camacju

I'm bad at landing. I can do the initial constant altitude burn but I can't target a landing with any accuracy, or do the final landing burn. I always end up floating down to the surface and wasting a lot of fuel

I usually name my ships "untitled space craft" or something directly related to the mission. "Cheap jool five" for, well, a cheap Jool-5 mission. Saves time thinking of a cool name

These are just off the top of my head for various milestones/techniques. Unmanned suborbital spaceflight: V-2, Bumper-WAC Manned suborbital spaceflight: Mercury-Redstone, X-15 Unmanned orbital spaceflight: Sputnik, Explorer Manned orbital spaceflight: Vostok, Voskhod, Mercury-Atlas Kerbin orbit rendezvous/docking: Gemini Mun flyby / Kerbin escape: Luna program, Surveyor probes Manned Mun exploration: Zond, N-1, Apollo, Nova Basic interplanetary exploration: Venera, Viking, Mariner Gravity assists: Galileo, Cassini (K-E-K-K-J route), Voyager, Pioneer (Jool assists to Kerbol escape), New Horizons Orbital resonances: MESSENGER, Parker Solar Probe, Helios 2 Rovers: Apollo 15-17, Lunokhod, Sojourner, Mars Exploration Rovers, Curiosity Docking: ISS, Mir, Skylab Reusable spaceflight, spaceplanes: Space Shuttle, Buran, X-15, X-20, X-37 Mass optimization: SS-520 SSTOs: HOTOL, Skylon, DC-X Asteroid/comet interceptions: Hayabusa, Rosetta

Don't worry, I used an atlas v 551 because I legitimately thought that was the correct one

This isn't very hard with gravity assists

@JacobJHC Okay, here we go! I took about 1k funds off for the final design, and there's a bunch of room to improve upon it. I had 2 fuel tanks more than necessary at the end, which could have made the transfer stage smaller, which could have made the launcher smaller, etc. Also the Laythe lander had way more delta-v than I needed. Finally I had >900m/s of EVA fuel which I didn't actually need. (Also I wasn't as aggressive as I could have been with unbolting fuel tanks, but I didn't bother because my margins were fine). Low cost Jool 5 - 24070 funds VAB, launch, Mun assists More space ping pong until Laythe Laythe and Tylo landings Vall, Bop, Pol landings Return to Kerbin

I'm gonna see if I can beat the low cost record for Jool 5: I'll take a much more aggressive gravity assist route to Tylo and drop the fuel tanker in elliptical Tylo orbit. I've probably over-budgeted fuel for this mission however

Where are NASA's responses? It would be fun to see them

Is that the Whiplash engine? I think you'd get a faster time with a Rapier. And even though it has a worse fuel consumption, the faster time should make up for it

That's pretty close to what I did with my hypersonic jet submission. This could pretty easily be scaled up also, and the air intake and cargo bay mass amortized down. Fuel efficiency wise, the Rapier at max speed is probably going to be optimal, just because it's got a high specific impulse and a high top speed. A few weeks ago, I was talking with Stratzenblitz on his discord server about fuel consumption like this and the conclusion was that a Rapier engine at low altitude on the edge of flame-out would be more efficient than the Goliath design he used, but would probably be harder to fly.

@ManEatingApe I finally ended up going the route of the Spider engine. 1738 funds, chair category In VAB Pre tilted booster for automatic gravity turn Burnout, coasting Circularizing. This lander is built around the decoupler, with the baguette, chair, and spider attached to it. Kerbin orbit Holding the jetpack seems to increase delta-v. Not strictly required but it's helpful Mun circularization straight to landing burn Final descent. At this point the lander becomes hard to control with just gimbal so Bill bails out Flag Ditched cylinder Mun orbit Return burn I can't add maneuver nodes in EVA so I had to eyeball the burn. That's why I barely have any fuel left Bill ditches the EVA pack to shed mass, and still almost burns up World record high dive?

After a bit of testing I've concluded that the third slot is too buggy to rely on. I'll switch tactics but will still probably be able to shave a good amount off the cost.

@ralanboyleMy submission was actually a pod ship. In the service bay is a 1.25 m crew cabin. You can see the interior in the crew portraits

@ManEatingApe There's another possible route for optimization that I wanted to run by you before attempting a mission with it. Kerbals normally have only two inventory slots, so the best way to optimize delta-v would be to have a jetpack in one slot and an EVA fuel cylinder in the other slot. With this method, the Kerbal would be able to land on the Mun with jetpack and have almost enough delta-v to return. Alternatively, the Kerbal would be able to finish off the Mun landing burn and jetpack all the way back to Kerbin. However, if you hold an item with your mouse, you effectively gain a third inventory slot, although you can't use the held item. With this method, the Kerbal can do the Mun capture, landing, ascent, and return, all on EVA pack fuel. I would have a cylinder and a pack in inventory, drain them, and then swap the empty pack for the full pack I was holding, and this would significantly reduce both reusable and expendable mission costs.

