New FAQs
Do you have no clue what's going on? Is everything weird and new to you? Make sure you've read the introduction first.
1. Installation & Troubleshooting
- What versions of KSP are supported by RP-1?
- How do I properly install a mod from GitHub?
- My reflective parts seem dark and glitched. Is TexturesUnlimited broken?
- I just launched the game and the KSC is all jittery and weird. How do I fix this?
- I can't enter any buildings, even with the sidebar buttons.
- My rocket disappears, the world goes dark, and NaNs are everywhere when I try to launch a rocket. What mod is causing this?
- Where are procedural solids?
- I can't switch the KSC!
- I can't see any continents in Map View or the continents are really hard to see.
- Why does Earth have no atmosphere in the main menu screen?
2. First Questions
- Why is it so dark?
- Wait, where are my parts?
- Why are there deprecated tank parts?
- Why is the tech tree full of empty nodes?
- Why am I still in the VAB when I try to launch a rocket?
- I'm on the launchpad, but my electric charge/liquid oxygen goes down. How do I fix this?
- Where do I get batteries from?
- Why can I select every tank type?
3. Building Sounding Rockets
- Why is my tiny rocket so expensive and takes so long to build?
- Why is my guidance unit so heavy?
- Why are these parts so costly to unlock?
- Why won't my sounding rocket engine light? (Vapor in feed line problems)
- How do I rescale my parachutes?
- Why are RealChutes so damn expensive?
- How can I get more dV out of my rocket?
4. Completing Contracts
- How do I add the payload I need for a contract?
- How do I complete the 3000 km downrange contract?
- How do I see how far downrange I am without accepting the contract?
- Why is it so hard to get into orbit?
- How on earth do I afford everything I need to build an orbital rocket?
- How do I stop my first orbit attempts from running into so many engine failures?
- Why is MechJeb PVG freaking out?
- Can I complete lunar flyby and impactor contracts with the same probe?
- I hit the moon with 40 kg of probe and the contract didn't complete. Why?
- What's the most efficient way to get into a Molniya or Tundra orbit?
5. KCT Recovery and Editing
- How do I recover a plane so I can fly it again?
- I recovered my plane but it says it's too big to fly again?
- Why does KCT edit say I've made expensive changes when I haven't touched anything?
- I've heard about airlaunching my planes. How does that work?
- Why can I recover to the SPH but not the VAB?
6. Advanced Questions
- Why did I lose all avionics control on my lunar probe?
- How do I build another pad at the same LC?
- Why can't I put any astronauts in a capsule?
- Why does KSP freeze and/or crash when I try to reroot parts in the VAB?
- How do I see biomes?
7. Using Other Mods
- Kerbalism: Why can't I transfer samples in uncrewed vehicles?
- kOS: Why do my scripts always kill the throttle?
- RealAntennas: Why does my electric charge goes down so fast?
First: make sure you've read the installation guide CAREFULLY and followed it exactly. The express install is always the best way to install. Also make sure that none of the non-CKAN mods on the mod list were installed via CKAN or you're likely to have the wrong and outdated version of things.
Also, don't assume that everything got installed right--sometimes CKAN rolls installation back without the user noticing. Most of the time, if you can't find a mod in your toolbar, it's because it's simply not installed. Check your GameData folder first.
RP-1 supports KSP 1.12.3/1.12.5 (if you can't downgrade to 1.12.3), and if you are installing/starting a new career you should definitely use this version. There are still legacy versions for KSP 1.10.1 or earlier, but those will not include the recent features added to KSP, and are frozen on the respective releases.
Good question. On the sidebar, there's a whole article that will teach you how. Here's the link.
If your TU/ROTanks parts look like this, then you'll need to go to the graphics options from the main menu and raise your render quality. Also make sure "reflection refresh mode" isn't set to "Off".
I just launched the game and the KSC is all jittery and weird. How do I fix this?
It's a bug that happens when opening a save at a KSC not at Cape Canaveral. Two scene changes will fix it, so just pop into the tracking station twice (might need to use the sidebar on the bottom left because it's probably hard to click on the messed up buildings).
Follow the install guide. Remove SSTU, SSTU Tools, and any other SSTU-related mods from your game.
My rocket disappears, the world goes dark, and NaNs are everywhere when I try to launch a rocket. What mod is causing this?
