Introduction: Your First Step into Space

Launching your first satellite in Kerbal Space Program (KSP) is a defining moment that transforms you from a spectator into a real mission architect. It is the bridge between building rockets that explode and understanding orbital mechanics well enough to place a payload exactly where you want it. This satellite will serve as a communications relay, a science platform, or the foundation for interplanetary missions. This guide takes you through every step—from part selection through circularization—so you get a stable orbit on your first try. No prior experience required, just a willingness to learn the basics of thrust, gravity, and staging.

Preparing for Launch: What You Need to Know

Before you enter the Vehicle Assembly Building (VAB), understand that a satellite mission has two phases: getting to orbit and then operating the satellite. You need a spacecraft that can survive the ascent and function once deployed. The key resources are thrust to push you up, propellant to accelerate, and electric charge to run the probe core, antenna, and science instruments.

Essential Parts Checklist

In the VAB, make sure you have at least these components:

  • Probe core (e.g., Stayputnik, HECS, OKTO2) – the brain of your satellite.
  • Battery or solar panels – without power, the probe core is dead.
  • Antenna – needed to send science data back or receive remote control commands.
  • Small fuel tank and engine – for orbital maneuvers; do not leave the transfer stage attached.
  • Decoupler or separator – to separate the satellite from its lifter once in orbit.

If you plan to do any science, add a thermometer, barometer, or mystery goo. But for a first satellite, just focus on surviving launch and maintaining communication.

Designing Your Satellite

Start small. Open the VAB and place your chosen probe core on the central node. Underneath it, attach a Decoupler – this part will later separate the satellite from the booster. Below the decoupler, stack a small fuel tank (FL-T100 or FL-T200) and a small engine (LV-909 Terrier for vacuum, or the Spark for upper stages). If you want an attitude control system, add RCS thrusters and a small monopropellant tank, though for a basic satellite you can rely on the probe core’s built-in reaction wheels.

Power Management

Solar panels are the best long‑term power source. Place them symmetrically on the sides of the probe core using Radial Attachment. Even small OX‑STAT panels work well for a low‑altitude orbit. If you are flying a dark-side orbit, add a Z‑100 battery to keep the core alive during eclipse. Test your design by pressing Alt + F12 (debug menu) to simulate full sunlight – ensure the electric charge does not drop to zero.

Antenna Placement

Place any deployable antenna (e.g., Communotron 16) on the satellite. If you have the Making History DLC, the RA‑2 antenna is excellent for a low orbit. Keep the antenna retracted during launch to avoid aerodynamic drag, and extend it only after reaching orbit.

Building the Launch Vehicle

Now stack the satellite on top of a launch vehicle. The most reliable first‑stage design uses a Swivel or Reliant engine with an FL‑T800 fuel tank. Add two solid rocket boosters (SRBs) strapped to the sides for extra thrust during liftoff. Use struts to connect the SRBs to the core to prevent wobble. A simple two‑stage setup works:

  • Stage 0 (first stage): Launch vehicle core + SRBs.
  • Stage 1 (second stage): Satellite’s own engine and tank.

Make sure the Thrust‑to‑Weight Ratio (TWR) at launch is above 1.2 (ideally 1.4–1.6). You can check TWR in the VAB by clicking the “Engineer’s Report” icon (box with a check mark). If the number is below 1.0, add more boosters or a stronger engine.

Delta‑V Budget Considerations

Aim for at least 3,400 m/s of delta‑V in vacuum to reach a 80 km orbit from the launchpad. The VAB’s delta‑V readout (if you have Kerbal Engineer Redux or MechJeb) will help you verify. Without mods, estimate by checking the fuel mass fraction. A rule of thumb: the total wet mass should be about 4–5 times the dry mass for the ascent stage alone.

For a deeper dive into delta‑V calculations, see the KSP Wiki Delta‑V page.

Launching Your Satellite

Once on the launch pad, double‑click the antenna to ensure it is retracted. Switch to map view (M key) to see your trajectory. Begin the launch sequence:

  1. Set throttle to 100%.
  2. Press Space to activate the first stage (SRBs and core engine).
  3. At around 100 m/s and 1000 meters altitude, start a gentle pitch‑over – tilt your rocket eastward (press D or use the SAS control) to about 5–10 degrees.
  4. Maintain a heading of 90 degrees on the navball. This is the equatorial launch direction from the Kerbin Space Center.
  5. When the SRBs burn out, press Space to stage them away. Continue with the core engine.

Gravity Turn (Ascent Profile)

A gravity turn uses Kerbin’s gravity to curve your trajectory naturally, saving fuel. As you ascend, gradually tilt your rocket so that the prograde marker (the green circle on the navball) stays centered. By the time you reach 10 km altitude, you should be tilted to about 45 degrees. By 25 km, you are nearly horizontal (about 20 degrees from horizontal). Do not pull the nose too far off prograde – that wastes fuel.

Watch your apoapsis marker in map view. Once it reaches 80 km (a safe low orbit), release the throttle. You do not need a higher apoapsis for this tutorial.

