KerbinGeographic & Scientific

Rendezvous � Map Creation � Configuration Files

Rendezvous

Rendezvous:The ExtremeChallenge. Page 2

Generating beautifulmaps from your datapoints. Page 5

Adding to the gameplay: Configurationfile editing. Page 7

July 2012 • Vol. I, Edition. 2

Contents

A Word from the Editor 1

Your how to guide: Low orbit rendevous 2

Your how to guide: Generating maps with QuikGrid 5

Mission Preparation and Debriefing: Editing the KSP configuration files 7

A Word from the Editor

Welcome to the second edition of the KGSS Journal - where science meets KSP. Membersof the KGSS enjoy injecting real science themes into their space program and this journalcan help you invent missions, craft and mission objectives outside of the mainstream flightsmost people fly.

This edition has a very handy article written largely by Kosmo-not on how to rendezvouswith craft in low Kerbin orbit - without mods. Simple maths is all that is needed and thismaths has been done for you. It is so simple it is hard to believe so if you find rendezvousby mod a difficult task - try rendezvous by maths - it’s even easier.

Part two of map making guide is in this edition and completes the guide on how togenerate your own 2D or 3D surface maps. If anyone has discovered some nice *free* mapmaking tools for PC and/or MAC then please let me know and I’ll advertise this to theKSP world.

Rich and Zephram Kerman have an in-depth article on how you can tweak KSP files fora bit of fun and frivolity, including pitfalls to avoid, what you should and should not tweakand how you can modify crew and ship characteristics.

If you enjoy reading the KGSS Journal and wish to see more quality articles in the future,please make a comment on the KSP forums. If more people comment on the journals thenwe’re more likely to keep this project going.

togfox

Acknowledgments

This journal would not have been possible without the hard work of Rich, togfox andZephram Kerman, to find us at www.kerbalspaceprogram.com please follow the link belowto the forum thread.

KGSS @ Kerbal Space Program Forums

Contributing

If you would like to be a part of future editions, please send your proposal to togfox viaforum private message using the following link.

togfox @ Kerbal Space Program Forums

Copyright Notice

Copyright KGSS 2012 all rights reserved. All articles published with original authorspermission. This KGSS journal is not endorsed by SQUAD and all rights are retained bySQUAD.

Your how to guide: Low orbit rendevous

Kosmo-not and togfox – www.kerbalspaceprogram.com

Difficulty IntermediateKSP version 0.15.2

Time 2 hoursMods None

KSP v0.15.2 does not support craft docking with each otherbut that doesn’t stop us practicing low orbit rendezvous.If you’ve ever tried to ’intercept’ a satellite in orbit you’llknow it is quite a challenge to get two orbits in sync andtakes much patience, even with mods and add-ons. InMarch of this year, Kosmo-not provided a simple means ofachieving an orbit rendezvous without mods and withoutplug-ins. Straight forward maths, presented in the easiesttable ever, can get you to where you need to be. Printedhere, with Kosmo-nots permission and some minor edits,is his original post. He describes how he enters an 80kmparking orbit before attempting to intercept a space stationorbiting at 100km. — togfox

I’m going to be jumping right into orbital ren-dezvous. There are two important things to knowbefore getting started: orbital plane change maneuverand circularizing orbit. I won’t be covering how to dothese two tasks, so you will have to look those up onyour own.

Let’s pretend we have a space station sitting in acircular orbit of 100km. Our plan is, of course, torendezvous with it. All of the tutorials I have seen onrendezvous involve a lot of guessing. This is becausewe have very basic instruments to guide us. But, thereis one piece of information that we have that can tellus almost exactly when to initiate our intercept burn:

distance to target. You can get this distance by hover-ing your mouse over the target diamond in your mapview.

For the purposes of this tutorial, launch will betimed to insert into a parking orbit of 80km, endingup a little behind the station. After achieving a circu-lar 80km, we wait to catch up to the point of interceptburn initialization. The question is: how do we knowwhen to do our intercept burn?

The math is not hard to understand. We start out withboth craft at the same point, and work backwards tothe intercept burn point. We know how much time ittakes to go from the burn point to intercept, and candetermine the position of the target at that time. Wecan then solve for the relative distance between thetwo objects.

