Can we talk about Life Support?

[Jouni]

How many MArs manned missions will be sent any time soon? None, because they are prohibitive. This was well hashed over during the Eisenhower and Kennedy administrations, and the science people almost universally agreed that manned flight was not about science, it was entirely political, and even military.

Manned missions are expensive, but that doesn't have anything to do with cost-effectiveness. Expensive things can be cost-effective, while cheap things can be very ineffective.

Of course, it's rather pointless to talk about cost-effectiveness in science, when you're trying to do something unprecedented and ambitious. If you can estimate cost-effectiveness in advance, you must already have a fairly good idea of what the results are going to be, and that doesn't sound like very ambitious science. Large-scale scientific projects are inherently political, because that's the only way you can justify spending billions in stuff that's so uncertain that you can't even estimate the benefits.

Every once in a while there is something like the Hubble repair, but the cost of the HST was ~2.5 million including launch… and it used Shuttle, which was ~1.6 million per launch alone. The repair was a launch, so if they could have launched a new HST for under ~700 million launch cost, it would have been cheaper just to replace it. The telescope was around a billion, and the 5 servicing missions cost ~1.6 billion each. Total space only costs were then nearly 10 billion. Even with identical launch costs, it would have been cheaper to launch 3 HSTs than 1 with 5 service missions.

You're using costs from different decades, and hence your conclusions don't make sense. That $2.5 billion figure for Hubble was its pre-launch cost in 1990 dollars, which is around $4.3 billion in 2010 dollars. Hubble's cost-to-launch was $4.7 billion, while total costs up to the first service mission were $5.8 billion, still in 2010 dollars. The total costs of the Space Shuttle program were around $1.5 billion per launch in 2010 dollars, but less than a third of that were actual launch costs that are included in Hubble costs.

[tater]

Yeah, I typoed million for billion. Bottom line is that the single largest manned contributions to basic science have been moon rocks (certainly cheaper via probe), and repairing the HST---which is itself a probe and only needed repair due to a flaw. That's it.

I think it is fair to assign 100% of Hubble service mission costs to Hubble, as that's literally the only really good science associated with shuttle (other satellites launched are still "probes," so only thinGS like repair that require a human get to count.

Again, manned flight is awesome, and it inspires me in ways probes don't, but it has nothing at all to do with maximizing science.

Edited February 8, 2015 by tater

[Sirrobert]

There's no such a thing as 'basic science'

The knowledge we are gaining about living in space could just as easely be concidered 'basic science', because it will form a basis for living in outer space.

There is also no such thing as 'maximaizing science'. In the real world there is no number of science points you can get from a biome. You can't say how much data x is worth vs data y, especially when you are talking about different fields (understanding outer space vs living in space)

And you can't even tell how much data x is worth in a specific field, because everything we know all interlocks. Things we learn about living in outer space can have far reaching effects in regular medicine for example

Edited February 8, 2015 by Sirrobert

[Jouni]

Yeah, I typoed million for billion. Bottom line is that the single largest manned contributions to basic science have been moon rocks (certainly cheaper via probe), and repairing the HST---which is itself a probe and only needed repair due to a flaw. That's it.

That remains to be seen. We've had spaceflight only for a short while, so it's probably better to wait for a century or two before making such assessments.. My guess is that the long-term experience of having people in microgravity on MIR and ISS will be more important than anything the Apollo Program or Hubble did, unless biological humans become obsolete.

I think it is fair to assign 100% of Hubble service mission costs to Hubble, as that's literally the only really good science associated with shuttle (other satellites launched are still "probes," so only thinGS like repair that require a human get to count.

Even if we assign a part of the fixed costs of the Space Shuttle Program to Hubble (which is a bit dubious accounting practice), the cost of Hubble itself is comparable to three Space Shuttle launches. Payloads tend to be more expensive than rockets.

[SaturnV]

That's what I suggested in another thread, kerbals need unique reason to explore, true science data

[Torquemadus]

How many Mars manned missions will be sent any time soon? None, because they are prohibitive. This was well hashed over during the Eisenhower and Kennedy administrations, and the science people almost universally agreed that manned flight was not about science, it was entirely political, and even military.

Early plans to send astronauts to Mars were based on similar thinking to Apollo. Apollo sends some astronauts to the Moon along with all of the consumables and propellants they'll need for the mission. Two astronauts land on the surface, but with limited consumables and surface mobility, they can't stay long or get much exploration done.

