RP 1 1.7 Early Rocket and Career Tutorial (WIP) - KSP-RO/RP-1 GitHub Wiki

Note: This tutorial is based on the one originally written for RP-1 v1.4, but is now updated for RP-1 v1.7. Key mods include Kerbalism, RealAntennas, TestLite, and all the RO part mods. The intended audience for this tutorial is anyone who is new to RP-1, or simply wants to speed up their early game and beat some historical dates.

RP-1 continues to grow and evolve. With all the changes between v1.4 and v1.7 of RP-1, it's time for an updated tutorial. This document will contain some design ideas for your first few rockets, including discussion of key considerations for each type. It will also look in detail at the first few missions from the VAB (and the SPH), including which ones are critical and which ones are optional. Lastly, it will look at what technologies you should unlock first (including a discussion of why), examine what technologies are needed for first orbit and first science orbit, and set forth a reasonable path to get there.

This guide was updated by norcalplanner in November of 2020. Welcome to the newest version of the career tutorial!

Table of Contents

1. New RP-1 Career Settings

2. Overview of Early Rocket Archetypes

3. Designing Your First Sounding Rocket

4. Building a Rocket

5. Go For Launch

6. Next Steps

§1: New RP-1 Career Settings

Note: This section may need to be merged with the existing article.

Selecting a Difficulty Setting

So you're starting a new RP-1 career. Congratulations! You have a lot of fun, interesting, and satisfying gameplay ahead of you. Full instructions and recommended settings for a new career can be found HERE but we're going to review a few key items in this tutorial as well. Start a new career and select your desired difficulty:

  • Moderate for experienced players
  • Normal for those new to this version of RP-1
  • Easy for those who are completely new to RP-1/RSS/RO and still learning the mechanics
  • Hard for masochists who have played many careers on moderate and want more challenge

Note that the primary things affected by the difficulty setting are funds and contract completion deadlines, so you'll earn more funds and have more time to complete contracts on easier settings. This tutorial is written based on moderate difficulty, but will point out where things will be different for those on easier settings. Also make sure to disable all contracts in the Contract Configurator screen other than the official RP-0/1 contracts. This includes disabling Scansat contracts, as RP-1 has its own Scansat contracts built in. Many players also disable pad ignition failures.

Choosing a Launch Site and Investing Your KCT Point

After choosing your new career settings and entering the KSC scene, select the RP-1 preset in KCT. If you've installed KSCSwitcher, DO NOT spend your initial KCT upgrade point unless you want to base your career out of Cape Canaveral, Florida. You still have to press the second button on that initial KCT window to proceed, but then simply close the window. If you don't have KSCSwitcher installed or simply prefer to stick with the Cape, skip the next step and invest your upgrade point in the VAB build rate.

Go into the Tracking Station and select the launch site you wish to use (Brownsville is good for beginners), exit, then pull up the main KCT window and spend your single upgrade point on upgrading the VAB speed to 0.1. Your first rocket will take years to build if you omit this step.

KRASH Settings

Before building any rockets, update the KRASH simulation costs from the KSC scene so you don't break the bank when testing your designs. You can either turn the costs off entirely, or set them to something very low, such as the recommended RP-1 Config.

Accept Your First Contract

Go into Mission Control and accept the “First Launch” contract. Total payout is a meager 6,000 funds, but we're going to earn a lot more. (Note: Players on normal or easy will have larger advances and contract completion payouts.) Before leaving Mission Control, look at the contracts and milestones which are already accepted by selecting the “Active” tab. We'll talk about these more in a bit, but for now just be aware that there are lots of these sorts of contracts which will automatically be accepted, even during flight, and will serve to reward you for pushing your program farther and faster.

§2: Overview of Early Rocket Archetypes

There are generally four early rocket types that a new career needs. Please note that the identifiers are arbitrary and have no connection to any formal rocket naming scheme. Click the links for images and further information.

  • Sounding Rocket Type 1

    • Construction: 0.30 m diameter – similar to WAC-Corporal
    • Typical Missions: First Flight, Sounding Rocket (Low), Karman Line, Suborbital Return
    • This rocket remains relatively unchanged from prior versions of the tutorial, although the engine now weighs a bit more so performance will be reduced somewhat.

