A maneuver node that touches a planet’s orbit is not yet an encounter. The target must be at the intersection when the craft arrives, the ejection burn must leave the current sphere of influence on the correct side, and the arrival velocity must fit the propellant or atmosphere available for capture. Transfer planning fails when those three jobs are treated as one prograde drag.
The workflow here is for stock Kerbal Space Program 1 on PC, Steam App 220200, through version 1.12.5. The 1.12 update added the stock Maneuver Creator and Alarm Clock apps. Use their current readbacks when available, but keep the manual checks below: a generated node can solve timing and delta-v without deciding whether the vessel can survive the departure, correction, capture, landing, and return.
Budget the mission from the destination backward
Before placing a node, write the burns in reverse order:
- return landing or final stable orbit;
- departure from the destination;
- surface ascent if the mission lands;
- descent or capture at arrival;
- mid-course correction;
- ejection from the origin;
- the launch to the parking orbit.
Assign margin to stages that cannot be rescued by another stage. A lander that spends its ascent propellant fixing the descent cannot borrow fuel from a discarded transfer stage. A return capsule does not need to carry landing legs through Kerbin re-entry, and a transfer stage does not need to land if the architecture separates those jobs.
Community delta-v maps are planning estimates, not guarantees. They usually assume reasonably efficient burns and a defined route. Add the values for the actual mission legs, verify whether aerobraking is assumed, and compare them with the stock stage readout in the environment where each engine will operate. A sea-level stage and a vacuum stage can show very different performance.
Use a low parking orbit as the first checkpoint
Establish a stable low Kerbin orbit before building the transfer. Both apoapsis and periapsis must remain above 70 km. The first-orbit guide covers that launch and circularization. A parking orbit isolates launch error from transfer error and lets the ejection burn use Kerbin’s orbital speed efficiently.
Check the vessel in orbit:
- the correct stage is active and has the expected vacuum delta-v;
- electric charge, communication, and attitude control will last through coast and burn;
- the engine can complete the planned burn in a reasonable fraction of the parking orbit;
- deployable hardware is in a safe state;
- the return and capture reserves have not been counted as ejection fuel.
A very low-thrust engine can have excellent delta-v and still perform a poor ejection if the burn lasts so long that the vessel travels far from the ideal point. Split orbits, use a higher-thrust departure stage, or accept a less exact trajectory rather than pretending the node is instantaneous.
Understand what each maneuver handle changes
- Prograde and retrograde primarily expand or shrink the opposite side of the orbit. They are the main handles for transfers and capture.
- Normal and anti-normal rotate the orbital plane. Plane matching is most direct at the ascending or descending node.
- Radial in and radial out rotate the shape of the orbit around the current body and can move an encounter without the same energy change as a large prograde edit.
- Node time changes where the craft leaves its current orbit and therefore where the transfer arc meets the target’s future position.
Change one handle at a time and watch the closest-approach markers. If a fine adjustment becomes uncontrollable, zoom in, reduce the handle movement, or use the node editor’s numeric controls. The goal is not to make the map line visually touch the target; the goal is to produce an explicit encounter marker and a useful periapsis inside the destination’s sphere of influence.
A Mün transfer is a timing lesson with a visible answer
Target the Mün from low Kerbin orbit. Place a prograde node and expand the projected apoapsis toward the Mün’s orbital distance. Slide the node around the parking orbit until the patched-conic line enters the Mün’s sphere of influence. The Mün must lead the departure point because it continues moving while the craft coasts outward.
Do not aim the line through the Mün. Adjust node time and prograde delta-v until the projected Mün periapsis clears terrain and suits the mission. A flyby needs a Kerbin return path. An orbiter needs enough retrograde delta-v to capture near Mün periapsis. A lander must reserve capture, descent, landing, ascent, and departure resources.
At the encounter, the trajectory is hyperbolic until a retrograde burn closes it into an ellipse. Burn near periapsis, where the craft is moving fastest and the capture is most effective. The Mün has no atmosphere to remove arrival speed, so an unpowered low pass remains a flyby.
Interplanetary windows solve where the planet will be
For another planet, first choose whether the destination is inward or outward from Kerbin’s orbit around Kerbol. A minimum-energy transfer uses an ellipse tangent to both orbital paths. The destination must have the correct phase angle at departure; otherwise the craft reaches the crossing point when the planet is elsewhere.
Use the Maneuver Creator’s transfer option or a current transfer-window tool to establish the date, then verify it manually:
- target the destination and view the solar system from above the orbital plane;
- advance time until the planned phase relationship is visible;
- place the ejection node in low Kerbin orbit on the side that sends the craft into the required Kerbol orbit;
- pull prograde until the path escapes Kerbin and becomes a solar orbit;
- adjust node time and burn components until an encounter appears.