Follow the install guide to the letter.
Gone. We don't use them any more.
Install KSC Switcher. If you already have, clear your input locks using F7.
If you are using TUFX, in Map View the Ambient Occlusion feature makes the land really hard to see. You can fix this by using a profile that doesn't have Ambient Occlusion enabled when in the Map View; the built-in Default-Tracking profile is a good choice. This setting is stored in persistent.sfs, so will have to be changed for every new career.
This is normal, unless your atmosphere is also missing when you try to launch a mission.
Because it's night. You can warp a few hours ahead to the next morning.
If you don't have parts in the VAB (but you can unlock them from the tech tree), then you probably installed FilterExtensions. It adds an option to "hide locked parts in the VAB" in the difficulty settings that is checked by default. Try to find and uncheck that and see if that works.
Conversely, if you're wondering where your favorite engines went, ROEngines might have cleaned them up for you. Here's how you can get them back.
RP-0 is a work in progress and probably always will be. An old save can still be used through the changes if some part we intend to no longer use are left in place and marked (Deprecated). Use alt+click on the part if you have Janitors Closet installed to hide them.
The big blank ones are "blue sky" nodes, representing "pure research". Or, in game terms, shared prerequisites for multiple downstream branches, with no parts of their own. Those are intended to be blank. Most of the late-tree blank ones are just 'nothing there yet'; chances you'll never get that far.
A few mid-tree nodes are blank by default but get some parts from optional mods; unless you feel like hunting some down, they can be treated like unofficial blue-sky nodes.
Your rocket was put into the KCT build queue, which you can see by clicking on the KCT button on the toolbar in the space center or by clicking on the launchpad. It will take some time to build--you can warp ahead to when it is finished. After it's been built, you'll need to roll your rocket out to the pad and then you can launch it.
Use a launch clamp. It'll keep your charge fresh until launch, and it'll keep your cryogenics topped off from boiloff on the pad.
Electric Charge (EC), can be added to Service Module (SM) tanks. Procedural Avionics cores have SM tanks built into them as long as your Avionics Utilization (the amount of the part taken up by avionics) is below 100%. The avionics configuration menu will let you add EC to a procedural avionics part.
To help you plan ahead, you can now select tank types you haven't unlocked. You cannot build with them though. If you open the tank selection UI, it'll only show you the ones you have unlocked. The KCT window in the VAB will also tell you if your design has a locked part.
You probably didn't tool your parts. Also, you need to assign engineers to your launch complexes in order for anything to build. At the start, each LC will have a very low efficiency, but this will improve with time and with materials science tech.
If you've tooled all your parts, you're getting close to maxing out engineers, and the efficiency has reached at least 30% and your rockets still seem like they're taking forever (more than a year is too long), then either you're using horribly inefficient designs or you're trying to do contracts that you don't have the tech for. Check out some real-life rocket designs & take note of which engines they used (this Wikipedia page is a good start) or attempt easier contracts while you await better tech.
There are two (main) types of avionics, science core and near-Earth. Near-Earth avionics includes all the heavy and power-hungry equipment needed to actively orient the spacecraft. Stuff like gimbles, advanced flight computers, and star trackers are why guided avionics tend to be so heavy and draw so much power. Larger rockets will also require more mass from their guidance units. For smaller and simpler rockets, there's another option, science core control. Consisting of simple time-delay circuitry and an antenna to send back data, these systems are much lighter, cheaper, and less power-hungry, but that comes at the cost of not being able to orient the rocket/spacecraft or throttle beyond on or off (using "X" and "Z"). Especially at the start, you should try to use science cores wherever you can get away with it (though some contracts will require guidance). As your tech improves, avionics will get lighter, less power hungry, and, eventually, cheaper. You will need deep-space avionics for control beyond 2x GEO distance, but you can learn about that when you get there by looking at the description in R&D.
Entry costs are paid to unlock items for use in the VAB. As you do research, a portion of the base salary of your researchers will go into unlock credit, which can be spent on entry costs and tooling. If you run out, you'll have to use your regular funds. Entry costs are modified by other items, for example, if you unlock a procedural Avionics Science Core Tech Level, Near Earth of the same level will be cheaper. This is true for many parts, especially for engines that were historically used together. Unlocking the RD108 will make the RD107 far far cheaper (180,000 funds down to 10,000), and vice-versa. Unlocking the LR-89 will make the LR-105 free. Sometimes, there is shared technology between multiple parts. The Nike, GCRC, and Castor solid rocket boosters all share an entry cost modifier for being hollow solid motors. Unlocking any one of those reduces the cost of the others.
