camacju

There's a change log somewhere on the KSP wiki

I got the main launch down to 76942 funds: And the resupplies down to 24830 funds: Three Duna missions now cost 126.6k or 42.2k per mission

Ok, here's my attempt at a no-mining architecture: VAB, launch Journey to Duna Return trip Second mission's rocket Sustainability calculation: 6400 liquid fuel at launch 6300 in LKO Journey to Duna and back costs just under 1600 liquid fuel Each resupply mission (new command pods and habitat) brings 500 liquid fuel After four resupply missions, 2k liquid fuel left - so this setup will last for five missions in total before a new dedicated fuel tanker needs to be launched Three missions will cost 141718 funds or about 47.2k each - five missions will cost 197576 funds or about 39.5k each. For only three or four missions however, the resupplies wouldn't need to bring fuel up. Cost with mining for three missions vs no mining: Resupply missions would have identical cost since I wouldn't need to bring fuel in either case. Only reason I have extra fuel is because I didn't optimize the rocket well. So this basically boils down to, how much funds can I save by ditching the Rossum fuel tanker and replacing it with a mining module? The launcher could be smaller, but definitely not 20K funds smaller, so mining will probably be more expensive up to 5 missions, beyond which I'd have to use a dedicated refueling launch. I think mining would break even at the sixth mission and definitely be cheaper for 7+ missions. Later today I'll try to optimize the fuel tanker and launchers for only three Duna missions. I could probably shave off a good bit of cost

Ok, the RTG is about half as expensive as I thought it was for some reason. Yeah that seems like the best option. Still though, 25k funds is probably enough to just launch all the required stuff for another couple missions. I'll do a non-mining submission just to see how low I can do three Duna missions however

Does your design use the large mining equipment? If so, then I think 42k funds is basically a low bound on a mobile mining rig. If you're using bipropellant rockets for everything, I could see a payback occurring after fewer than three missions, but my design uses about 2000 liquid fuel per Duna mission and launching 5000 more liquid fuel to LKO costs a lot less than 42k funds.

This idea isn't that crazy actually. Since you disallowed solar panels on the mining rig, that means that either RTGs or fuel cells must be used as power generation. RTGs are extremely expensive so fuel cells must be used to optimize cost. The small Convert-o-tron and drill-o-matic aren't efficient enough to make a net profit from fuel cells, so the large ones must be used. The large convert-o-tron consumes 30 electric charge per second and each large drill-o-matic consumes 22.5 electric charge per second. This means that three fuel cell arrays are required. The mining rig also will need rover wheels, and the medium rover wheels aren't large enough to drive around a 2.5 meter rover without some offsetting, so large wheels are required. The minimal mining rig costs about 42k funds and weighs 13 tons. In contrast, launching 13 more tons of liquid fuel tanks instead of the mining rig will be more than enough for one more full Duna mission, and a 42k fund refuelling mission can launch enough liquid fuel to complete five Duna missions instead of the required three. So unless more than five Duna missions are flown, at least with the design I'm currently using, a mining rig will be a lot more expensive than just launching extra fuel for three Duna missions. And even in real life, fuel mass will probably be a lot less than the mass of a refinery, especially if xenon is used for the tug spacecraft.

There's this: https://link.springer.com/article/10.1007/s40295-020-00229-w In case it's paywalled, here's the abstract: Lunar gravity assist is a means to boost the energy and C3 of an escape trajectory. Trajectories with two lunar gravity assists are considered and analyzed. Two approaches are applied and tested for the design of missions aimed at Near-Earth asteroids. In the first method, indirect optimization of the heliocentric leg is combined to an approximate analytical treatment of the geocentric phase for short escape trajectories. In the second method, the results of pre-computed maps of escape C3 are employed for the design of longer Sun-perturbed escape sequences combined with direct optimization of the heliocentric leg. Features are compared and suggestions about a combined use of the approaches are presented. The techniques are efficiently applied to the design of a mission to a near-Earth asteroid. Edit: Also, there's the Nozomi spacecraft, which used multiple Earth and Moon flybys due to having a smaller than expected delta-v budget . Unfortunately, the spacecraft failed before it could get to Mars, but there's definitely historical precedent.