Achieving Orbit: Circularization

After reaching 80 km apoapsis, you are still suborbital; your trajectory will come back down. The next step is to burn at the apoapsis to raise the periapsis above the atmosphere. Follow these steps:

  1. Switch to map view and locate your apoapsis (Ap) tag.
  2. Wait until your spacecraft is about 30–45 seconds from reaching Ap.
  3. Point your nose in the prograde direction (the green circle on the navball).
  4. Set throttle to 50% and begin a steady burn.
  5. Watch the periapsis (Pe) marker. Keep burning until the Pe rises above 70 km (the edge of Kerbin’s atmosphere). For a stable orbit, aim for a Pe between 75 and 80 km.
  6. Cut throttle as soon as Pe reaches your target. You are now in orbit!

If you have trouble with fine‑tuning, create a Maneuver Node at the apoapsis, pull the prograde arrow until the orbit becomes circular, and then execute the burn using the node’s marker. For a helpful guide on maneuver nodes, check the KSP Wiki Maneuver Node article.

Deploying the Satellite

Now that you are in a stable low Kerbin orbit, separate the satellite from its transfer stage. Press Space to activate the decoupler. Immediately switch to the satellite’s control (click ‘Control from Here’ on the probe core). Next:

  • Extend solar panels – right‑click each panel and select “Extend”. Watch the electric charge gauge; it should begin increasing.
  • Deploy the antenna – right‑click it and choose “Extend Actuator” (or similar). You should see a connection indicator in the top‑left corner: a green dot means a good connection to the Space Center.
  • Activate science instruments (if any) – right‑click them and toggle “Deploy” or “Run Experiment”.
  • Rename the satellite for clarity: press the **i** key to open vessel info, then click the pencil icon next to the name. Use something like “ComSat 1” or “Moho Relay”.

De‑orbiting the Transfer Stage

To avoid clutter, de‑orbit the now empty upper stage. Switch to the stage (use [ and ] keys to cycle vessels nearby), and if it has fuel, burn retrogade to lower its periapsis below 25 km so it re‑enters and burns up.

Using Your Satellite

With your satellite in orbit, the real fun begins. From the Tracking Station, you can monitor its orbit, check its electric charge, and view any science data it collected. Use the satellite to:

  • Complete contracts – the game often offers “Place a satellite in a specific orbit” contracts. You can now fulfill those with minor adjustments.
  • Transmit science – if you have experiments, right‑click the antenna and select “Transmit” to send data home for science points. Each transmission uses electric charge.
  • Relay communications – if you are playing with the CommNet system (default), a satellite with a powerful antenna can relay signals from other vessels to Kerbin. This is vital for missions beyond Mun orbit.

For advanced users: you can now plan your next mission using the satellite as a surveyor. If you installed the SCANsat mod, your satellite can map terrain and resources. Without mods, you can still use the KSP Orbital Mechanics Calculator for planning burns.

Troubleshooting Common Issues

Even experienced players run into problems. Here are fixes for the most frequent failures:

  • Not enough delta‑V. You run out of fuel before achieving orbit. Solution: Add a larger fuel tank to your second stage, or use a more efficient engine (Terrier for vacuum). Also, try a more efficient gravity turn – tilt earlier and shallower.
  • Satellite spins uncontrollably. This usually happens because your solar panels or antenna create asymmetric drag. Retract everything during launch. If it spins after deployment, enable SAS (T key) and use reaction wheels.
  • No power after deployment. Batteries drained during launch. Add a second Z‑100 battery, or ensure you extend panels quickly. If you have no panels, the probe core may have a small internal battery; turn off unnecessary systems (like lights) to conserve power.
  • Orbit decays. If your periapsis is below 70 km, atmospheric drag will eventually bring you down. Raise the periapsis to at least 75 km for a stable orbit.
  • Can’t control the satellite. This means you have no antenna or no connection to Kerbin (if using CommNet). Add an antenna that works at that distance (Communotron 16 is fine for low orbit). Also check that you placed the antenna on the satellite, not on the booster.

Next Steps: Beyond the First Satellite

Your first satellite is a springboard. Now that you understand the basics of ascent profiles and circularization, you can experiment with:

  • Geostationary orbit – a 2,863 km circular orbit above the equator. Perfect for constant communication.
  • Polar orbit – inclination 90°, good for mapping the whole planet.
  • Mun or Minmus satellites – use the same skills with a larger delta‑V budget (about 4,500 m/s total).
  • Kerbnet access – a satellite with the SCANsat mod can unlock resource overlay in the map view.

Finally, consider installing the Kerbal Engineer Redux mod for real‑time delta‑V readouts and encounter planning. It removes guesswork and lets you focus on exploring the Kerbal system.

External Resources for Further Learning

For a deeper understanding of orbital mechanics, read the Braeunig’s Basics of Spaceflight (excellent real‑world orbital mechanics primer) and the KSP Wiki Advanced Orbiting Tutorial. You can also watch a detailed video walkthrough by Scott Manley that shows the exact technique described here in action.

Congratulations! You have joined the ranks of Kerbal engineers. Use that satellite to unlock more parts, gather science, and plan your next voyage. The stars await.