iEvermore

Thanks for the replies. I am pointing at the center or mass. I keep the pivot locked once I'm aligned. I'll try pulling instead of pushing the roid tonight to see if that changes the outcome. Thx

Good day all. To start, I'm really enjoying this new patch. Loving all the new parts !! So last night I was able to build a ship, get myself off to an asteroid, and grapple it with relative ease. However, after I realized my 3 nuke setup was not enough to move the rock into orbit within a reasonable amount of time, I sent up another less efficient powerful one. Once I got everything setup, I realized that each time I engage the engine, the rock slowly starts to spin. (Same thing happens with nukes, just on a much slower scale that I didn't noticed right away.) I targeted the center of mass and made sure I was dead on the pink dot, (Like in docking) but it still spins. After I realized I could warp time to stop the spin, I kept trying to pivot my ship bit by bit to counter but no luck. Anyone have any suggestions? I see people have been doing it successfully with smaller rocks but the principals much be the same. I'm cannot remember the size of the asteroid right now, but it's much much larger than the large tanks we just got. I'm using the new large single engine we just got since the nukes were not powerful enough. I'm pushing, not pulling the asteroid. Thanks for your time.

I have a similar design and had a similar problem. (That's a lot of payload fuel mind you...) What I did was set up a scaffold system coming from the top of the top lifter tanks and then strut the scaffold girders to the payload and lifter at multiple points. Once you get high enough you lose the scaffolding due to stage asparagus separation you should be ok because the lifting thrust will no longer be as powerful. If by chance that doesn't work. Add two midsize engines with small tanks to the payload with a fuel line to the lifting stage to save your fuel in the payload. If all else fails, you can share your craft file and I'l fiddle with it for you or you bring that puppy up in 2 parts and assemble in orbit. Docking ports are much stronger yes, However I prefer the clean look of separators, especially on ships I have no desire to dock. It's just personal preference.

I have a few lifters that I can use for most payloads. However in some cases it's better to build your lifting stage around your payload instead of under as rryy mentioned. Sometimes too tall is your problem.

Throttle down. That's the problem. Hit "X"

Pics please. Also, seems your doing this manually, just confirm you are not using Mecheb. Make sure you check where your center of mass is. If it's above the half way mark that's your problem. In VAB, take off the stages up to where you normally get the problem, (ie: if stage 3 is your problem, click and drag off only stages 1 and 2), then check your center of mass, it will be different than checking your craft as a whole. If so, adjust the ship to bring the center of mass below the half way mark of the ship. Also, try some winglets. I'm sure COM is your problem though. Happened to me enough.

Docking 2 ships together was certainly one of the hardest things for me in the beginning. The first successful one I jumped out of my chair in excitement ! I enjoyed landing on the moon but the docking overshadowed it a little. I was much more thrilled with Duna landing since it was the first ship I built from the ground up on my own and got it to another planet. I went a little crazy with the F1 button on that mission.

Awesome!! That's what it was! I engaged all engines and it had no problem!!! Thanks for ur help guys!

Ok so having the 40's inactive during the landing is messing it up?

Oh yes spins at least 3-4 times around before I have to take over. Could it be because I have engines on it that aren't being used? I have 4 nukes and 4 l 40's. I only use the 40's when I'm going to take off full of kethane. Perhaps that is what's confusing it? I have the no problems landing this ship manually. Just the specific targets are hard to do.

Just replaced my files with those. Attempted it again with no luck. Same problems.

I'm using 2.0.7. I got it off space port.

Hello all, I seem to be having trouble with mechjeb. I can land my ship on duna no problem manually and the "land somewhere" function works. Problem I have is with land at target, it seem to under cut the landing prediction, tries to correct, and then sends the craft into a spin in 100km orbit. I abort and re engage it but it does the same. Any ideas what it could be? My ship is in 100 km orbit when I star and the target in almost on my orbitable path. Should I try from a higher or lower orbit? Not sure what the problem is....

Sweet!! Nicely done! Have fun.

Worked perfectly. Only cost me 450m/s to adjust pernapsis. Much better! I'll work on minimizing it. Thanks for all your help.

Thx guys. I will give it a try tonight.

