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Get Jeb Home from another planet!


Tassyr

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Yeah, I've come to realize that getting home from Eve especially is going to be quite an ordeal. As far as I can tell, it's got both higher gravity and a thicker atmosphere than Kerbin, which, while making landings easier, looks like you'd need to build a rocket big enough to land a lander that's more powerful than a normal interplanetary craft. Duna is quite a bit smaller and seems much more feasible. I can see what I can do about that.

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Managed to get Jeb to Duna and back home to Kerbin with all stock parts. Launched him in a one-man pod to Duna; once I got there, I circularized my orbit and descended to about 90,000m. Retro burn to drop my periapsis to 5,000m. The landing craft was simple - one-man pod, parachute, large 1m tank, small 1m engine, four legs, and ladder stuff. Once I got into thicker atmosphere I opened the parachute and ignited the engine. I kept the engine on idle until close to the last minute, and then used it for some braking. It was actually much easier than landing on the Mun or Minmus (the parachute kept me stable).

Getting him home was much more complicated. I used a three-man pod and had one crewmember climb out (the only non-original Kerbonaut; I felt that Jeb should be recovered by his original crewmates), and yes, I built a ladder all the way to the ground because it seemed like cheating if the disembarking crewmember died. I launched the recovery rocket towards Duna and circularized my orbit when I arrived. Lowered my orbit to about 400,000m then switched back to Jeb and his lander. I launched the lander from Duna and reached a circular orbit at 120,800m (with almost no fuel remaining). I carefully brought the three-man pod in for a rendezvous at that altitude. It was tough (the final approach for a rendezvous is harder with the three-man pod, in my opinion, because it isn't nearly as nimble), but eventually I brought the two craft into a stable orbit about 20m from eachother. At that point, Jeb EVA'd and floated over to the recovery vehicle. After he was on board, I fired up the engines and returned to Kerbin.

It was hard, but I think the two rocket solution is probably the most reliable (with stock parts) for landing on the other planets and returning. That way you don't have to worry about landing a cruise stage, which in my case are always fuel-heavy, NERVA-powered monstrosities.

I included screenshots (I'm pretty inexperienced with forums, so I might have done it wrong...) of Jeb on Duna's surface, the extra crewmember safely disembarking, and the lander and recovery vehicle rendezvousing through the window of the recovery vehicle.

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I got my three Kerbals back albeit with a "trick" of simulating a docking rendezvous back with the interplanetary stage after ascending from Duna. The new nuclear engine just plain rocks, it carried them both ways on just one and a half of the largest stock fuel tank. Here's the lander view and the brave kerbaunauts:

kerbaler-sur-la-dune.jpg

The whole spacecraft was ~380 tons at launch, it used stock parts for the lander and interplanetary stage, KW rocketry parts for the ascent stage to save on lag (puny computer). I used aerobraking both ways (supplemented by a long slowing burn on Duna arrival), aiming for periapsis @ 10 km above ground at Duna and periapsis @ 27 km above ground at Kerbin, which was sufficient to kill al velocity - touchdown back home in the middle of ocean, nearby a curious luminous spot ?

Total mission duration: 525 days :o

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I agree on the two man part as well. Mostly because my system cries a little inside when I try doing it single rocket. The amount of power required to get the return lander even off kerbin is astronomical (no pun intended). For my system it is just murder with that initial launch. I have been working on optimizing it more. But single ship to duna should be possible. When I get home this evening, I am going to rebuild my kerbin launch stage and will try for dune again. Though secretly bop has been my first objective when I saw the naming list.

Either way, I am almost there and first step I did was build a minimal lander capable of launching. I did so using fuel tanks with enough nuc burn time to make the interplanetary and acheive a capture. Keeping this light as possible. Launch consists of combines nuc and solid booster. Below this I have my landing engines and orbital capture combined together. This has been fairly reliable and should be good for duna, but the higher atmo and g planets will probably want a space plane booster/lander. To get off has just been as many 2m assemblies I can have going and firing at once. I repeated lots, but am arguing thermodynamics with a friend while typing. how fitting ^.^

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I've done several return trips to Duna now. Every time I go I realise I severely overestimated the strength and size of the rocket I would need to return to Kerbin.

I have also put a spaceplane on Eve. That super thick atmosphere chokes your velocity both horizontally and vertically. I do not see it working.

An airbreathing stage on a rocket might still be the best way though. It could be the only way to get into thin atmosphere without unlimited fuel.

In fact, the basic jet engine might finally have a purpose on Eve. Presumably the Superjet chokes on the smog.

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syx. Something I played with was using jet engines for vtol thrust. With their fuel efficiency to thrust output, could it be possible to use them for majority of vertical ascent on eve? Get up high then SRB rest of the way out of the atmo. That is the way I designed my Duna lander in this way but using liquid engines. I use my lander/takeoff to get off surface to get out of gravity well, then fire off the larger SRBs to burst into orbit. Finish off with some nuke engines in a lightweight format, and I can get back easy. Provided I time my transfer correctly. That is the worst part I find :D. Advice on launching from kerbin or am I on the right track with just go overkill with brute force to get into space?

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I'm in agreement that a jet ascent stage is going to be your best bet on Eve. I've got a stock 3-kerbal lander prototype (because multi-year voyages get lonely) that climbs on basic jet engines and then lights the aerospikes. My reasoning is that the weight tradeoff of hauling the jet engines to Eve as opposed more rocket fuel should be much more favorable in the thick atmosphere. It's far more than enough to get off of Kerbin, and it just might do the trick on Eve if my thrust to weight is high enough for Eve's gravity. I'm still fine-tuning it (and its massive launcher) and haven't been able to test it on Eve yet.

The real problem is that I can't keep the part count low enough. I'm using sixteen basic jets, each with its own nacelle, radial decoupler, and struts to keep it all stable. Simulating the lander's many parts on top of an enormous booster during launch is almost too much for my computer to handle, when the same computer manages to launch larger rockets with much less complex payloads. I might just post the craft file and see if anyone has suggestions to keep the part count down.

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