The traditional plan to go to Mars does things the same way. You send a huge spaceship (dubbed Battlestar Galactica by critics) that hauls all of the propellants and consumables needed for the mission from Earth. Once you get to Mars, you send down some crew members in a lander to do a short "flags and footprints" visit to the surface. The landing party have limited consumables and surface mobility, so they can't stay long or get much actual exploration done. To avoid having to wait around for the next return window to open up, the mothership is sent on a high deltaV trajectory to get a gravity assist from Venus to get back to Earth.

The mothership is far too big to launch from Earth, so it has to be assembled on orbit at massive and insanely expensive shipyard facilities in Low Earth Orbit and/or the vicinity of the Moon. This is handy if you want to justify a space station and/or Moon base programme, as these are considered mission critical to get to Mars. It's also handy if you want to justify massive spending on zero gravity medical research, advanced propulsion systems development, and so on. Of course, it's not a lot of use if you plan on actually exploring Mars, because the mission doesn't do very much of that. You'd be far better off sending probes instead.

Since the Apollo missions flew, NASAs crewed spaceflight programme has been kept ticking over in idle mode. The Space Shuttle programme was created to give the astronauts something to do. When it became apparent that the cost of launching satellites via the shuttle was vastly more expensive than launching them on expendables, the shuttle was left without a clear role. Space Station Freedom was therefore conceived to give the Shuttle something to do. With the collapse of the Soviet Union, the Russian space agency also needed to be given something to do to keep them from heading off to build missiles for whoever. Henceforth, Space Station Freedom became the ISS, which was deliberately designed to require the most complex on orbit assembly possible, therefore helping to keep the Shuttle occupied for as long as possible. With the station built, the astronauts can literally go around in circles while doing research on the already well understood effects of radiation and zero gravity on themselves. Meanwhile, hardware orphaned from the cancelled Constellation Programme continues to be very slowly developed in case any of it comes in handy later on.

Modern thinking about human space exploration revolves around In Situ Resource Utilisation (ISRU). Most of the propellants and consumables needed for the mission are produced from local resources. This greatly reduces the size and expense of the spacecraft used to get there. In this regard, Mars has a huge advantage over Earth's resource poor Moon. Precursor missions are sent out to establish the best location for a permanent base. All later flights land at the base, which acts as a jumping off point for expeditions to explore the planet on a global scale. The base soon develops into a settlement. A very good example of how this approach would be used is Robert Zubrin's

mission plan.

[Pthigrivi]

For me, if life support is to be meaningful, it needs to have consequences. Specifically, death, rather than how the snacks mod uses reputational damage.

I think this could pretty easily be resolved with a check box in the difficulty menu. There is the grisly question though of what happens to kerbals who die in capsules... can they be extracted or is the module just dead? Either way, I'd still argue for the Hibernation option for default normal difficulty. I think it poses stiff consequences (you could add the reputation hit and the loss of all experience levels a Tristan suggested) while still offering the possibility of rescue and salvage. There's a lot of gameplay there I think, going out to a module of dormant kerbals and waking them up and bringing them home.

What advantage is there, to sending a kerballed mission somewhere, as opposed to a robotic mission ?

Irrespective of the real life question (which is super interesting), inevitably the implementation of life support is going to impose big weight and cost burdens to kerballed vs non-kerballed missions. I think the advantage to still doing it will become more apparent as they flush out higher level kerbal skills. If for instance you needed kerbals to do an impactor experiment or run a resource processor the advantage would be much more obvious. Its also a reason I think tying experience loss to failing to support kerbals makes sense, as in the future this will be the real reason you have them.

Whatever system is used it should be possible to re-supply and store a large amount of life support. Regenerative systems would be good later in the tech tree, as well as creation from resources. Life support systems should consume the most electricity a space vehicle uses.

The big question is how much life support by weight would a Kerbal consume per day? Humans consume around 6-10kg per day. Should a ton of LS support a Kerbal for 100 days (without regen tech)?

I totally agree. I'd been working with 1kg/day as I was thinking it through, but there could be more nuance to this. It seems enough to be considerable over the long haul without being a burden for short flights. To keep things simple and parts count down I thought Life Support could simply be a state that habitable modules have, a slider from green to red. The weight could be considered already factored in to the weight of the existing modules. As Torquemadus suggested different modules could have a larger supply or support kerbals more efficiently. It would have to be easy to understand, I think it could literally be measured in days. What matters I think is the minimum rate of loss even with scrubbers. This will control the need for collecting resources in situ. Imagining that Roverdude is well along in making a single fuel resource system, lets assume there would be a single life support resource, and it could be drilled and processed with the same basic equipment. This resource will have its own tanks, (I happen to like H20 for this, as it could be refined into potable water, LF and O2.) This resource would be consumed by covering life support losses and by greenhouses to make Snacks.