I was thinking something like this NASA proposal: Multiple separate habitat "buildings" that don't need to be connected by pipes, but can be. Or this one: Multiple special purpose buildings

A couple further questions: -Would a survey satellite (to determine the best place near the south pole to mine ore) need to count toward launch cost? If so, that's fine, but it would be easier if I could have a survey done before landing. -Are crew cabins allowed for a surface habitat and for vacuum flight? It's only for the ascent vehicle and Duna lander that command pods are required? -How reusable are we allowed to get? For example could I pull a SpaceX and use the same booster for all three/four Duna missions? Or is all Kerbin-atmospheric rocket hardware required to be single use? Similarly what's the restriction on reusing the Duna lander? -Does each Duna habitat have to be contiguous or can it consist of several separate "buildings" within a few meters of one another? If it must be contiguous, can it be assembled with EVA construction once on Duna? -Is ISRU required? If I find that I can do three Duna missions for lower cost if I don't use ISRU vs if I do, will I be allowed to do that? If this isn't in the spirit of the challenge, then please let me know. My general plan now revolves around the fact that the nuclear engine is efficient but expensive, so I want to use it for as much stuff as possible. Duna mission 1: Crew launches with command pods, nuclear tug, mining module, orbital habitation, and surface habitation Mun transfer Nuclear tug lands with mining module, refuels, goes back to orbit Duna transfer Nuclear tug lands with surface habitat and command pods, detaches habitat, launches back to orbit Kerbin transfer Command pods detach from nuclear tug and land, nuclear tug injects into low Kerbin orbit Duna mission 2: Crew launches with just command pods and surface habitat Mun transfer Refueling nuclear tug at Mun The mission will then proceed the same as mission 1 Duna mission 3: same as mission 2

Okay - would the following general infrastructure/plan be ok? I'll admit I haven't read much about Artemis's Mars plan so I don't know what would be in the spirit of that. Infrastructure: -Surface mining base - set up in some way, the exact way doesn't really matter -Fuel delivery rocket -Nuclear tug with 8 seats in Kerbin orbit Plan: -Lander and surface habitat launch and dock with nuclear tug -Tug transfers to Mun orbit where it's refueled by fuel delivery rocket -Tug uses Kerbin and Mun assists to aerobrake around Duna with only ~225 m/s spent -Standard Duna landing - parachute down, rocket back up, dock with tug -Tug uses Ike and Duna assists to aerobrake around Kerbin with <400 extra m/s spent -Lander parachutes down -Repeat

Are spaceplanes allowed even? Or does everything have to use vertically launched rockets? Also I'm assuming we have to land a new 8-seater habitat for each of the four missions?

I'm curious as to why you'd want to do it in 0.19

This is probably the smallest useful SSTO that I've made: Weighs 4447 kg, brings a 620 kg payload into orbit. This is not the lightest possible Rapier based SSTO due to the payload, but it's close to minimal.

The problem with KSP is that the aero model isn't super realistic. With fairing and heat shield glitches you can get some crazy payload fractions on a RSS SSTO plane. Ferram Aerospace will help with that but it's still not completely accurate since that would take up way too much processor power. Anyway, your calculation says that an optimized two stage to orbit rocket with first stage recovery will always be way better than a single stage rocket. This is true for carrier spaceplanes also - something like the Sänger (jet powered carrier plane, rocket powered shuttle) will have a higher payload fraction, just because you won't need to lug all those fuel tanks all the way to orbit.

I'm pretty sure KSP uses double precision floating point for almost all of its values, just to avoid overflow issues like this. Edit: In 1.11 KSP changed from single precision to double precision for dV and orbit calculations. They made no mention of the time counter. However, just from a programming standpoint, it doesn't make sense to keep years in a 32 bit counter and other time units in a different counter since the two are closely related. There are about 35 million seconds in a year, and if you keep the number of 1/60th seconds in a counter, that's 2.1 billion per year, or very close to the signed 32 bit limit. So I'm guessing that KSP time is stored as 60ths of a second in a signed 64 bit integer. (Signed because Kerbal Alarm Clock displays negative times so I assume there's support for it). There's actually precedent for this - the original incarnation of Unix time stored 60ths of a second.