Entry Cost Modifiers (ECMs) are shown in the part description in the R&D/VAB (even though it's a bit complicated to understand).
If you're not using full avionics (you shouldn't be if you're just trying to go straight up), then you cannot alter your throttle once in flight (besides turning it on/off with "X" and "Z"). Make sure you turn your throttle to max while you're still on the ground and have control.
Other reasons your rocket might not be working:
- You're not using a high-pressure tank but you are using a pressure-fed engine (of which the Aerobee is one).
- There's no fuel in the tank.
- You removed the EC of your procedural avionics accidentally.
- You have no launch clamps (some engines require launch clamps to start. Wait until the engine has reached full power before releasing the clamps)
If you've done those but get vapor-in-the-fuel-line issues, you're suffering from ullage problems. Ullage is the bubble of vapor in the top of a tank of fluid. If you start accelerating backwards (as can happen from drag), your fuel will slosh to the top of your tank and the ullage will move backwards. If that vapor gets into your fuel lines, your engine will no longer be lit and you will have a problem. In RO, this is represented as engines not igniting unless the fuel is settled. You can right click on an engine to see the fuel status (eg. unstable, risky, stable), or look at the engine icons in the staging display. Red and orange engines will not ignite as their fuel is not settled.
There are a few methods you can use to stop ullage problems. The first, and perhaps the simplest, is to light the engine while the previous stage is firing, known as hotstaging. This is generally simpler and was used on rockets such as the R7. If you're building an Aerobee-esque rocket with a solid kick stage underneath it, as recommended in the first launch guide, you should fire it still in the ground, along with the Tiny Tim. Then, once the Tiny Tim burns out, you can decouple it and continue on your way. For liquid fueled engines with longer burn times, you will want to stage 1-2 seconds before burnout. The timing can take a little trial and error; mods like Better Time Warp which slow down time can also help you be more precise.
If you need to ignite an engine after a coast and you can't hotstage, you can use either small solid separation motors or RCS. Be careful though - if you're low in the atmosphere, early RCS configs may not be powerful enough to overcome aerodynamic drag and maintain a positive acceleration. For this reason, hotstaging is recommended for early sounding rockets.
Go to the action groups screen, select the parachute, and choose "next/prev size" from that big menu.
Go to the action groups screen, select the parachute, configure it for the payload you want to recover and Apply the changes. Don't configure it while your entire rocket is attached.
"Moar boosters" still works, but not nearly as well in Realism Overhaul as it does in stock KSP. Many times it's much more efficient to minimize payload mass and mass fraction or advance in the tech tree, than making a bigger rocket. The tanks that you will be able to build will improve with your research of Materials Science and your avionics will improve with the Avionics technologies. The earliest tanks have a very poor mass ratio. Mass Ratio is the dry mass compared to the wet mass. Similarly for Avionics, you will be able to use much lighter avionics as you advance. Due to the tyranny of the Rocket Equation, every kg matters. It is very important to upgrade your tanks and avionics as soon as you can to get more Delta-v from each stage. The first of these upgrades will massively improve your rocket's performance. However, as you go for more ambitious milestones, you will definitely need bigger rockets. The best way to do this is usually by using more advanced engines, with greater thrust and better Isp, instead of trying to create monstrous designs with early engines.
Some Contracts require payloads. Sounding Rockets, Weather, Communications, and Navigation Satellites all have unique "payloads". Sounding rocket payload can be loaded into a high-pressure tank, but the rest require a special payload part. Sounding rocket payload is used to simulate the experiments and ballast that were historically loaded onto sounding rockets. Satellite payload abstracts the requirements of a specific satellite into a single resource. For example, a communications satellite requires solar panels, batteries, antennas, data storage, etc., but RP-1 models this as just some mass of CommSatPayload. You can add the payload using the Tanks GUI from the tank part's PAW in the VAB.