Attached is a table I made with the distance to tar-get you have to wait for (any distance further than100km, and you won’t see it due to the visibility limit).In the case of this tutorial, the distance we need it50.4km (680km row, 700km column. Kerbin’s radiusis 600km). When we come within 100km range, thetarget diamond will appear and we watch the rangeuntil 50.4km is achieved. Then we burn prograde,raising our apoapsis to 100km to match our target.

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You then just need to wait half an orbit. We watchas the space station passes overhead and then ap-proaches from behind. Burn at apoapsis to completethe rendezvous maneuver. That wasn’t so bad, wasit?

The table is also the same for Mun orbits from480km to 600km (Mun’s radius is 200km). — Kosmo-not

Editors note: The same table can be used to move froma higher orbit to a lower orbit by burning retrograde andby using plug-ins like the Rendezvous feature in mechjeb,you can do transfers greater than 100km as the plug-intells you distances between craft - you don’t have to rely onvisible sight. :)

Acknowledgments

• Kosmo-not’s guide on rendezvous,Kerbal Space Program Forums

• Kosmo-not’s rendezvous table,Kerbal Space Program Forums

• Photography by togfox

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http://kerbalspaceprogram.com/forum/index.php?topic=14780.0

Your how to guide: Generating maps with QuikGrid

togfox – www.kerbalspaceprogram.com

Difficulty IntermediateTime 1 hourOther QuikGrid

In the previous edition of the KGSS journal, I de-scribed how surface data points can be collected usingthe crxTelemetry mod. If you followed the instructionscarefully, you’ll have a .csv file with three columns:

• Longitude• Latitude• AltitudeWith this data, you now have enough information

to plot a 2D topographic contour map or a 3D map ofany geographic feature you like. Follow these stepsand see how easy it is:

• Download Quikgrid from http://www.

galiander.ca/quikgrid/ (sorry - no Mac ver-sion).

• Install and launch QuikGrid.• Select FILE then Input Scattered data points.• Select Input metric data points.• Select your .csv file.and there you have your 2D map. There are some

settings you can use to tweak your map:• select the EDIT menu, then “number of grid

lines”. This increases your map resolution buttakes longer to draw a map

• select the EDIT menu, then “grid generation op-tions”. I use the values, from top to bottom: 1,

100, 2000, 2000• select the EDIT menu, then “view data point

options”. You can turn marks on or off or makethe marks large or small.

If you need some (large) .csv files for Kerbin, theMun and Minmus, check out the KGSS thread forlinks to these files.

To finish, here are some more useful command forviewing your maps:

• Left click and Page Up allow you to zoom intoyour map and Page Down lets you zoom out

• The arrow keys allow you to move around yourmap whilst you are zoomed in

• The HOME key resets your zoom level• Alt 2 and Alt 3 switch between 2d and 3d mode

(also available on the VIEW menu• When in 3d mode, use the bottom and right

scrollbars to change your viewing angle• When in 2d mode, right click any map location

to see it’s co-ordinates. Use this to plot your nextlanding site. NOTE: For some reason, quik griddisplays lat/long co-ordinates in the reverse or-der to KSP. You need to read the Quikgrid Yvalue first, then the X value. The Z value is thealtitude at that point

Figure 1: 2D Map of Minmus generated using Quikgrid

Acknowledgments

• Photography by togfox

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AboveThe three heav-enly bodies of theKerbol solar sys-tem - togfox

LeftZepher class rocketenjoying the ker-bolrise - ZephramKerman

Mission Preparation and Debriefing: Editing the KSPconfiguration files

Rich and Zephram Kerman – www.kerbalspaceprogram.com

Difficulty IntermediateKSP version 0.15.2

Time 1 hour

KSP has been built in a fashion which facilitatesmodification by developers within the community.One small facet of the modification opportunitiesavailable, is the editing of KSP’s configuration files, ofwhich there are four types:

• Settings file (.cfg): This defines the runningcharacteristics of the game, such as terrain de-tail and sound volume of the user interface. Thiscan be found in the top level directory of theKSP game folder.

• The persistence and the quick save files (.sfs):These store the current state of the game world,and can be located in the saves folder.

