AdvancedFlightComputer

Maneuver planning, burn execution and closed-loop guidance for Kitten Space Agency.

AdvancedFlightComputer adds quick-tools to the Transfer Planner (set Pe/Ap, match/set inclination), flyby targeting so a Hohmann transfer arrives as a flyby instead of an impact, multi-pass burn splitting for Oberth-efficient departures, RCS-only burn execution, automatic staging with spent-booster drop and configurable staging delays, automatic removal of finished burns, powered guidance that flies an ascent to orbit, a booster boostback and a pinpoint powered landing, and it lets the planner target interstellar comets on hyperbolic orbits.

Maneuver Quick-Tools

New plan types in the stock Transfer Planner dropdown:

• Set Periapsis / Set Apoapsis - single burn at the opposite apse to raise or lower one apse to a target altitude.
• Match Inclination - plane-change burn at AN or DN to align with a target orbit's plane.
• Set Inclination - plane-change burn at AN or DN to set an absolute inclination angle. Reference plane selectable: Ecliptic or Equatorial.

Right-click the controlled vehicle's orbit and open Advanced Flight Computer to select a quick-tool. Quick-tools can plan a single burn after the last planned burn that changes the trajectory.

Flyby Targeting

The stock planner aims every transfer at the target body's center, so a well-timed Hohmann arrives as an impact. Tick Target flyby periapsis in the Transfer Planning window and the departure burn is aimed at a periapsis you choose instead, so Create fires the flyby directly.

• Periapsis is entered against a selectable reference: Surface, Center or Atmosphere. The Atmosphere option only appears for bodies that have one, and a request below the safe floor is refused.
• Flyby side picks which side of the body you pass, in the target's own orbital frame: Inner, Outer, North or South. A side whose axis lies along the approach direction cannot be reached and is greyed out.
• Works for moon flybys and for interplanetary targets, as a single burn or split across multi-pass passes.
• The section reports the approach speed, the impact parameter, the departure delta-V next to the impact-aimed one, and the periapsis the propagated trajectory actually reaches.

Limitation: the plan is impulsive, the burn is not. On a near-escape departure the periapsis actually flown drifts from the requested one by roughly the finite-burn loss. Trim it with a small correction burn, or split the departure across several passes.

Multi-Pass Burns

Split any planned burn into multiple passes across successive orbits to reduce finite-burn loss. Instead of one long burn that sweeps a large arc away from periapsis, the engine fires in shorter bursts near periapsis on each orbit, the way real lunar kick stages raise their orbit with several perigee burns.

Supports Hohmann departures, apse burns (Set Pe/Ap), inclination changes and circularize. Includes a 3D orbit preview with per-pass markers, automatic execution via Auto burn mode, and an inline pass list with remaining dV and burn time. Particularly useful for low-TWR spacecraft such as ion engines, small kick stages and nuclear tugs.

With automatic staging switched on and automatic burn removal left on, a multi-pass execution runs hands-free from first ignition to final departure.

RCS Translation Burns

Execute a planned burn on RCS thrusters alone, no main engine. Useful for small corrections, where rotating the whole vehicle for the main engine can cost more than translating, and for vehicles with no active main engine.

The stock Auto burn button stays the trigger: a burn runs on the engine when an active fueled one exists, otherwise on RCS. Per-burn options sit below the burn editor: Execution, Attitude and Allocator. Two attitude strategies, Hold and Align, with an Auto mode that estimates the propellant for both, including the slew, and picks the cheaper one. Execution is closed-loop against the game's own delta-V accounting. Burns stay in the stock save format, and RCS arming survives save/load including mid-burn. An optional LP allocator solves the fuel-optimal jet-select problem over the individual thrusters and stays opt-in.

Automatic Staging

Activates the next sequence whenever the active engines run out of propellant, and drops burnt-out boosters while the rest of the stage keeps firing. Works during auto-burns (continues the burn instead of aborting) and manual burns.