While you can put sounding payload in service modules, if you're putting sounding payload in anything more fancy than Conventional Tanks-HP, I'd say you've probably gone the wrong way. Service modules are very expensive, especially for the contracts that require sounding payload.
You need about 6000 m/s dV to complete this one. If you need help designing this rocket, follow the tutorial.
Open the MechJeb menu in flight and turn on the Flight Recorder window or the Ascent Stats window. Unlike the Flight Recorder window, the Ascent Stats window has unlimited memory, so it won't stop recording your downrange distance after a time.
Orbit is hard, taking about 9.2-9.4 km/s of delta-v to reach, once you account for drag and gravity losses during ascent. One thing that can help a lot is better and lighter tanks. The tanks that you will be building will improve with your research of Materials Science. The earliest procedural tanks (conventional ) have a very poor mass ratio. Mass Ratio is essentially how heavy the rocket is without fuel, or the dry mass compared to the wet mass. Due to the tyranny of the Rocket Equation, every kg matters. It is very important to upgrade your tanks as soon as you can to get more Delta-v from each stage. Upgrading your tank materials from sep-steel to sep-al and beyond will massively improve your dV. By the time you get to orbital rockets, you will probably want to move into integral tanks for even better performance. Take a look at the tank types wiki page for more information.
Other things that can help is not having to always push heavy avionics around. Using an unguided kick stage (a high-thrust, quick burning stage, such as an Aerobee or vacuum-optimized solid motor) can help you get a lot more dV out of your top stage of your rocket. After your last guided stage burns out, you will coast to a few seconds (~20/30) before apogee. Then, you will point your rocket at the horizon using RCS. To keep the kick stage pointing in the right direction, you will need to spin it up, just like space organizations did historically. Use RCS to spin your whole rocket before igniting your kick stage and releasing it. Hopefully, that will be enough to put your payload into orbit! This graphic might also help you.
Accepting either Early Satellites program will give you a lot more income. It's probably now also time to start saving up a little, as your unlock credit might not cover everything you need for an orbital rocket.
First, check and see if you're significantly overburning any of your engines, but the most likely issue is that early engines just aren't all that reliable and early real-life rockets failed a lot too. A success chance in the neighborhood of 50% for your first orbital launch is entirely reasonable, and, while launches and launch failures will give more DU for your engines, it's not unheard of to only get to orbit on your fourth attempt. When you unlock 1958 Orbital Rocketry you will have some more reliable engines and some more reliable configs for your existing engines.
See The MechJeb PVG Bible for a full guide, but there are a few likely issues. MechJeb will struggle to go directly from the pad into a very high orbit, so it's often best to go into a parking orbit with PVG and then maneuver your way to your final orbit with other tools. Another common issue is forgetting to turn off coasts by setting a fixed coast length of 0 seconds. For later rockets, a short coast phase may be acceptable, but you still need to make sure PVG doesn't try to coast for too long. Finally, MechJeb can have issues figuring out how to launch into a perfectly circular orbit, so if it won't initialize, try changing from targeting 180 km x 180 km to 175 km x 185 km and setting attach altitude to the periapsis if that doesn't fix it.
Yes, this is intended. If you miss the moon (like many historical impactors did), you'll get the consolation prize of a flyby.
Are you sure you had EC at impact? Otherwise, because of how ContractConfigurator updates, this contract in particular can be buggy. Use the Alt+F12 contracts menu to force it to complete if you fulfilled all the requirements.
Molniya and Tundra orbits are very similar. Both are designed to linger over the northern latitudes. In real life (and in Principia), an orbit with 63.4° of inclination will be more stable, and satellites in these orbits will play roles similar to the ones GEO satellites do at lower latitudes.
Launch into a low circular orbit (150 km) with the right inclination. Your argument of periapsis means you'll want an apogee high above the north pole and a perigee near the south pole. Thus, when you're at the maximum southern latitude you will reach (that would be 63.4° S), burn to raise your apogee to either just above GTO height (37-38Mm) for Molniya (approximately 2,400m/sec) and slightly less than double of that for Tundra (67Mm, approximately 2,770m/sec). You're unlikely to have connection during this burn, so create the maneuver node in advance and ask MJ to execute it.
After that burn, you'll want to raise your perigee until your orbital period is half a sidereal day (or a whole for Tundra). This should requires less than 200m/sec. A low-thrust motor/RCS makes this burn more accurate. Congrats, you've got a Molniya (Tundra) orbit.
