Hope the Monolith wasn't watching...

[MaxL_1023]

I might have doomed my space program. I did it before 2010 - am I alright?

A relatively safe landing in a Europan Canyon. Sadly, I am on the wrong side of the moon to see Jupiter. Perhaps a good thing if those pesky monoliths choose to detonate it again...

 

 

Here are some craft pictures:

The probe has ~2500 m/s of delta-v and uses Aerozine50 + NTO as hypergolic fuel. I put every science instrument that would fit on it, including SCANsat and some of DMagic's gear. The main instrument suites were the stockalike thermometer, barometer, gravity detector, etc. 

Now, to get this to Europa I made a knockoff Nova booster. Shown at a distance for scale - this does not really fit in the VAB! Stages 1 and 2 (8 and 6) get it into any orbit below about 400KM (I made it to a roughly 250km x 250km orbit with a few hundred m/s to spare). Stage 3 (4) gets it to Jupiter, with enough margin for course corrections. Stage 4 (2) was just barely enough to get me in a circular 400KM orbit of Europa, starting from just after my Jupiter Capture Burn. Stage 5 (0) is the Europa lander - it might be able to manage Luna if you make a perfect approach. Mine was not so optimal due to seat-of-the pants probe flying. 

The booster basically uses a mishmash of rocket technology. The RD-107s are a fair bit better than F1-As due to higher ISP, which at this scale offsets the TWR difference. I used a Kerolox first stage on a radial core to keep the rocket small enough to kind of fit in the VAB - I could have used ~30 SSMEs here but that would be a little ridiculous. The central core is 6 SSMEs - it is sized in tandem with the Radial boosters to provide enough power to reach orbit. The third stage is basically a 2.5x scale Saturn V third stage using two uprated J2-X engines - they were the best large, restartable Hydrolox engines I had. The Fourth stage uses 4 Aestus-II engines - they have a 340s Vacuum ISP which is very impressive for Hypergolic fuel. Kerolox or Hydrolox boils off on the way to Jupiter, and a solution to this was simply to use storable fuels. If I had no boiloff I would have used RL-10s here.

The net result was managing to land on Europa with under 300m/s of delta-V to spare. I suspect that with better piloting this could make it to any of Jupiter's moons, with the higher gravity of Ganymede and Callisto offset by better approach and Jupiter-SOI maneuvering. It might need some gravity-assist help to get to Io due to the high approach velocities. 

Next up will be a mission to Neptune!

Edited August 29, 2016 by MaxL_1023
Added more Pictures (and boosters!)

[UnusualAttitude]

Hey, well done making it all the way out there! Some pictures of your craft, maybe?

[MaxL_1023]

Thanks! I will put some up later today. 

I needed 26k m/s of delta-v to get that lander to Europa, so I basically used a massive rocket. 

Stage 1: 4 radial cores with 2 RD-107s each - ~3.9k km/s

Stage 2: Central core using 6 SSMEs - this got me to a 250km orbit ~5.7km/s

Stage 3: 2 J2-X engines - this got me to Jupiter encounter from Earth Orbit  (~7.2km/s)

Stage 4: 4 Aestus-II engines (most efficient hypergolic engine I could find) - this was used to get me into Europa orbit from a Jupiter Flyby. I needed 6K m/s of delta-V, since low-energy orbit changing doesn't exist and Jupiter's moons don't do that much with gravity assists. (~6.5km/s)

Stage 5: 8 1KN thrusters to land on Europa (~2.5k m/s)

It was easier to land on Titan - all I needed was any encounter and the atmosphere did the work. Titan's atmosphere is so thick that I didn't even need a parachute (I used one, and was falling at 0.4 m/s).

 

The next spot I want to aim for is Neptune and Triton - any tips for how to land on Triton without needing to haul a LEO-capable rocket to Neptune?

Edited August 29, 2016 by MaxL_1023

[UnusualAttitude]

Wow, extra well done for doing this with existing tech.

1 hour ago, MaxL_1023 said:

The next spot I want to aim for is Neptune and Triton - any tips for how to land on Triton without needing to haul a LEO-capable rocket to Neptune?

