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LS would be particularly important for warships... letting all the air out is generally unhealthy. Minus LS, they might as well be drones.

So far we have what, the HST repair/service? They flew 5 such missions. I think it is fair in this situation to look at total costs for a shuttle launch, which is like the figure in the video above. 5 service missions, plus one for delivery results in nearly 9 B$ in Shuttle costs alone. The instrument was what, about 1.2B$? That's 10.2 B$, total. The HST was ~11 mt, so We had 3 possible non-shuttle launch systems, Titan IIID (used for the very related Keyholes), Atlas V, or Delta IV M. All would have been cheaper than a Shuttle launch. So ~1.7 B$ to build and launch. Broken? Launch a newer one. 10.2/1.7 = 6 new HSTs. Literally a new HST delivered to orbit for every single HST related Shuttle flight. I have a scheduled maintenance coming up on my Rover...I'll be rather miffed if the service bill is 80 grand.

Station was "make-work" for Shuttle to keep the launch cadence up. Nothing Shuttle did could not have been done better or cheaper (or both) by other technologies. Station would have been built in fewer loads, with another HLV---Shuttle was itself an HLV that wasted most all the payload to LEO on the Orbiter vehicle itself. Faction in the cost of Shuttle, even replacing the HST with a new one would have been cost-effective vs the too high cost of launch via shuttle, plus the repair mission. It was a colossal waste of resources, IMO. I said the same thing back when it first flew, as did many space nuts I knew. For this to matter the first step is to demonstrate that repairing something is cost-effective vs launching a replacement.

I'd not go so far as the bolded bit. What it adds is a time limit given the amount of mass you have added. KSP being KSP, the player is given limited information, so in terms of a stock implementation, you have to operate under the assumption of no KER or MJ to give you dv information, and in fact that trip duration will be sort of trial and error. The player can always stretch a maneuver node to the target world, and have some idea of 1-way trip time, but what will the return look like? As a result, they'd be prudent to send stuff ahead, just in case. If you do see that you've not planned well, you need to think about a resupply that is perhaps not the most efficient... In short, it adds all kinds of novel missions (planned and unplanned) into gameplay, so I don't agree it adds nothing. My only reason for wanting habitation in there somehow, even if it's as simple as placing the best LS equipment in "hab" parts, is to avoid the single mk1 capsule being a thing.

I've experimented with some insane craft in sandbox akin to those @JoseEduardo has posted (like some of the 1970s VSSTOL concepts Boeing worked on). One part I find myself using for different things is the petal fairing. I assume that it must not have a full closure option for a coding reason, right? Seems like a toggle for it to be an interstage or a full fairing would be sort of cool. The deployed petals might have some utility as added surface area for propulsive EDL...

I used a tank, a fairing, and the M1 engines. Honestly cannot remember which tank. Also, getting the fairings to properly separate was difficult. They'd deploy, but the force seems designed for sane rockets . If anything even bumped them, BOOM. Perhaps force should scale with size?

José, I was messing with this add-on this morning (trying for a SSTO in k64 ), and Eventually I got an unresponsive VAB, and it the log has a bunch of null refs. One example: [EXC 10:40:32.769] NullReferenceException: Object reference not set to an instance of an object EditorLogic.<SetupFSM>m__E7 () KerbalFSM.UpdateFSM () EditorLogic.Update () I got several others. I just removed SNAoP, and got no nullrefs. I can try again later (have a bunch of family stuff the rest of the day).

From a gameplay POV, I think that LS adds mass, and a time limit as a function of that mass. Habitation is partially subsumed in LS if you make parts like the HH contain enough of the LS gear/supplies (remember that some of LS is machinery that is not consumed). Honestly, for stock with the appropriate tweaking of which parts get what LS functions, habitation can become a non-issue---you'd need a HH for X crew just because that has some of the LS machinery required for long duration missions. Done.