Old guides often publish one phase angle, one clock-face ejection point, or one target speed for each planet. Those can explain the geometry, but they are not a substitute for the current save’s node. Parking-orbit altitude, inclination, burn duration, planetary eccentricity, and the exact departure date alter the result. Use the live encounter and periapsis markers as the authority.
Correct inclination where the planes cross
After targeting the destination, inspect the ascending and descending nodes. A normal or anti-normal burn at one node reduces the displayed relative inclination. Make large plane changes where orbital speed is lower when the mission geometry permits it, but do not force a separate expensive correction if a small normal component can be combined with the ejection or mid-course burn.
If the projected solar orbit reaches the correct distance but no encounter appears, inclination is one likely cause. Another is timing. Toggle between a small node-time adjustment and a small normal correction; do not add hundreds of meters per second in random directions while the closest-approach markers are hidden or on the wrong revolution.
Execute long burns around the node, not after it
Point at the maneuver marker and stabilize before the burn. Start approximately half the estimated burn duration before the node time so the planned impulse is centered on the node. For a long burn, watch the real trajectory rather than blindly reducing the remaining delta-v number.
Reduce throttle for the final portion. Stop when the actual patched-conic path gives the desired encounter, even if a small maneuver remainder persists. Engine response, staging, and steering error can make the mathematically complete node worse than a slightly incomplete burn with a good destination periapsis.
Delete or disable the completed node after verifying the real orbit. A stale node can hide the current closest-approach markers and make the next correction appear to act unpredictably.
Make one cheap correction after leaving Kerbin
Once outside Kerbin’s sphere of influence, place a correction node early in the solar transfer. Small normal, radial, and prograde changes made early can move the arrival periapsis substantially. Aim for a safe encounter first, then refine the altitude needed for capture or aerobraking.
Do not lower periapsis into an atmosphere unless the craft is designed for that heating and the mission deliberately uses aerobraking. An atmosphere can save capture propellant, but it turns navigation error into a thermal or impact failure. For a first visit, a conservative high periapsis with a powered correction is easier to read and recover.
Arrival is a new orbit problem
Enter the destination’s sphere of influence and place a retrograde node near periapsis. The projected path should change from an open flyby to a closed orbit when enough velocity is removed. Choose the first orbit for safety and future burns, not for appearance:
- a high capture orbit costs less initially but may require another burn to reach a lander or moon;
- a low capture orbit can make operations convenient but demands more immediate delta-v and may approach terrain or atmosphere;
- a moon assist can change energy without a full engine burn, but it adds another timing dependency;
- aerocapture requires a heat-capable, stable craft and a tested periapsis range.
Set an Alarm Clock entry before long coasts and leave time to orient, retract vulnerable hardware, and confirm the correct engine. Time warp should end well before the sphere-of-influence change and the capture burn.
Reserve the return before landing
At a planet or moon, rebuild the return plan with the actual remaining resources. Check ascent delta-v, transfer window, plane alignment, Kerbin encounter, and re-entry hardware. If the margin has vanished, change the mission: remain in orbit, collect remote science, use a relay or tanker, or postpone the landing.
A one-way surface landing is not a successful crewed return mission. The most dangerous transfer-planning error happens before descent, when the map still shows a reachable surface and hides the cost of leaving it.
Read the map symptom before touching the node
| Map symptom | Likely cause | Controlled correction |
|---|---|---|
| Transfer crosses the target orbit with no encounter | Wrong phase or inclination | Adjust node time, then reduce AN/DN error |
| Encounter appears on a later solar revolution | The chosen energy and timing miss the first window | Decide whether the long coast is acceptable; otherwise rebuild the node |
| Destination periapsis is inside terrain | The encounter is real but unsafe | Use a small early radial or normal correction |
| Capture reserve disappears during ejection | Departure stage underperformed or budgets were shared | Abort to Kerbin orbit or switch to a flyby before arrival |
| Node remainder grows after the marker passes | The burn is late or the craft cannot turn quickly enough | Stop chasing the old vector and rebuild from the actual orbit |
For a mission that must meet another spacecraft rather than another world, use the rendezvous and docking route. It uses the same orbital vocabulary but a different objective: matching position and velocity within one sphere of influence.
Official planning-tool and version sources
Transfer geometry was cross-checked against readable orbital-mechanics, delta-v, injection, Career, and synchronous-orbit community references. Their fixed speeds and clock-face directions were not repeated as universal current answers; the article uses live patched-conic and resource readbacks instead.