Early Orbital Rocket Tutorial

Early Orbital Rocket Tutorial

After you've completed the 3000 km downrange contract, the next step is to launch a satellite into orbit. To demonstrate one way of accomplishing this milestone, this tutorial will show you how to build an analog of a early American rocket, the Thor-Able. As with the early career tutorial, please note that this is simply one way of progressing in an RP-1 career. There are many paths to success!

This will be a two-stage rocket, using an AJ10-37 upper stage and an LR-79 lower stage. Both of these engines are unlocked in the 1956-57 Orbital Rocketry tech node. The rocket will also use integral fuel tanks, which are lighter and more capacious compared to earlier conventional (separate structure) fuel tanks.

Let's design the rocket from the top down. First, create a satellite using a procedural avionics part. This extremely boring satellite uses the TL3 science core configuration. This tech level reduces power draw dramatically, while also continuing to reduce mass compared to earlier versions. This particular science core has a radiation detector, a thermometer, and a barometer all integrated into the core (select the "Configure Experiments" button to enter this menu), and is therefore capable of completing the First Science Satellite contract. It also has 10,000 EC, which will allow it to power the experiments in orbit and broadcast the results back for quite some time.

Next, we're going to add a fairing base and a fairing. You can see that this rocket uses a 1.25m diameter for the upper stage, which is wider than the 0.81m diameter used historically. There are a couple reasons for doing this, including reutilizing existing 1.25m tooling that you'll already have if you've been flying X-planes. However, the main reason is aesthetic - the original Thor-Able looks like an electric toothbrush, which is suboptimal. This rocket has an appearance closer to a later Thor-Ablestar or Thor-Agena.

Once you've placed the fairing base and fairing halves, it's time for avionics which can actually control the upper stage. Select another procedural avionics part and attach it beneath the fairing, adjusting it to 1.25m diameter. Configure the avionics to use the Near-Earth TL2 "Early Avionics" configuration, and set the controllable mass to be around 2.5 tons. Add a few hundred EC to power the avionics, and leave the RealAntenna stuff alone - the defaults are fine for this early rocket.

Next, select a procedural integral fuel tank, and place it beneath the avionics. Increase the diameter to 1.25m and the length to around 1m, and select the HP (high pressure) variant in the tank's PAW (aka the right-click window). Be sure to increase utilization to the maximum of 95 percent to take full advantage of the tank.

We'll need a way to provide ullage and attitude control, so select the smallest RCS thruster part (the 28/45N one) and place four of them near the bottom of the fuel tank. Configure the RCS thrusters to use HTP, which is a nice compromise between cost, power, efficiency, and tank size for early rockets. Click on the "Show Tank UI" button, then add just 2 units of HP to the tank.

Select the AJ10 Series (Early) engine to power this stage, which will have the beginning AJ10-37 configuration. Place it on the bottom of the fuel tank, then fill the remainder of the fuel tank with UDMH and IWFNA using the button in the PAW. Fine-tune the length of the tank so you have somewhere between 1m 50s and 2m of burn time. Please note that the AJ10-37 configuration is one of the least reliable engines in the game, and will fail early and often if you're using Test Flight or TestLite. Upgrade this engine to the next configuration as soon as you unlock the 1958 Orbital Rocketry node.

The engine will need to be covered for proper aerodynamics, so select an interstage fairing base, and place it so that the top "floating" node is the one that connects