If the stack is 5000t, then it's under 50% cargo (F9 puts about 4% launch mass in LEO)

SpaceX people mentioned large doors... at some point (a few meters) for hauling cargo out. Regardless, the craft itself (MCT) is huge, and must mass more than 10 tons just for its own structure, fittings, LS, etc. They're not claiming 100 mt of cargo landed, they are talking about landing a 100 mt spacecraft on Mars, some of which some is cargo. Basically, as a reality check, MCT is a Shuttle Orbiter (which had a max liftoff weight 109 mt, with a useful cargo load of ~25% of that). If MCT mass is not included in the 100 mt to the surface, the craft itself will mass nearly 100 mt alone... maybe total mass 180? (that's a 4% payload fraction to LEO assuming the 4500 mt guesstimate for the stack total) So 55% cargo.

The Sims reference is absurd WRT habitability. There need be no "micromanaging." It's not subjective, at some level it's objective. There is no way a year long or greater mission happens in a mk1 pod (or cockpit), regardless of LS supplies. Microgravity requires exercise just to deteriorate less quickly (you deteriorate regardless). This is not happiness, or morale, it's physical, just like having improper nutrition or oxygen levels. Kerbals seem roughly analogous to people (and that allows for plenty of slop for gameplay, I'm not seeking to replicate people). So you need a facility like a hitchhiker just for the exercise equipment. You also need recyclers, etc, which take room. For a stock system, that would sort of be the point of the hitchhiker. I would calibrate that from a gameplay POV such that for any long duration mission you need at least one per 4 crew, and if it's a really long mission, maybe that increases to 1 for 2 crew, then 1 per crew. It need not be more complex than that for stock. USILS puts the recyclers in the lab.

They have talked about large doors, but the bulk of the craft is leaving, so it would be supplies. The first one would likely be left on the surface anyway. There is no way 90% is left on Mars. The craft itself is likely at least 30t. In the Mars DRAs, the lander/ascent vehicle is 30t. The transfer vehicle is 30t.

I'm unsure what % actually gets left, honestly. I doubt anything like 90% of the payload is left at Mars. The vehicle itself is the payload.

There are some aspects of "habitation" (which I'm fine with as a term) that are in fact "life support," though. They are related in a complex way. Take a habitat centrifuge as an example. Its a huge quality of life issue, if for no other reason than how the bathrooms would work. It's also a LS issue, since microgravity will wreck people over time, even with a rigorous exercise program, irreversibly in some cases. In the case of a Mars/Duna mission, it can also affect how well people can do their jobs once they arrive---or how long they need to take it easy before they can function normally again.

I usually play career, and on scaled up solar systems, and I always run concurrent missions, and I use LS. I never warp missions to completion from start to finish. I make sure any bases are well supplied, then I might warp to a maneuver node. In fact, with concurrent missions, I find LS actually gives me something to do. I run a few supply missions, rotate crews, then maybe it's time for a mid course correction on longer missions.

My i7 iMac does fine. Airbook certainly is more taxed. My ancient PC needs stuff turned way down (which reminds that I need to build a new gaming rig at some point).

SLS is certainly capable, but it's a capability we don't have a plan for, which makes it a waste. We can certainly use it for large probe missions, but those need to be developed and paid for as well, and only really huge, really expensive missions need SLS. So NASA is stuck with a 2B$ fixed cost, plus marginal launch costs, plus costs to develop and build giant class missions.

Yeah, I disagree with any 100% perfect recovery system on the scale of KSP spacecraft. It's much more plausible for landed facilities (because there are inputs possible short of delivery by other spacecraft). Not long after I started playing I landed Jeb on Duna... as I recall, the craft was not substantially different than a Mun lander, except that it had a parachute or 2 (3?), which allowed it to use almost all the fuel for ascent. So a lone kerbal in a tiny pod for a RT Duna mission. Every expedition since has looked rather more like Mars Direct---even without adding in LS mods. You also cannot forget that everything is connected. LS adds meaningful TIME to KSP.

Well, given that they will be struggling to find work for it, maybe they will invent some.