H20 -

Life support > Without scrubbers, H20 is consumed by Life Support at .002t/day. With scrubbers, it is consumed at .0001t/day, 1/20th that rate.

Snacks > Snacks are consumed at a rate of .001t/day. Using a Greenhouse, Snacks can be replenished consuming water at a rate of .0001t/day, 1/10 that rate.

This would mean that a backup tank of water would be consumed by a facility equipped with adequate scrubbers and a fully functioning greenhouse at .0002t/day. For flights even to Minmus, scrubbers are a no-brainer, but the break even by weight for a greenhouse would be 900 days for 1 Kerbal, 300 days for 3 kerbals, and 100 days for 6 kerbals.

Does anyone have a nice list of one-way and round trip flight times factoring ideal transfer windows to each body?

My personal opinion is that there would be a single harvestable resource (water ice) that could be refined into both life support and LF/O, but would require a catalyst that weighed 1/50th what it produced in fuel but cost 5x as much by weight to refine. This would not only help sync up the break-evens, but would make the whole process of resource extraction easy to understand and challenging enough to force trade offs.

Edited February 10, 2015 by Pthigrivi

[Daze]

I totally LOVE the idea of OP, i really hope Squad will look for a similar solution.

[Tw1]

I think it can be further simplified. Living things need a certain amount of Food, water and air per day- these could all be rolled into one life support resource. Having scrubber units separate from pods does not seem logical, it will just add to the part count. Instead, consider them part of a pod. Air scrubbers, toilet, climate control and food prep systems, can all be abstracted by adding an electrical demand when a kerbal is inside.

Using scrubbers as the life support recycling also seems odd. Instead, some larger unit would make more sense, and provide more balance- there should be a zone where it may or may not make more sense to just bring a little more Life support, rather than always dragging around the recycler. A life support recycling plant would be big, more suited to motherships, bases, etc.

I seems to me the easiest way to implement "Recycling" would be as something that simply reduces the rate of use per kerbal. Otherwise, a waste resource is needed. Magic generation of new life support from nothing should be avoided, even with several recycler/greenhouses it should still be possible to run out of life support. The only way to permanently exist away from Kerbin should be ISRU.

Happiness is an interesting concept, but it doesn't consider that there are introverted people who have traveled the world solo, spending months alone, yet being fine. A character in my Oceans of Eve story was sort of inspired by one of these.

Some kerbals would be introverted enough to be satisfied with only remote communication.

Personally, being stuck with another person who I didn't find completely awesome, doesn't sound like something that would add to my happiness.

I think if some happiness mechanism was to be implemented, basing it around the available space in the ship would be better. Everyone likes to move around, and introverts like me need somewhere to get away to.

I made this diagram for a previous debate, but it still provides a good overview of my thoughts on life support. Which, apart from the above mentioned details, doesn't seem too far off things being discussed in this thread.

Also, I'd let suits have a few hours worth of life support, to allow for some orbital EVA shenanigans. Those can be fun.

The traditional plan to go to Mars does things the same way. You send a huge spaceship (dubbed Battlestar Galactica by critics) that hauls all of the propellants and consumables needed for the mission from Earth. Once you get to Mars, you send down some crew members in a lander to do a short "flags and footprints" visit to the surface. The landing party have limited consumables and surface mobility, so they can't stay long or get much actual exploration done. To avoid having to wait around for the next return window to open up, the mothership is sent on a high deltaV trajectory to get a gravity assist from Venus to get back to Earth.

These plans have always struck me as wasteful and dumb. If you're going to spend months to get somewhere, the time spent there should be enough to make it worth it.

This basic apollo style thinking is has been a problem in KSP's development. The science system is currently build around quick visits- get in, do the science, get out.

But in KSP you can to things real life space programs don't have the resources to, like set up bases, and send larger, more elaborate missions. But there's only a few minutes worth of science to do. But this is getting off topic.

Edited February 10, 2015 by Tw1

[Sirrobert]

H20 -

Life support > Without scrubbers, H20 is consumed by Life Support at .002t/day. With scrubbers, it is consumed at .0001t/day, 1/20th that rate.

Snacks > Snacks are consumed at a rate of .001t/day. Using a Greenhouse, Snacks can be replenished consuming water at a rate of .0001t/day, 1/10 that rate.

