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 guide covers everything you need: core mechanics, the best builds, equipment worth investing in, location progression, and the tips that actually make a difference.
Core Mechanics
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. Hohmann transfer orbits are the most fuel-efficient way to reach other planets. Understanding periapsis, apoapsis, and inclination changes is essential for every mission beyond Kerbin orbit.
staging
Rockets are built in stages that separate sequentially — typically boosters first, then lower stages, then upper stages. Asparagus staging (where outer tanks feed into center tanks before decoupling) maximizes delta-v by dropping empty mass early. The staging sequence editor lets you group decouplers, engines, and fairings into logical separation events.
delta-v budgets
Delta-v (change in velocity) is the currency of spaceflight in KSP. Getting to Low Kerbin Orbit costs about 3,400 m/s, reaching the Mun costs about 860 m/s more, and Duna requires about 1,000 m/s from LKO. The Tsiolkovsky rocket equation (displayed in the VAB) calculates your craft's total delta-v from fuel mass, dry mass, and engine Isp.
docking
Docking requires matching orbits with a target vessel, then using RCS (Reaction Control System) thrusters for fine approach. Set the target vessel as your navigation target, align your orbit, then close distance using the docking mode controls. Docking ports must face each other and approach at less than 1 m/s relative velocity. Docking is essential for space station construction and orbital refueling.
science collection
In Career and Science modes, you collect Science points by running experiments (Crew Report, EVA Report, Mystery Goo, Thermometer, etc.) in different biomes and situations. Each experiment yields diminishing returns when repeated in the same location. Transmitting science via antenna gives partial value — recovering experiments on Kerbin gives full value.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Pilot | S | Sits in the command pod providing stability assist during all maneuvers. | Experience Level (gained from reaching new celestial bodies) |
| Engineer | A | Manages surface base operations, repairs equipment, and operates mining rigs. | Experience Level for ISRU efficiency bonuses |
| Scientist | A | Runs EVA experiments across biomes and processes data in orbital labs. | Experience Level for experiment reset capability |
| Tourist | C | Sits passively while you fly them to their destination and back safely. | None — tourists have no skills |
| Rescue Target | B | Fly to the stranded Kerbal, EVA them to your ship or dock, and return to Kerbin. | Pilot skill for rendezvous maneuvers |
Pilot (S-Tier): Pilots provide SAS hold capabilities at various levels — Level 1 holds prograde/retrograde, Level 3 unlocks maneuver node hold, and Level 5 gives target hold. Without a pilot or probe core with SAS, you can't lock heading during burns. Essential for every crewed mission.
Engineer (A-Tier): Engineers repack parachutes, repair wheels and landing legs, and boost ISRU drill and converter efficiency. A Level 3 Engineer makes mining operations viable by increasing ore extraction rates. Essential for self-sustaining bases on other planets.
Scientist (A-Tier): Scientists can reset experiment modules (like Mystery Goo and Science Jr.) for reuse without returning to Kerbin. They also boost lab processing speed in the Mobile Processing Lab. A Level 5 Scientist can reset every experiment, making multi-biome missions far more efficient.
Tourist (C-Tier): Tourists are contract-generated passengers who can't perform any actions — they just need to visit specified destinations. Tourist contracts pay well but add dead weight to your craft. Useful only for income in Career mode.
Rescue Target (B-Tier): Rescue contracts place stranded Kerbals in orbit or on surfaces that you must retrieve. Successfully rescued Kerbals join your roster permanently. These missions teach rendezvous and docking skills, and rescued Kerbals often come with experience.
For full build breakdowns with gear and stat priorities, see our Kerbal Space Program builds guide.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| SRB Booster | Solid Rocket Boosters provide massive thrust at low cost but cannot be throttled or shut down once ignited. | First-stage boosters on all early career rockets |
| Mainsail Engine | The RE-M3 Mainsail is KSP's workhorse heavy lifter engine with 1,500 kN thrust and 310s vacuum Isp. | Main stage engine for medium-to-heavy launch vehicles |
| Nuclear Engine | The LV-N Nerv nuclear engine has only 60 kN of thrust but an exceptional 800s vacuum Isp, making it the most fuel-efficient engine for interplanetary transfers. | Interplanetary transfer stages for Duna, Jool, and beyond |
| Ion Engine | The IX-6315 Dawn ion engine provides incredible 4,200s Isp but only 2 kN of thrust, requiring enormous electricity reserves (xenon gas + solar panels or RTGs). | Lightweight deep-space probes and satellite repositioning |
| SAS Module | The Advanced Inline Stabilizer provides torque to rotate your craft without using RCS fuel. | All crewed and uncrewed vessels for attitude control |
SRB Booster: Solid Rocket Boosters provide massive thrust at low cost but cannot be throttled or shut down once ignited. The Kickback SRB delivers 2,300 kN of thrust, making it ideal for first-stage boosters. Pair 2-4 SRBs with a liquid-fuel core stage for cheap, powerful launchers.
