sarbian Posted January 22, 2015 Share Posted January 22, 2015 Sorry skips but your "fix" does not makes sense. There may be a problem with the time estimate but replying to the sim that it must slow down to 90% of the current speed does not makes sense. Link to comment Share on other sites More sharing options...
Furious1964 Posted January 22, 2015 Share Posted January 22, 2015 The resonant orbit change your orbit so the new Orbital period is a ratio of your current one. Warning : explaining from memory. I may invert some things So say you have Sat A & B next to each other on the same orbit with an orbital period of 60 minutes . You use the resonant orbit to ask for a 4/3 orbit for A then you have A on a 80 minutes orbital period with a Pe of 200km and an Ap of more (not willing to do the math now). After 1 orbit you ask for MJ to circularize at Pe (200km). You end up with A & B on a 200km orbit with A 120° (1/3) behind B.Same as WuphonsReach explained.I'll try to do some graph to explain it tonight.Can I do a Hoffman Transfer and a Resonant orbit change at the same time? Link to comment Share on other sites More sharing options...
smjjames Posted January 22, 2015 Share Posted January 22, 2015 I don't think you can combine maneuver nodes, but you can do them one right after the other. Link to comment Share on other sites More sharing options...
LameLefty Posted January 22, 2015 Share Posted January 22, 2015 Can I do a Hoffman Transfer and a Resonant orbit change at the same time?You misspelled "Hohmann Transfer" ... No, not really. As described above, a resonant orbit is simply one that has an orbital period that is a ratio of another. A Hohmann transfer is meant to get your craft from its current orbit to intercept a target in a different orbit in the most efficient manner. Link to comment Share on other sites More sharing options...
Furious1964 Posted January 22, 2015 Share Posted January 22, 2015 Do I need to put the second satillite in a parking orbit?- - - Updated - - -I've been trying dozens of times to get this right and failing. My first satillite isn't even over the KSC. Link to comment Share on other sites More sharing options...
LameLefty Posted January 22, 2015 Share Posted January 22, 2015 Do I need to put the second satillite in a parking orbit?- - - Updated - - -I've been trying dozens of times to get this right and failing. My first satillite isn't even over the KSC.What are you actually trying to accomplish? A constellation of satellites in the same orbital plane? Orbital rendezvous? Link to comment Share on other sites More sharing options...
Furious1964 Posted January 22, 2015 Share Posted January 22, 2015 3 satillites over kerbin. In a triangle configuration. Link to comment Share on other sites More sharing options...
LameLefty Posted January 22, 2015 Share Posted January 22, 2015 3 satillites over kerbin. In a triangle configuration.Serbian's post, that you quoted above in post #8902, tells you exactly how to put one satellite 120º behind another. Do that twice and you'll have three satellites each 120º apart around Kerbin. Link to comment Share on other sites More sharing options...
skips Posted January 22, 2015 Share Posted January 22, 2015 Sorry skips but your "fix" does not makes sense. There may be a problem with the time estimate but replying to the sim that it must slow down to 90% of the current speed does not makes sense.FixedUpdateCoastToDeceleration() drops you from the coast state to the LandStep.DECELERATING if the ship's speed is greater than 0.9 times the speed returned by MaxAllowedSpeed(). To prevent changing state you need to return a speed that is 1.11111111 times larger than the ship's speed. For that reason, you must divide vel.magnitude by 0.90. I added the 1.0 just to make sure that the finite precision issues did not cause any problems. I can assure you that this code actually prevents the simulation from attempting to traverse the last 1000 meters at 1 meter per second speed.skips Link to comment Share on other sites More sharing options...
sarbian Posted January 22, 2015 Share Posted January 22, 2015 Yes, but it's not used only there. If there is a problem with the logic of FixedUpdateCoastToDeceleration then it must be fixed. But sending back a magic value does not fix the problem, it just hide it. Link to comment Share on other sites More sharing options...
skips Posted January 23, 2015 Share Posted January 23, 2015 sarbianThe change makes the routine meet the contract that is defined in its definition i.e., allow the atmosphere to slow the spacecraft. The original implementation of the returned a zero when the plan was to end and apparently the caller was supposed to recognize this flag. It appears that the autopilot code was rewritten without taking this requirement into account and the person who rewrote the autopilot decided to arbitrarily return the value 1, which corrupts the landing simulation. If the plan is intended to track the required maximum velocity all the way to the ground, then it will need substantially more information than the original design gave it.skips Link to comment Share on other sites More sharing options...
xytovl Posted January 23, 2015 Share Posted January 23, 2015 The speed policy is for powered landing.The simulation already integrates the drag during reentry, then asks the policy if it should fire the engine. Changing the engine simulates a different piloting behaviour. The correct change would be to return touchdown speed for the last meter, and increasing values for the suicide burn part. The problem is that it can't be accurate over a few hundred meters in the atmosphere.I would replace it with a backtracking system where different actiation times are tested until we find the precise moment where it is an atmospheric suicide burn. Link to comment Share on other sites More sharing options...
smjjames Posted January 23, 2015 Share Posted January 23, 2015 Maybe just see how NASA programs landing guidance????Just an off the wall thought, lol. Link to comment Share on other sites More sharing options...
Starwaster Posted January 23, 2015 Share Posted January 23, 2015 Maybe just see how NASA programs landing guidance????Just an off the wall thought, lol.They crib off of KSP forums. Link to comment Share on other sites More sharing options...
Rock-it-man Posted January 23, 2015 Share Posted January 23, 2015 Hey guys,I've checked and re-checked everything and I can't get it to work.Vanilla install of 0.90 (non-steam) downloaded MechJeb 2.4.2 from curse, put the Mechjeb2 folder and all its contents in the gamedata folder.I can see the Mechjeb parts in VAB and SPH and I can install them on a craft, but the MechJeb UI doesn't show up. The tab in the top right doesn't show up like it used to. Suggestions? Link to comment Share on other sites More sharing options...