This would mean that a backup tank of water would be consumed by a facility equipped with adequate scrubbers and a fully functioning greenhouse at .0002t/day. For flights even to Minmus, scrubbers are a no-brainer, but the break even by weight for a greenhouse would be 900 days for 1 Kerbal, 300 days for 3 kerbals, and 100 days for 6 kerbals.

Does anyone have a nice list of one-way and round trip flight times factoring ideal transfer windows to each body?

My personal opinion is that there would be a single harvestable resource (water ice) that could be refined into both life support and LF/O, but would require a catalyst that weighed 1/50th what it produced in fuel but cost 5x as much by weight to refine. This would not only help sync up the break-evens, but would make the whole process of resource extraction easy to understand and challenging enough to force trade offs.

No, if you're going to make it that complicated you'll go right back to the old, shelved resource system with 10 different resources, and 20 ways to mine and refine them. It needs to be simple. Mods can add complexity to it, but the base system needs to be simple.

It needs to be possible to make an entirely closed loop system for Kerbals to live on, at a large cost in electricity and weight. Something that might be to heavy to just bring along on missions to planets, but would allow for permanent independant crafts (station and ground base). It needs to still be possible, if difficult, to leave a station on LKO, timewarp to Elloo, and have the station still be active

[Pthigrivi]

I like it! You could be right about separating snacks from air and water, it adds a lot of complication. I could definitely see a system where it was simply "life support", with backup tanks that could extend it. These tanks could also be refilled using ISRU or with greenhouses. The trade off would be very simple in this instance, just the weight of carting supplies vs the weight of carting drill rigs and or greenhouses. Scrubbers could be added, though not necessarily, as a part that would extend how long life support lasted, but would top out at maybe 75%.

I thought about space as an option, but I do think its important that the thing that makes kerbals happy is other kerbals. This is generally true of humans as well. How social a kerbal is and how fast his or her happiness depletes could even be a product of their "courage" stat. I did also add a training module part that could restore a kerbals happiness without returning to Kerbin. It would be heavy, but maybe worth it on very long journeys.

[Capt Snuggler]

I'm all for making manned missions harder (heavier). Probes will finally have a proper role to play in exploration and mission planning.

Mission planning as a whole needs some love. I know we can get our note pads and calculators out and just do it but it would be good to have some intuitive polished mission planning tools available, at least for leaving Kerbin orbit.

I would think its reasonable that a Mk1-2 would have enough life support built in to get to the Mun and back + some mission time. This allows for initial manned exploration so a player can get a taste for manned interplanetary return missions.

I think to get beyond Kerbin orbit should require specialist life support extension equipment (scrubbers and reclaimers) as well as additional life support tanks.

For ease of use I would be content with life support resource being measured in "Mission Days". Add another Kerbal to the crew and you will see an overall reduction in mission days (faster consumption of LS). Bolt on a scrubber, reclaimer or green house to multiply the mission days. (these parts slowdown the consumption of life support resources)

green houses could have the additional ability to convert mined resources + waste + electric charge in to life support.

waste could also be vented to reduce mass.

In short:

life support measured in "mission days"

more kerbals speed up consumption of LS

more scrubbers/reclaimers when turned on slow down the consumption of LS

green house slows down LS consumption and also allows conversion of waste + unknown mined resource + electric charge = life support.

Edited February 10, 2015 by Capt Snuggler

[Louella]

I think, that a system with no more than 2 consumable resources would be best.

Like, managing food, water and air, when you need all 3 anyway, just adds parts with not much gain for it.

I say 2 resources, because of some alleged quirks of Kerbal biology. I've read things suggesting that Kerbals are some kind of amphibian, but I don't know how official that is.

But anyway, amphibians hibernate.

So that gives an opportunity for 2 resources. Air, and nutrients (food&water). Hibernating kerbals would still consume air (but at a reduced rate), but not nutrients. Hibernating kerbals obviously couldn't control the spacecraft. Kerbals could hibernate, to conserve resources, allowing a bigger window for a rescue mission. Active kerbals consume more air and consume nutrients, but can fly the spacecraft, and do other activities.

Still need to consider what kind of window for rescue there should be.

Because of such things as transfer windows, say a mission to Duna. It launches at the ideal window, but by the time it lands and falls over on landing, requiring a rescue ship, then Kerbin has moved and is no longer in the ideal window.

So, basically, if the rescue ship, isn't already at Duna, then the crew is in a really awkward spot, aren't they ?

So, need to decide between:

1. A single mistake or failure, everyone dies, no rescue ship that isn't already there would make it.

2. There is a window for rescue, which might be extended by hibernating, but only so far.

3. As long as the landing isn't fatal, the Kerbals can wait to be rescued indefinitely.

Real world is 1. Where things are currently in stock is 3. Where do we want the game to be ?

