How do i get safely back to kerbin?

[badjass]

Ok, SO.
I'm in quite a pickle.
I challenged myself to get from low kerbin orbit to duna and back using a craft below 1 ton. It went pretty good so far. I've already landed and taken off from duna and this is my situation now.
I have 554 delta v left. I know this is just under what i would need to get to kerbin so i went eva with jeb and pushed with his eva pack to save enough delta v so i could get a kerbin encounter with 30 delta v to spare.
The problem is that i can't aerobrake hard enough because jeb would explode (i did not use a heatshield because that would be too heavy). Luckily the fuel tank functions as a very weak heatshield for jeb.
After lots and lots of trial and error i managed to use the mun to slow myself down before aerobraking in kerbin, with this move I could still only dip down to 65 000m without burning jeb to a crisp. This was still not enough to get into a stable orbit. All i need is to get into an eliptical orbit and from there i can handle it. Any tips i could use to manage this?
The situation i'm showing below is just when i got into duna orbit, i have not done eva with jeb yet.
I think all the info needed is on the sceenshot. I dont want to give my save because i do not want an exact step by step guide on how to do it. I just want some handy tips  Thx in advance  

Edited January 24, 2018 by badjass

[Cpt Kerbalkrunch]

Using the "dip a toe" technique (just barely entering the atmosphere), combined with the Minor flyby, should have lowered your solar orbit considerably. If time isn't a consideration, multiple flybys should allow for a safe free-return if you save what you have left for adjustments.

Just zoomed in on your screenshot (I'm on my crappy phone), and saw that you're Kerbal's in a command chair without any kind of enclosure. I still think multiple flybys are the only way, but I'm not so sure he'll survive. Kerbals don't have all that much heat tolerance.

Edited January 24, 2018 by Cpt Kerbalkrunch

[James Kerman]

I agree with the captain.  You will burn up trying to re-enter with that rig so I would put your kerbal into a stable kerbin orbit and send up a rescue pod.

[badjass]

24 minutes ago, Cpt Kerbalkrunch said:

Using the "dip a toe" technique (just barely entering the atmosphere), combined with the Minor flyby, should have lowered your solar orbit considerably. If time isn't a consideration, multiple flybys should allow for a safe free-return if you save what you have left for adjustments.

Just zoomed in on your screenshot (I'm on my crappy phone), and saw that you're Kerbal's in a command chair without any kind of enclosure. I still think multiple flybys are the only way, but I'm not so sure he'll survive. Kerbals don't have all that much heat tolerance.

I agree with the captain.  You will burn up trying to re-enter with that rig so I would put your kerbal into a stable kerbin orbit and send up a rescue pod.

This final stage was normally designed to get back to kerbin surface starting from the mun. I have used this before and i know that my kerbal does not burn up when comming from the mun. So i'm sure i can land this as long as i can slow down enough to get any orbit around kerbin.
I will try the multiple flyby technique, thanks :)

Edited January 24, 2018 by badjass

[bewing]

Your Mun gravity slingshot can be timed better than that. If you time it right, you can get fully captured into a high Kerbin orbit just with the slingshot -- you might not even need to burn at munar Pe at all.

You need to save all you can for the final Kerbin reentry, though. Even from LKO you'll need another couple hundred m/s of dV to survive down to 50km altitude.

 

Edited January 24, 2018 by bewing

[Spricigo]

3 hours ago, badjass said:

I challenged myself to get from low kerbin orbit to duna and back using a craft below 1 ton.

That caught my attention, is possible that  the root of your problem is how you picked the objective.

What is special about that 1t limit? why not 1.01t or0.99t? Notice, the issue is that you put an arbitrary limit and, after that, designed your craft to stay below that limit instead of above the required performance. So you ended doing the wrong question all the way: "A heatshield will put me over 1t?", "An antenna will put me over 1t?" You should have asked yourself "What is necessary to survive reentry?" "What I need to control the craft?"

 

In any case you are in Low Duna Orbit, with limited fuel and want to know how achieve orbit around Kerbin. Apparently no time constraints.

I'd go with a gravity assist from Ike to send me towards Kerbin. The ideal situation is a single assist sending me in a Hohmann trajectory that will meet Kerbin at the first time I hit periapsis, not so ideal is to reach Pe whan kerbin is not there and  doing a small adjustment to meet kerbin  one or a few orbits later.

Inside kerbin's SoI is the inverse procedure,  Mun assist to capture. Ideally a single one will send me in trajectory that allow aerobraking followed by a small burn to raise the periapsis and end up in LKO. (assuming Jeb cannot resist reentry, which seems to be the case)