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[PART, 1.0.2] Anatid Robotics / MuMech - MechJeb - Autopilot - Historical thread


r4m0n

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Just wanted to drop in here and add a MechJeb 2.0 tip for anyone who might be interested:

If you, like me, hate launching your planetary probes into orbit only to find that you have to wait 47 days -- at 50x warp -- until your Hohmann transfer node lines up, there is a way to fix that (besides launching into a ridiculously high orbit so you can use maximum warp).

The secret: you can set rendezvous-with-target nodes.... on the launchpad.

Say I want to send a probe to Duna. I target Duna, then use the maneuver planner to set a Hohmann transfer to target. I don't really care about this node -- it's basically just a placeholder for the eventual final transfer node. What it does, though, is provide a node in the future at roughly the proper time for a transfer.

Next, I fire up the helpful warp helper. I go to "warp to next maneuver node"... and set the lead time to be an hour. Then, warp.

Now, I do two things. First, you DELETE the transfer node. You don't need or want it. Then, you launch into your desired orbit.

Once you're in your desired Kerbin orbit, bring up the maneuver planner (make sure you're still targeting Duna or whatever planet you're transferring to), and set a new Hohmann transfer to target.

Voila, your time to the node should be some number less than an hour. (For me, it's usually been about 45 minutes or so.) Which takes far less time to warp to at 50x.

This is basically like using Protractor to wait until the theta is right; you're just letting MechJeb do all the work.

"Hohmann transfer to target" doesn't work between planets, only between a planet and its moon? At least if I try to use a Hohmann transfer to get to, say, Dres (as I write this I have a probe warping its way to the transfer node in 90 days or so), MechJeb 2.0.7 reports "not in same sphere of influence" (paraphrasing).

Anyway, the rest of this method is, in principal, correct... If you are able to launch your probe in a single launch. If you need to assemble your probe in orbit (like I do, I don't have heavy launch capability yet :(), then you can't warp your way from the pad. I guess now, as I am in a 300km parking orbit, it allows warp up to x100 (I think, might be x1000), but 90 days warping takes forever. Guess I could get my probe to plot the original 90 odd day plan, go to space centre, and then put something on the pad, set Kerbal Alarm Clock, warp, go back to my probe on the alarm, and have MechJeb replot the transfer... But, when I did this in the past, it plot the new transfer some distance in the future (even if I went back to the probe with an hour before the original plotted course), so I was never able to make this work. Very frustrating. :mad:

I reported this previously in this thread, but it would be nice if the interplanetary transfers would use the same calculation used by Kerbal Alarm Clock; MechJeb doesn't agree with KAC, or Protractor, or http://ksp.olex.biz/ ... This I find to be a real pain.

Edit: Yup, just confirmed this. Still had 91d to go on first plot, so, went to pad, set alarm for 90d. Went back to craft on the alarm, replot; next plotted course, in 124d. :mad::mad::mad:

Edited by tek_604
Updated with tested alarm
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"Hohmann transfer to target" doesn't work between planets, only between a planet and its moon? At least if I try to use a Hohmann transfer to get to, say, Dres (as I write this I have a probe warping its way to the transfer node in 90 days or so), MechJeb 2.0.7 reports "not in same sphere of influence" (paraphrasing).

You're correct -- it's a different option in the Maneuver Planner from the Hohmann transfer module. And I forget the exact name of that option. My bad. Basically, you set up a planetary transfer using the planetary transfer option, not the Hohmann option. (The planetary transfer option calculates, I believe, a near-Hohmann transfer that's not 100% optimized but which occurs at the next reasonable transfer alignment position.) Then warp to a short time before that node. When you orbit, you generate the actual transfer node.

You could still do this with an assembled flight, too -- just increase the "before" point on the warp-to-node option such that you have enough time to launch and assemble what you need to assemble. It's ultimately just a warping tip, not a transfer tip.

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This is a really stupid question and the answer is probably somewhere but will mechjeb 2 work with mechjeb 1 ships? I ask because I dont want to have to rebuild all of my ships with mechjeb on them.

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This is a really stupid question and the answer is probably somewhere but will mechjeb 2 work with mechjeb 1 ships? I ask because I dont want to have to rebuild all of my ships with mechjeb on them.

I'm 98% sure that you can effectively retrofit all your existing MechJeb 1 ships with MechJeb 2.0 by adding the MechJeb MODULE text to the CFG file for the cockpits/capsules/probe core parts that the ships are using. (I think the persistence file just records ships as a collection of parts, and the part file data is drawn upon when you unpack the ship into the program. Hence, changing the underlying part will "update" the ship the next time it's loaded.)

Also, I'm 89% sure that 1 and 2 can be run side-by-side at the same time without conflicts.

So basically... yes.

Edit: You can also hack the persistence file itself to change the 'old' AR-202 case to the 'new' one, I think, but that's a lot harder to pull off.

Edited by daver4470
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I hope the maneuver planner can add gravity acceleration / deceleration options:)

Can you explain what "gravity acceleration / deceleration options" would be? I'm not sure what you're referring to.

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What did you do with the landing autopilot in 2.07....it freaks me out .....mechjeb is "pulsing" the engines to decelerate ....drives me nuts ....where is the good old suicide burn?