  • Sounding Rocket Type 2

    • Construction: 0.38 m diameter – similar to Aerobee
    • Typical Missions: Suborbital Return, Early Intermediate Altitude, Low Space Bio Return
    • This rocket is a larger version of the Type 1, with an increased diameter to allow use of the early biological sample container. To push this larger rocket with confidence, you'll need either the XASR or AJ10-27 engine upgrade. Note that some players choose to skip this diameter, choosing instead to either put the biological sample capsule onto a 0.30 m rocket and pay the aerodynamic penalty, or place it on a larger Type 3 rocket.

  • Sounding Rocket Type 3

    • Construction: 1.65± m diameter – similar to A-4
    • Typical Missions: Intermediate Downrange LV, Difficult Altitude, Low Space Film Return
    • Based on WWII-era V-2 rockets with either an RD-100 series or A-4 series engine, this larger sounding rocket has much more capability. It also takes much longer to build, especially if a controllable probe core is fitted. There's some flexibility in the rocket diameter - smaller sizes (such as 1.5 m, used in the example rocket) offer cheaper tooling and less drag, but larger sizes (such as 1.8 m) will provide better future growth opportunities.

  • Sounding Rocket Type 4

    • Construction: 1.65± m diameter – similar to WAC-Bumper
    • Typical Missions: 3000 km Downrange, Difficult Downrange LV, Late Difficult Altitude
    • Essentially a combination of a Type 3 with a Type 1 or 2 as an upper stage, this two-stage rocket is the most capable of the early sounding rockets. With just a few early upgrades to engines, tanks, and possibly avionics, it should be possible to easily complete the 3000 km Downrange Contract. Experienced RP-1 cavemen may also achieve success with a three-stage RD-100 / WAC / WAC design without the upgrades, but it's not recommended. A stretched and upgraded version of a Type 4 rocket, with better engines, lighter tanks, some RCS, and a third stage added on top, may be good enough to put your first satellite into orbit.

§3: Designing Your First Sounding Rocket

Note: Before we get started building and launching these rockets to complete various contracts, please understand that this walkthrough is offered merely as one way of progressing at a healthy pace when starting a new RP-1 career. Many will have different ideas, and that's great! There are many roads to success!

We're going to start with a Type 1 sounding rocket, based loosely on the WAC Corporal. Note that this and the other example rockets all use the legacy Redstone texture, as the dark horizontal band near the top of each tank makes it easier to see how the tanks are configured and assembled.

Avionics and Tanks

Enter the VAB, then unlock and select the 0.30 m WAC-Corporal sounding rocket core. You can also use a procedural core if desired, but procedural cores offer no mass advantage at this point in the game, and cost much more due to the need to tool them. We'll cover procedural probe cores in more detail when we get to the Type 4 rocket.

Next, select a procedural "separate" tank and attach it beneath the science core. Right click the tank to bring up the Part Action Window (“PAW”), then select the high pressure variant (“Tank-Sep Steel-HP”) and use the sliders to match the diameter of the 0.30 m science core.

Note: Procedural parts are a big thing in RP-1. You'll spend a lot of time with the PAW open as you design your rockets.

The tank must be the high pressure variant, or the Aerobee engine we're going to use won't work properly. There are several locations in the game interface which indicate whether an engine is pressure-fed and therefore requires a high pressure tank, such as here:

Copy the tank and attach the copy on top of the probe core, then bring up the PAW and choose the “Smooth Cone” shape. Cycle through the different cone shapes and pick one that looks nice and pointy. “Peaked #1” is probably going to be the best cone shape from an aerodynamic perspective, so you may wish to choose that one. (Tip: You may want to get in the habit of specifying all tanks as smooth cones, even if the top and bottom are the same diameter, as it will make modifying existing designs easier in the future.)

Engines and Burn Times

Unlock the Aerobee engine and add that to the bottom of the sounding rocket. Right click each tank and choose the fuel mixture for that engine (which should be Aniline/Furfuryl/IRFNA-III). Right click on the engine to bring up the reliability data from TestLite (currently at 0 du), and note the rated burn time of 47 seconds for this engine. You can always burn five seconds over the rated time without any concern, and can frequently burn a little longer than that with minimal risk.

