Kerbal Space Program Walkthrough — Start to Endgame

Kerbal Space Program puts you in charge of a fledgling space agency on the planet Kerbin, where you design, build, and fly rockets using realistic orbital mechanics. The game uses a simplified but accurate Newtonian physics model — you need to understand delta-v budgets, transfer orbits, and staging to reach other planets. With Career, Science, and Sandbox modes, KSP caters to both structured progression and creative engineering. The modding community adds thousands of parts, visual overhauls, and automation tools that extend the game indefinitely.

This walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. Follow this path to avoid common traps that stall most players.

Quick Progression Summary

Phase 1: Getting Started — Kerbin

Your home planet with thick atmosphere, perfect for testing rockets and planes. Kerbin has multiple biomes each yielding unique science. Its two moons, Mun and Minmus, are visible targets for first interplanetary missions. Launch from the KSC at the equator for maximum orbital velocity boost.

Level/Difficulty: First flights, suborbital, orbit Key Rewards: Early science from KSC biomes, crew experience from orbit

What to Do in Kerbin

1. Learn orbital mechanics. KSP uses patched conic approximation for orbital calculations — you plan maneuver nodes on your orbital path showing prograde, retrograde, normal, anti-normal, radial in, and radial out burns. Spend your first session getting comfortable with this.
2. Pick Engineer as your starting build. It's the most forgiving option.
3. Achieve stable Kerbin orbit (both apoapsis and periapsis above 70km) before attempting the Mun — if you can orbit, you understand 80% of what you need for the whole game.
4. Acquire your first equipment upgrade — Mainsail Engine or whatever's available.
5. Clear all main content before moving on.

Phase 1 Checklist

• Understand orbital mechanics fundamentals
• Engineer selected and functional
• Kerbin main content cleared
• Ready for Mun

Phase 2: Early Game — Mun

Kerbin's large moon with no atmosphere — you must use engines for landing. Surface gravity is 1.63 m/s2, requiring about 580 m/s for landing from low orbit. Multiple biomes provide rich science. Landing on the Mun is the game's first major milestone.

Level/Difficulty: After achieving stable Kerbin orbit Key Rewards: High science yields, crew experience boost

What to Do in Mun

1. Work on staging. Rockets are built in stages that separate sequentially — typically boosters first, then lower stages, then upper stages. This system becomes critical from here on.
2. Farm for Mainsail Engine if you haven't already. It's the key upgrade for this phase.
3. Asparagus staging gives 20-30% more delta-v than parallel staging with the same parts by dropping empty mass early while continuing to fuel the center stack.
4. Complete all objectives before pushing to Minmus.
5. Consider whether Pilot might suit your playstyle better than Engineer.

Phase 2 Checklist

• staging integrated into gameplay
• Mainsail Engine acquired
• Mun fully cleared
• Ready for Minmus

Phase 3: Mid Game — Minmus

Kerbin's tiny outer moon with extremely low gravity (0.491 m/s2) and a slightly inclined orbit. Despite being farther than the Mun, landing on Minmus requires less total delta-v — about 180 m/s for landing. Its flat areas provide easy, safe landing zones. Best first landing target.

Level/Difficulty: After first Mun flyby Key Rewards: Easy high-value science, ore mining practice for ISRU

What to Do in Minmus

1. Master delta-v budgets. Delta-v (change in velocity) is the currency of spaceflight in KSP. This unlocks a new layer of gameplay.
2. Start working toward SRB Booster. It's the best equipment and becomes accessible around now.
3. Minmus is actually easier to land on than the Mun despite being farther away — its low gravity means you need only about 180 m/s for landing versus about 580 m/s on the Mun.
4. This area is the main skill check. If you can clear it, you're ready for late game.
5. Start investing in docking for the tactical depth you'll need going forward.

Phase 3 Checklist

• delta-v budgets mastered
• SRB Booster acquired or in progress
• Minmus fully cleared
• Ready for Duna

Phase 4: Late Game — Duna

The Mars analogue with thin atmosphere (20% of Kerbin's) that allows partial aerobraking and parachute-assisted landing. Transfer window from Kerbin occurs roughly every 2 years. Its moon Ike is tidally locked and visible from the surface.

Level/Difficulty: After Mun/Minmus mastery Key Rewards: Major science bonuses, interplanetary crew experience

What to Do in Duna

1. Finalize your build. You should be running Pilot or Engineer with optimized gear.
2. SRB Booster should be your primary. If you don't have it yet, prioritize getting it.
3. Install Kerbal Engineer Redux or MechJeb mods — KER shows delta-v readouts in the VAB and in flight, while MechJeb can automate maneuvers while you learn the physics behind them.
4. science collection optimization starts here. Small improvements compound into massive advantages.
5. Farm this area for the resources needed to push into Eve.

Phase 4 Checklist

• Build fully optimized
• SRB Booster upgraded to max
• Duna fully cleared
• Ready for Eve

Phase 5: Endgame — Eve

The Venus analogue with crushing atmosphere (5x Kerbin's) and high gravity. Landing is easy — returning from the surface is the hardest challenge in KSP, requiring over 11,000 m/s of delta-v. Do not attempt Eve return missions without extensive planning.

Level/Difficulty: Advanced players only Key Rewards: Highest science multiplier, ultimate engineering challenge

What to Do in Eve

1. Eve tests everything. Come prepared with your best build and gear.
2. Aerobraking at Duna saves about 1,000 m/s of delta-v — set your periapsis to 15-20km on approach and let atmospheric drag capture you into orbit for free.
3. The endgame loop: run Eve, optimize gear, push harder content.
4. Experiment with Rescue Target for a fresh take once you've mastered the standard builds.
5. This is where science collection mastery separates good players from great ones.

Phase 5 Checklist

• Endgame content on farm
• Best-in-slot gear acquired
• Eve fully cleared
• Ready for challenge content

Common Progression Mistakes

• Building rockets without checking delta-v — launching a 3,000 m/s rocket when orbit requires 3,400 m/s means you'll fall back every time.
• Forgetting solar panels or batteries on probe missions — probes die without electricity, and many players discover this halfway to the Mun.
• Ignoring TWR on launch vehicles — a TWR below 1.0 means your rocket can't lift off, and below 1.2 means excessive gravity losses.
• Not using fairings on payloads — exposed landers and stations in atmosphere create massive drag, flipping rockets and wasting fuel.
• Burning at the wrong time during interplanetary transfers — ejection angle and timing matter; use a transfer window planner or maneuver nodes.

Key Tips for Smooth Progression

1. Achieve stable Kerbin orbit (both apoapsis and periapsis above 70km) before attempting the Mun — if you can orbit, you understand 80% of what you need for the whole game.
2. Asparagus staging gives 20-30% more delta-v than parallel staging with the same parts by dropping empty mass early while continuing to fuel the center stack.
3. Minmus is actually easier to land on than the Mun despite being farther away — its low gravity means you need only about 180 m/s for landing versus about 580 m/s on the Mun.
4. Install Kerbal Engineer Redux or MechJeb mods — KER shows delta-v readouts in the VAB and in flight, while MechJeb can automate maneuvers while you learn the physics behind them.
5. Aerobraking at Duna saves about 1,000 m/s of delta-v — set your periapsis to 15-20km on approach and let atmospheric drag capture you into orbit for free.

For detailed build optimization, see Kerbal Space Program builds. For quick wins, check tips & tricks.