Here's a quick jet engine powered submission for fastest time. Probably pretty good fuel cost wise too but I forgot to calculate it. On launchpad Cruise. This is about 100m/s slower than max cruise but that won't make too much of a difference. Maybe I'll re-fly it if necessary Steering. The only lift comes from body lift on the air intake so I have to be careful managing lift and drag. Deploy the service bay and go retrograde to slow down Landed at 7min 48sec. More than half fuel left means this has the range to go back to KSC. From subsequent testing when I was trying to get as high a speed as I could. This is pretty fast. The main point where I lost time was from engine flameout when I was trying to go over the mountains instead of around them. I coasted for a few minutes at 1800m/s until I got low enough to restart the engines, which probably lost me a good amount of time. Staying at low altitude and steering using body lift is probably going to be the best for this.

You may want to change fuel cost and launch cost to fuel cost per seat and launch cost per seat. Otherwise, single seat designs will be the best way to go. I think the best way to attempt this is going to be a Rapier powered vertical launch, come screaming in over the desert airfield at mach 6, and airbrake to land vertically. Basically you're half tailsitter plane and half depressed trajectory ICBM. edit: best as in fast time and low fuel cost. also can probably return to ksc

Alright, here's my first attempt at an actual replica mission. Here goes Design of spacecraft: Launch, Duna transfer: EDL: Surface operations:

Looks pretty fun. I haven't had much experience building replicas - gonna see what I can do.

??? This isn't level 1 tech. There's no tech restriction at all - only the funds restriction. With only level 1 tech and a 10000 fund limit? I don't think that's possible

Oh, I'm sure someone can beat this. I left a lot of room for error on this mission - I just packed in as much fuel as possible into the 10000 funds available.

Using Tylo and Vall to capture around Jool Tylo assist Eeloo intercept Rendezvous with tanker In low Eeloo orbit Descent Landed on Eeloo! Ascent In orbit around Eeloo Docked with fuel tanker I got a very low cost Jool transfer but I had to wait 40 years. But what's 40 years in a >210 year mission? Using Tylo to swing around retrograde and also get a plane change I need to use almost all of my gravity assist from Tylo in order to do the plane change, so I can't go to Kerbin directly. Even if I could, I wouldn't, since the reentry is far too fast for the unshielded kerbal to survive. So I bleed off speed using an Ike assist followed by a Duna aerobrake - Duna's cold atmosphere is much easier to scrub velocity. Surprisingly enough, there aren't any temperature gauges showing up. Transfer from Duna to Kerbin Reducing fuel consumption or speed is entirely unnecessary at this point - I have enough fuel for a propulsive capture. However, it can't hurt to do more gravity assists. A Mun assist reduces my velocity relative to Kerbin. This means that I can capture purely through aerobraking, even if the Spark engine did get a little toasty. Second aerobrake - still getting a bit hot. I'm pointing normal to scrub off velocity faster in the upper atmosphere. Pointing prograde will shield the kerbal behind the large fuel tank so I don't have to worry about heat here. I attempt to land on the VAB but the lander is simply too heavy for just a kerbal parachute. Plus it's extremely hard to control. In the end, I simply bail out and land on the KSC grounds. We have landed on Moho, and then landed on Eeloo, and then come back to Kerbin, all with a rocket that costs less than 10000 funds. The mission used 42 gravity assists and took over 210 years. Good thing kerbals don't age

Is aero trickery (node occlusion, etc) allowed? If so, then I could make a pretty good attempt at this...

By the way, the route I took to Moho was based on something discovered by Chen-wan Yen in 1985. Yen used two Venus gravity assists, one to lower the orbit and one to get a plane change, followed by several Mercury assists and deep space maneuvers on the opposite side of the orbit. In this manner, the delta-v needed to capture around Mercury was substantially lessened. In effect, this technique multiplies the effectiveness of your deep space maneuvers while also splitting the long burn up to reduce gravity losses.

Moho assists 4 and 5 Moho assist 6 Moho assists 7 and 8 Eeloo transfer Eeloo capture Moho assists 9 and 10. Now the orbit is really close to Moho's orbit, so I can capture on the next intersect. 450 m/s to capture, instead of 2000+ from a direct transfer. Much more efficient! Moho capture In Moho orbit with half the tanker's fuel left. Landed on Moho. The lander was designed to land and return, but only with a jetpack-less Kerbal. So I had to get out and push for my deorbit burn, and my margin was much smaller than I had anticipated. Moho ascent Barely had enough fuel to get back to the fuel tank Taking stock of fuel remaining. I have a lot more fuel than I expected from the Moho assists so I can do a direct Eve transfer. The FL-T200 will run out during the correction burns but I'll keep it since it has a solar panel on it. Eve assist puts me onto another Eve intersect two years later, and gives a plane change also Substantial correction burn so I intersect Kerbin's orbit at the descending node, where I'll do another plane change Second Kerbin assist will put me onto an intercept with Jool Next: Jool->Eeloo, rendezvous, landing

Weren't you working on something for the liquid fuel only challenge? Anyway, I feel like the best way to do this is by using Breaking Ground props with a sailplane design