Note: Engine burn times and reliability are key considerations in RP-1. Engine choice and rocket design heavily influence each other, since many early engines have no throttling capability and short burn times. Many designs, particularly early in career, involve firing the engine a little longer than the rated burn time.

Now stretch the top and bottom tanks until you get a burn time in the MJ or KER window of around 54 or 55 seconds (reflecting an actual overburn of only 2 or 3 seconds, since TestLite gives each engine 5 seconds of extra burn time for free). The important thing here is that both tanks on this rocket have the same maximum diameter (0.3 m) and length, so we only have to tool one part. Before we leave the tanks, set their priority in the PAW so that they will drain bottom to top – this will help keep the CoM higher up in the rocket, making it more stable during launch. If tank priority controls aren't visible, go into the game settings and enable Advanced Tweakables to display them.

We'll cover the fins and Tiny Tim booster shortly, but the completed rocket should look something like this:

Minimizing tooling costs is important, particularly in the early career. However, it's still important to tool most of the procedural parts you're going to build, as it greatly reduces cost and speeds up construction time of your rockets. (The cost savings will come on subsequent rockets and follow-on designs which reuse existing tooled tank sizes, particularly diameters.) Also note that the diameter of a part for tooling purposes is the maximum diameter, so the smooth cone and the cylindrical tank are considered the same part as long as they're the same length.

Fins and Drag

Now unlock and select the early fixed B9 procedural wing part. Place four of them around the base of the tank just above the engine. Press J while over the wing to access the B9 tweakables menu, and make them into small, thin, and very swept fins. The leading edge should be swept more than the trailing edge. Make sure that no portion of your fins project further down than the bottom of the engine, or drag will increase considerably. When you have the shape right, right click on the fins and reduce the strength down to 0.20 (or 0.15 if you're feeling brave) to save weight. Here's a screenshot showing what these sort of low-drag fins look like, including the B9 procedural wing settings:

Minimizing drag, particularly transonic drag, is a key part of this (or any) rocket design, particularly if it will go supersonic deep in the atmosphere. If the fins are too large, not swept enough, or project beyond the bell of the rocket engine, then the rocket won't go as high as it otherwise would. For this early sounding rocket, it can mean the difference between reaching space or not. If you're looking for feedback on your fin design, open up the FAR window and select Transonic Design as shown above, then look at the "Mach 1 Wave Drag-Area" figure as you fine-tune things. Here's the FAR drag data for this rocket:

V1.7 Tip - Aerobee engines are slightly heavier now, and aerodynamic heating has increased somewhat compared to older versions of RP-1. It may be necessary to keep the fin strength up at 0.20 or higher to avoid fins being burned off on ascent, and it will be very difficult for a Type 1 rocket with starting tech to break 150 km in altitude due to the increase in rocket engine mass. If you're reusing a design from a previous career, you may need to tweak it a bit.

Decoupler, Booster, and Clamps

Add a 0.30 m procedural decoupler below the engine (be sure to reduce the impulse and force to zero so staging doesn't knock your rocket off course), then add a Tiny Tim booster beneath that. Copy and paste another set of your fins to the bottom of the solid booster, possibly making the fins a bit larger or putting them in 6x symmetry if more stability is needed on launch. Add a launch clamp, and use the offset tool to position the clamp so that it doesn't interfere with the fins. Then adjust the staging so that both engines ignite at the same time the launch clamp is released, with the procedural decoupler in the next stage above. Note that the Tiny Tim only burns for around a second, so you'll need to stage almost immediately after launching. The Tiny Tim also has a thrust curve and two variants with different thrust levels, so try both out and see what works better for you.

Scientific Experiments

Lastly, let's put on some science gear. To keep the cost down on this first rocket and get it built and launched sooner, we're only going to add the thermometer and barometer, which each weigh less than a kilo and cost only 1 fund. Since they have the same weight, place them on either side of the probe core, then use the offset tool to move them to the inside of the probe core. (On future rockets with procedural cores, it will be possible to configure the core to include certain experiments, resulting in fewer parts and a cleaner design; we'll cover that in a later part of the tutorial.) Here's an image looking down inside the rocket, showing the science gear offset into the center of the rocket.

Tip: With Kerbalism it's a good idea to turn on all science experiments, including those on the probe core, while in the VAB.