Also need to consider what the game is supposed to be about. Just exploring, or establishing a permanent presence, that sort of thing.

With a goal of establishing a permanent presence, then a more detailed system could be worked out, with things like orbital greenhouses, transferring wastewater to the greenhouse and receiving freshwater and food, and much more.

With just exploring, then a more simple system of "life support" as an abstract resource is all that is needed, which simplifies the process of understanding for newer players.

[Pthigrivi]

Yeah 2 resources was my intuition as well, but especially when you start trying to make greenhouses and ISRU work things seemed to get really needlessly complicated. After thinking about it today I really do think just one "Life support" resource is the best move, especially since failing to understand it means either killing your kerbals or losing their experience. Especially if it was measured in "days", you could very easily see just how long your vessel had, and make some educated guesses by comparing that to maneuver projections. After all, it doesn't much matter if you run out of food or run out of air, if it kills you it kills you. The fun should come from problem-solving, not from needless juggling of overcomplicated systems.

First I did some research. These are my best guess at one way and round trip missions to each planet factoring ideal to and return transfer windows. If any of these numbers seems way off let me know.

Mun - One way: 1.25d, Round Trip: 2.5d

Minmus - One way: 9.25d, Round Trip:18.5d

Asteroid Missions - Round Trip, 25d - 215d

Moho - One way: 110d, Round trip: 310d

Eve - One way: 165d, Round trip: 890d

Duna - One way: 300d, Round trip: 1170d

Dres - One way: 555d, Round trip: 1290d

Jool - One way: 1050d, Round trip: 2530d

Eeloo - One way: 1560d, Round trip: 3320d

These will serve as a kind of balance metric. My thinking is to help beginners get used to the idea life support isn’t something you should have to worry about for a Mun mission, but maybe you have to start when going to Minmus, and certainly before going interplanetary. So let me try this again:

Life Support - Measured in "days" and slowly slides from green to red based on the number of kerbals on board. Different crew capsules could have different loads, but lets assume each starts with 3 days worth for each available seat. There are however 3 ways to extend this:

Life Support Tanks - Generally these are sized so that each kerbal consumes 4kg per day by default. Visually they could be designed to look like they hold air, water, and snacks. Tanks don’t empty, they slide from green to red as they become waste. Life support/waste can be pumped from one tank to another, at which point players could easily jettison waste tanks if they desired.

Small Life Support Tank - (.625m inline and spherical RCS size radial)

- 0.125t

- 160f

- Supports 1 Kerbal for 24 additional days (necessary for Minmus, but not Mun missions)

Medium Life Support Tank - (1.25m inline and large RCS size radial)

- 1.5t

- 2400f

- Supports 1 Kerbal for 360d, or 3 kerbals for 120d etc.

Large Life Support Tank – (2.5m Inline)

- 7.4t

- 12000f

- Supports 1 Kerbal for 1800d, or 3 Kerbals for 600d, or 6 Kerbals for 300d etc.

Scrubbers – These basically increase life support efficiency at the cost of weight and power. They will probably be essential for interplanetary missions. Because their reductions are across the board, the more kerbals using one the more cost effective it is. However, adding additional like scrubbers will not reduce consumption past the first.

Waste-o-matic Jr. – (1.25m low-profile inline)

- 0.6t

- 1200f

- Draws 0.5e/s

- Kerbals on-board consume life support at 50% their normal rate (worth it for 1 Kerbal after 150d, and 3 kerbals after 50d)

Waste-o-matic Sr. – (1.25m materials bay size unit)

- 1.2t

- 3200f

- Draws 2e/s

- Kerbals on-board consume life support at 25% their normal rate (worth it for 1 Kerbal after 300d, 3 Kerbals after 100d, and 6 Kerbals after 50d)

Greenhouses – Greenhouses use energy to convert waste into usable life support. When facing sunlight they provide some of their own power and are balanced based on average daily life support output, meaning these numbers would hold at Kerbin but more power would be needed farther from Kerbol. Greenhouses can be set to continual production, stand-down mode, or daylight auto-switching, but if left without power they become defunct and will no longer produce life support.