Use the KCT menu in the sidebar in flight mode. Under "SPH" there should be a big recover button. You can do the same thing for unlaunched rockets (for example, if you had an ignition failure and need to roll back and out again) to recover them to the VAB. If you click the normal Recover button, you can also choose "Recover to SPH".
Sometimes this happens when using parachutes. Use the edit function of KCT (in the * menu next to that vehicle) and press "B" to move it back down (this is a shortcut provided by Editor Extensions, which you should totally download if you haven't already). If your plane's pointing up, rotate it back to horizontal. Make sure to extend your landing gear if they're closed!
You have untooled parts on your vehicle; you can use the RP-1 menu in the VAB/SPH to check what they are. Tooling all parts will make sure that a 0% edited vehicle is considered 0% edited. This is not intended behavior, and fixing this is on the to-do list.
It used to be you had to build a whole airplane to airlaunch your X-Plane, but those times are no more! KCT has a built-in airlaunch capability for vehicles built or recovered via the SPH. To simulate an airlaunch, launch a regular simulation, and then click on the KCT button to bring up the airlaunch menu.
Step 1: Research some plane nodes to unlock airlaunch tech. It's always free to unlock them.
Step 2: Once you have airlaunch tech unlocked, you will have the option (in the KCT window) to Airlaunch a newly built or recovered plane rather than fly it off the runway.
Step 3: There are 4 airlaunch levels, which correspond to the real capabilities of historical planes used for airlaunching X-planes. As a result, there are dimension and mass limitations for airlaunching, and different range, altitude, and velocity capabilities for each level. You can tweak these before you are airlaunched. You can look in R&D to see what the capabilities of each airlaunch tech level are.
The result: you will sit on the runway for ten seconds (there's a countdown). Make sure your gear is retracted, your flaps are up, and your airbrakes are down. Throttle will be reset after the countdown, so once you're in the air, you'll need to throttle up and ignite your engines. The extra starting speed & altitude of airlaunching vs. taking off from the runway will aid you in your X-plane exploits.
KCT airlaunch does not guarantee you won't tear your pilots apart with poorly-designed hypersonic rocketplanes.
Here's a brief video demonstrating using use of the KCT Airlaunch function.
You can recover to the VAB... when you get 80s era Shuttle tech. That was the first time a vertically-stacked rocket was reflown, and the reason we limit rocket reuse until it was feasible.
Some types of avionics are more simple and only function near the earth, (up to 2x GEO altitude - 72Mm). Make sure you're using Deep Space avionics if you're going further than that and want to keep control.
At the bottom of the KCT menu there's an indicator that tells you what LC and what launch pad you're on. Press the "new" button to build another.
Make sure you've trained them first. You'll need to do proficiency training first (can take a very long time, but never expires) and then mission training before each flight.
Never reroot radially attached procedural parts!
In the Alt+F12 cheat menu, there's a checkbox you can select to show biomes.
Uncrewed sample transfer is an in-game difficulty setting. It’s on by default and off in hard games.
After a script ends, it resets the throttle to whatever it was originally. If you never manually put throttle up, it'll return it to 0 when it's done. Either remember to set the throttle up before starting your script or put something into the script to keep it running until the throttle can be set to 0. WAIT UNTIL FALSE. at the bottom of your script will do the trick. Other more advance methods would be waiting for the throttle to go to 0 (by some other method) or until you're in orbit/not accelerating/landed/whatever situation makes it safe to turn the engines off. You can also change the "manual" throttle by using SHIP:CONTROL:PILOTMAINTHROTTLE - this is equivalent to setting the throttle yourself via the keyboard and will persist when the script finishes.
This is described in the comment at the bottom of this example script from the kOS wiki (which is also linked in our sidebar).
If you came from RemoteTech, you probably have CommNet still off. You must enable CommNet in the game settings, then save and load the save you've just created. Don't forget to read the RA wiki--it's linked on the sidebar.
This is a strange bug that is consistently present with waypoint manager and RSS. Luckily, it's pretty harmless, so you just need to close the "Sun" tab and you won't be bombarded by the waypoints. You won't need to put any waypoints on the sun anyway.
Got more questions? Head over the RP-1 discord server and ask them there.