omelaw

what was the lowest Dv margin you haved for a flight?

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I was about 200 dv short of making it back from the Mun on a rescue mission a few days ago, As it turned out, I got very lucky with 4 different Mun encounters with only a small amount of Mono left which just did get me down into the Kerbin atmo. Ive never been so lucky before, not even close to that lucky before. Was completely dry. Took a lot of orbits before it finally came down. I feared that I would land on a mountain at night and plunge poor Jeb to his doom. That is the luck I normally have. I went out immediately and bought a single lotto ticket, Thats no joke! The lotto ticket didnt work out as well. :wink:

Edited by Kevin Kyle

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I safely set down a 1-man lander on Tylo with 6.4l of fuel remaining in the tanks. 

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Two highly negative dV margin situations worth noting, both in Hard career mode a year or more ago.  And not surprisingly, both happened when I was playing without a dV calculator (which I sometimes do to make the gameplay more seat-of-the-pants and exciting).

First situation:  My Duna surface return vehicle was underpowered and didn't have enough dV to reach orbit.  Jeb (we will assume it was Jeb; who else?) had to abandon ship in the upper atmosphere at sub-orbital velocity and use his EVA pack to finish getting himself into orbit.  This was in the days before EVA Kerbals had the navball, so the real trick was coordinating the rendezvous with his driverless orbital vehicle that couldn't maneuver because there was no way to command it without Jeb aboard.  Ultimately Jeb got there and it all worked out, but there was a lot of tedious orbiting trying to line up the rendezvous on very limited fuel and no nav ball.

The other, more dramatic one was getting Valentina home from Duna, in an earlier version of KSP before heat damage (more on this later).  She thought she had enough gas for a quick detour to the nail salon on Ike on the way home, but, surprise, she didn't.  Fuel pooped out midway through the Duna/Ike departure burn.  She had to bail out and finish the departure burn back to Kerbin with her EVA pack and then navigate interplanetary space for a year or so with only the company of her spacesuit.  Worse, I had no funds to launch a lifeboat to come get her... I had burned up all my funds on her Duna mission.  So she valiantly plunged directly into Kerbin's atmosphere (pre- heat damage) and then used the helmet-first landing trick to survive hitting the ground.  Against all odds she got home alive, toting a fair amount of science, and earned me enough mission success funds to keep going.

 

 

 

 

Edited by Yakky

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56 m/s putting my orbital construction station into orbit of a moon of Urania from a planet pack.

 

Ion engines are fun.

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-30 m/s, using a 3m tall stack as a crumple zone on mun, leaving only a Mk1 capsule on the dirt, and a successful primary mission goal.

Original plan was to land beside the ISRU rig and refuel for the return, but Val ended up hitchhiking home.

 

More recently, Jeb was excited about nailing a trajectory to the SoI of dres from within Minmus' SoI.

20 days later, a rescue ship is on its way to meet them since the backup pilot determined that the trajectory is actually a 4km/s flyby with only 2500m/s in the tanks, so the planned asteroid ISRU won't be possible.

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On my first Duna mission, one of my ships arrived with only a few liters left in the transfer stage.  I hadn't been watching the outbound burn that closely, so that was a bit of a surprise.

Fortunately, this was a ship that was being broken up for parts that would land on the surface; it didn't have to turn around and go home.

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Not exactly what you're looking for, but I ran out of monoprop during the final approach to a docking, and just drifted in the last 10 meters without any control.

Nothing but net.

Edited by RoboRay

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11 hours ago, RoboRay said:

Not exactly what you're looking for, but I ran out of monoprop during the final approach to a docking, and just drifted in the last 10 meters without any control.

I had this too.

My lander ran out of fuel and monoprop like 75m off a big honking station (managed to bring the lander to a dead stop).

I then had to dock the station to the lander ...

It was quite a hairy manoeuvre and it took almost an hour.

Edit:
After that incident I made sure I always had a small robotic tug/rescue/refueller dock at every station.

Edited by Curveball Anders

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0.1-0.2 m/s or even dry, with fumes in the monopropellant tank and Kerbals' jetpacks. Jeb pushing the capsule to dock with his last units of gas. Horrible stories. LOL

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Sent my first rocket to orbit in 1.2. It wasn't designed too well, and ran out of fuel with a periapsis of around 68,000 m. I had to upgrade the astronaut complex so Jeb could get out and push.

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Basically 0.  I was coming back pretty hyperbolic on one of my missions and still had periapsis at Kerbin at about 80,000 km.  I got a little more from decoupling and then Jeb got out and pushed with his RCS thrusters and managed to get me down to about 25,000 km which was enough to aerocapture in one pass.  Definitely got a lot of use out of the heat shield on that one!

Edited by Falran

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It'd be nice if our kerbals could grip on to the command module when pushing with RCS on EVA wouldn't it?

nothing worse than initializing a rotation on your capsule and never being able to get back in!

Edited by Leafbaron

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You guys make me feel like such a paranoid, perpetually over-engineering chump; the worst I've ever been at (for a manned mission, anyways) was 350 m/s with 4 days of spare life support, and that was after a botched exit from Minmus SOI that left me sailing out of Kerbin SOI (never did find out if that was me making a mistake or a KSP bug).

Granted, I kinda treat it as a feature-not-bug that my transfer stages usually have enough dV to complete lunar insertion, despite being intended to be just enough to get payloads to lunar injection.

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