voneiden
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Posts posted by voneiden
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Consider taking a look at the illustrated tutorial in my signature. It teaches how to do a interplanetary transfer with a mid-course plane change in a relatively fuel efficient manner. I've gotten good feedback on it, so I think it should be quite easy (and quick) to follow.
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Alrighty, here's my current bugger list on the Mission Architect from yesterdays (solo) practice mission.
Bugs and unexpected behaviour
- Double tapping arrow keys while navigating the event list actually opens an event (is interpreted as a double click?)
- "Get state from KSP" can still return negative true anomaly for hyperbolic orbits, but requires the value to be [0,360] to be accepted in the orbit definition window. Manual modulo 360 does the job as a temporary fix.
- "Get state from KSP" doesn't set the orbit reference body? My vessel was in SoI of Minmus, get state returned valid orbital elements for the Minmus orbit, but it left the orbit body droplist selection as Kerbin.
- If there is already an optimization window open, opening a new optimization window from the menu bar/keyboarod shortcut closes the old one, erasing all unsaved constraint settings. Would be nice if the existing window would receive focus instead. I managed to do this somehow twice in a row :-)
- Altitude constraint wants boundaries in degrees (instead of km?)
Feature requests & ideas (do use your own judgement)
- Be able to change constraint associated event after definition (because if user adds a new event before other events, previously defined constraints will likely point to wrong event numbers)
- Relocate constraint associated event droplist from the bottom of the optimize window into the "define new constraint" popup (=better visibility)?
- Remember previously selected constraint associated event instead of defaulting to the last event, or default it to the same event that is currently selected for optimization?
- If events are deleted, some constraints seem to get sometimes deleted automatically too. I would rather delete/reassociate them manually. Alternatively they could be disabled?
- Being able to quickly see from the event list which events have optimization enabled. For example adding an asterisk before or after the event type? Coast with TA Opt set would look like "2 - COAST* - To Periapsis". "*COAST"? "*COAST*"? Bold text? Maybe not possible in the list box. I'm aware I can check it in the Optimize window, but that still requires tapping through all the events.
^ Many of the above seem to be somewhat relevant in my opinion when I have created a mission plan and am attempting to fly through it. Updating the vessel state after executing burns in KSP and creating correction burns etc requires adding/deleting/moving events, but generally the mission constraints do not change. As it is, it requires quite a bit of repetitive redefinition of constraints. In addition to being a repetitive task, it also takes time: the faster the mission planner can respond to the dynamic nature of the mission, the less waiting time for the pilot.
Remarks
- CTRL+O for optimize is great for left handed people.
- CTRL+R for reoptimize is great for right handed people.
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Hi Arrowstar,
do you prefer me to drop my future notes and what not here instead of reddit? Maybe it's more organized in one place that way. I'll see if I can get a proper multiplayer test for the newest update. Maybe this time we actually hit Minmus.
I accidentally selected yesterday on the Mission Architect an inertial dV maneuver instead of the usual orbital dV maneuver. Noticed it resulted in an error, and after a bit of tinkering I also got another kind of error. Now I know you're really fast at fixing stuff but these are really low priority. I don't even know in what case I'd use inertial maneuver over orbital maneuver.
Case 1 - Attempting to minimize distance to body with a single inertial node and coast.
- Error message: Objective function is undefined at initial point. Fmincon cannot continue.
- Error trace: http://pastebin.com/G36HWrwH
- Mat file: https://dl.dropboxusercontent.com/u/17806420/objective-undefined.mat
Case 2 - Attempting to maximize spacecraft mass, minimize inclination or eccentricity instead in Case 1
- Error message:
There was an error optimizing the mission script. Attempted to access eventLog(0,; index must be positive integer or logical
- Error trace: http://pastebin.com/GAWbaMfv
- Mat file: same as above
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Does the Altitude setting actually do anything? More often than not, it seems that raising everything up five meters or so would make a good location perfect, but it doesn't seem to work.
Apparently according to other users it doesn't really seem to change anything. I uploaded a new version that adds a bit of config tweakables as suggested by Nathan.. uhh.. already a month ago.. and allows disabling the surface flattening feature. No radical changes here otherwise. Download at the first post.
