What was your closest call in terms of delta-V?

[Frank_G]

I deorbited a kerbaled command pod, returning from Duna with only internal RCS of the capsule left for the maneuver. It took three aerobreaking rounds around kerbin to finally stay within the atmosphere and make it to the surface. Good i did not forget the RCS thrusters... which i am very good at usually

[ManaaniWanderer]

A Mun return that left me out of fuel at a PE of about 68km, that thing took ages to finally land and thank Thrust I didn't have a life support mod installed or the poor Kerbal would of died.

[StrandedonEarth]

A Laythe ascent after a powered landing. Don't know the numbers but it took several quickloads to find the right ascent profile, which included draining the RCS tanks on lift-off, and an atmosphere-top-scraping orbit. The tanker had to come down and dock with the lander while trying to stay out of the soup.

[samstarman5]

If ever you want to test the limits of economizing delta-v, take the Kerbal X on a Mun mission. It has been said to be able to at least land on the Mun as it is built. I've only managed to make LKO, myself, but that was less-experienced me.

[Tex_NL]

Send an SSTO plane to recover a crew in LKO. The plane was left with less than 0.1 m/s dV after rendezvous.

Fortunately I could refuel and bring the crew back home safely.

[Cirocco]

First return mission from the Mun, I ran out of fuel with a periaps of about 200km. Being determined not to let Jeb die, I got out and pushed until near jetpack depletion, got back in, got out, rinse, repeat ... for about half an hour until periaps was around 30 km and Jeb landed safely.

[legodragonxp]

For me it was a manned return from Jool. I hit zero fuel with a periapsis of 63,000m to Kerbin. Took like a dozen aerobrake passes to finally get down.

[ArmchairGravy]

My closest shave was having .7 units of fuel left in my lander after leaving Layethe and docking with the main ship.

[PwnedDuck]

I mistakenly built my Laythe lander for a more kerbin-like atmosphere. The RAPIER engines switched about 10000 feet before I thought they would and when the now inefficient lander ran out of fuel completely I had to get Jeb out (at 30000 feet, this was) and EVA pack him into orbit and back to the station. Had about 2% fuel left when he got to the hatch.

[Rickenbacker]

Adjusting my orbit for aerobrake at Kerbin (coming back from Eve or Jool, can't remember) and finally achieving an aerobraking maneuver with DeltaV in the double digits, 30 or so, left.

[Nothing But Rubus]

the closest call i can think of is when my lander (designed for such locations as ike or pol) left lathe's orbit with around 180 units of fuel for a bop encounter which then got flung out into an extremely high solar orbit past eeloo thanks to tylo. the brave kerbal inside managed to alter to an encounter with the dunar atmosphere after a long 36 years and by the end, the fart n' fume driven lander safely crashed into the side of duna where rescue is likely to come.

ps. the kerbals who were waiting for Geneman kerman on bop were not impressed.

[-root]

What was your closest call in terms of dV

Took a minmus lander to the mun. Baaaad idea. Had 250dV or something by the time i got it back to orbit around the mun. Got a kerbin periapsis of about 40km with 2s (12dV) left in the tank. Mid course correction burn got me down to about 20km. Smashed the lander through the upper atmosphere at about 3km/s (because i'm impatient like that) and completely redlined the G force meter.

Edited June 13, 2014 by -root

[Soda Popinski]

In my first Jool mission (I'm still at it), I brought along a kethane miner needed to not only get back, but have enough fuel to make landings on the Jool muns. I had to skim the surface at 8500 meters (max mountains at 8000 meters) to get the lowest delta-V for a landing - going 800 m/s. Loaded up all the fuel into the kethane probe/miner/lander - 800 m/s worth (a bit of RCS to spare). Landed with 0 fuel.

It's in my Jool Mission in my sig, Vall Update.

[Spatzimaus]

Close calls make for the best stories.

Long, long ago I was just starting out, having just bought the full game after toying a bit with the demo. I'd landed on Mun twice, returning safely both times, and wanted to go a bit further. I figured Minmus was the obvious next target. So, I added more fuel to my Mun rocket, the Pink Koala 3, and took off. (At the time, I didn't really know the delta-V difference between the two moons, so obviously this was overkill.) The lander itself was a general-purpose design, with four parachutes, ladders and legs, and all the other things you need to land on any body. Here it is, pre-launch:

(That picture wasn't taken at the time of the mission itself; I just kept the design around, and once I got the Engineer mod I attached the module to the old design to see how inefficient it was.)

Unfortunately, when I tried to intercept Minmus, the optimal trajectory happened to pass through Mun's SOI. This made it very hard to set up an intercept with Minmus. So, I screwed up. Rather than do the rational thing and go around another orbit or two to let Mun pass by, I decided to try for Ike instead. (Yes, at the time this seemed like a smart decision.) That overkill on the design helped here, as I had plenty of fuel for the trip, and the intercept with Duna's SOI was simple enough.

Again, I screwed up. Not knowing how to fine-tune an intercept I entered Duna's SOI in nearly a polar orbit, which made an Ike intercept extremely unlikely. So I decided to go for broke, and went to land on Duna itself. This used up the last fuel in the LV-N transfer stage.