I used to have the same problems. You can see some of my earlier posts asking for help.. - assuming u have the same inclination as target... - Basically, you need to watch your speed and where your "Prograde" is. What I do, is this. From the beginning I get myself into orbit, I mark my target, and I set up a lower orbit if I need to catch up, or a higher orbit if I need to slow down. (This depends whether or not the target is in front or behind me in orbit.) I do this the second I detach my ascent rockets. - Then I time warp until I'm as close as I can get, sometimes you need to tweak it with maneuver nodes, but for the most part if your no more than 5-15km different in orbital height it will be close. Note it will take a few full orbits to get closer, but you will see each time around the planet you get closer and closer. - Once I'm within let's say 20km away from target, I switch from map view to ship view and switch my camera to "Chase" - I slow down by burning Retrograde. You watch your target speed above your Nav ball to see this. - Once I get it to about 0.1 - 0.5m/s. I then turn the ship towards the pink prograde of the target and burn until I get the Yellow prograde to line up. Now this will need constant adjustment as you move closer. This is because of how orbital mechanics work and you constantly need to adjust your self. Once it gets too far off like your yellow prograde is on the edge of the Nav ball, I go find my Yellow Retro grade and zero out the speed again. Then once is slows to 0.1 - 0.5 I burn toward the pink prograde again. You may need to rinse and repeat this a few times, but you will get there. I had a hard time with higher speeds as I got closer so I choose to keep it at a comfortable 10m/s for anything under 2km. Some people are different, but I find this gives me a lot of time to make adjustments. Time warp is your friend. - Once you get closer I switch to docking mode. This turns off your engines and moves you to only RCS control. You toggle between Vertical/Horizontal/Speed adjustments to pitch adjustment. You hit space bar to move between the two. (Now keep in mind, by the time you switch to docking mode, you need to have your speed down to not much more that 1-1.5m/s depending on the size of your craft. You will spend too much Mono trying to slow down if your going too fast. ) - Now that your in Docking mode, you keep adjusting your ships trajectory (Prograde marker) with the WSAD keys to keep your yellow prograde aligned with the Pink target Prograde. (Note: in docking mode, the direction your nose is pointing does not matter, only where the yellow prograde is in relation to the pink one. This changes when you actually need to make contact, but I worry about pointing the nose only at the last 10m. Just don't let it go crazy) WSAD adjusts horizontal and speed and Left Shift and Left Control changes vertical. Keep in mind some times making any type of movement will change your speed to target, you need to keep it under control. Should your Prograde marker disappear you are at 0.0m/s and just need to hit W to speed up toward target. Here is a video that helped me understand it a bit. You should subscribe to Scotts Youtube channel. He has a lot of helpful tools. http://youtu.be/AHkY3FusJIQ He doesn't use the Docking mode, but you can chose what you like. Let me know if you need more info. I've done a lot of research before getting the hang of this.

I've been practicing Aero breaking and have figured it out for the most part. But today I had an epiphany and thought I may not be starting the maneuver correctly. I'm starting off by acquiring orbit and then aero breaking to bring down the Apo. But I spend enough fuel burning Retro trying to obtain orbit and bringing the Per to the proper height. (20km on Duna). What I was thinking today was if I actually need to obtain orbit first or if I can move my Per without getting orbit first. Here is an Idea of the situation I'm talking about O = Duna ------ = Trajectory P = Per ...................O.......................... --------------P------------------ Per is 5,000,000 Now, is there a way I can bring the Per to the correct altitude without having to acquire orbit? How would I go about plotting a maneuver node to do this? Looking at this as a 2 dimensional diagram I would simply need to thrust up to bring my Per closer, but using the Nav ball in 3D to do this is not a simple task. I've only found one video that was in German and he is doing what I want, but I cannot understand how he got his trajectory there in the first place. What I did see though was the Aero breaking took him from escape trajectory to orbit. I'm figuring this is the most efficient way compared to the way I'm doing it.... Using the blue maneuvers' on the maneuver node does change my "angle of attack" to bring it closer without orbit, but it still seems inefficient. If this is the only way then so be it, but I figured I should ask for input. Let me know your thoughts.

Ps u know u MUST have SOME velocity prograde to get closer right? I just thought about ur "increasing distance" comment. If u retrograde too much u are now moving away from the target. The two prograde must be lined up and have some sort of velocity.

I guess i would need to know what your velocity is at compared to the target. What you want to do is make sure both prograde markers match up and leave the speed alone until your closer. At 500m I would move to docking with RCS and use time warp for more control and less spinning your craft around. Again if u tell me your at 500m and relative velocy is 100m/s then yes slow down on retrograde with engines. You always want to be moving towards the prograde of the target. You sometimes need to adjust many times but at 500m from target you'll have this down pat in no time.

Scared the crap out of me when you released SE's. LOL I have no idea what this is, any mods installed?

Thanks a lot for the input guys. I'll check our your ship when I get home tonight. I've been practicing the Aero breaking and I'm getting pretty good at it. I've done it twice at Duna already. Still not perfect but I can at least slow down.

I originally had 4, I bumped it to 6 because I found I spent too much time at full throttle to land and helped me land with the Rover as well. My Rover is jettisoned by decoupling and using 4 tiny SRB's and then I open 4 chutes to land it about 0.5km away if I time it right. I could do better with a controlled landing with a sky crane like I do on the Mun but I tend to crash it on Duna and find reloading saves a bit of a cheat. It works fine for the Mun since the impact is often light and worst case I rep the wheels. But that's no big deal I guess. I reload plenty of times with failed launches. I mainly put the module on to save the stranded Kerbals but I guess it's not needed. Just evened out the look a little. I do land the whole ship, but I found that what was left was not much bigger than a lander in the first place. Perhaps removing the module will allow me to remove some of the nuke's. I'm guessing since I'm landing on Duna I could create a small lander that would land with parachutes and limited fuel, which in turn leaves much more for take off. I just need to be able to land the lander, w/Kerbals, and the rover. Perhaps landing all that at once is too heavy... I'll give it a try tonight and then fine tune.

Ok I will certainly give it a try. Vanamonde very impressive ship. I'll use the pics as a guide. If anyone can provide a craft file that would still be helpful to dissect it. If not possible then that's ok. I had not thought of putting together a larger ship in orbit. I always found the wobble to be nuts. But I guess I could look into Quantum struts. I try to keep the game as Vanilla as possible.

I haven't learnt how to Aerobreak just yet. It's on my list of things to learn. This is when you barely enter the atmosphere and allow it to slow you down? I've actually done it once by accident but I find it hard to control. It ended up causing me to force land and I had to reload and try again.