Completely different landing modality, however. Remember that it's more than just mass, there is also g load to consider. A robot is far more amenable to harsher EDL forces than people are. The reality is that NASA is extremely interested in Red Dragon precisely because they have never landed anything even roughly analogous to landing people, and RD would actually be flying that sort of manned EDL profile.

My style of play is one that embraces the realities of life support. If you don't, then turning it on at all is outside of your style of play. If you think that as long as a being has food/air/etc for 20 years, they'd be fine living alone in the volume of a port-a-potty for that period, then maybe LS isn't your thing at all . (EDIT: I'm using "you" generically, not to mean you in particular) I agree they are certainly different, and something I would prefer split in USILS. Your craft lands on Duna, too far from the pre-landed hab, for example. Your descent vehicle includes supplies for a long period of time, but it's tiny. You could totally survive there for as long as your supplies last. Since KSP gives kerbals nothing at to do, that is functionally the same as the kerbal being a tourist---he's there consuming LS, nothing more, until rescue. Having him die because he's in no more space than a mk1 pod would be silly, IMO. So I think we are in agreement. So I'd like both taken into account, but not treated identically. Lack of LS should equal death. Insufficiently habitable? Not death, but perhaps at an extreme results in the kerbal being ineffective at their job (which now is a tourist as the only option). Another option would be that bad habitation eventually reduces skill levels, then they become tourists. Still meaningless minus something like KAS/KIS where they might do something on EVA. I see habitation as actually the easier to wrap noobs around, but I agree they should be separate. "Easy" might be no LS at all. "Normal" life support (and I'm conflating habitation and LS here, even though I agree they should be separate, but bear with me!) would be along the lines of: "Trips of X to 4X weeks require 1 Hitchhiker (or equiv volume of living space) for every 4 kerbals or they risk becoming ineffective at their jobs" "Trips of greater than 4X weeks require one HH per 2 kerbals (or equiv)." After that time period, they start becoming tourists. Perhaps skill 0 right away, skill 1 after 1 week, and so forth. Done. Super simple "LS" with no supplies to even worry about. "Hard" LS would add in the actual LS supplies with death, plus the habitation stuff.

Dragon 2 is about 6 tons.

Proving it means relaunching one. It;s very likely going to happen soon, but it is not proved, or proved reliable/cost effective until they actually do it a few times. F9 Stage 1s that have landed have never been to orbit. That's a lot more velocity than they have. No, they won't, F9 stage 1 is not an orbital craft. Hardly fast, but certainly relatively fast. Until it exists it's not proven. Theoretical and mature enough to use for people are 2 different things. Red Dragon will be the first largeish payload to Mars ever. We will not know until they do it. Possibly after multiple tries.

What will they fly on it? You're talking about SLS sized payloads. They have SLS, and fallacy or not, they will consider "sunk cost." Not to mention the jobs program aspect. SLS is alreay in a situation where there are not enough payloads, and the marginal cost of launch is only really a thing if they launch at some reasonable rate, otherwise it's bet to look at total cost. Could SLS get cancelled? Sure, but it won't happen very quickly, or without a fight, as many people are employed in SLS related work, and they are intentionally in as many districts as possible. It;s like military base closures. The Pentagon has wanted most bases closed for as long as I can remember, but every time one is suggested, it becomes "critical" to national security as far as that State and it's representatives are concerned. The same will be true of swapping BFR for SLS.

@ShotgunNinja, I agree, ideally habitation would have the end result tend towards tourism (astronauts become tourists), with LS failure meaning death (which I always turn on in a LS mod if it's an option). That would be a nice thing to see in USILS (as least as a configurable thing). Anyone here listen to the Space Rocket History Podcast? A few episodes ago was Apollo 8. Borman became ill not long after launch---a GI illness. Spewing from both ends. They had no LEM, so it was 3 guys in a volume not dissimilar from a small SUV for days that was also effectively an outhouse. The diver that was there when the hatch opened after splashdown apparently reeled backwards, and the strongest asked if it was because they looked so bad, and he said, "no, it's the smell!" Quality of life matters .