It's two 1.25m service modules clipped into the same space, with some fuel and engines, probe core, etc Look at the AeroGUI when I'm about to crash - drag is exactly 0 newtons. Each service bay blocks the other service bay from receiving any heat or any drag force, and they both shield anything inside them. This is also the easiest way to do a Jool dive. Mk2 parts have a huge amount of drag in general - I almost never use them. The corresponding Mk1 parts are lighter and have less drag. My Breaking Ground install's slightly broken so the science instruments don't actually work. So I don't know exactly how the impact will translate to science. However if it's a physics related problem you can always switch back to your science station while the impactor's still suborbital and wait for it to crash. It'll still crash but won't be loaded with physics.

Had to get up and do something else in the middle. Took about 40 minutes, but probably closer to 25 minutes of actual playing KSP. Overengineered craft in VAB On pad Liftoff Booster jettison Kerbin orbit Eve transfer Eve insertion Detaching the impactor Deorbiting Aerobraking using the transfer stage as a partial heat shield The final stage wasn't even used Chutes deployed Instruments deployed. My Breaking Ground install's broken so this is the best I can get Deorbiting impactor Impactor entering atmosphere Impactor about to crash Impactor crashed Proof of 100% reentry heat (This is what I mean by a dragless craft.)

You've gotta go even lower drag than that probably. Alright, let's go. It's 9:05 PM for me right now, and I'll try to speedrun this.

Just make a very low drag craft using fairings and service bays

For the low cost sub-challenge are multiple launches allowed? For example if I had two 10000 fund launches, would that be a total cost of 20000 funds? I'm planning to do this with the additional restriction that no launch can be above 10000 funds, so I'm planning to launch the Laythe and Tylo landers separately (among other things) and dock them in Kerbin orbit.

A possible restriction would be to disallow launches over 10,000 funds. This is always a fun challenge for me because it really limits what you're able to send up at once, but it's still permissive enough to go to almost any planet or moon and return in a single launch. The two exceptions are Eve landing and Jool deep dive (as far as I know). For those destinations or multi-destination landings (Jool 5, grand tour) you're basically required to do multiple launches, and similarly space stations become a lot more useful. The mobile science lab is possible to use, but again you'll have to launch several modules for it to actually get anywhere. Same with ISRU. This doesn't make KSP much more grindy - you just have to design your rockets to be as cheap as possible. Science will probably be limited to thermometer, barometer, and goo canister - so you'll probably have to go interplanetary to finish the tech tree. In a similar vein, you can start with an initial budget and disallow yourself from spending any more than that. You "win" if you achieve some set goal - you "lose" if you spend over that amount. I guess that's part of the mission builder from Making History but if you don't have the DLCs you can still set a spending cap. A good goal (but pretty standard) is planting a flag on every solid planetary surface.

This was a fun challenge - here's my submission: In VAB Launch Launch stage burns out In orbit, kick stage spent Jool transfer - transfer stage isn't enough to do it Sepratron does most of the rest Course correction 1 to get somewhere near Laythe Trajectory after first course correction Second course correction Trajectory after second course correction Using the last of the solid fuel to brake Aerobraking Chute deployed Landed (splashed?)

I have a mod that puts a red target icon over your estimated landing position, and it shows up even if you're landed (so in this case it is in the sky). If you look at the Kerbal Engineer heads-up display, you can see that the biome is "Water" which is Kerbin exclusive. Also Bill's helmet cam shows a normal sky Wouldn't that be embarrassing? I don't have any planet mods so the only other possibility would be Laythe. And I already visited there. If you don't have enough funds to build a SSTO in the first place that's not an option anymore (: Launch cost optimization is more fun than a SSTO as well. And anyway, SSTO to Laythe and back isn't the most fuel efficient option - it's more efficient to have a SSTO deliver your spacecraft to Kerbin orbit and go from there.

Part 1: Launch Part 2: Journey to Laythe Part 3: Doing stuff at Laythe Part 4: Return trip

Inflated or deflated makes no difference to the aero properties. I'll re-fly the mission without that.