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If the engines are pulsing that usually means the ship is way out of balance. I tried landing my skycrane with a empty orange tank docked horizontally under it and it freaked out. Try moving fuel around the ship to level it out or something to rebalance it as best you can and see if that fixes the problem.

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I'm 98% sure that you can effectively retrofit all your existing MechJeb 1 ships with MechJeb 2.0 by adding the MechJeb MODULE text to the CFG file for the cockpits/capsules/probe core parts that the ships are using. (I think the persistence file just records ships as a collection of parts, and the part file data is drawn upon when you unpack the ship into the program. Hence, changing the underlying part will "update" the ship the next time it's loaded.)

Also, I'm 89% sure that 1 and 2 can be run side-by-side at the same time without conflicts.

So basically... yes.

Edit: You can also hack the persistence file itself to change the 'old' AR-202 case to the 'new' one, I think, but that's a lot harder to pull off.

That's the hard option, the easier one is to just return your old ships, or just end their flights and relaunch them with the new Jeb installed. hard to do for probes or sats but for any flyable ship its doable. Stations are obviously a harder replacement so altering their files might be the better option. But most ships a return or delete option with a relaunch with the new Jeb is the better over all option.

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So has anyone found a fix for the micro-stutter(lag for the people who don't know what micro-stutter) is, which increases with the amount of MechJeb windows that are open?

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For rocket i do 7.5 start, 50 finish turn, 50% degree, to and 100km orbit. I can put this for all orbits, 75, 150, etc...

Nope, doesn't work either. Maybe I'll try MechJeb 2 and see if that works. If not then I guess it's just a lost cause

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You could still do this with an assembled flight, too -- just increase the "before" point on the warp-to-node option such that you have enough time to launch and assemble what you need to assemble. It's ultimately just a warping tip, not a transfer tip.

I wouldn't mind, if MechJeb would stick to its original plan. But, if you have a ship in orbit, that says 90d, then go away, warp to this time, and recalculate, it generates a new transfer at a new time, usually far in the future... again... Anyway, I think I'll try to use Protractor to see if I can get on with that.

And for the record, the mission I went for to Dres, I went for it anyway, but, the transfer didn't work. Ended up going to Duna. Not too bad, needed to map and scan Duna for topography and kethane anyway. :D

But, I'd also like to add, for pretty much everything else, I use MechJeb. Launching, no problem, orbital rendezvous (which is freaking awesome to watch btw), docking, no problem (except that you have to persuade it the last 2m or so, seems ole MechJeb wants the flight controller to make sure all is well for the last 2m!), Mun and Minmus transfer, landing autopilot (which is also awesome!).

Actually, there is one other problem? Dunno if you can fix this one though. If you dock, the Vessel Information gets all muddled. Part of this I am sure is due to the staging becoming "entangled" (for want of a better term) by the game engine, but even after reordering the staging, the Vessel Information doesn't get updated with the new Delta V stats. This is a little annoying, as you end up with a stage with fuel and an engine, but MJ reporting 0m/s Delta V. End up flying this bit by the seat of my pants. Guess I have to do something this method I suppose :sticktongue:

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When using MJ for interplanetary injections I highly recommend a base altitude around kerbin of 500-600k so it can warp at full speed, it will still take a little time but no where near as much being limited 50-100x warps at lower orbits.

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If your talking about the bug I posted a pic of on page 115 then try not to alt-tab away from the game while it is loading. Simple but it seems to work though I have not a clue as to why.

yeah, this seems to work for me too, very odd!

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Alt-tabbing while loading does some other nasty stuff even to vanilla. One thing I've seen it do every time is turn parts black. Like the half-developed parts you see in add-on development. So just don't do that ever.

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theres a link back a few pages with the dev builds. ive been using those and the landing autopilot works pretty good now.

running -nolog in the exe line of a shortcut seems to help with the alt tabbing since it isn't spamming the log with the d3d lost stuff.

on another note

anybody else having problems getting the rover autopilot to work?

seems heading entries of either 090 or 90 seem to wig it out. and it doesn't seem to be holding either speed or heading.

Edited by COL.Neville
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theres a link back a few pages with the dev builds. ive been using those and the landing autopilot works pretty good now.

running -nolog in the exe line of a shortcut seems to help with the alt tabbing since it isn't spamming the log with the d3d lost stuff.

on another note

anybody else having problems getting the rover autopilot to work?

seems heading entries of either 090 or 90 seem to wig it out. and it doesn't seem to be holding either speed or heading.

The rover autopilot works fine for me, I have only tested it roving around KSC though. I will be heading to Duna soon so I can try it there aswell

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@r4m0n and The _Duck, I installed 2.0.7-35 to test it out. It makes my game unplayable. Planets I'm orbiting or landed on physically disappear and make those ships or landers inoperable. Kerbin turns into giant blue globe of light and Mun, Minmus, Duna vanish totally as if their physical models are removed from the game.

I put existing 2.0.7 back in and it all worked fine again. So um serious bug there.

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@r4m0n and The _Duck, I installed 2.0.7-35 to test it out. It makes my game unplayable. Planets I'm orbiting or landed on physically disappear and make those ships or landers inoperable. Kerbin turns into giant blue globe of light and Mun, Minmus, Duna vanish totally as if their physical models are removed from the game.

I put existing 2.0.7 back in and it all worked fine again. So um serious bug there.

I've had that bug happen to me several times before with vanilla KSP, so I'm not sure if that's Mechjebs fault.

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