Flight Profile and Testing

We're going to try to reach space on the initial launch. In contrast to previous versions of RP-1, launch the sounding rocket straight up at first. Subsequent launches with more powerful engines can be angled a few degrees to the east or west to hit nearby biomes, but this first launch needs every advantage it can get. Note that precise flight paths aren't as critical with the Kerbalism Science system, since it's no longer possible to gain an experiment's entire value by dipping into a particular biome for a few seconds.

Now it's time to test your creation. Save the design, then click the KRASH button to enter a simulation. If everything works well, your rocket should barely leave the atmosphere.

§4: Building a Rocket

Tooling and Building a Copy

Once you're satisfied, enter the RP-1 window and go to Tooling. Choose “Tool all” and watch how the cost and build time of the rocket both plummet. Thanks to tooling, our example rocket drops from 323 funds to 82 funds, and the time to construct it improves from 94 days to 66 days. Hit the launch button to start construction on the rocket. You may want to construct a second one to use as a backup in case there are problems with the first launch.

Note: Building multiple copies of a rocket is common in RP-1, especially with new designs when engine reliability may not be the best, or when you're trying to launch during a certain transfer window. It's also important to keep the VAB busy all the time if you wish to maximize your career's progress. In this case, we want the VAB to start building the second rocket while the first one is being rolled out to the launch pad.

What about the SPH?

While this tutorial focuses more on rockets and the VAB, recent changes to RP-1 do still encourage using the SPH to build planes in addition to your rockets. However, it's not as easy of a choice as it used to be, due to the new single build queue. Back in RP-1 v1.4 - v1.6, building a plane was essentially a "free extra" due to the SPH's separate (albeit slow) production line. Now, building a plane will delay rocket production due to the single build queue in the customized version of KCT used by RP-1. There are different schools of thought whether your first plane should be a Cessna analog for lower cost science gathering, a barely-supersonic jet with early parts, or a rocket-powered X-plane. If you do choose to build a plane, make sure that you include the same science instruments on the plane that you placed on the sounding rocket.

With the new single build queue, constructing a Cessna analog can still make sense as your first build - just design it in the SPH, then slip it ahead of your sounding rocket in the build queue. (You may want to cancel your backup sounding rocket if you decide to build a plane first.) If the plane exceeds 1,000 meters in altitude and makes a steep climb at some point greater than 50 m/s vertical velocity, that plane flight will complete the First Launch contract. And as long as you're flying around, you may want to break the 5 km manned altitude record, and gather as much science as you can. It may be a little boring, but flying around for 45 minutes to hit the three biomes near Cape Canaveral (or two plus hours to hit the six biomes near Brownsville) will net a significant amount of early science and jump-start your research. You'll also receive 5 additional science points after landing for recovering a craft from an atmospheric flight. Here's a picture of an ugly Cessna analog which costs only 35 funds to construct:

Other types of plane may also be an option for your first launch. An early supersonic jet in particular will allow you to complete some significant contracts early (such as breaking the sound barrier) unlocking many of the lucrative X-plane contracts. Building such a plane is challenging and will require a lot of testing if you haven't designed one before (or you can pull one off of the craft files channel in discord). Regardless, some sort of plane should probably be built and flown relatively early in your career. It may also make sense to wait a bit, then build and launch a plane as your third or fourth launch while you're waiting for the next Tech node to unlock, such as the Post-War Rocketry Testing node with the RD-101 and XASR. You can still make good progress without flying planes early, but you may lag a little behind others in a race-to-space competition.

Flying planes is much easier with the Atmospheric Autopilot and NavHUD mods installed. Add them if you plan to fly planes to any significant degree. Here's NavHUD in action helping line up our Cessna analog on final approach.

Speeding Up the Single Build Queue (Optional)

If you've followed these instructions, you should have between 20,300 and 20,500 funds in your account. If you're feeling brave and don't plan on rushing your first rocket or plane, bring up the Upgrades tab in KCT, and [gulp] spend 20,000 funds on an upgrade point, leaving you almost broke. Use the upgrade point to increase the build rate of the VAB. Your sounding rocket should now take less than 60 days to build. (Those playing on normal or easy can purchase another upgrade point or two and increase the speed further, if desired.)

