Very cheap Mun landing and back

[George Kerman]

Inspired by a discussion on another thread, I started to think, what is the cheapest rocket that can put a kerbal (in a command pod, no EAS-1 external seat shenanigans) on the Mun and then have him come back.

And I came up with this:

https://www.youtube.com/watch?v=TlN4CVfHcsk&feature=youtu.be

I scrapped everything I could. Who needs them legs anyway? Who needs aerodynamics or control surfaces? I know what you're thinking... who needs a HEAT SHIELD anyway??

I dare you to do something cheaper.

[=BB= Misophist]

Publicado originalmente por RoofCatA:

...My brain is working on Duna already. To avoid engineer for chute packing plus probe and antenna, you could use 2 separate radial chutes - 1 for Duna and one for Kerbin return with pilot. Im just curious, do they lose weight or change drag after firing?

In 1.1.3 they did not. At least AFAIK. They certianly didnt change the flight properties of my mini plane (0.625m main body), and they where a considerable portion of the weight.

[=BB= Misophist]

Publicado originalmente por RoofCatA:

Publicado originalmente por George S. Patton:

In 1.1.3 they did not. At least AFAIK. They certianly didnt change the flight properties of my mini plane (0.625m main body), and they where a considerable portion of the weight.

I have the same suspicion. Squad loves accurate details, but not too many. Actually I have Duna window on my main install. Could as well fool around. Not sleepy yet anyway. Stupid brain :D

I know the feeling. I think I may install tweakscale and get back into tiny planes and stuff again. Those are really fun

[Forward Bias]

I've learned so much from this thread already :)

[Ambitious Dreamsickle]

having a little cry of frustration here... my 160'000$ delta 4 heavy build with nerv landing rocket on a lander runs out of gas on landing. took 38 minutes to land and it went bingo 200m off the deck. still the landing can survived however wow... it certainly does not do any justice trying that again for a while without a sure plan to insert under 370 km direct insert is maybe not the most economical way...

[tkraftson]

George, nicely done. I liked the video, but I the KER data was blurry, so I couldn't read much. I have 1400 hrs. in but never used or thought to use a spark engine -- had no idea it could move a pod and fuel tank. Thanks for the entertainment -- you rank right up there with Scott Manley--but I prefer your music and notations to his persistent commentary.

[George Kerman]

Publicado originalmente por tkraftson:

George, nicely done. I liked the video, but I the KER data was blurry, so I couldn't read much. I have 1400 hrs. in but never used or thought to use a spark engine -- had no idea it could move a pod and fuel tank. Thanks for the entertainment -- you rank right up there with Scott Manley--but I prefer your music and notations to his persistent commentary.

Thanks for the compliments. It's probably because the Mun landings were rendered at 1280x720 but the rescue was rendered at 1080p; I'll do 1080p and higher encoding quality from now on. Do you see any difference? I see some. About the Spark and this game, it's easy to get into the routine of using the models you know and not trying something new. I had a very shallow learning curve in the beginning, also because the tutorials were kinda crap in the early days and wanted to learn by myself, not look up online help. I have 1700 hours but I still have plenty of things to learn I'd say.

[George Kerman]

Publicado originalmente por RoofCatA:

took my 5700 Mun lander, added one drag chute, one radial and one small solar panel. Went for Duna.
Mun gravity turn on the way to Duna, landing on 5500m "highland", Ike gravity turn on the way back... went out of fuel with Kerbin Pe 23oookm. Theoretically, if you plan all the angles better and save even more somewhere (Kerbin launch?), may be doable. But it's not really serious business plan. Rather pain in the @ss. More tests needed.

I know what you could do! You shoulda done a Minmus assist into a Mun assist into Kerbin low PE! :P . Now seriously, did you do some solar orbit corrections or went on a straight trajectory from the start? I wanna realize how much is it to save. You certainly seem to have done anything possible to do that. It shouldn't cost much to move that peri lower, maybe less than 10m /s.

Can I use your model in a video if I get it working? I don't have much time today but tomorrow I'm gonna get back to making videos and testing things.

[George Kerman]

Publicado originalmente por Junoberries:

having a little cry of frustration here... my 160'000$ delta 4 heavy build with nerv landing rocket on a lander runs out of gas on landing. took 38 minutes to land and it went bingo 200m off the deck. still the landing can survived however wow... it certainly does not do any justice trying that again for a while without a sure plan to insert under 370 km direct insert is maybe not the most economical way...

