Teutooni

So I have finally decided to do it. The Grand Tour. Single launch from Kerbin orbit (assembly on orbit obviously), visit every landable body in the system and return - with crew and science! I will be attempting this without ISRU, as this is my last attempt at mastering the Tsiolkovsky rocket equation before moving on to ISRUs, fueling depots and permanent bases for good. The first and most important step is determining the route and landers. I have made prototype landers and a suggested route, and I am posting it here so you can give suggestions to improve them, or to get ideas for your own missions. Mun and Minmus are done with the Ion Lander, detailed later. The first interplanetary trip will be Eve, since it is close and requires the most massive lander. I need to get rid of that monster as soon as possible! Here is my Eve Lander (craft file). Weighs 40.6 tons, it is a 6-core asparagus using aerospikes. Tested using Hyperedit, rated for 500m landing altitude (did not test sea level). Requires a decent gravity turn to make it into orbit. Includes a small deorbit module that has 84 m/s delta-v. Starting orbit: anything it can survive heat-wise, or about 150 km circular. From eve, it's logical to take the trip to Moho. Instead of bringing the whole mothership (MS), I modified my ion powered lander with extra fuel and engines to bring TWR up to be able to land on Moho. It will be taking the trip to Moho and back to Eve alone. Craft file. Total mass: 6.8 tons with Moho tanks, 3.8 after it discards them on Moho. This configuration will also be the one landing on Mun and Minmus at the start, plus Ike later, with refueling aboard the MS. It will also serve as a tug, leaving the science package on the MS and tugging most landers to their rated starting orbits (10km for most without atmosphere). Next stop Duna. Ike lander is the IonTug with science package, same as above. Duna lander (craft file). Mass 3.3 tons. Needs to be put on aerobrake/suborbital trajectory by the ion tug. Should have plenty of delta-v for any lowish orbit. Next up, Jool. Out here, solar panels don't provide enough power for landings, so I designed a quick reusable landing module, that will be used on Vall, Bop, Pol (maybe ion is enough for Pol?), Dres and Eeloo. Craft file. Reuses the Ion lander's science package. Mass without the science package (as it is already accounted for in the Ion lander): 2.4 tons with minimal (24 units) monoprop. Total mass 3.4 tons again minimal (48) mono. Fuel tank mass 1.7 tons, needs to be considered on the MS design for refuels. Laythe lander (craft file) will land on water, to simplify things. Also because it is a water moon. Weighs 8.2 tons, with room to optimize the fuel amount (doesn't need it all). And finally, Tylo lander (craft file). Mass: 6.4 tons. As with most landings, needs to start from 10km orbit with full fuel. Returns to same orbit. The budget is tight, little room for errors. From Jool the journey would go to Dres and Eeloo, but as those reuse the Vall/Bop/Pol lander they need no special attention. Total Lander payload mass, counting 0.9 tons of xenon for each ion tug mission, and 1.7 tons of LFO for the far lander for each refuel: 79.9 tons. Neither the tug nor lander will need a full refuel for every mission, so there is some margin. Add 3.4 tons of monoprop, some crew, structural etc. and the entire payload should be less than 100 tons. Tonnage summary: Eve 40.6 Gilly + Moho 6.8 Duna 3.3+0.9(xe) Ike 0.9(xe) Laythe 8.2+0.9(xe) Tylo 6.4+0.9(xe) Vall,Bop,Pol 2.4 (initial) + 0.9(xe) + 2x(1.7+0.9(xe)) Dres,Eeloo 2x(1.7) The reason I am not counting Mun and Minmus is because the refueling tank (0.9t xe) doesn't need to be moved at all and can be discarded immediately. To sum up route: - From LKO, take the ion lander and land on Mun and Minmus, rendezvous with MS back in LKO. - Transfer to Eve, land and discard the 40-ton lander. - Take the ion lander, land on Gilly, continue to Moho, get back to Eve and rendezvous. - Transfer to Duna, land on it, take ion lander, transfer and land on Ike, rendezvous with MS on Duna orbit. - Transfer to Jool. Order of landings depends on the orientation of the moons. Basically park the MS somewhere, take the tug and push the landers in position in turn, land and rendezvous with the tug, return to MS to refuel and pick up next lander. After Jool, dump the ion lander as it will be pretty useless at these distances. - Transfer to Dres, land with the FarLander. - Same with Eeloo. - Back to Kerbin. At this point the only objective is to land back on Kerbin with the crew and science intact. Possibly with only minor course corrections and a heavy aerobrake. I did test most of these, excluding Moho lander. Will need to run some tests on it as it only has ~1.1 TWR on Moho at arrival. It does have some monoprop though, so I'm thinking of constant altitude landing with monoprop assisted suicide burn at the end. I have not yet attempted to design the mothership. It will probably be nukes with many stages, plus possibly an initial super-heavy chemical stage for the Kerbin->Eve transfer.