Routinely rushing rocket builds, which was a valid tactic in older versions of RP-1, is now much more expensive and therefore no longer as appealing of an option. While there may still be a limited role for rushing in a competitive race into space, its use in a typical career should generally be reserved for those rare occasions when you're in danger of missing a contract deadline.

That said, if you do choose to rush your builds to speed up your launches, now is the time to do it. Rushing will never be cheaper than it is at the beginning of a career due to the low cost of your earliest rockets and planes. And if you're playing on Normal or Easy difficulty, your funds situation should allow you to do both - speed up the VAB build queue first, then rush the first launch with your remaining funds.

§5: Go For Launch!

Press “Warp to Complete” to fast forward to when your rocket is done, then press the green “Rollout” button next to your completed rocket. Warp to Complete again to fast forward to the rocket being on the pad. If it's night time, warp to morning so you can enjoy the visuals of your first RP-1 rocket launch. Press the green “Launch” button to get this party started! Here's what the demonstration rocket looks like on the pad, with info windows showing:

Check your staging, throttle up, take a screenshot or two for posterity, and check the Kerbalism window (in the upper right) to make sure that all the science experiments are on. Press the space bar to launch, then press it again to stage either a moment before the SRB burns out, or just before the decoupler overheats. If everything is going well you'll now be heading up at breakneck speed, passing Mach 1 approximately 10 seconds after launch. Here's an image further along in the launch, as the fins are starting to heat up:

Kerbalism will automatically collect and transmit science so you don't have to worry about setting action groups or clicking science instruments like a madman. You'll see a number of notifications blinking in the corner; most of these are the auto-accepted contracts and milestones we mentioned earlier. You'll be blowing through these, collecting lots of funds and setting many new records for height and speed during this launch. If things go well, your rocket should barely escape the atmosphere, reaching an apoapsis of around 145 km.

Your nosecone and fins will likely burn off and explode as your rocket falls back to Earth and reenters the lower atmosphere, but stay with the rocket all the way to the ground - Kerbalism is still collecting and transmitting science right up to the point where it either loses signal, or is destroyed due to lithobaking.

Congratulations! Your first flight is complete!

§6: Next Steps

First Launch After Action Review

If everything went well, then the rocket should have reached space and you've completed a lot of milestone contracts. This example rocket broke all speed milestones up to 1,200 m/s, and all the altitude milestones up to 140 km. The funds balance is now over 25,000, and we gathered over five points worth of science.

But What If Something Went Wrong?

Maybe TestLite decided that your rocket engine would have a bad day. Maybe staging was incorrect, or maybe the experiments weren't on. That's OK! It's why we have a backup rocket under construction (or can easily add a backup rocket to the queue). Add another rocket to the queue as insurance for the second flight if desired, or simply roll the dice and hope that the second launch will work better than the first. But first, let's start researching some science.

Buying Tech Nodes

Note: This subsection may need to be merged with the existing article.

Head into the R&D complex. If you gathered at least five science points on the first flight, you can now purchase every starting technology. I strongly recommend purchasing Post-War Rocketry Testing first (located in the middle of the tree) for better rocket engines, followed by Post-War Materials Science (lighter fuel tanks) and Early Tracking Systems (lighter avionics), then the other starting technologies. These nodes will be helpful in your quest to launch heavier payloads further, thereby allowing you to obtain more science and funds at the beginning of your career. Purchasing these three nodes will make the 3000 km downrange contract easier to complete. Purchasing the Supersonic Plane Development node is now a slightly lower priority due to the single build queue, but you can move it up to the second spot in the queue if you're planning on a more plane-heavy early game.

Accepting More Contracts

After exiting the R&D complex, head back into Mission Control and look at the available contracts. The next key contract to accept is "Karman Line". Not only does it have a large payout, but it can be completed by the rocket you already have under construction. Other lucrative contract opportunities will be opened up once you complete it.

After accepting Karman Line, you may wish to also accept the "Downrange Milestone (3000km)" contract if your first rocket made it to space. You won't be completing this for a little while, but the 19,000 fund advance and the lack of a deadline make it free money at this point. Alternately, if you're planning on launching a supersonic plane soon (or have already launched one and will be launching it again after recovering it to the SPH), accept the "Break the Sound Barrier" contract. Note: Advances and payouts for all these contracts will be higher if playing on normal or easy.

