Monday, July 1, 2013

Kerbal Space Program: Landing and Returning from Eve (using kethane jets)

One of the most difficult tasks in the game Kerbal Space Program (KSP) is returning a vessel from the surface of Eve.  With Eve having 1.7 times the surface gravity, and nearly 5 times the atmospheric pressure of Kerbin, this is no mission to be taken lightly.  And although it is Kerbin's closest neighbor, it generally requires more Delta-v to reach than Duna due to its 2.1 degree inclined orbit around the sun.  But as one of our presidents would have put it, "we choose to go to Eve and do the other things, not because they are easy, but because they are hard!"

Mission Parameters

  • Construct a ship in low Kerbin orbit (LKO) capable of taking Jebediah to the surface of Eve and back home to Kerbin.
  • Eve lander will use the KE-J65 turbines (kethane atmospheric jet engines) for a vertical takeoff.
  • Once leaving LKO, no new parts can be added to the mission, including refueling tankers.
  • May refuel by mining kethane.
  • The ship will consist of 4 parts...
    • Eve Lander - for getting Jeb to the surface of Eve and back into orbit.
    • Kethane Miner - to mine kethane on the surface of Eve's moon, Gilly.
    • Kethane Probe - small satellite to be placed in Gilly orbit to find deposits of kethane.
    • Mothership - the ship that will hold most of the fuel and engines for getting this mission where it needs to go.
  • Game version - KSP v0.20.2 - the most recent as of June 2013
  • Mods Used
    • MechJeb 2.0.7 - Used for extra information only, no autopilot.
    • Kethane 0.6.1
    • KSPX 0.2.2 - I had not intended to use any other mods, but I accidently used one part from this, a 2m to 1m structural adapter used on the tops of several fuel tanks to make them look a little less ugly.  I suppose it could easily be substituted for a stock nose cone; but by the time I remembered that it was a mod part, I was already in orbit around Eve and did not want to restart.
And finally, Jebediah put in a special request to land on Gilly as well (as he couldn't allow himself to be so close to a world without touching it).  Since putting a second lander can on the Gilly miner was out of the budget, we told Jeb that if he wanted to touch Gilly, he would have to do it himself.  So we will also watch as Jeb attempts to land on Gilly, and return to the ship, using only his EVA jetpack and no instrumentation other than his communications with the computer on the Mothership.

Imgur Links

Design Phase
Phase 1 - LKO to Gilly Orbit
Phase 2 - Mining Gilly and Jeb's EVA Landing
Phase 3 - More Gilly Mining
Phase 4 - Landing on Eve
Phase 5 - Return to Orbit
Phase 6 - Return to Kerbin

Future Planned Missions

 This whole mission was pretty much a practice for my planned Grand Tour.  Will need to do some design tweaking before that however.  I would love to make that Eve lander much lighter, but I think I am definitely on the right track with these kethane turbines.

I also want to do a single-launch Duna/Ike mission that will be a test of my all-purpose lander for the Grand Tour.  This mission will also include bringing a rover down with Jeb to the surface of Duna, picking that rover back up, then taking that same rover to Ike.
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4 comments:

  1. parajaredJuly 23, 2013 at 1:44 PM

    Nicely done,
    I like your idea of launching each section separately then docking them together in space. My designs have been failing because I have been trying to launch everything at once.

    Landing Jeb on Gilly then rocketing him back to the spaceship is friggin epic.

    The "top brass" flag comment was hilarious.

    Are you going to launch miners to the moons of each planet for your grand tour, or are you going to re-dock the probe and miner every time?

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    Replies
    1. ShibolethJuly 23, 2013 at 7:38 PM

      Thank you!

      Separate launches definitely makes it a bit easier, provided you are comfortable with docking. It's not impossible to do a single-launch land-and-return from Eve, if that is your ultimate goal. Even without mods it's still possible, but the launch vehicle will be enormous, and will likely slow your frame rate down to a crawl, which is why I opted for using Kethane, which made the lander a bit lighter. By no means was my lander the lightest or most efficient tho, I will likely redesign it before my grand tour.

      As for landing Jeb on Gilly, it's actually not as difficult as I expected it to be, and can be done easily using less than half of the EVA fuel. The only thing really hard about it was maneuvering without the use of the navball. I believe it is also possible to this on Minmus, altho I have yet to try it.

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    2. ShibolethJuly 23, 2013 at 7:48 PM

      As for the details of the grand tour... I currently have an all-purpose lander design that can land and return to orbit from the surface of any planet or moon in a single stage except for Eve, Laythe, and Tylo. So for the grand tour I will probably bring 3 landers with me, the Eve lander, an SSTO spaceplane for Laythe, and a Tylo lander. The upper stage of the Tylo Lander will simply be my all-purpose lander that I will then re-use for each landing after that.

      You can see my all-purpose lander here http://imgur.com/a/cck5s#3

      I will also be bringing one of those rovers with me, so Jeb can do a bit of exploring on each world. That one can be returned to orbit, and I plan to bring some spare rovers to land on Laythe, Eve, and Tylo that will be staying behind, due to the ridiculous problem of returning something like a rover back to orbit on any of those worlds.

      As for mining the kethane on the grand tour: I will really only need large amounts of kethane for the Eve lander. I will probably bring a similar mining rig with me, then leave it at Gilly again, since I don't want to bring all that extra weight to any other planets. Same goes for whats left of the Eve lander, I will simply leave it in Eve orbit, as I wont need it anywhere else. Gilly and Eve will likely be my first stop, followed by Jool so I can dump the spaceplane as well as the lower stage of the Tylo lander.

      My all-purpose lander can also mine kethane for refueling on the surface, but its really too small to bring any significant amount to orbit. However, it can come away from most surfaces with a small net gain in fuel, so most landings will be a wash when it comes to overall fuel usage... After that, it is simply a matter of packing enough fuel in the mother ship for interplanetary burns.

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    3. ShibolethJuly 23, 2013 at 7:55 PM

      And in case you are wondering about my progress on the grand tour, I haven't done much more than the Eve trip and testing my all-purpose lander. I have designed several SSTO spaceplanes for Kerbin, but I'm gonna try to come up with something new, since it is much easier to get spaceplane to orbit on Laythe, and I can make them much lighter than is required for Kerbin.

      However, I have put most of this on hold, since v0.21 could be released any day now. Once I upgrade, and I get at least kethane updated and working for the new version, I will try to get back on my plans for a grand tour.

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