48-7S "Spark", Skipper being a close second. The spark used to be downright OP before 1.0, and still I find nearly all my "every gram counts" landers and probes gravitate to using it. It just hits this sweet spot of high TWR and decent ISP for it's size. Skipper because I love the model - I think it's the best looking rocket engine in the stock game.

Liquid fluorine or ozone oxidisers would give neat ISP, but are suicidally unstable. Afaik, even at cryogenic temperatures, pure ozone can trigger a spontaneous explosive chain reaction via normal heat fluctuations, breaking down into O2. Imagine launching that stuff on a shaking rocket.

Incidentally, using just maneuver nodes, it takes exactly 951 m/s to reach Kerbin escape from 70.1 km orbit. As you can see in this picture, 950.9 m/s is still "inside the SOI", with apparent apoapsis well over Jool's orbit. I think the node system uses infinitely large SOI, i.e. real escape velocity. Doing the actual burn instead of fiddling with nodes gives numbers close to 938 m/s and 84Mm SOI radius.

As I understand it, to leave Kerbin SOI, the minimum you need is the Hohmann transfer orbit to Kerbin SOI. Plugging the numbers into the transfer equation: sqrt(u/r1)(sqrt(2*r2/(r1+r2))-1), where u = G*M, r1 is initial circular orbit (670000 m) and r2 is the edge of SOI (84 159 286 m), I get 937.854 m/s. Which seems about right according to my experience. Add the orbital velocity (I was lazy and used browser calculator: http://files.arklyffe.com/orbcalc.html) of 2295.5 m/s and the burnout is 3233.4 m/s. The actual escape velocity from Kerbin, using Ve = sqrt(2*u/r), is 3245.9 m/s from 70km circular orbit. There is a difference of 12.5 m/s. Which seems to confirm what OhioBob just posted while I was writing this.

I once designed and built a great arkship with closed lifesupport loop for 10 kerbals (TAC-LS + USI), several landers for exploring every landable body, robotic fuel miners and refineries, etc. Iirc it was close to 400 parts with over 800 tons mass. It was designed to be able to explore everything and never need to return. You can see where this is going don't you? Just turning the thing was measured in orbits, not minutes or seconds. Needless to say it never left kerbin SOI, it was simply too painful to play. The most difficult/complicated thing I've done mission-wise is probably an unmanned duna mission with remote tech signal delay. The mission included 5 separate probes carried by one rocket: a communications hub with large antenna, an orbiter with SCANsat equipment for both duna and ike, plus landers for both. Landing with and without atmosphere become quite interesting when there's over a minute signal delay. Both are doable, but need some tricks. Piloting-wise the most difficult thing was landing a 200-ton spaceplane on Tylo with TWR of 1.2. It was fusion powered (KSPI), so insane delta-v but low TWR. Iirc a suicide burn distance would have been almost outside Tylo's SOI. It was a great educational experience - I think everyone should familiarize themselves with constant altitude landings. Literally the farthest I've been is Eeloo, but don't really consider that a significant achievement. Just pack enough lifesupport for a decade or two and it's not that different from any interplanetary trip. Still haven't returned from Eve on any version.

