Back to Kerbin from Mun North Pole

[AmpsterMan]

Okay guys and gals, I need your help. This was my first ever attempt (and success) at making it into Mun's north pole. Now the problem. My ship was designed to be able to make it to Mun and Minmus without any problems, but I never even thought about giving it enough delta-v for a polar landing. I have about 600L left of fuel on my ascent stage and I don't know if that is enough to make it back to Kerbin. Here are some pic's of the situation

I already tried doing some SCIENCE on how best to get to Kerbin by enabling the infinite fuel cheat and then trying different ascent profiles and headings but they all require too much delta-v. That is why I come to you. If any of you know, can you direct me in the most fuel efficient way to get out of here? And if that is not a possibility, any tips on trying to rescue my Kerbals will be great.

Persistance and Quicksave files

Edited September 16, 2012 by AmpsterMan
Added persistance and quisave files

[djnekkid]

My best guess would be to burn more or less streight up, perhaps with a slight (10-20deg) pitch southwards. Get an AP of 2200-2300km, and your craft should be caught by kerbins SOI. Your orbit around kerbin would be more or less 90degrees inclined, but that should really not matter methinks... Timewarp until kerbin SOI, wait for AP, or if you are close, retroburn and land, or just touch the atmosphere (35ish km) to reduce your AP, and then you can more or less predict where to land. Just use F5/F9 to quicksave/load

In my next upcomeing video am I gonna fly t/r the Mun. I do however land on the equatorial plane (ish), and then land a stonethrow from KSC. It just need to go thru the videoediting software first.

I guess the morale is, an orbit is an orbit, no matter the inclination. If you post your persistancefile i can give it a shot

[AmpsterMan]

My best guess would be to burn more or less streight up, perhaps with a slight (10-20deg) pitch southwards. Get an AP of 2200-2300km, and your craft should be caught by kerbins SOI.

This is more or less what I did in what I would think is the best ascent I had. It wasn't a 90 degree inclined orbit however because I didn't get rid of the moon's orbital velocity (or so I think that is why)

I uploaded the persistance and quicksave files to mediafire if you would like to try them out.

Edited September 16, 2012 by AmpsterMan

[EndlessWaves]

Did you try burning retrograde with respect to the mun's orbit (i.e. head left on the second picture)? I don't know if it's the most fuel efficient way to escape but that's the first thing I'd try.

[AmpsterMan]

Did you try burning retrograde with respect to the mun's orbit (i.e. head left on the second picture)? I don't know if it's the most fuel efficient way to escape but that's the first thing I'd try.

I did, sort of. The issue is that it is not just burn to 270 degrees heading, I had to burn at a heading of 120 degrees by eyeballing it. I ended up with a super crazy and inefficient orbit (in fact, i got caught by Mun as I reached periapsis and promptly crashed into the moon XD)

[EvilotionCR2]

Get your apoapsis to 20 KM.When on apoapsis,BURN TO KERBIN,until you reach mun escape.Then retrograde until is your periapsis inside of planet.

[Jimbow]

If you get to Kerbin SoI and your out of fuel to de orbit fully you could try to use some of your remaining rcs. Thats saved me a few times.

[AmpsterMan]

Get your apoapsis to 20 KM.When on apoapsis,BURN TO KERBIN,until you reach mun escape.Then retrograde until is your periapsis inside of planet.

I usually get my apoapsis to 10km. My issue is that unless i get a nearly perfect ascent and Trans Kerbin Injection burn, I don't think I'll have the fuel to make it to Kerbin.

If you get to Kerbin SoI and your out of fuel to de orbit fully you could try to use some of your remaining rcs. Thats saved me a few times.

Hmmm... That might just work in a pinch.

[djnekkid]

Ookei, I made it... I tried not to do too much fuel bug, so 99% were on full throttle. Your main problem seem to be that you have quite little fuel left compared to the weight of your ship. Your second problem is that you have the tiny parachute, and that one cant handle a 3man pod.

Anyway, I did liftoff, and immedeatly ditch the 3 extra tanks and legs. After a few secons I headed 270 degrees, with a 5-10 or so degrees pitch. Now carefully pay attention to the AP, and JUST when it hits escape veolocity, hit 'x' and cut the throttle. Now wait until you are at AP, and retroburn until you are at your desired PE, and pretend that you land As I saied, the small shoot' isn't big enough to take the big pod safely to the ground

[simplemunrockets]

First off, quicksave. Then launch and try to get home to Kerbin. If that doesn't work, quickload and get into Munar orbit and launch a rescue mission.

[Vanamonde]

RCS isn't very strong, but a long burn can make a significant change in your velocity, especially if you apply it at the right time. The right time in this instance is at apoapsis of your Kerbin-descent trajectory, because any change you make there is magnified by the length of the descent. You can easily change the altitude of your periapsis by whole kilometers, and remember that if you get it below about 40,000m, it will only take a few aerobraking passes to de-orbit the ship. If you can get the periapsis down to about 20,000m, you probably won't come out of atmo again. Note that that last part will no longer work when later updates take G forces and re-entry heating into account! Well, it will still work, but it won't be survivable.

[AmpsterMan]

Ookei, I made it... I tried not to do too much fuel bug, so 99% were on full throttle. Your main problem seem to be that you have quite little fuel left compared to the weight of your ship. Your second problem is that you have the tiny parachute, and that one cant handle a 3man pod.

Anyway, I did liftoff, and immedeatly ditch the 3 extra tanks and legs. After a few secons I headed 270 degrees, with a 5-10 or so degrees pitch. Now carefully pay attention to the AP, and JUST when it hits escape veolocity, hit 'x' and cut the throttle. Now wait until you are at AP, and retroburn until you are at your desired PE, and pretend that you land As I saied, the small shoot' isn't big enough to take the big pod safely to the ground

Thank you so much for doing it and explaining it so well! About the tiny chute, the ship I was flying was an experimental one and so i wanted to see if the small chute would work. I guess it doesn't. My ship is a success i suppose; it was only meant to take Kerbals on an equatorial landing and instead is able to do a polar one . Thank you so much for your help!

Note that that last part will no longer work when later updates take G forces and re-entry heating into account! Well, it will still work, but it won't be survivable.

Yes when that update comes out I will have to change my descent trajectories SIGNIFICANTLY XD.

[Foursh]

I think the best way is to head towards 40 degrees, and about 30 or 40 degrees up. You should get a trajectory that looks like this:

[spoiler=]

I was using the fuel bug fix and I still had over 100L of fuel left.