As a heads up to everyone, I've been testing Arrowheads KSPTOT tool during the past days and it's really neat. We attempted a few multiplayer sessions with a friend combining KSPTOT and KSPMC. It was quite fun to attempt to cooperate to achieve a common goal but unfortunately we missed our destination Minmus because KSPTOT thought it was somewhere where it wasn't. Arrowhead is mighty fast at fixing issues and that among many other things have been solved during the past week or so.
I find it's especially neat for planning approach burns to create trajectories that allow directly landing on certain geographical coordinates, or just optimizing for a capture orbit that allows descent to certain coordinates after one orbital revolution. The possibilities are endless.
KSPMC is still WIP, but is pretty good for general flight following already.
Edit: I figured that the bugged Kerbin/craft issue I've been having is purely dependent on a corrupted the craft in persistent file (parts get all mixed up order). If I fix the vessel manually Kerbin appears OK again. So I doubt it's related to moveksc.
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Has anyone had issues with .. a bugged world when you resume an existing flight? I haven't had time to enjoy actually playing with this mod and I just realized as I attempted to resume a flight that half of the planet was missing. Assuming it's related to this mod I released, KerbTown might do the job better considering it's now updated.
Slightly offtopic, Arrowhead just released a new version of the KSPTOT and I managed to run a first multiplayer test with my mission control plugin with a friend yesterday. KSPTOT is really neat and my first impression was that it would make my mission control project completely obsolete, but I was delighted to find that they actually seem to support each other. KSPTOT is excellent for planning the route, while my MC seems to be better suited for monitoring and guiding the active flight, at least for now.
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Hey, cool!
You might want to retain independent settings for the PQSCity and the MapDecalTangent; at times it's easier to place KSC directly on the terrain without also placing the MapDecalTangent under it. And/or you probably need to either automatically or manually figure out the radial offset (i.e. altitude above sea level) for both, probably independently.
Might also be worth looking at how KerbTown does things, since I'd hazard a guess it's better than how I do.
Thanks for your work Nathan (and of course everyone who's contributed to RSS)! I tried to utilize KerbTown some months back to achieve the same thing but couldn't get things quite working.
I might add some features if there's demand but generally this is just a little quick and dirty hack to make the stock game a bit more challenging. Now all we need is some proper ground tracks. My ground track rendering projects have been stalled for who knows how long, so I hope Rich succeeds with his NASA Mission Control Software project.. that would be such a blast!
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Did you use a bit of the system in RSS that allows changing location? Just asking because all those license and credit stuff. But I guess NK will welcome this anyway
When we are speaking licenses , you may want to add a license too..Hi voneiden,I am aware that you have included a licence in your source code (thanks for doing this) but it is also required to mention it in your post.
Yep the license (and credits) are in the source file which I've now included into the zip so that the whole package comes with the license. License also added in the main post above as per forum rules. Sorry, it's been a while since I've released any plugins.
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Howdy folks,
So I spotted that the people over at Real Solar System figured a way to change the location of KSC which is something I've wanted to do for quite a while.
So here be a tiny mod that allows everyone to change the location of KSC on Kerbin while not doing anything extra. The default config changes the latitude to 28.9411 degrees north and longitude to 20.1116 degrees west. The latitude is quite similar to Kennedy Space Center which should add some nice new challenges to the game.
Tips if you want to find your own place
To look for new places you might want to use HyperEdit. You can see your coordinates using something like Kerbal Engineering Redux or just from the map view when your vessel is landed (you need to convert the hour-minute-second values to decimal values though).
To convert from hour-minute-second to decimal value use the following formula: hour + (minute + (second / 60)) / 60. For example 15°10′20″N = 15.1722 . North is is positive, South is negative. East is positive, West is negative.
In addition when you change the latitude and longitude, the orientation of KSC gets messed up (Runway 09 does not point towards East). I'm sure there's an equation to calculate the correct orientation angle from the latitude and longitude but unless you figure it out you have to correct the orientation manually. The config file has extra tip on how to find the correct orientation setting.
Download kscmove-1.1.zip (2014-05-17) (Source included, license: CC-BY-SA as per RSS)
Download kscmove-1.0.zip (2014-04-14)
Edit: Also please do let me know if somebody already did a plugin like this. Thanks.
Edit: This "Launch Azimuth" article from Orbiter Wiki might be helpful when planning your new inclined orbits.