Virtualgenius Posted January 23, 2015 Share Posted January 23, 2015 Do you have the toolbar installed and is it sandbox or career Link to comment Share on other sites More sharing options...
Rock-it-man Posted January 23, 2015 Share Posted January 23, 2015 Toolbar? Haven't heard anything about a toolbar?- - - Updated - - -Sandbox. I've used mechjeb before, it's always worked for me till now. Link to comment Share on other sites More sharing options...
pargentum Posted January 23, 2015 Share Posted January 23, 2015 Differential trottle + KW slow starting engines = loss of control?I am launching an asparagus rocket and tried to enable Differential Trottle option in Utilites. During vertical ascent it went OK, but when I begin the gravity turn, rocket started oscillating around two axes and after several oscillations went into uncontrollable spin. I noticed that at least one of engines was completely shut down during the spin. This happened both with Ascent guidance and manual ascent with SAS enabled. I managed to launch it with disabled Differential Trottle, so I am sure there is nothing wrong with the rocket per se. I also tried to fight this using TAC fuel balancer without success, so I am practically sure this is because engines do not react to trottle fast enough.Here is the picture of the ship to explain what kind of rocket layout I use: https://lh5.googleusercontent.com/-KVoPKLFVSEw/VMDLZR9XZGI/AAAAAAAACCc/SdnJf77suG0/s1280/screenshot177.png External stages (black conical tanks) use KW Titan-T1, internal (orange cylindrical tanks) KW Griffon XX. I can provide .ship file if necessary.By the way, I managed to land the second small asparagus (sitting on the top of orange tanks) to Eve and lift it back to the orbit! Link to comment Share on other sites More sharing options...
sarbian Posted January 23, 2015 Share Posted January 23, 2015 Rock-it-man : Windows ? Installed in program Files ? Log ?Maybe just see how NASA programs landing guidance????Just an off the wall thought, lol.Sure. "Excuse me Sir, can you send me the code for you multi million dollar program so I can use it for my pet project ?".Not the first time I see that argument so I'd like to remind people that the various space agency have advantages over us : - They know the specifications of what their program will pilot when they code/setup it - They don't have to write code that work with the amazing vessel design MJ has to cope with (this is sarcasm for those whose detector is broken) - They can do countless simulation in datacenter filled with CPU - They work with a world where the physic does make sense - Their world does not slow down with the number of part on the ship - They get paid for it and don't have to earn money with day jobs.But then we have advantages over them too : - We know stuff like our velocities, positions and mass to the last digit in real time. - We can read the all the law of physic - No one dies when we mess up. (Not sure about that one given the tone of some post I had to deal with in the past) - F5 and F9 Link to comment Share on other sites More sharing options...
Virtualgenius Posted January 23, 2015 Share Posted January 23, 2015 NASA uses KSP I have seen it, my guess there getting ideas for the SLS Guidance system from MJ Link to comment Share on other sites More sharing options...
Meumeu Posted January 23, 2015 Share Posted January 23, 2015 Differential trottle + KW slow starting engines = loss of control?I am launching an asparagus rocket and tried to enable Differential Trottle option in Utilites. During vertical ascent it went OK, but when I begin the gravity turn, rocket started oscillating around two axes and after several oscillations went into uncontrollable spin. I noticed that at least one of engines was completely shut down during the spin. This happened both with Ascent guidance and manual ascent with SAS enabled.That's not surprising, if the engines are slow to start MechJeb won't be able to apply the correct torque on the engines. It might work if the attitude control response is slower than the engine response but that's just a gut feeling, I've never tried this. Link to comment Share on other sites More sharing options...
sarbian Posted January 23, 2015 Share Posted January 23, 2015 (edited) I guess it could be fixed by replacing the "float mainThrottle = vessel.ctrlState.mainThrottle;" in MechJebModuleThrustController.cs by "float mainThrottle = e.currentThrottle;" to get the engine actual throttle. The engine wrapper may need an update for that one too. Edited January 23, 2015 by sarbian Link to comment Share on other sites More sharing options...
smjjames Posted January 23, 2015 Share Posted January 23, 2015 @ sarbian: heh, yeah, it wasn't entirely serious and I did say off the wall. Link to comment Share on other sites More sharing options...
LameLefty Posted January 23, 2015 Share Posted January 23, 2015 NASA uses KSP I have seen it, my guess there getting ideas for the SLS Guidance system from MJUm, no. You've seen some animations and stuff for public consumption.Real work is done with dedicated simulation software like MATLAB and, for spacecraft operations, control and display, STK (Satellite Toolkit). These are aerospace-industry standard tools that have been developed over decades. Don't get me wrong - KSP is fantastic for armchair astronauts and what Sarbian and a handful of others have done with MechJeb is nothing short of amazing. But it's not the real-world. Link to comment Share on other sites More sharing options...
Starwaster Posted January 23, 2015 Share Posted January 23, 2015 Um, no. You've seen some animations and stuff for public consumption.Real work is done with dedicated simulation software like MATLAB and, for spacecraft operations, control and display, STK (Satellite Toolkit). These are aerospace-industry standard tools that have been developed over decades. Don't get me wrong - KSP is fantastic for armchair astronauts and what Sarbian and a handful of others have done with MechJeb is nothing short of amazing. But it's not the real-world.It's humor. Try to understand this.Nobody seriously suggested that NASA is using MechJeb OR KSP for anything... Link to comment Share on other sites More sharing options...
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