I confirmed OP's observations about precoolers - they have no real effect. Test vehicle was this (craft file). Needs tweakscale because I couldn't be arsed to make the wings out of multiple parts. First run: Whiplash with precooler replaced by empty mk1 fuel tank (mass 0.2t): speed at 17km level flight: 1430 m/s Second run: Whiplash with a precooler emptied of fuel and air intake closed (mass 0.2t): speed at 17km level: 1428 m/s Third run: RAPIER with an empty precooler with air closed: speed at 20km level 1684, can just barely make it to 1703m/s by doing a shallow dive from 21 to 20km. Fourth run: RAPIER with precooler replaced by empty fuel tank: speed at 20km level 1687 m/s, can also barely make it to 1702m/s in a shallow dive. Fifth run: RAPIER with precooler empty of fuel but air intake open: speed at 20km level 1685 m/s, can make it to 1705m/s in a shallow dive. Absolutely no difference. Intake air from precooler reads 0.0 at those speeds/altitudes. I did not use any autopilots so the tests might not be entirely valid, but I think it is safe to say the effect is negligible if there at all. Any difference in speed could easily be accounted for by small differences in pitch angle.

Balance-wise I think it's ok. I'd actually reduce the thrust at mach 2-3 a little and maybe compensate with slightly less steep decline in performance at higher altitudes.

Here is a thought experiment for you. Consider regular movement through quantized spacetime. If a macroscopic object such as a person moves the smallest possible distance does he die? There is no motion between the states, one time instant he is somewhere and the next he is somewhere else. What if he moves not to an adjacent 'pixel' but skips a few, does he die? If the person gets disintegrated, transferred as information and reconstructed, is that any different? Does it even matter if you are dead while in transit?

Non fui, fui, non sum, non curo. In other words, I don't give a damn how I am buried. I suppose I will donate everything usable to medicine/science, as I see that as a sensible thing.

Much easier to design a unit that self-destructs upon re-entry. De-orbit and blow up a small explosive aboard, scattering anything useful to a million pieces that burn fast. They want something back, and that something is test items/data for analysis.

"You" is a vague concept and if you can define it precisely you will have your answer. As a side note the Schrödinger's Cat has nothing to do with consciousness. It deals with the cat's fate being decided by measuring a quantum state, and prior to the measurement the cat is effectively both dead and alive. It could be a rock, and it would be simultaneously an intact and a smashed rock if the experiment was modified to destroy a rock upon activation instead of killing a cat. Again, answering whether quantum fluctuations affect our consciousness or if "you" die when there's an exact copy somewhere is entirely dependent on what the mind precisely is and how you define "you". If you define "you" as a conscious, thinking entity then you die every night. If "you" includes subconscious mind and memories, reflexes etc. it gets messy. If you lose your memory due to illness, do "you" die? There are cases where brain injury has completely changed one's personality. What if you learn something that deeply affects you and makes you change, did the old you die? If you define "you" as a learning process that guides your body, then you die when said process stops. These are just to mention a few definitions.

We are not talking about sending the first ENIAC of AI, we are talking about cosmic timescales. Billions of years. A recent ted talk mentions current experts believing we'll have a human-level machine intelligence in 20-30 years. That is, as good as us in everything, including creative thinking. I am not talking about sending one massive skynet to space, I'm talking about a population of superintelligent machines. Machines that could be more "humane" than us. This is ofc very optimistic, but I see it as our best shot at surviving the challenges of spaceflight on long timescales.

The problem is there is no clear consensus afaik as to how metallic hydrogen behaves if it can be produced at all. It could be metastable under mild pressures, possible needing to be cryogenic. But yeah, that is probably even more far-fetched than tail-landing 100-tons-empty lifting stage needed for 60-tons payload to LEO.