If your first rocket didn't break 100 km due to an engine failure or other reason, then the "Altitude Sounding Rocket (Low)" contract should also be available. Accept it if offered, and wait a little while to accept the 3000 km downrange contract.

Purchasing More KCT Upgrade Points

Note: This subsection may need to be merged with the existing article.

Between the rewards earned from the first flight (if it went well) and the advances for the newly accepted contracts, you should now have over 40,000 funds. Exit Mission Control and go into the KCT window. Purchase two KCT upgrade points (or more if playing on normal or easy), and spend them on improving the VAB and/or the R&D complex. Let's discuss the options:

  • Two points into R&D. Putting a lot of points into R&D early will speed up your initial research, bringing new techs like the XASR engine and lighter fuel tanks to your door sooner.
  • Two points into VAB. Further speeding up the VAB will increase the pace of new rocket construction, allowing you to fly more missions (including more complex and lucrative missions) in the same amount of time.
  • One point each into R&D and VAB. Splitting the baby, speeding up each a little bit.

The choice is up to you, but I recommend that you put both points into the VAB. While new tech is important, recent races with the single build queue have demonstrated that your career will progress more quickly if you place the first few points into the VAB to increase your program's launch tempo. Then, once you've sped up your VAB a bit (around 6 or 8 points invested in your VAB), start investing points into R&D as well, but at a lower rate until it's time to accept the first orbital contracts. Note that this gets into areas of personal play style and preferences, so players may have strongly held differences of opinion regarding what should be prioritized in the first year. Whatever you do, don't let your funds balance just sit there doing nothing. Invest in your program!

Side Discussion – 13 Free Science Points?!?

One of the less obvious rewards known to veteran players is that the game provides bonus science when recovering craft. The first craft to be recovered from an atmospheric flight will net 5 bonus science points, while the first craft recovered from a suborbital flight into space will net 8 bonus science points. Use that parachute or land that plane earlier rather than later to earn bonus science! Remember that every 20 science points earned results in a free KCT upgrade point, so each science point is effectively worth 1,000 funds worth of KCT upgrades in addition to its value in unlocking tech nodes.

Second Milestone Contract – Karman Line

This one is straight forward. Whether your first launch was a sounding rocket or a plane, you'll now launch the Type 1 sounding rocket that's currently under construction. Launch this one straight up as well - some of the experiments on this rocket take 10 or more minutes to complete, and so there's value flying the same mission profile again from a science-gathering standpoint. As with the previous mission, consider adding a backup rocket to the build queue for fastest progress just in case of an engine failure or other mishap.

If your first launch was a plane or a sounding rocket which didn't make it above 100 km, be sure to grab the Sounding Rocket (Low) contract from mission control before launch for some extra funds.

As before, once this mission is complete, purchase a few more KCT upgrade points, then visit the R&D complex to put additional tech nodes into the research queue.

Third Milestone Contract – Sub-Orbital Return and Recovery

Now we really start to get into different ways to proceed based on player preference. Some will choose to build a 0.38 m Type 2 rocket to take advantage of the early bio sample container. Note that this rocket, being a bit heavier than the Type 1, really needs at least the XASR engine, so hopefully that's the first tech node that you're researching if you're going this route. Here's a picture of a Type 2 Rocket, including a 0.38 m inline RealChute part and decoupler (configured to enable crossfeed), configured to complete the first suborbital bio sample mission:

Others may choose to stick with a modified Type 1 rocket, adding a resized 0.30 m inline parachute and decoupler. Note that until you have the XASR engine, you may need a bit more "oomph" to launch this slightly heavier rocket to space. It may be a good idea to use two or more Tiny Tims off the pad, whether firing at the same time or sequentially. Here's a picture of a modified Type 1 Rocket with a 0.30 m parachute, which can be launched before you have access to any engine upgrades:

Still others will take this opportunity to jump up to the much larger Type 3 rocket, using an RD-100 or A-4. This option will give you more capabilities in terms of flying cameras, larger sounding rocket payloads, and greater downrange distance, all at the cost of being more expensive and slower to build. Here's a 1.5m Type 3 Rocket with a parachute:

Note: Some players who are min-maxing hard and racing to orbit caveman-style will ignore this contract and go straight for the 3000 km downrange contract with a Type 4 rocket. The thought with this option is that completing the downrange contract opens up the first orbit and first science satellite contracts, which have the largest fund advances in the early game. This large early injection of funds allows for greater progress earlier; the downside is that your downrange rockets will have limited du and fail more often, making this a riskier approach. This strategy is not recommended for those new to RP-1.

