle and may break under the gentle shuddering of micro-meteor impacts. If the atmosphere has any oxygen left in it, the O2 will combine with whatever is left, again causing corrosion. Water in the air will do the same.
For your very long term power needs, a nuclear damper moderated fission RTG ought to be able to provide modest (10s of kW) amounts of power for centuries.
While the classic CT/Striker fusion plants have very short power supply lifetimes, the fuel supply requirements for these plants makes no real sense. The output of a hydrogen bomb comes from fusing a few micrograms of Hydrogen. Assuming the rest of the plant will not fall apart lacking maintenance, a Kg of hydrogen should provide a good amount (order of a Megawatt) for centuries if not millennia.
My problem isn't the power requirements, its how the rest of the equipment stays functional after long periods unattended. Left in a vacuum, metals begin to vacuum weld together, plastics erode and break down. Left in extreme cold, everything becomes brittle and may break under the gentle shuddering of micro-meteor impacts. If the atmosphere has any oxygen left in it, the O2 will combine with whatever is left, again causing corrosion. Water in the air will do the same.
When your multiple megawatt fusion power plant is scaled back to a few kilowatts, you'll find that your fuel lasts much, much longer.
To that end, quoting a recent Time magazine article:
"By contrast … the lithium from a single laptop battery and the deuterium from 45 liters of water could generate enough electricity using fusion to supply an average U.K. consumer’s energy needs for 30 years."
Now, perhaps fusion reactors don't work at scale (i.e. a multi MW reactor doesn't work well when the flame is turned down to 0.0001 of output).
That would suggest then that the best "backup power" is simply the smallest reactor you can have handy, waiting to be turned on. A Mr. Fusion(™) and a 5 gallon tank of even gaseous hydrogen. Just enough for a few years of a few 1000 watts, just to power a few heaters, an airplant, and some light bulbs.
To that end, quoting a recent Time magazine article:
"By contrast … the lithium from a single laptop battery and the deuterium from 45 liters of water could generate enough electricity using fusion to supply an average U.K. consumer’s energy needs for 30 years."
Now, perhaps fusion reactors don't work at scale (i.e. a multi MW reactor doesn't work well when the flame is turned down to 0.0001 of output).
That would suggest then that the best "backup power" is simply the smallest reactor you can have handy, waiting to be turned on. A Mr. Fusion(™) and a 5 gallon tank of even gaseous hydrogen. Just enough for a few years of a few 1000 watts, just to power a few heaters, an airplant, and some light bulbs.
To give you an idea, there was a 1 MW reactor up and running... in a navy test facility. The energy cost to run it was 1012 kW. The expected curve from that design, which is the most efficient yet in the real world (and the data's 2 years old, because the navy ain't talking about it any more) is to get the cost down to a mere 1001 kW, but up the energy recapture to 1005 kW...
So 1.005 MW of plant is only expected to produce a net gain of 4 kW... 2.5 orders of magnitude less out than total energy of reaction.
Note that the navy may be able to extract more than the designer, because the exhaust is useful for boiling water, too, and so might pull another 10 kw out...
If they'll do so and they'll have a fusion reactor that actually produces net power... That would be a huge achievement and a breakthrough for humanity.
Lycanorukke
SOC-13
Since we're sticking with CT, if you use the Robots book, you can get a fuel cell spitting out 90 Kw, 100 L in size, and uses a combined 3.6 litres of Hydrogen and oxygen for 1 hour (at tech 15 you can get 270Kw out for the same amount of fuel). So with 1 Dton of Hyd/Oxy mix as fuel you could have 90 Kw for 3750 hours/156 days. But most importantly the fuel cells output is scalable, as the listed output is the maximum output.
Using MT for calculating power draw low berths pull 1Kw each (or 2Kw for an emergcency). So say with 10 low berths (10Kw) your 90Kw/h cell could run for 1404 days/3.8 years or ~10 years with the TL15 model with 1 dTon of fuel.
Now extrapolating the rules a bit, every 3 years the main reactor spins up and fires up the purification plant for a few hours, splitting the stored H2O from the fuel cell back into H2/O2 and then shuts down again. That 30 days of fusion fuel could turn into 100s of years. Or even more if you use multiple dTons of storage.
Using the same book, a 1 litre battery at TL12 holds 1 Kw/h. So 1 litre can power a low berth for 1 hour. A dton of battery can run a low berth for 13500 hours/1.5 years. At TL 15 this increases to 10.7 years. Not as good as fuel cells (which can run 10 times as much before 'recharge') but still useful, especially as you dont have to worry about H2/O2 explosions.
Using MT for calculating power draw low berths pull 1Kw each (or 2Kw for an emergcency). So say with 10 low berths (10Kw) your 90Kw/h cell could run for 1404 days/3.8 years or ~10 years with the TL15 model with 1 dTon of fuel.