Hydrogen, obviously. Hydrogen + time => everything else. Has very nice energetic properties (fusion fuel, LH2/LOX, has a lot of interesting phases that are also very energetic). Atomic hydrogen reacts with almost any element, also forms one of the strongest chemcal bonds known with itself.

Considering the constraints outlined in the op, I'd say it would require some rather exotic fuels like MSMH to be able to lift heavy payloads reusably. As I understand it reusability cuts into payload fraction and would make large payloads prohibitively costly. Given STP metastable metallic hydrogen SSTOs with incredible payload fractions would be possible. 1500 second Isp with similar thrust to RP-1/LOX, yes please!

The way I see it, intelligent biological life is not well suited to surviving cosmic timescales. Evolution is a powerful adaptive process, life can thrive almost everywhere on earth. But we know of only one example of life leaving earth. It requires not adaptation, but prediction. Something biological evolution is incapable of. Which leaves intelligence, the predictive component. (yes evolution produced intelligence but is not itself capable of prediction and intelligence is not necessarily tied to evolution). If we can design a machine that is at least as intelligent as us, our legacy has a fair chance of surviving cosmic timescales. Machines are much better suited to space travel. No need for complex lifesupport, no need to live on planets or have artificial gravity, can be very small compared, etc. They could be a true spacefaring civilization with no need to land on planets except perhaps to mine resources or nostalgy or tourism or something. If we define them as our offspring, then we have a fair chance to survive a long time.

I use KCT and KAC, but havent yet run parallel missions. Just returned from a mission that did a manned landing on Ike and Duna. Was a couple hundred delta-v short on reenterinng Kerbin so planned a rescue tug for when the lander returned to Kerbin SOI. I could have done lots of tourist/satellite contracts but couldn't be arsed. Now that I have the duna science I will probably set up something reusable for tourists while I wait for the transfer to Eve to complete.

I miss the old interstellar nukes (I believe it was last updated for .25). They were fairly complicated, had cool looking radiators, different nuclear fuels, different propellants etc. Iirc the first fission nukes had worse TWR and Isp than stock, which was and still is ridiculously easy to use. Later models especially large fusion rockets started getting huge Isp, but up to that point they were imo fairly balanced and more fun to use than stock. As to the op question, thats the direction I'd like stock to go.

Back in 2012, can't remember which version. I guess it was pretty typical: 1st attempt: too aggressive on the lithobraking. 100m/s too agressive. Splat. 2nd attempt: way too careful, managed to land but wasted all the fuel meant for return. Technically a successful landing. 3rd attempt: managed to touch down but was a bit rushed and sloppy, rocket fell over. 4th attempt: wider lander with lower CoM, landed with enough fuel for return.

Never gave it much thought, but as Val is the newcomer and just as badass as Jeb she strikes me as Jeb's niece or something.

Laythe - beautiful ocean moon with a breathable atmosphere, what's not to like?

When you take your spaceplane for a stability test flight, reach orbit, see that you can reach Minmus and land there. Then you notice you still have 36 tons of fuel as payload, unlock it and do a flyby of Laythe.

Haha true words. Trips to Jool are always so much fun. It's easy to encounter and there are always many interesting opportunities to encounter with 5 moons in the system. My most science in 1.0 is just ~500 with a munar landing on the border of 2 biomes, although I am planning to do a full Duna+Ike exploration mission that should be around 5k science. My most science ever was a heavily modded Jool-5 a couple of versions ago with a fusion powered SSTO.

I agree, it was never sensible. But when has KSP ever been about being sensible? Don't get me wrong, it's good that it's at least quite difficult now if not impossible. That's awesome! See this is why I come to these forums, to get ideas when I am hitting a wall myself. This definitely gave me ideas for improving medium-sized SSTOs. (I define medium sized as generally using mk2 hull with 25-75 tons wet).