Mission target: place a small crewed capsule in a stable Kerbin orbit, verify that its periapsis is above 70 km, then lower that periapsis for a controlled re-entry and recover the crew. Reaching space is only the middle checkpoint. A launch that produces a high apoapsis but leaves the periapsis inside Kerbin is still suborbital.
This route is for the original Kerbal Space Program on PC, Steam App 220200, in stock version 1.12.5. It is not a Kerbal Space Program 2 tutorial. The official 1.12.4 patch repaired the Basic Flight, Go For Orbit, construction, and suborbital tutorials, so those training missions are useful again; the route below adds the failure readbacks that the short lessons do not always make obvious.
The flight has four gates
- The stack survives staging. The next engine lights only after the spent stage separates, and the parachute cannot fire with the launch stage.
- Apoapsis clears 70 km. This gives the upper stage time outside the atmosphere to turn horizontal.
- Periapsis also clears 70 km. Only then can the vessel coast without returning to the atmosphere.
- The return system remains attached. The capsule needs control, electric charge, heat protection appropriate to its design, and a parachute that can deploy in a safe state.
Make a named save before launch. If the mission is in Career mode, also check that the intended altitude, orbit, science, and recovery contracts have been accepted before triggering their milestones. For a first practice flight, Sandbox removes the facility and technology constraints; the flight mechanics are the same.
Build backward from the capsule
Start with the part that must return, then add only the systems needed to move it through each gate:
- a command pod or probe core with control and enough electric charge for the coast;
- a parachute placed in its own final stage;
- re-entry protection and a decoupler that leaves the protected face pointing into the airflow;
- an upper stage that can circularize in vacuum and later make a small deorbit burn;
- a launch stage with enough thrust to leave the pad and enough control to begin a gradual turn;
- decouplers arranged so discarded engines and tanks move away from the live craft.
Open the Engineer’s Report and inspect every stage in the staging stack from bottom to top. The first press of Space should release clamps and light the intended launch engines. A later stage should separate empty hardware before the next engine fires. The parachute belongs alone at the top of the sequence. Do not treat a green report as proof that the rocket can fly; it catches assembly hazards, while thrust, stability, drag, and piloting still have to agree.
Use symmetry for radial boosters and control surfaces. Keep heavy parts close to the centerline, and keep the thrust line passing through the mass of the vehicle. If the rocket begins to bend before leaving the tower, adding more steering authority can make the oscillation worse. Shorten or brace the stack, reduce abrupt control input, and confirm that no engine is pushing off-axis.
Run a pad test before spending the whole vehicle
At the launchpad, do not stage immediately. Confirm the navball is in Surface mode, SAS is available, the throttle is where the first liquid engine expects it, and the staging list has not been rearranged by the last edit. Right-click the parachute and verify it is not in the launch stage. If the craft has deployable solar panels, keep them protected during ascent rather than using them as structural parts.
A short vertical test is valuable when the design is new. Watch for three failures: the rocket cannot clear the pad, the nose cannot hold near the attitude marker, or the structure starts flexing faster than SAS can correct. Revert and change the cause. Do not continue a damaged test flight merely because it may still cross the space boundary.
Turn east without fighting the prograde marker
Launch near vertical and allow the rocket to build stable airflow before beginning a small turn toward 090 degrees, east on the navball. The turn is not one hard pitch command. Let the prograde marker begin moving east, then guide the nose close to it while the vehicle gradually becomes more horizontal.
The correct timing depends on the rocket. A slender vehicle with strong control can begin earlier than a wide, draggy stack. Read the symptoms instead of copying one altitude:
| What you see | What it usually means | Next attempt |
|---|---|---|
| The prograde marker falls away and the rocket flips | The turn was too aggressive, the craft is aerodynamically unstable, or control is overcorrecting | Use a smaller initial pitch, reduce steering, and repair mass or drag placement |
| The rocket is still nearly vertical when apoapsis passes the target | Too much energy went into height rather than sideways speed | Begin the gradual turn earlier or spend more of the upper burn near the horizon |
| Apoapsis stops rising while the engine still burns | Thrust is low, the vehicle is too heavy, or the pitch became too horizontal too soon | Hold closer to prograde and restore a modest upward component |
| Parts glow or aerodynamic effects become severe | The ascent is pushing too hard through dense air | Reduce throttle or use a less draggy, more stable stack |
Open map view periodically rather than flying by the altimeter alone. When apoapsis rises safely above 70 km, stop raising it unnecessarily. A target around low orbit gives a first vehicle less distance to circularize and less energy to remove on return. Coast toward apoapsis outside the thick atmosphere; time warp should be back at real time before staging, attitude changes, or the burn.