Now extrapolating the rules a bit, every 3 years the main reactor spins up and fires up the purification plant for a few hours, splitting the stored H2O from the fuel cell back into H2/O2 and then shuts down again. That 30 days of fusion fuel could turn into 100s of years. Or even more if you use multiple dTons of storage.
Using the same book, a 1 litre battery at TL12 holds 1 Kw/h. So 1 litre can power a low berth for 1 hour. A dton of battery can run a low berth for 13500 hours/1.5 years. At TL 15 this increases to 10.7 years. Not as good as fuel cells (which can run 10 times as much before 'recharge') but still useful, especially as you dont have to worry about H2/O2 explosions.
The point being: they're expecting 0.1% return over cost of producing fusion. There's no reason to expect that a 20MW tokamak will return 20 MW out, nor even 2 MW out. The expectation is about 200kW out from that 20 MW reactor.
Hell, if the Navy's reactor has panned out, we won't find out until 10 years later...
kilemall
SOC-14 5K
Since I'm operating largely reactive engines, I always figured at least 50% of it went out the tailpipe.
This has been discussed before, and I see several questions to it:
A) Jump capacitors are thought to hold the power for a short time. I'm not sure they can hold it for longer times, so being able to be used for long-term backup power...
B) Those 36 EP translate to 9 GWx20 min (they are energy, not power). That translates to 3 GWxh. As a week has 168 hours, if it must keep it for a week, its true power is the equivalent to a 17.85 MW PP.
While this is still a good amount of power for a week, see that MT (the only versión I know to give us the power needs for life support) you need 74 kW per KL to keep full life support (just 4 kW/kl if you turn off artificial gravity and inertial compensators). So you could hold about 243 kl (18 dton) in full life support, or 4500 kl (333 dton) without gravity for a week with 1 dton of capacitators. And that's without the power needed by staterooms (3 kW/stateroom, 2kw/small stateroom or emergency low berth and 1 kW per low berth).
So, a typical free trader would need (with gravity off) 10800 kW for basic life support (4 kW/kl, 2700 kl) and about 50 more for accomodations (IIRC, I don't have my MT:IE Handy now).
So, one dton of jump capacitors (as said before about 3 GWxh) would last about 276 hours.
The same free trader has jump 1, so it has 1 dton (200x1x0.005) of capacitors, that would hold (as told above) about 3000 GWxh. At a consume rate of about 10850 kW, it would last for about 276 hours, so about 11.5 days, if
- they are fully charged (something not likely, less so if in jump)
- they can hold the power for so long periods (see A above)
- no more systems are needed (I didn't include computer and communications power needs as they are low in comparison, but I guess a mayday message will be sent periodically)
- OTOH no parts of the ships may have the power cutt off
And, as always YMMV (and your Traveller version too
)
kilemall
SOC-14 5K
I would be inclined to agree normally given their function, except for the black globe can buy more rule, which suggests they only get explosive and otherwise unstable when their capacity is exceeded.
Right now I am going with a metallic lithium-hydrogen technology at 1 million atmospheres, with more risks the closer it is to full power.
I would agree that the capacitors are rated for x GW-hours not generation, and for argument's sake accept the 3 GW-hours for now as a reference point.
I have no experience with the MT ruleset whatsoever, although in-context commentary on this forum suggests to me it was a Striker-gearhead-wonky version.
That number seems awfully high for life support, even for grav. The stateroom figures seem much more in line with what I would expect, and in line with the life support per person cost structure that is apparently pretty universal to the series.
I was not talking about any explosion possibility, but, as they are not thought (nor built) to hold power for any length of time, they may well leak it quite quickly, becoming empty in just some hours.
See that their function is just to accumulate the quickly mounting energy that the JD produces and to release it, also quite quickly, to the lantanum gird to achieve the jump.
The BG captured energy is sent to them, and may be used in the folloing turns (according to HG and MT), but that's just a few minutes after they become so charged, not being stored for days.
That's what I've read here (that MT is a direct offspring of Striker in craft design) but as I have no experience with Striker (in this sense I'm opposite of you
), I cannot confirm it, though I trust most people that have told me this.Right, MT power needs are absurdly high, and, coupled with the inefficiency of the PP (in fuel use), endurance uses to be quite shorter than expected (you can see a clear example in this thread, with the MT designed ship, and compare it with the MgT version latter in the thread.)
This was explained by Mr Furgate in the Q&A in Traveller's Digest issue #13 by comparing it with computers program memories, that have risen by full magnitudes as computer memory has become cheap (he expects in his answer that same will happen with power once fusion makes power cheap).
This does not explain though why if you build a TL6 submarine (just an example) it would have those very high life support power needs too, despite power not being cheap at this TL...