You'll get there with more practice ( = play) and more theory (tutorials, videos, discussions...). Don't worry, be happy.

[=BB= Misophist]

Publicado originalmente por RoofCatA:

....

If you want to do it the easy way, buff up your launch stage a bit. Use it for circulization and possibly some of the transfer

[Ambitious Dreamsickle]

Publicado originalmente por George van Doorn:

Publicado originalmente por Junoberries:

having a little cry of frustration here... my 160'000$ delta 4 heavy build with nerv landing rocket on a lander runs out of gas on landing. took 38 minutes to land and it went bingo 200m off the deck. still the landing can survived however wow... it certainly does not do any justice trying that again for a while without a sure plan to insert under 370 km direct insert is maybe not the most economical way...

You'll get there with more practice ( = play) and more theory (tutorials, videos, discussions...). Don't worry, be happy.

okay so i slept on it (kind of) and i came back with the numbers
Dv (retrograde) / t = deceleration (64kn)
----------------------------------------------------------
F (fuel) = 1400 units of fuel
so if i have 1400 units of fuel burning at a rate of 64 kn I have roughly
21.875 minutes of thrust...
if i take a direct approach and burn at half than i have 43.16 minutes of burn time...
the issue is the deceleration bell curve is far too gradual when staging a direct "head on" insertion. and i end up being forced to engage thrust at 300km agl
which over 43.16 minutes is not very efficiant at all.

so

the most efficiant approach is to aim for 8500m and decelerate against the gravity pull on the craft in retrograde about 15 seconds after parigee to avoid slingshotting off into deep space.
however skimming the peaks.

there in of it's self is the issue. so 0.98g gravitational force on an object going 750 m/s with a deltav coefficant of 64 kn = t 14 second burn time to achieve elypse at full burn.

to achieve a safe landing I will have to decelerate 177 m/s to a velocity of 573 m/s over that 14 second span to reach stable orbit. from there i will have to set my thrust to half to decelerate and compensate for stable retrograde to the serface.

this should account for 26% of my overall fuel payload by touchdown if my calculations are in fact feasable...

[Ambitious Dreamsickle]

take that and shove it in your payload fairing mun!

[Ambitious Dreamsickle]

not bad for a 34 tonne craft :) in mun's gravity it comes out to be 5.8 tonnes (hence why i didnt really bother to include the mass, not to mention that freefall pretty much makes it seem weightless when dealing with 64 kn (nerds out hardcore)

[Caliban]

Publicado originalmente por RoofCatA:

Sorry
http://steamcommunity.com/sharedfiles/filedetails/?id=814558030

There's no way that works. I tried replicating it and couldn't even get to Mun. Post a vid if you can actually do it.

EDIT: After reading page 2 apparently is does work with some crafty flying, so I'll shut my face.

[George Kerman]

https://www.youtube.com/watch?v=6OLpSmaDDjo

Credits to RoofCatA for the initial design that I modified to be even cheaper. Had a pickle at landing, but there was nothing I haven't seen before. I'll let you guys see for yourselves, might be useful for future reference if you haven't tried doing this.

[George Kerman]

Publicado originalmente por RoofCatA:

you should have used sharp nose cone though. It has better performance on high speed craft on Kerbin since v1.2. Gives you more speed for the same fuel. I know it's abit more expensive (and heavy), but it should be default choice in the latest version for everything that goes supersonic. Just as educational measure. So people don't get wrong ideas about "neglectable" drag.

The basic one is cheaper, that was my whole philosophy. That's why I didn't use battery and used the panel instead. Trying to save every penny. But yeah, good point for people looking on this thread to learn things. I've done a few tests before and the small one would get me to Duna with 2.5-2.8k dV left which is enough to get back.I go cheaper wherever possible.

Publicado originalmente por RoofCatA:

Also, I got impression, you approached Duna on a clockwise orbit. Why would you do that?
Air has more speed that way and may slow down a bit more, but so is your speed as well respective to the planet. So what's the point, does it really help?

I was trying to get a clockwise encounter with Ike as well to look cool(er), but ultimately i said "**** it". So yeah, it was an inaccuracy on my part. It doesn't really mean much anyway for landings.

Publicado originalmente por RoofCatA:

Plus you can righgtclick on closest approach markers like on any others to see how your burns change them in real time.

That would mean burning fuel or not doing a composite burn with prograde, radial and normal components all in one. If I have precision node, might as well use it for the slightest increase in efficiency.