Hydroponics Bay – (2.5m science lab size cylander, rotates to face kerbol)

- 3t

- 6000f

- Draws 2e/s when not operating, and 6e/s when producing

- Replenishes life support equal to 3 kerbals’ consumption every 6 hours while in operation (worth it for 3 kerbals after 300d in Kerbol or polar orbit, and 600d when not)

Large Greenhouse – (3.75m dome)

- 4.5t

- 9000f

- Draws 3e/s when not operating, and 9e/s when producing

- Replenishes life support equal to 6 kerbal’s consumption. (Worth it for 6 kerbals after 275d Kerbol or polar orbit, and 550 when not)

All of these factors should be calculated by the game, giving a single "Remaining Life Support" number in days both in the VAB and in the vessel resources bar in flight. This way you could play around in the VAB swapping out different parts and watch the days remaining rise and fall and aid your decision making. I think until you get to greenhouses things are intuitive enough for a new player to navigate them, while still offering some fun challenges to veterans who want to optimise off-world farming. Not knowing what the resources paradigm is its hard for me to say how ISRU would fit in, but I imagine life support could be directly filled by drilling a life-support resource. Depending on the weight of the rig this could lead to some interesting trade-offs and synergies between greenhouses and ISRU strategies. We'll almost certainly be needing a larger reactor in the future, but another interesting strategy might be powering greenhouses by drilling fuel nearby and running it through a fuel cell.

Edited March 28, 2016 by Pthigrivi

[Torquemadus]

KSP, in it's current 0.90 form, encourages us to send Kerbals on "Apollo Style" missions, which haul all of the propellants they need for the return trip from Kerbin. Since we don't have to deal with life support consumables, we also don't have to worry about what our Kerbals breathe, drink, or eat, on these long-duration missions. We don't have to produce electrical power to run life support systems and heating. We also don't have to provide the crew with a bathroom!

Life support may seem like a rather dull exercise in logistics, until you start to think about the bearing it has on abort options.

Currently, these are two kinds of abort. The first is caused by running our of fuel. The second is caused by accidentally damaging the ship, usually during landing. These require that the crew await rescue, either on the surface, or stranded in orbit somewhere. Depending on launch windows, this could possibly take years.

Introducing life support provides numerous additional ways for the crew to die. Fortunately, ISRU is on hand to provide them with numerous additional ways to survive!

We don't know exactly how ISRU and resources will work yet, but it should offer ways to abort to a safe haven. Even if the crew can't get home, they might still be able to tough it out at an outpost for a long time if it can be kept resupplied.

[Capt Snuggler]

Yeah 2 resources was my intuition as well, but especially when you start trying to make greenhouses and ISRU work things seemed to get really needlessly complica...*snip*

You pretty much nailed it. good post dude.

I think if you really wanted to add another resource to the mix in addition to LS, my vote would be for fatigue. Kerbals should get tired and take naps. it would give you a reason to send multiple kerbals and include rovers in your missions (right now there is little to no reason to do this.)

I posted a thread about it some time ago and while I agree there are some issues that need to be worked out, I still think the idea has merit.

one issue people pointed out was having to micro manage crew rotation and duties - it would get tiresome. but I think it could be solved with a crew schedule or work rotor (per ship) similar to how it works in prison architect. kerbals would move around performing their duties on board (like tending to green houses) autonomously. the player can still interrupt and take control at any time to perform EVAs or perform maneuvers.

anyway single resource life support, as you describe it, is sounding pretty good.

now hopefully stock ISRU doesn't just consist of plugging your ship in to the ground and filling your tanks...

Edited February 11, 2015 by Capt Snuggler

[Sirrobert]

Yeah 2 resources was my intuition as well, but especially when you start trying to make greenhouses and ISRU work things seemed to get really needlessly complicated.

I love it. Very well thought out

[Torquemadus]

My opinion is that life support should be fitted around ISRU and the "live off the land" strategies it allows. It should avoid (at least for now) simulating approaches that are better suited to permanent basing efforts further into the future, such as bioregenerative life support.

Bioregenerative life support uses life forms such as plants and bacteria to recycle air and water. Some versions also attempt to recycle human waste into food. According to the articles I've read on these methods, such systems are turning out to be quite complex and unreliable. Also, producing food that is actually edible (and doesn't taste like the **** it has, in fact, been fertilised with) has proven to be problematic!

Current near term mission planning for human spaceflight calls for the use of robust physical-chemical systems that take advantage of locally available resources where available. The resources that can be used depend on where you are:-

On Earth's (resource poor) Moon, you can get oxygen out of the rocks by crushing, screening, and melting them at high temperatures. The hardware needed to do this is quite heavy duty and power hungry in nature, but the methods required are well understood. This gives you oxidiser (but not fuel) and breathing oxygen. Water exists in extremely cold permanently shadowed craters at the poles, but the probes that detected it were not able to determine whether this was in the form of concentrated pure ice deposits, or in less accessible forms such as (rock hard) permafrost. Probes that can settle this issue through active sensing methods, such as ground penetrating radar, have been proposed, but not yet flown. Depending on what form the water is in, it may be very difficult to extract. Many of the resources needed to run industries to meet basic human needs are unavailable on the Moon and will have to be imported (at potentially prohibitive cost).