• The ship files (.craft): These keep all of yourfeats of engineering safe and can be found inthe Ships folder, which is neatly divided intothose which were built in the Vehicle AssemblyBuilding (VAB) and those which were built inthe Space Plane Hanger (SPH).

• The part files (also a .cfg): These files containthe parameters for the vehicle parts you have in-stalled, such as mass and drag. Naturally, theseconfiguration files can be found the in the parts

folder.This article aims to present some of the tools

needed for editing these files, and then to demon-strate some of the reasons for doing so.

The Tools

There are several pitfalls which can be encounteredwhen editing these files, but the majority of themcan be avoided by the use of the appropriate tools.The useful features of these applications will be high-lighted, this way you can make your own decisionsabout which editing tool to use. However, for thepurposes of this article we will be using notepad++.

The number one issue that people encounter whenediting these files, is caused by the different charac-ters used to signify the end of a line in each of theLinux, Mac and Windows operating systems. Thisissue was partially fixed somewhere between KSPversion 0.14.4 and 0.15.2 as the Mac and Windowsversions now contain configuration files with the ap-propriate line endings. Before this fix, there wereproblems when saving the files with a program such

as WordPad, which modifies all the line endings fromthe Linux markers, which is all KSP understood atthe time, to the Windows markers, resulting in KSPbecoming confused. While this fix solves the problemof editing the files locally, if you take part in collabo-rative efforts across multiple operating systems, youcan end up with configuration files which contain amixture of different line endings. Files such as thiswill still fail to load correctly in KSP.

Figure 2: Desired editing features in notepad++

The editing software feature which is required toavoid this issue, is the ability to display line endingsas shown in figure 2, which is an example of a per-sistence file with Windows line endings. With thisvisible, it is easy to see if their usage is consistentthroughout the entire file. The endings will appear asCR or LF for Mac and Linux systems respectively.

The second issue that people run into, is failingto match their curly braces. To help avoid this situa-tion, it is useful to have your editing software performparenthesis matching, this is demonstrated in figure 2by the red bar in the margin.

Finally, there are some issues to be aware of whenediting the persistence file while KSP is running. Thegame loads the file when you enter the environmentwith the VAB and the SPH, and writes to the file whenyou exit to the main menu. Therefore, if you wishto make any changes they must be made, and savedoutside of this region, so the game does not overwritethem.

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Figure 3: Runway markers help with night landings. The markers are just debris, perfectly positioned byediting their names, latitudes and longitudes.

So what can we do with this?

There are plenty of useful tricks which can be appliedto these files to improve the KSP game play, just someof these is what we will describe next.

Changing the Names of the Crew

Fancy yourself as the next Jeb? Let’s start with an easymodification, simply open persistent.sfs, find thename of the crew member which you wish to rename,and replace it with your own. We show this in theexample below by changing the value of the nametag to ’togfox’. KSP will automatically capitalise allnames.

CREW {name = togfox

}

Runway Markers

Trying to land on the runway at night is difficult, asthere are no landing lights. In order to improve thissituation, it is possible to strategically place debris, asshown in figure 3. This can be done by editing debrisparts into position off the end of the runway:

• First, find three bits of debris. (You might haveto crash intentionally if you’ve never crashedbefore.) In the photos I used Tosh’s hstwCart,

but anything will do. You can also start withthree intact vessels.

• Next, taxi a working spaceplane to the east endof the runway (towards the water) and park itthere. This temporary vessel will serve as yourreference point for latitude and longitude. HitEsc, and go to the space center. (Do not endflight.)

• Make a backup copy of your persistent.sfs file.It’s ok to put it in the /saves/default/ direc-tory, as long as it has a different name. I usuallyuse “Copy of persistent.sfs" since that’s the de-fault.

• Now open persistent.sfs with notepad++ orwhatever you prefer. (Do not use WordPad.)

• Use ctrl-F to find the first debris you plan toedit, and change the following lines to look likethis:

name = inner markers i t = SPLASHEDlanded = Fa lselandedAt =splashed = True. . .l a t = −0.04

( This should match the l a t i t u d e of yourr e f e r e n c e o b j e c t . )

lon = −74.4( This should be a shor t d i s t a n c e fromyour r e f e r e n c e o b j e c t , according toyour own preference . )

a l t = 0 . 0

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• (Optionally) remove any unwanted parts fromthe debris vessel (like a command pod or Mech-Jeb, if present), replace parts, etc.

