Trying to save return mission

[eliterrell]

I'm a newbie, just doing my first trip to Duna. Finally figured out how to land, left a base consisting of a habitat with 2 Kerbals, and got the rest of the ship back into orbit on the way home.

I didn't really pick a time for my return flight, so the transit was really messy and wasteful but I had plenty of fuel for it. Anyway, I was in the processes of fine tuning things, I had my Kerbin periapsis down to 51,000 km, when I was called away. I THOUGHT I put my computer to sleep but apparently did not. When I came back hours later, my ship was on the screen, spinning at insane speeds. When I got it slowed down, I saw the engines were gone. Actually one of my three engine pods was torn right off, apparently by the rotational force. All my fuel was still there so I didn't leave anything on, must have been a bug.

I didn't put RCS on this thing, but I did put 2 separator rockets on my command pod. They have enough delta V to screw up my encounter with Kerbin any way I burn them so presumably when I get closer there should be a solution that will let me hit the planet.

Flight Engineer says they provide 114 m/s. But they are mounted on the surface of the Command Pod, so they are not parallel to my axis. As they are on opposite sides of the pod the total thrust is on my axis, but my guess is that Flight Engineer is providing that figure based on rear facing rockets and some of my force will cancelled out. Can someone confirm that?

I say that because I did a little math and, in purely linear terms, I should be able to displace 51Mm if I burn about 5 days before my periapsis. So I spent some time save scumming, fast forwarding to the correct time and separating on an orientation perpendicular to my path. Couldn't get any closer than 26Mm. I played with changing the time too but I since I don't know how far off am its pretty rough going. If someone could help my figure out the actual delta V I'm getting from 2 separators on the tilted surface of a Mk1 pod that might be a step in the right direction.

It would also help if I could place maneuver nodes. But the game doesn't want to let me. I can only put a node on my purple orbit after it's shifted by my Kerbin encounter. I can't put one on my light blue current orbit. Is that how the game works or am I going something stupid? Nodes would be super handy to figure things out.

Thanks to anyone who can answer any of my questions or give me general pointers,

PS You may wonder why, if I'm willing to save scum a solution why don't I go back before I messed up. Well, I would have. When I got my ship to a stop and saw the devastation I instantly thought "no problem I'll just load my quicksave" ... and hit F5 to do it. Yeah, I'm a newbie.

[Sirine]

Your ship spinning? at vacuum space? insanely? how?

ok. Simple way. If you are using PC, try this http://ntfsundelete.com/

Un-delete your quick save and put it back to where you are before.

[SRV Ron]

Hitting escape will pause the game. Sleep mode can have unexpected effects as you found out.

There is a bug in the game that, when you switch views to different ships and return, may cause parts to fly off when the physics kicks back in. Best to quick save before switching views to different ships just in case things go flying apart when they shouldn't.

"Hit F5 to load?" Oh well, just like hitting the space bar when you wanted to hit M. Start over again if you can revert back to the launch phase.

[Kasuha]

Why don't you send a rescue mission?

[eliterrell]

I'm on a Mac and no Time Machine right now so I can't get back to my old save.

I didn't actually put my Mac to sleep, it was on and the game running, several hours. Yeah, I should have paused it. Also I had not been switching views prior to leaving. When I came back it was rotating many, many RPMs and I don't think there's a reasonable explanation why.

@Kasuha intercepting my spacecraft as it approaches Kerbin would be an option for someone better at the game than me. Right now I think my best bet is to get a solution to colide with Kerbin using those separation rockets.

[Kasuha]

@Kasuha intercepting my spacecraft as it approaches Kerbin would be an option for someone better at the game than me. Right now I think my best bet is to get a solution to colide with Kerbin using those separation rockets.

Assuming your ship is on interplanetary orbit now I guess what you need to do is interplanetary rendezvous. It's not that hard, I accomplished in on my first attempt after some two weeks of playing the game. Without using any mods, just playing with maneuvers and using navball, and with just a bit of experience in planetary orbit rendezvous.

You don't need to do it right now, too. You can leave your guys orbiting for a while, perform some other missions, perhaps run some rendezvous training, then you can return to them and bring them back to Kerbin safely.

Rescue missions are fun, too.

[eliterrell]

Update: After almost a week of trying I successfully corrected my orbit using the separation rockets. My math was almost useless. In the end it came down to brute force experimentation.

Stock KSP is not the best for this kind of approach. Trying to warp to a specific time is difficult. Many times you will go over your target. Precision aiming on the nav ball is equally tedious. It tells you your heading but it is hard to guess your elevation if you're off the orthogonal directions. I wasted a lot of time trying things, collecting useless flawed results until I downloaded the Kerbal Alarm Clock and Steam Gauges.

Kerbal Alarm Clock lets you stop warping at a specific time. No going over at high warp, no waiting forever at low warp...then going over anyway because you dozed off.

Steam Gauges has a heads up display that is many times better than the nav ball for quickly finding an exact direction.

Once I'd got these two mods, it only took one more session to nail down my solution.

[Kasuha]

Kerbal Alarm Clock is sure a great tool but it is also possible to just get used to time warping and get to the desired time precisely enough without wasting unnecessary real time and without overshooting. It's better to watch the remaining time counter though (and put a maneuver at critical spot even if you don't plan anything there) as the ship in orbit may accelerate or decelerate.

There is just one moment in KSP where it is really beneficial to be spot on on the navball and that is during the landing. In all other cases it does not really matter if you are a bit off as it is easy to correct for it. You don't have to be spot on with your planned maneuver - it assumes that you apply the delta-v at single moment and doing so over period of time generates some drift anyway. I actually learned to plan a maneuver, get my ship in position, then after starting my engines I remove the maneuver and watch what the real orbit is doing as that is what will actually happen. More or less, for instance when returning from Eeloo using single maneuver to Kerbin the difference between Kerbin periapsis shown at Eeloo and where I actually (would have if I did not correct) arrived was about 100 km. Missing my airbrake height by 100 km would be a real bummer.

And that's another reason to not rely too much on such things as the Alarm Clock - it is better to actually watch your orbit and apply corrections with RCS on the course to ensure the most accurate results.

Real space probes and ships do so, too.

What I wanted to say is - these tools are sure great and make the navigation a lot easier. But it is possible to do these things without them with some practice. And there is a soft boundary between getting some help, making the game a bit easier, and cheating.

Edited September 25, 2013 by Kasuha