Lunar regolith contains trace amounts of Helium 3, which is needed to run clean burning fusion reactors. Fusion reactors currently under development burn hydrogen isotopes in the form of deuterium and tritium. Deuterium is present in moderate amounts in seawater on Earth, and is available in much greater percentages on Mars, making it a potentially lucrative export resource. Tritium is radioactive and needs to be made through nuclear transmutation in a breeder reactor. A deuterium-tritium reactor emits much of it's energy as neutrons (much as a fission reactor does), which means that they can also be used in conjunction with a breeder blanket to produce tritium. Neutron emissions from such reactors will eventually cause the reactor lining to become radioactive, which will eventually require that it be replaced. This means that early generation fusion reactors will still produce low grade nuclear waste (still a huge improvement over high grade waste from fission reactors). Burning helium3 with deuterium produces an (almost) completely clean reaction that produces (mostly) protons instead of neutrons. This makes it much easier to produce electricity from them, greatly increasing the amount of power that can be produced from a given amount of fuel, and greatly reduces the amount of low grade waste produced. Helium3 is worth orders of magnitude more than it's weight in gold at current pre-fusion prices. Russia and China have declared their plans to go after Lunar Helium3 in the near future. Helium3 mining falls outside the scope of KSP, but players should be aware of it's existence. Helium3 is extremely abundant in the outer solar system (sufficient to provide humanity with unlimited energy from now until the Sun dies) and has sufficient enthalpy for starship propulsion!

The composition of asteroids varies considerably. Some are literally worth their (trillions of tonnes) weight in gold due to their precious and semi precious metal content, but lack ISRU resources. Some are the other way around. Some offer a mix of both! There are lots of "spent" comets wandering the inner solar system that have plentiful water and other volatiles beneath their surface, buried beneath other materials that shield them from the Sun.

Mars is essentially a frozen (and somewhat smaller) second Earth! In the shorter term, it has a carbon dioxide atmosphere that can be used to produce oxygen and carbon monoxide, which can be used as a low grade rocket fuel. If you can obtain or bring some hydrogen as feedstock, you can make methane, which is a much better quality rocket fuel that can get you back to Earth. Carbon dioxide can also be pumped and liquefied to use as moderate performance propellant for nuclear rockets. Water is obtainable as water ice (at high latitudes), permafrost (bring some dynamite), subsurface brines, or geothermally heated (enough to power a base) subsurface water (which is also a good place to look for extremophiles). Mars is also the only other place in the Solar System where you can perform large scale greenhouse agriculture using natural sunlight. Using natural sunlight for agriculture doesn't sound like a big deal, until you find out how power intensive it is to produce enough food to feed a single human with artificial sunlight! The elements needed to produce fertiliser are also easily obtainable.

In the longer term, Mars has all of the resources needed to support a major branch of industrialised human civilisation. Due to the deltaV requirements to get from Mars to other places in the inner solar system, Mars will have a huge part to play exporting food and manufactures to places where launch costs from Earth are prohibitive.

What, then, should we use to model life support requirements in KSP? We need to separate short term "travel light and live off the land" ISRU from longer term economic development of the Kerbin system. In the long term, people who play KSP need to be made aware that economic development in space is achievable, affordable, and desirable in the long-term. However, it's also important to avoid creating confusion between what can be done in the near-term and what will follow thereafter. It's important that players are not confused into thinking that ISRU is a far future approach that can't be used in the near-term.

[Sirrobert]

Let's focus on making the whole thing fun to play before linking it to real life developments

[Tw1]

Scrubbers – These basically increase life support efficiency at the cost of weight and power.

-snip-

Greenhouses – Greenhouses use energy to convert waste into usable life support. When facing sunlight they provide some of their own power and are balanced based on

Definietlly agree with everyone that the best way would be one unit of L.S. supports one kerbal for one day.

But I still don't think having separate greenhouses and scrubbers makes sense. In my experience with life support mods, very good recyclers make it quite easy, and reduce the role ISRU has to play.

Setting up an ISRU based life support supply system would be a great "natural"* goal that could emerge in the game.

*by natural, I mean it emerges out of need, not because the game tells you to do it.