Haven't tried Neptune yet myself, but once you're there it should be much cheaper than Europa delta-vee wise, as Neptune doesn't have the massive gravity well that Jupiter has. Triton's surface gravity is also half that of Luna, and less than Europa. 

The hard part is getting there: either you do a standard low energy transfer (about 40 years if Transfer Window Planner is to be believed, which is why IRL we haven't orbited Neptune yet ), or you do a high energy flyby. Anything else will require a combination of electric propulsion and nuclear reactors, cause there ain't no sun out there. You'll need Nertea's Near Future mods for these.

Or you just disregard my advice and, as you say, send an LEO-capable rocket to Neptune. Might be possible with NTRs. Whatever you choose do, please keep us informed. 

 

[MaxL_1023]

I have gotten to Neptune in previous versions (just not landed or orbited Triton) by doing a hyperbolic transfer. An extra 1 Km/s applied in LEO can get you to Neptune inside of the 15 year deadline the contracts give you. 

I try to get into orbit by having a very low Perapsis (2000-5000 KM depending on how glitchy I think the gas giants are - Jupiter blew me up at 15000KM before) and using oberth to capture for reasonably cheap. 

My plan would be to encounter Neptune retrograde, try and capture into a very elliptical orbit, do two plane change burns to match Triton out near my Apoapsis, raise my PE until it touches Triton's orbit, then burn retrograde to lower my AP until I encounter Triton on the next orbit. Then, try for a low pass (think under 50km, maybe higher if they gave Triton an atmosphere) and burn a crap ton to try and get into orbit using whatever Oberth effect I can get. Then, once I am in orbit I can scansat and land using about 2 km/s, easily attainable for a probe.

I have just been spamming RTGs for power - electric propulsion is too slow in RP-0 since they have real thrust values. 

I am also not sure how to use NTRs, since Liquid hydrogen boils off in RSS/RP-0 and there is no such thing as active cooling as far as I know. 

Edited August 29, 2016 by MaxL_1023

[UnusualAttitude]

Triton does indeed have an atmosphere (which is unfortunately far too tenuous to be of any use to capture).

3 hours ago, MaxL_1023 said:

I am also not sure how to use NTRs, since Liquid hydrogen boils off in RSS/RP-0 and there is no such thing as active cooling as far as I know. 

You could try this. It doesn't stand up to high time-warp, unfortunately. Alternatively, you could try liquid methane or liquid ammonia for lower ISP, but reduced boil-off. At least NTRs could come in useful for your transfer burn.

But yeah, you're pretty much hitting the brick wall that is exploring the outer solar system without some game-changing tech. Good luck!

 

[MaxL_1023]

OP updated with pictures. 

[MaxL_1023]

Neptune Mission Starting - I threw 3000 tons into orbit using 42 Energia Booster engines on 8 15m Radial Cores (RD-170, more powerful then the original Saturn V F1) followed by a 25m core stage using 40 SSMEs. I don't have a picture yet - it was too big to fit in the VAB and launch nearly crashed my game. Here is what I put into orbit - my ascent path was less than ideal (and the game was running at about 10% speed at launch I piloting was a bit sketchy) and I had a little more fuel than I needed in my second stage. I usually aim for about 10k for LEO just to be on the safe side. I am not sure how much delta-v I will need to get to Neptune inside of 15 years (contract requirement) and then land on Triton - if 24km/s isn't enough I will just have to try and plot a Jupiter gravity assist or something. 

[UnusualAttitude]

Wow. Just, wow. 

[MaxL_1023]

Now I need to figure out a way to plot a hyperbolic transfer. The normal maneuver node was telling me I needed way too much delta-V, especially since my inclination was optimal for a Hoffman orbit and not that type of transfer. I would have needed 16k to get to Neptune in under 15 years, when I am sure I did it for 10-12k m/s before. In the meantime I am going to land Kerbals on the Moon and stick a science lab in Lunar orbit - I need some more science points to get nuclear engines. RP-0 comes with a nice one which has a LH2/LOX mode with a decent TWR. 

Edit: I figured it out - thanks to Mechjeb and their porkchop plots. ~11.5 km/s gets me there in just over 13 years!

Edited September 1, 2016 by MaxL_1023