• Do ctrl-C to copy the changes you’ve madeinto the clipboard.

• Now find the second debris item.• Do ctrl-V to paste the changes.• Rename it "middle marker". lon = -74.3 (This is

a little bit further east.)• Find the last debris item, and paste those

changes again.• Rename it "outer marker". lon = -74.1 (This will

put it a fair distance from the others. It’s a goodspot to point your plane during the initial ap-proach.)

• Save and exit the editor.• Go to the tracking station and select your tempo-

rary spaceplane. When it loads, hopefully youwill see those three marker debris out there inthe water, in a perfect line.

• Wait for twilight or dark, when the debris labelsturn white, then take off and enjoy the help!

Removing Debris from the Environment

Sometimes the game will slow down to unbearablelevels, one of the ways to alleviate the lag is to re-move some of the debris. This can be done with-out affecting any of your current flights by openingpersistent.sfs, and removing all the VESSEL entrieswhich have “debris” appended to their name:

VESSEL{

pid = 0name = Drag V I I I Debriss i t = LANDED

. . .

Copying Ships Across Save Files

During your time playing KSP, you will completesome historic missions, such as your first Mun land-

ing. If you want to copy this into a new persistencefile simply find the vessel name and copy the entireVESSEL entry. This consists of the VESSEL tag andthe surrounding curly brackets. Once this has beencopied, paste it at the bottom of your new persistencefile.

Modifying Ship Parts

To modify a part, in this example a fuelTankSmall:Copy the directory of the part, /KSP/Parts/fuelTankSmall, and give it a new name, i.e./fuelTankSmall2 Within this new directory, openpart.cfg with your favourite editor and modify thefollowing lines:

name = fuelTankSmallt i t l e = FL−T250 Fuel Tankdescr ipt ion = The T250 tank . . .fuel = 250 .0

to look something like the following:

name = fuelTankAwesomet i t l e = FL−T3000 Fuel Tankdescr ipt ion = The T3000 tankwas ’ borrowed ’ from ani n t e r−dimensional a l i en , andas such i t has seeminglymagical p r o p e r t i e s of s torage .

fuel = 3000 .0

which essentially increases the amount of fuel the tankcan hold. Finally, save and exit the editing softwareto complete the changes.

What does it all mean?

For reference, the authors have attempted to put to-gether a glossary of configuration file syntax in theform of table 4, which can be found on the final pageof this article.

Acknowledgments

• Unistrut’s post on editing persisent.sfs for fun, profit and lag reduction, Kerbal Space Program Forums• Photography by Zerphram Kerman

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Figure 4: Glossary of configuration file syntax

Tag Keyword DescriptionPART uid Instance number for the part.PART parent Reference object.PART position X, Y, Z location of the part in reference to the vessel’s root.PART rotation Orientation of the part.PART srfN Radial attachment.PART attN Attachment to the top/bottom, and the number of parts attaching

here.PART mass Current mass, including any contents.PART temp Temperature, similar to hit points.PART state Specific to part type.PART qty Amount of contents (fuel, etc.), this is a float.Other part-specific

variables can be stored here, such as MechJeb’s modes and settings.PART allowFlow True|False, Boolean logic to enable or disable fuel flow from this

tank.CREW state 0 means dead, 1 means available and 3 means the Kerbal is in flight.CREW badS Personality trait.CREW name Name of the crew memberCREW ToD Time of day.ORBIT SMA Semi Major Axis.ORBIT ECC EccentricityORBIT INC Inclination.ORBIT EPH Ephemeris.ORBIT REF Sphere of influence: 1 = Kerbin, 2 = Mun, 3 = MinmusVESSEL stg The currently active stage.VESSEL met Mission Time Elapsed for this vessel.VESSEL landed Usually blank, but can be KSC or runway depending on your loca-

tion.VESSEL sit Can have the values: SPLASHED, LANDED, ORBITING and ES-

CAPING.VESSEL pid Vessel serial number

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