One thing that must not be forgotten, 50% does not just double the time it takes. You'll recover 50% of the original supply, then 25% of what you recovered, then 12.5% of that....

Recyclers must be balanced carefully.

[Alias72]

Here's a suggestion!

as was mentioned there would be a crew consumables resource. There would also be a life support module. The life support module would convert electricity and crew consumables into time for your Kerbals to not die. Newer life support modules use more electricity and less consumables to simulate the switch from open loop to closed loop systems. Everything else would be behind a "black box". Essentially all you're doing is converting Electricity and Crew Consumables into Crew endurance which Kerbals use as they go. This would also provide a framework for EVA suit endurance as it would only be able to store a certain amount of "endurance". say 1 days worth.

[Pthigrivi]

Thanks guys You and Tw1 convinced me. I hear what you're saying about the scrubbers, I'm just trying to give some simple options so players have a to make hard choices.

Life support may seem like a rather dull exercise in logistics, until you start to think about the bearing it has on abort options.

I totally agree. Some of the most interesting things happen when things go wrong and I have to scramble to salvage. This was also sort of the impetus for hibernating kerbals. There would be consequences for failure, but still the possibility of rescue. I also agree on how important ISRU should be for this, but without knowing more about what RoverDude has cooked up for us its hard for me to think about integration.

I think if you really wanted to add another resource to the mix in addition to LS, my vote would be for fatigue. Kerbals should get tired and take naps. it would give you a reason to send multiple kerbals and include rovers in your missions (right now there is little to no reason to do this.)

Yeah I like it man. This is sort of where I was going with "happiness". I'm thinking now though since life support is so consequence heavy it might be nice if the mental component was a reward system. Maybe:

Happiness - Kerbals leave the launchpad with 100% happiness. After that, a lone Kerbal will deplete at 1% per day, meaning they will reach zero in 100 days. For each additional Kerbal on board, Happiness depletes at half the rate, meaning 2 Kerbals will be happy for 200 days, 3 Kerbals will be happy for 400 days, 4 Kerbals 800 days etc. At the time of reaching a goal Experience pays out at 50% for unhappy Kerbals and 200% for Kerbals at 100% happiness. The whole experience system needs some major work, and obviously if this was part of it everything would have to be balanced around it to make interplanetary missions more rewarding.

Aside from bringing extra Kerbals, Happiness can be extended with the following modules (Percentages stack with multi-kerbal bonuses, but not with other module bonuses)

Small Living Quarters - 2.5m cylinder

- 2t

- 4200F

- draws 1e/s

- Reduces happiness depletion for up to 3 kerbals by 75%

Large Living Quarters: 3.75m cylinder

- 5t

- 6800F

- draws 3 e/s

- Reduces happiness depletion for up to 9 Kerbals by 75%

Training Module - (inline Dodecahedron approx 3.75m)

- 5.5t

- 9500F

- draws 2 e/s while dormant and 12 e/s while operating

- Replenishes Kerbals' Happiness up to 90% and allows level-up without returning to Kerbin

So 3 Kerbals with a small living quarters will arrive at Duna at 75% Happiness, and 6 Kerbals with 2 small or one large quarters will arrive at 97%. You could of course just bring a training module, but it would come at a steep cost. I guess this is a lot of modelling to request haha, but with about 12 new parts I think there's the bones of a real-feeling colonization platform.

Edited February 12, 2015 by Pthigrivi

[Invader Myk]

Happiness: I think this could be an important part of encouraging multiple kerbal missions. Basically lone Kerbals would slowly grow unhappy over the course of weeks or years

This is an amazing idea, even for stock.

Is there a mod that does this already?

As far as the general life-support being stock, I agree with the standard dev answer of not in the core game.

I like how the various life support mods add variety to the game ranging from none (stock), simple (SNACKS), and complex (TAC-LS and that other one).

I do not like the idea of hibernation because it removes a difficulty dimension that has to be deliberately added.

[Sirrobert]

One thing that must not be forgotten, 50% does not just double the time it takes. You'll recover 50% of the original supply, then 25% of what you recovered, then 12.5% of that....

Recyclers must be balanced carefully.

What do you mean with that?

Like you recover when you return, thus get more cash back? I doubt supplies would be that expencive, so it wouldn't matter

[Pthigrivi]

I think what he means is if the scrubbers continuously preserve 50% of what's left you end up in that log curve. My rule on them was was simplified to say that Kerbals themselves use life support at half the rate with it attached and running. It may not be realistic but I think it should be simple and predictable enough that players could see in the VAB what the trade-offs were.