Fourth Milestone Contract – 3000 km Downrange

Once again, there are multiple routes to go forward. With recent changes to RP-1, there are now more and varied contracts to complete at this point in a career. Some players will choose to first fly a few of the bio sample missions or film missions for additional science with a Type 3 rocket, especially if the Post-War Rocketry Testing node isn't unlocked yet. Others will gain du on newly unlocked engines a bit more cheaply with sounding rocket altitude contracts or downrange launch vehicle development contracts. Aviation aficionados will be busy unlocking better cockpits so they can start their X-plane program. And a dwindling minority may still choose to build so-called “deathsticks” consisting of a cockpit on top of a Type 3 rocket, completing the Break the Sound Barrier contract that way. (While still a somewhat viable if ahistoric option, make sure to watch both heating and the altitude rating of whatever cockpit you're using. Also include enough parachutes so that your pilot survives the “landing”.)

But whether you jump into it right away or you choose to fly some other contracts first, the 3000 km Downrange contract is the next big one to accomplish. This will be the most difficult mission to date, and will likely require extensive simulation. For a two-stage rocket, you need to have Post-War Rocketry Testing unlocked, so you have access to XLR41/RD-101 and XASR engines. Things will get even easier if you've unlocked the first nodes for materials science (aluminum tanks) and tracking station (lighter procedural avionics).

Here's an example showing one way of constructing a Type 4 rocket which can complete the 3000 km Downrange contract. This rocket is constructed with the purchase of three science nodes, Post-War Rocketry Testing, Post-War Materials Science, and Early Tracking Systems. Key parts enabled by the upgrades include the XLR41 engine for the first stage, the XASR engine for the second stage, the first tank upgrade (Tank-Sep-Al and Tank-Sep-Al-HP) for both stages, and the first science core avionics upgrade for a lighter core on the second stage. The overall appearance looks like this:

The upper stage is simply a stretched and upgraded variant of the first 0.30 m rocket we designed, but with two tiny separation motors angled to provide both ullage and spin stabilization. The first stage is a streamlined 1.5 m design, with a procedural avionics part in between the two tanks to allow full control of the first stage. The streamlining is key, as this rocket has a high TWR and will be going very fast in the lower atmosphere. Note how large and low the fins are on this rocket; this is necessary to keep it aerodynamically stable with the relatively heavy engine at the bottom when the fuel tanks are empty. (The original A-4 design included a heavy and unfriendly payload in the nose, which allowed it to have smaller fins and remain aerodynamically stable.) Also note that the strength of the fins was adjusted from 0.65 down to 0.4 to reduce their mass and gain some additional delta V. Here's an image in the VAB showing delta V and some other figures:

MechJeb's SmartASS should be used with this rocket. With the high TWR and associated "spicy" ascent, this design works best by cranking it over 15 degrees immediately after launch, then locking surface prograde with a -1 degree pitch adjustment. The goal is to be pointed somewhere between 40 and 45 degrees above the horizon when the first stage burns out. Wait a second or two for the altitude to go above 60 km (where the air is just a bit thinner), then quickly trigger the ullage motors followed by the XASR. I've managed to get this as far as 3,800 km downrange, so it should be fairly tolerant of slightly suboptimal ascent profiles. Here's a picture of it after staging as the second stage coasts up to apogee:

If you're finding it difficult to fly this high TWR design, try increasing the length of the first stage tanks to reduce the initial speed off of the pad. For example, stretching the lower stage tanks to 6.5 m will increase that stage's burn time by 20 seconds and reduce the initial TWR from 2.45 to 2. Note that you'll need to reduce the amount you tip over - I found that 9 degrees worked well with the revised design.

Also note that this rocket will require spending additional funds in the VAB for tooling the tanks and avionics, and possibly engine unlocks if you haven't already unlocked the XLR41 and XASR. This is one of the first times in an RP-1 career when you should limit your purchase of KCT points to make sure you have enough funds while designing your rocket in the VAB. Simply design, tool, and start constructing a few copies of the rocket first, then purchase any desired KCT points afterward.