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Thanks for pointing out. Maybe I'll be back, to reach the airstrip in below 1m 52s it needs.. more.. boosters.. I'm back! Post above updated.
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Below both of my attempts!
Attempt 1 (disqualified)
Joining the fun with booster-only design. It comes in 3 stages: 1st stage goes straight up, 2nd goes straight horizontal and 3rd tries its best to get down as fast as possible. Landing with drogue chute opened at last moment.
1 minute, 46 seconds to touchdown. Could probably go a tiny bit faster by not going above 11 km altitude. Biggest time waster every time opening the chute a bit too early.
Attempt 2 (1 minute 45 seconds)
Same style as above, but more boosters in the first stage and more SAS for faster turning. The extra SAS allows the 3rd stage to point its nose downwards faster under all that drag. The booster cuts out at 1:30 which would be the ideal landing time, but unfortunately there's still some freefalling to do before touchdown. Could probably go faster by adding a few more boosters.............
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Good luck for the next record breaker! It's certainly still possible to go faster!
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http://forum.kerbalspaceprogram.com/threads/48342-How-to-warp-into-Eve-Gravity-Influence-in-the-correct-angle
This is the way...the raw way. No tweak, no config, no edit, no mods.
Doesn't look like a very fuel efficient way to me if you're doing plane changes that close to Eve. I think OP here is more interested in a direct off-plane transfer as one would do in Orbiter with the help of IMFD.
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Just as a tip: tweaking the conic patcher on the fly while playing makes life a lot more easier, perhaps give PreciseNode a try.
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Am I missing some key trick?
I think based on your description you're not actually using the target mode in the navball. Have you selected the target vessel through map view? If yes, does your Navball read "Target" instead of the usual "Orbit" ( Here it reads orbit: http://wiki.kerbalspaceprogram.com/wiki/Navball )?
If yes to both then once after zeroing out relative velocity, you aim at the target and accelerate a bit and you should start closing in. If the approach is slow you may have to correct your trajectory a few times because the direction your ship is flying in and the direction of the target will be drifting slowly apart.
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What attitude controls do you have on the rocket? That should not happen at least according to my experiences.
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Extraplanetary Launchpads allows for placing portable launchpads and runways. I think it can be configured not to require any resources to operate. So you can use HyperEdit to move a launchpad to the KSC2.
I really wish this would be implemented natively because I'm bored myself of launching from the equator. Latitude would make things more challenging!
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So where is your ship now? Landed or Duna orbit? Ah erm, nevermind. Good altitude periapsis altitude for Kerbin aerobraking is 25-30 km
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I'm going to expand a little bit what others have already suggested.
Direct rendezvous from launch. Assumes target has roughly constant velocity (=circular orbit)
- Through experimenting, measure the time (t) in seconds it takes to reach apoapsis from launch. Also estimate the angle between apoapsis and KSC (α).
- (Optional? Assumes launch towards East!) For greater accuracy: mark down the elapsed time (tα) when measuring α. While our ascent vehicle is flying, Kerbin is also rotating. This means the angle between apoapsis and KSC looks smaller when it is measured than it would look at launch time. Angular velocity of Kerbin is (Ékerbin = 2pi/21600 = 0.0002908882 rad/s = 0.0166666667 deg/s). Thus it can be calculated α2 = α + Ékerbin*tα
- Solve the angular velocity of the rendezvous target: ̉ۡtarget = v / r, where r = 600 000 m + h
- Calculate how many degrees rendezvous target moves during ascent: β = Étarget * t
- To get the angle x you should have between your target and KSC at launch time: β - α or β - α2
Example case 1 (not a real test case, arbitrary numbers chosen):
Space station is orbiting on a circular orbit at 250 km with a velocity of 2038 m/s.
Step 1: The launching vehicle is tested with the following traits:
- Time to apoapsis t = 10 min = 600 s
- Angle to apoapsis α = ~40 degrees (measured at 7 min = 420 s)
Step 2: Kerbin's rotation: 0.0166666667 deg/s * 420 s = 7 degrees. Thus α2 = 40 + 7 = 47 degrees
Step 3: B]̉ۡtarget = v / r = 2038 m/s / (250 000 m + 600 000 m) = 0.00239764706 rad/s = 0.137375057 degrees/s
Step 4: 0.137375057 degrees/s * 600 s = 82 degrees
Step 5: x = 82 degrees - 47= 25 degrees
So, the launch should occur when target is 25 degrees away from KSC.
