My screwy Eve lander works, but there are bigger problems

[Plusck]

16 hours ago, Cpt Kerbalkrunch said:

@Victor12, I don't like to give repetitive advice, but I would advise the same for you as I did for another player on this subforum. First off, I'm not advocating completing scrapping your mission and starting from scratch, but I think you might end up doing that yourself. Eve really needs to be done backwards. The ascent vehicle comes first. If you want to lift 7 Kerbals, that's fine, you can do so. Just design your ascent vehicle, Alt-F12 it to Eve orbit, turn on ignore max temperature, and get it down to the surface. Now see if it can make orbit. It most likely won't. Go back to the VAB and make some tweaks. Then try it again. And again. And again until you can make orbit. Now add your shields, turn heating back on, and see if it can reach the surface. It most likely won't. Go back to the VAB and make some tweaks. Then try it again. And again. And again until you can reach the surface. Congratulations. The hard part is over. Now build a transfer stage to get it to Eve from LKO. Then build a launch vehicle that can get the whole thing off of Kerbin and into orbit in the first place. This is the way I go about Eve missions. All the trial and error will teach you an awful lot about the Purple Widow Maker. Hope all goes well.

That is very good advice.

The alternative (which is what I did) is:

- copy someone else's design (roughly, with my own sauce);
- fly it over several months to Eve while doing other career stuff;
- try 10 times to get it down to the surface without breaking up;
- send the failed lander off from Eve to Laythe instead where it should work;
- test improved design by throwing it around even more harshly in Kerbin's atmosphere;
- send second mission;
- get there, take another 6 tries to get it down from orbit; fail to do so;
- send a grappler to snag the interplanetary drive section, refuel it, and use that to reduce velocity high in the atmosphere;
- finally succeed more by pure luck than by anything else.

[bigcalm]

23 hours ago, Cpt Kerbalkrunch said:

@Victor12, I don't like to give repetitive advice, but I would advise the same for you as I did for another player on this subforum. First off, I'm not advocating completing scrapping your mission and starting from scratch, but I think you might end up doing that yourself. Eve really needs to be done backwards. The ascent vehicle comes first. If you want to lift 7 Kerbals, that's fine, you can do so. Just design your ascent vehicle, Alt-F12 it to Eve orbit, turn on ignore max temperature, and get it down to the surface. Now see if it can make orbit. It most likely won't. Go back to the VAB and make some tweaks. Then try it again. And again. And again until you can make orbit. Now add your shields, turn heating back on, and see if it can reach the surface. It most likely won't. Go back to the VAB and make some tweaks. Then try it again. And again. And again until you can reach the surface. Congratulations. The hard part is over. Now build a transfer stage to get it to Eve from LKO. Then build a launch vehicle that can get the whole thing off of Kerbin and into orbit in the first place. This is the way I go about Eve missions. All the trial and error will teach you an awful lot about the Purple Widow Maker. Hope all goes well.

This is entirely correct.  The Eve launcher needs to get the tiniest payload that your mission parameters require into orbit around Eve - that should be your only consideration.   If you want to then do something with what's in orbit, send a separate craft to go and pick it up.

For what it's worth, here are some of my failures and successes.  More is learned from failures obviously!:

1-man ascender - failure - too unaerodynamic - essentially went up to around 150ms and then decided it didn't want to go up any more and fly sideways instead (even after ejecting parachute assembly and landing legs).

1-man ascender.  Failed.  Again, too unaerodynamic, not enough dv to make orbit.  However.  Ripping the fins off the upper stage gave me this that made it:

This is precisely the same craft as was shown in the previous pic, except without the fins on the upper stage (and obviously, landed).  This made it to orbit so easily that I didn't even have to use the final stage at all, compared to the one with fins that couldn't make it.  Lesson learned:  Make it as aerodynamic as is possible.

I've also been designing shiny new ascenders in the last few days to re-assault Eve properly.  To test I now hyperedit to Eve orbit and go from there so I know they work before sending the real mission.

A twenty man ascender.  I'm helped significantly by parts from SXT mod (I think, it might be near future), notably, a 17-man crew capsule that weighs just 6.75 tons, and the wonderful Tsar-Pushkas engines that actually provide decent thrust at sea level on Eve and are 2.5m engines.  Scaling this back a bit and replacing with mainsails should be highly do-able and replacing the crew capsule with a hitch-hiker pod should make it stock though - and get you orbit for 7.  Really surprisingly easy to fly but if you don't land on flattish terrain, there's going to be explosions.  As it's ISRU (in the middle can't see it in the screenshot, lots of non-fatal explosions on take-off), it'll take many many days to refuel before being ready to ascend.

A 3 man ascender that's very nearly stock (I have a MechJeb and some supplies from MKS mods - all these really do is make the payload heavier).  All tested, a little tricky to ascend with but has enough delta-v to cope with minor piloting error. 

Finally, the next pic isn't an ascender, but it does indicate how you can use heatshields as really draggy fins and keep your lander stable on entry to Eve atmosphere without burning up.  I've used this strategy quite a bit:

 

 

 

 

 

Edited January 5, 2018 by bigcalm