When to Accept First Satellite and First Science Satellite Contracts?

Access to these two contracts, and their large fund advances, is one of the main reasons for completing the 3000 km Downrange contract. (The other reason is all the funds gained from the numerous height and speed milestones you'll complete during the launch.) The decision about when to accept these first two orbital contracts depends entirely on your experience, play style, and risk tolerance. Whatever you decide, understand that there's a two-year clock ticking as soon as you accept either of these contracts, and that failure to meet the deadline runs the risk of bankrupting your space program. It's the biggest decision to date in managing your career.

My own personal rule of thumb is that there are three prerequisites for accepting these contracts. First, I must have gathered enough science points to at least start researching all required nodes for the first science satellite. In other words, the tech tree in the R&D complex should look something like this:

This allows you to focus mostly on accelerating your program rather than being concerned about whether you'll be able to gather enough science to unlock all needed nodes.

Second, it has to be an appropriate time on the calendar. My own benchmark as an experienced player is the latter half of 1952 or later. While it is possible for an experienced player to complete the 3000 km Downrange contract and accept the first two orbital contracts before 1951 is over, thereby committing to first orbit sometime in 1953 with a "caveman" rocket, doing so will be a stressful experience with many opportunities for failure. It's not recommended for those still figuring out RP-1.

If this is your first or second RP-1 career, consider waiting until 1954 or later to accept these contracts – doing so will give you a bit more latitude to recover from setbacks, while still potentially giving you the satisfaction of beating Sputnik. Just make sure that you're using the time before accepting the contracts productively, completing other contracts to earn funds, science, rep, and du for your engines. (This is also an opportunity for you, the player, to gain additional experience in running your program while the stakes are lower.) With recent changes to RP-1 there's now more to do at this point in your career, so rushing straight towards the first orbital contracts isn't necessarily the best idea any more.

Third, I must have constructed the first Mission Control upgrade. This upgrade costs just 25,000 funds, and will allow you you to have three contracts accepted simultaneously. This is a necessity if you want to keep completing other contracts after accepting the First Satellite and First Science Satellite contracts while you wait for necessary technologies to unlock. Forgo buying a KCT point and put the Mission Control upgrade into the queue sometime in late 1951 so that construction will be completed by the time you need it.

Invest in your program during this time by purchasing KCT points and unlocking new hardware. Keep your VAB busy constructing rockets to complete contracts, and use the SPH to fly high performance planes (which is outside the focus of this tutorial), completing the many lucrative speed and altitude records which are available. However, it's best not to purchase any major facility upgrades at this time, with the exception of the previously mentioned Mission Control upgrade.

When you do finally pull the trigger and accept the contracts, there are two things you should do. First, order a 60-ton launch pad from the KCT menu. While it's possible to get to orbit with a 20-ton rocket if using American engines, things are much easier with the larger pad. (Many of my first orbital rockets are between 25 and 30 tons.)

Second, use most of your your remaining funds to purchase KCT upgrade points, and pump 3/4 or more of those points into the R&D rate so that you have more points invested in R&D than in the VAB. While you'll still be flying additional missions to complete contracts while you're waiting for various tech nodes to unlock (which are needed for the First Science Satellite contract), it's critical that you prime the pump and speed up your research rate as soon as possible. Shoot for a final ratio of twice as many points in R&D as in the VAB when investing your points. Keeping that relationship as your career progresses generally works well, although you'll develop your own preferences as you gain more experience.

Contract Cooldown Timers

As you're completing various early contracts, both before and after accepting the first satellite contracts, be aware that some of them are on "cooldown timers". This newer game mechanic slowly increases the payout over time of a particular contract, such as the Difficult Sounding Rocket contracts, then resets it to zero after you complete it, encouraging you to complete different types of contracts rather than spamming the same one over and over again. If you ignore a particular type of contract long enough, the payout can get quite high. For example, an Intermediate Sounding Rocket contract might start with a total payout of X, but may increase up to 2X or 3X if you avoid it for long enough. Be sure to check the different contract payouts in Mission Control as you're deciding which contracts to complete.

[more to follow]