Mainsail Engine: The RE-M3 Mainsail is KSP's workhorse heavy lifter engine with 1,500 kN thrust and 310s vacuum Isp. It's the go-to engine for large rockets' first and second stages. While heavy at 6 tons, its thrust-to-weight ratio makes it essential for getting heavy payloads to orbit.
Nuclear Engine: The LV-N Nerv nuclear engine has only 60 kN of thrust but an exceptional 800s vacuum Isp, making it the most fuel-efficient engine for interplanetary transfers. It's heavy (3 tons) and weak in atmosphere, so use it only on upper stages. Multiple Nervs in parallel solve the low-thrust problem.
Ion Engine: The IX-6315 Dawn ion engine provides incredible 4,200s Isp but only 2 kN of thrust, requiring enormous electricity reserves (xenon gas + solar panels or RTGs). Ion drives are for lightweight probes on deep-space missions where burn time doesn't matter.
SAS Module: The Advanced Inline Stabilizer provides torque to rotate your craft without using RCS fuel. Larger craft need multiple SAS modules or reaction wheels to maintain stability during burns. SAS works with pilot skill levels to enable heading holds.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| Kerbin | First flights, suborbital, orbit | Early science from KSC biomes, crew experience from orbit |
| Mun | After achieving stable Kerbin orbit | High science yields, crew experience boost |
| Minmus | After first Mun flyby | Easy high-value science, ore mining practice for ISRU |
| Duna | After Mun/Minmus mastery | Major science bonuses, interplanetary crew experience |
| Eve | Advanced players only | Highest science multiplier, ultimate engineering challenge |
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.
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.
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.
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.
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.
Tips That Actually Matter
- 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.
- 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.
- 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.
- 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.
- 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.
- Quicksave (F5) before every major maneuver and quickload (F9) when things go wrong — KSP is about learning from failure, and quicksave eliminates the frustration of repeating long launches.
- Use the maneuver node system: click on your orbital path, drag the prograde/retrograde handles, and fine-tune with the +/- buttons for precise burns.
- Check your TWR (thrust-to-weight ratio) — you need at least 1.2-1.5 on the launch pad for Kerbin, but only 0.5+ for vacuum stages since there's no gravity drag.
- Fairings reduce drag on non-aerodynamic payloads and should be used on every orbital rocket — they split open at configurable altitudes and dramatically reduce atmospheric losses.
- For your first interplanetary mission, send an unmanned probe to Duna — it's forgiving, teaches transfer windows, and you won't lose a crew to a design mistake.
Common Mistakes to Avoid
- 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.
Frequently Asked Questions
How do I get to orbit in KSP?
Build a rocket with at least 3,400 m/s of delta-v and a launch TWR of 1.3+. Launch straight up until 10km, then gradually tilt east (90 degree heading) to about 45 degrees by 20km. Continue tilting until horizontal by 40km. Coast to apoapsis, then burn prograde to raise periapsis above 70km.
What is delta-v and how much do I need?
Delta-v is change in velocity — the total speed change your rocket can produce. Kerbin orbit needs about 3,400 m/s, Mun landing and return needs about 6,500 m/s total, Duna round trip needs about 5,500 m/s from LKO. Install Kerbal Engineer Redux to see delta-v readouts in the Vehicle Assembly Building.
Should I play Career or Sandbox mode?
Start with Science mode — it gives you the tech tree progression without the budget management of Career. Science mode teaches you to plan missions around experiment collection, which naturally builds skills. Switch to Career for contract challenges, or Sandbox for unlimited creative builds.
How do I dock two ships?
Get both ships in similar orbits, set one as target, burn toward it until within 200m, then switch to docking mode. Use RCS (H/N for forward/back, I/J/K/L for translation) to align docking ports. Approach at under 1 m/s, keep ports aligned using the navball target indicator.
What to Read Next
- Best Kerbal Space Program Builds — Detailed breakdowns with gear, stats, and playstyle guides
- Kerbal Space Program Tier List — Current meta rankings
- Kerbal Space Program Walkthrough — Step-by-step progression from start to endgame
- Kerbal Space Program Beginner's Guide — First session essentials
- Kerbal Space Program Tips & Tricks — Advanced strategies and hidden mechanics