Again, I screwed up. I didn't know you could re-pack parachutes en route, and I knew I'd need them upon return to Kerbin, so I did a powered landing on Duna without any chutes. Duna's atmosphere obviously did most of my braking, not that I understood the mechanics of that too well, but amazingly I landed without breaking anything:

So I took off again, dumping the four outer pods on the lander in Duna's upper atmosphere. I flew most of the way home on the little bit of fuel contained in the core of the lander... but the key word there is "most". I ran out of rocket fuel just after circularizing inside Kerbin's SOI, a bit outside of Minmus' orbit.

All I had left was the 100 units of RCS monoprop in the lander (this being before they implemented the 50-unit tanks), so I used the horribly inefficient RCS jets to lower my periapsis to just inside Kerbin's atmosphere. Amazingly it was just enough; upon splashing down in the ocean of Kerbin, I had a whopping 7.81 units of monoprop remaining:

So yeah. I know others have had missions where they ended up having to get out and push, but this was incredibly close to a failure for me, and I made sure after that to know my designs' capabilities a bit better. That old design wasn't the most efficient thing, but it worked so well that once they added career mode my initial landers all looked very similar to this.

[rdfox]

Not counting being the first documented case of getting out and pushing (which resulted in my designing with a 10% delta-V budget safety margin from then on!), my closest would be my old standard large modular interplanetary transfer stage's launch vehicle, which would put the transfer stage module and its orbital maneuvering tug into LKO with 8 m/s left in the top stage, reliably. (I would then dock the transfer stage to the spacecraft, and as many additional stages as necessary to it for a parallel-burn to get as much delta-V as I needed--hence modular, as I ended up with big square blocks of these things...)

[Hannu]

Couple of days ago I transported extra lander with normal crew ship to Jool's orbit. Normally the craft have plenty of reserves. So, I thought that I can transport about 10 t lander, if I use lander's fuel. I chose poor transfer window and when I arrived to my station I had 4 m/s left.

[DunaRocketeer]

I did a Mun landing early on on my career mode, with some *very* tight margins. I was burning toward Kerbin after landing on the Mun, and ran out of fuel before my trajectory took me into the atmosphere. I had no propellant, no rcs systems aboard, and unlike others here, I didn't think to get out and push.

What I /did/ have was my launch abort system. I decoupled my capsule for maximum effect, and burned the escape rockets. Jeb returned home triumphant!

[TotalNewb]

I was coming back from Dres, after getting into Kerbol orbit I noticed I had only 300 m/s ÃŽâ€v left, which I used to correct my inclination a little. Then, I spent an hour using RCS and pushing to finally get a collision course with Kerbin.

[LongbowEOD]

It was a long time ago (0.13 or 0.14 probably), but the basic memory remains fairly intense in my mind: Landed on the Mun, took off headed back to Kerbin. Finished a (probably highly inefficient) TKI burn with a perikerb of somewhere around 60km and 0 fuel remaining. This is back before EVA, so "get out and push" was not an option. So the only option was to sit and wait for the wisps of atmosphere to slow it down. I forget the details, but it took something like 10 orbits to reenter, and the kerbonauts wound up spending something like 3 Earth weeks just going around and around.

[cantab]

I've used the escape rockets for extra delta-V before now, though I fired them soon after reaching orbit - after all, it's better to use your lower Isp propulsion first. (For the same reason, if you actually EXPECT to have to complete a burn on your RCS, do the RCS bit first then fire the main engines.)

[ammonia_ocean]

I set off to Moho in an enormous multi-part ship with something like 12km/s of delta-V. Something like five years later, I finally got back into Kerbin's SOI, and decided to go for ~realism~ by detaching the lander from the transfer vehicle and landing it in the ocean, while the transfer vehicle aerobraked to circularize its orbit and then got refueled for a second use. The only issue was that the transfer vehicle was in an almost-perfect polar orbit (actually possibly one of the best polar orbits I've pulled off, certainly better than the ones I've launched into), and had 686m/s remaining. So I sent up my mightiest*, most capacious† fuel tanker: the Type 2.

However, I ran into some difficulties when I discovered that the transfer vehicle's orbit was still moderately eccentric, and that I'd failed to launch the Type 2 exactly into its plane. Moreover, the Type 2 had the launch stage as its only maneuvering engine. While this layout (intended to keep the ship's size down) usually provided more than enough delta-V to perform minor maneuvering burns for equatorial rendezvous, it didn't have enough to match the transfer vehicle's orbit and plane. Consequently, I switched over to the transfer vehicle, changing planes and then circularizing my orbit. In the end, my fuel gauge was empty and Flight Engineer read -- for my remaining delta-V. I wasn't sure exactly how much I had left, probably about 8m/s, but I was definitely glad that I'd rendezvoused with a fuel tanker.

[Majorjim!]

Landing via EVA on Moho, my first visit. I had to shed parts of my ship as it ran out of fuel.

I EVA'd the Kerbal and used the jetpack to land!

It was so tense!

[benjee10]

I did an Apollo-style mission (Mun Orbit Rendezvous) and rendezvoused with my CM with 0.01 units of fuel remaining in the LEM. That was really quite nail biting!

[Guest]

My first landing on Duna. I ran all out of fuel a few meters above ground, slammed into the ground. Nothing exploded, but the craft did worryingly spin around, sometimes completely horizontally. Luckily there was a bit of RCS and the SAS was great, else I'd have a tipped over probe with broken solar panels on the surface of Duna.

[Mokmo]

Eve return... barely enough to make sure the kerbin reentry worked.