SSTO's for Mun use only won't rendezvous with my orbital stations.

[Lef-T333]

I have been trying to build a ship capable of going from the surface of the Mun up to my orbital station in orbit around the Mun and back down to the surface where my mining operation is. It has to carry as much fuel as possible (~6K in LFO & 1500 in Mono).

I've made a dozen variations of ships that are capable of going up into orbit and back to the surface with full tanks. The problem arises when trying to rendezvous with the station.

I set up a rendezvous maneuver with the station so there's less than 1.0 distance of separation between the 2 ships at closest approach. Every time after finishing the maneuver, the separation distance starts at 1.0 or less but increases over time. No matter how many maneuvers I do, the distance at closest approach keeps slipping further away. I've even tried a fueling ship that I've successfully used in the past to dock with the station. I just put some wheels on it and put it down on the surface, but it won't rendezvous with the station after lift off.

Does any one have any suggestions as to what might be going on? I've never had the separation distance change after a maneuver like this. All my other types of ships (rockets, refuelers, station components, or small science landers) have no problem making rendezvous', just these darn SSTO's.

[Edax]

I have been trying to build a ship capable of going from the surface of the Mun up to my orbital station in orbit around the Mun and back down to the surface where my mining operation is. It has to carry as much fuel as possible (~6K in LFO & 1500 in Mono).

I've made a dozen variations of ships that are capable of going up into orbit and back to the surface with full tanks. The problem arises when trying to rendezvous with the station.

I set up a rendezvous maneuver with the station so there's less than 1.0 distance of separation between the 2 ships at closest approach. Every time after finishing the maneuver, the separation distance starts at 1.0 or less but increases over time. No matter how many maneuvers I do, the distance at closest approach keeps slipping further away. I've even tried a fueling ship that I've successfully used in the past to dock with the station. I just put some wheels on it and put it down on the surface, but it won't rendezvous with the station after lift off.

Does any one have any suggestions as to what might be going on? I've never had the separation distance change after a maneuver like this. All my other types of ships (rockets, refuelers, station components, or small science landers) have no problem making rendezvous', just these darn SSTO's.

Unless your orbit is perfectly matched, your going to drift away from your target at the "closest seperation". What you want to do right before closest approach is burn retrograde in "target" mode till you and the station are no longer moving in relation to each other. Then find the target the nav ball, and burn towards it slowly. You'll want to monitor orbital drift and burn towards where the station will be. On the orbital map, you should maintain the slow burn until the orbital map slowly shows your closest separation to be 0.0km.

Edited July 10, 2015 by Edax

[Lef-T333]

This doesn't happen after closest approach.

This happens right after the burn to get a close approach of less than 1.0, and way before I even get to the closest approach. As soon as I finish the burn, the closest approach distance drifts further and further out from each other.

[Edax]

So the orbital map implies your still moving after you've stopped? If the markers are twitchy, it could indicate a physics clipping issue. (You ARE in orbit right? Not on a sub-orbital trajectory out of the Mun?)

Edited July 10, 2015 by Edax

[Lef-T333]

Definitely in orbit.

I lift up to an altitude just above where my station resides, then burn into orbit. Once in stable orbit I create a rendezvous maneuver to come within 1.0 of the station. After the burn for rendezvous maneuver the markers show a steady 1.0 or less (no twitching), but then they start to drift away from each other. By the time I get to where the closest approach point was they're easily 5.0 or more apart from each other.

[Yasmy]

Are you leaving both RCS and SAS on? If so, your drift could be caused by RCS changing your orbit.

Do you have a lot of part clipping? That could cause phantom forces.

Are you processing fuel in flight? Maybe moving mass from one part of the ship to another is causing a problem. (I hope not. It shouldn't.)

If you time warp, does the closest approach change during warp?

If you don't mind digging through save files,

1) quicksave when you have a close rendezvous set up.

2) manually copy the quicksave somewhere else

3) wait until the rendezvous has drifted apart

4) quicksave and back it up again

5) Find the ORBIT sections for the two crafts in the two different quicksaves.

If either of the ships is drifting, it will show up in the orbital parameters.

[Lef-T333]

SAS is on, but no RCS.

Some of the 12 designs I've made have parts clipping, but others do not, and all have this problem.

I don't move fuel around unless docked.

While time warping the distance does not change, but as soon as I come out of warp it starts right back up.

I will look through some save files to try and figure this out. Thanks for the suggestion.

[KerikBalm]

This doesn't happen after closest approach.

This happens right after the burn to get a close approach of less than 1.0, and way before I even get to the closest approach. As soon as I finish the burn, the closest approach distance drifts further and further out from each other.

LIkely due to phantom forces.... they should go away during time warp. As sooon as you get to 1.0 seperation, time warp, that should put the vessel on rails, and get you to the rendevous.

I've had phantom forces do weird stuff like this... sometimes its tiny and is only noticeable on interplanetary transfers (where I can focus on the planet and see the orbit slowly drift)... other times... well, the craft is basically unflyable then.

[Scarecrow88]

I've had situations where trying to rendezvous things just won't go as they should no matter what manoeuvres I do and I don't have a problem with rendezvous and docking. The only way I have found to resolve the problem when stuck in that situation is to quit out to the Space Centre and then reload. It's almost as if it's resetting the physics or something.

[Cerberus738]

Do you have a klaw installed on that ship? or use one recently? I found the klaw part causes lots of strange phantom forces.

[ko1Stein]

I often have a weird bug that could be responsible for this.

Sometimes, even with the most sane rockets, the command pods momentum gets "stuck" after exiting timewarp. This causes the orbits to shift and the ship to bend, especially when fireing the engines or using the reaction wheels. Entering timewarp or saving is not possible. It only happens with specific ships, so if this is the cause, designing a slightly different, new ship and restarting the game should fix it. (Perhaps the most annoying bug I have ever found, because I didn't discover a proper fix)