Circularize while the clock passes through apoapsis
Create a maneuver node near apoapsis and pull prograde until the projected periapsis rises above 70 km. The node is a plan, not an autopilot. Point at the maneuver marker, note the estimated burn duration, and begin roughly half that duration before the node so the impulse is centered around apoapsis.
Watch the map during the burn. Apoapsis should remain near the vehicle while periapsis climbs around the far side of Kerbin. Reduce throttle as periapsis approaches the target. Stop when both markers are above 70 km. A nearly circular orbit is convenient, but perfection is not required for this mission.
If apoapsis races higher while periapsis barely moves, the burn began too early, the nose is not truly prograde, or the vessel has already passed far beyond apoapsis. If the time to apoapsis becomes negative and periapsis remains inside the planet, the circularization was late or the upper stage lacks thrust. Recover if possible, then add upper-stage margin or start the burn earlier; holding full throttle after the geometry has gone bad spends fuel without restoring the intended circle.
Prove the orbit before leaving the controls
Let the vessel coast for part of an orbit and make four checks:
- apoapsis and periapsis remain above 70 km;
- electric charge is stable or recoverable rather than draining toward zero;
- the return capsule, decoupler, and parachute are still present in the correct sequence;
- the remaining stage can make a retrograde deorbit burn.
If this flight is the foundation for a longer trip, use the transfer-planning guide before pulling a maneuver node toward the Mün or another planet. A first orbit vehicle should return now rather than becoming an improvised deep-space craft.
Lower periapsis, then separate from the engine
Place the deorbit burn so the projected landing region is over open terrain or ocean, not directly above a mountain chain. Point retrograde in Orbit mode and burn until the opposite periapsis enters the atmosphere. A periapsis around 25–35 km is a practical test range for a simple low-orbit capsule, not a universal magic number: vessel drag, mass, heat protection, and starting orbit all change the result.
A periapsis only just below 70 km may skim the atmosphere and require several passes. A very deep entry removes speed quickly but raises heating and deceleration. Make a small burn, read the projected path, and adjust before committing. Quicksave before the burn if the mode permits it.
Jettison the service or propulsion stage only when the capsule no longer needs it. Switch the navball to Surface mode as the atmosphere begins to control the craft, hold retrograde, and keep the heat-protected side forward. Do not time warp through a separation, a sudden attitude change, or parachute deployment.
Deploy the parachute by state, not by panic
The parachute icon and part menu show whether deployment is unsafe, risky, or safe. Wait until speed and atmospheric pressure make deployment safe for the installed chute. Staging it high does not mean it will fully open immediately, but staging while the indicator is unsafe can destroy it. Keep the capsule stable and let drag remove speed.
Use terrain altitude for the last part of descent, especially over mountains. Confirm the canopy transitions from the partially deployed state to fully open and that the displayed surface speed is falling to a survivable value. If the chute never becomes safe, the entry is too fast, the capsule is unstable, or the return mass exceeds the recovery system. That is a design problem for the next launch, not a reason to keep pressing Space.
A failed orbit tells you which gate to rebuild
- Only apoapsis exceeds 70 km: the launch reached space but did not gain enough horizontal velocity. Repair the gravity turn or circularization stage.
- The upper stage has fuel but no control: preserve electric charge, verify a pilot or probe connection, and reduce wasteful steering on the next design.
- The craft tumbles on ascent: fix stability and control authority before adding fuel.
- The projected orbit changes in the wrong direction: confirm the navball mode and maneuver marker; prograde at apoapsis raises the opposite side.
- The capsule survives heat but hits the ground: inspect chute state, staging, terrain altitude, and return mass.
In Career mode, the career-start route explains how to turn this one flight into science, facility access, and funded next missions without repeating empty launches.
Official game and version records
The flight checkpoints were reconciled against readable stock-game physics, basic-orbit, controls, and Career walkthrough references. A 2013 guide that describes older SAS behavior was treated only as historical context, and blocked pages or KSP 2 material were not used to establish KSP 1 actions.