I'm going to test this now to see if I wrote complete nonsense. BRB.
Example case 2 (tested in KSP):
Step 1: The launching vehicle is tested with the following traits:
- Time to apoapsis t = 7 min 49 s = 469 s
- Angle to apoapsis α = ~47 degrees (measured at 2 min 39 s = 159 s)
Step 2: Impact of Kerbin's rotation is about 2 degrees. So α2 is 49 degrees.
Step 3: The rendezvous target is at 200 km circular orbit flying 2101 m/s. Angular velocity 0.15 deg /s.
Step 4: During the ascent the target moves 70 degrees.
Step 5: 70-47 = 21 degrees.
I used Kerbal Engineering Redux to see the phase angle to the target ship before launching. When the phase angle hit 339 degrees (21 degrees before 360) I slammed launch and followed my ascent profile:
- Full thrust to 150 m/s
- 50% thrust to 6 km
- 75% thrust to 10 km, pitch 45 degrees east, thrust 100%
- After staging, pitch 25 degrees east. 100% thrust until apoapsis hits 200 km
The result:
I'm pretty sure if your angles are +- 5 degrees you will still get a decent intercept so there's no need to be as meticulous as I was.
Also step 2 doesn't seem to make much of a difference for low kerbin orbits. - Through experimenting, measure the time (t) in seconds it takes to reach apoapsis from launch. Also estimate the angle between apoapsis and KSC (α).
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That video is always beautiful to watch and listen.
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Ah, this looks great. There would have been quite a bit of work to implement all the stuff on TODO list to maneuver node improvement. Considering this does all it did, I can drop MNI for good and focus on KSP Mission Control without feeling like I'm neglecting anyone who uses MNI! I'll add a redirect from the MNI thread to here.
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If you got the time, take a peek at the tutorial in my signature
Try to set up to around 150,000 meters. QUICKSAVE (F5), because the game sometimes glitches and the periapsis in incorrect. Once you enter Joolian SOI, make a final node if neccesaryRemember not to use time warp when crossing a SoI boundary:
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Mun won't be of much help in an assist to LSO. It is generally worth less than 100m/s. Your biggest asset here will be Moho. By repeatedly getting gravity assists from Moho, you can get down into a orbit that goes between Moho and LSO. From there, you must burn at LSO to circularize.
Or Eve. Easier to reach and bigger gravity well. Though Moho has shorter period. Not sure which one would be faster, perhaps a good idea to consider both.
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now place a maneuver node in the map view as seamlessly to the ground as possible(better to be above the ground) you will now have a rough guess in time till you hit the ground
Alternatively, use the cockpit view which features a nifty radar altimeter (and vertical speed meter and of course the navball).
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Joystick works great for atmospheric flight, but I never found it very useful for space flight. Space flight (precision flight, like docking) tends to be more about applying gentle impulses so I actually prefer the keyboard there.
Also if the joystick has little dead zone or slight calibration issues it's gonna easily cause slow unwanted rotation in space.
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I was looking into a way to plot a space trajectory (like KSP does) for a project of mine but was unable to find anything other than complex physics writings.
Is there any chance I could get a push in the right direction?
How did the developers for KSP research this?
Welcome to the forums, there are a few solid books on the matter. A pretty sound choice is "Fundamentals of astrodynamics and applications" by David Vallado. Books like this might be pretty hard to find though. Could you perhaps clarify if you're interested (as ZRM mentioned) in plotting the trajectory through physical simulation or through the 2-body problem ("rails")? The former is quite trivial with basic physics equations.
The latter has many different methods which do involve somewhat complicated mathematics. Presume your project involves programming? If yes, what language?
When we are speaking licenses , you may want to add a license too..
[WIN/MAC/LINUX] KSP Trajectory Optimization Tool v1.6.9 [New MATLAB Version!]
in KSP1 Tools and Applications
Posted
I've been gone for a while, but I sure am glad to see KSPTOT is still around and better than before. There's even launch window analysis! Yess, thanks Arrowstar!