• AUTOSTAGE toggle button on the EngineControl gauge panel. The switch belongs to the vehicle, so an armed craft keeps staging when you control another one. The same switch is on the Mods settings page for installs without KittenExtensions.
• Control-module guard - a sequence that would separate the last control module is never staged automatically.
• Auto-burn continuation - keeps the burn mode at Auto through staging so planned burns do not abort.
• Cascade staging - stages again if the next stage is empty or only has decouplers.
• Spent stage drop - sheds burnt-out boosters as soon as they quit, and refuses when the separated parts still feed a retained engine.
• Configurable staging delays - independent delays for decouplers and engines per part variant, with on-screen countdowns.

Settings under Settings > Mods > AUTOSTAGE, with a per-vehicle override in the part window. The config is Documents\My Games\Kitten Space Agency\mods\AdvancedFlightComputer\autostage.toml; nothing is written to a game save.

Automatic Burn Removal

In stock KSA, a completed auto-burn stays in the plan until you click Delete. AFC removes completed burns automatically: auto-burns as soon as the flight computer flips out of Auto on completion, confirmed through the same delta-V reversal the stock flight computer uses, so a burn that flamed out before its target stays in the plan and can be resumed after staging. RCS burns are removed on their completion. Manual burns are never touched. Switch on the Mods settings page, on by default.

Powered Guidance

Closed-loop guidance that flies the vehicle for you. Open the AFC Guidance menu in the top bar, switch Enabled on and open the panel with Show panel. EXECUTE, ABORT and RETARGET act on the selected tab. Demo video: https://youtu.be/hSUcV6tx3oY

• Ascent flies UPFG, the Space Shuttle's ascent guidance, to a target periapsis, apoapsis, inclination and LAN, optionally holding the argument of periapsis too and otherwise inserting wherever the burn costs least dV, with an optional launch window, g-limit and booster reserve. Launching to a target vehicle flies a co-elliptic chase orbit below it. Staging goes through automatic staging.
• Boostback flies a separated booster back toward its landing site with a settling burn, a flip, the boostback burn and an entry attitude, against an impact prediction through the atmosphere.
• Deorbit and land flies the whole chain from a low orbit: the deorbit burn, a fuel-optimal powered descent with G-FOLD or the 6-DOF solver, and a terminal hover to touchdown.
• Land from here starts only the powered descent and the hover, from where the craft is now.

Guidance takes a craft only when you press EXECUTE, and it lets go when you abort, take over the attitude or arm the stock Auto burn. An abort during the powered descent or the terminal hover leaves the engine as it is, so the craft does not drop. The hover refuses a craft whose thrust at minimum throttle exceeds its weight, and a descent that would hand over to it flies its own plan to touchdown instead. G-FOLD suits airless bodies and agile landers that point with RCS. The 6-DOF solver models the vehicle rotation, so it handles boosters with high rotational inertia and descents through an atmosphere. The native solvers ship with the mod. See the guidance documentation for how it works.

Hyperbolic Targets

The stock Transfer Planner filters out bodies with eccentricity >= 1. This mod lets it target interstellar comets (Oumuamua, 2I/Borisov, 3I/ATLAS) by patching the planner's time-of-flight and alignment math to handle unbound orbits.

Installation

1. Install StarMap (required) and KittenExtensions (only for the Hyperbolic Targets feature and the AUTOSTAGE gauge button).
2. Extract the SpaceDock zip into Documents\My Games\Kitten Space Agency\mods\AdvancedFlightComputer\, or install it with the mod manager Borea.
3. The game auto-discovers new mods on next launch.
4. If you still have the standalone AutoStage, AutoRemoveFinishedBurns or PoweredGuidance folders under mods, delete them, because a disabled mod still applies its XML patches. Their settings are imported on the first load.

Dependencies

Credits

The powered guidance is the work of Oliver Cairns (cairn5), co-author of the project. PEGAS by Noiredd is the reference and foundation for the UPFG implementation. G-FOLD follows Acikmese and Ploen (2007) and Acikmese, Carson and Blackmore (2013). Clarabel and SCS are the conic solvers behind G-FOLD and the 6-DOF guidance.

License: MIT. Vendored solver code keeps its own permissive upstream licence. Source Code & Full Changelog: https://github.com/Maximilian-Nesslauer/KSA-AdvancedFlightComputer Forum thread: https://forums.ahwoo.com/threads/advanced-flight-computer.783/

My other mods: DeltaVMap (interactive delta-v subway map and transfer-window planner) | MeasureTools (click-to-measure ruler and protractor in the map view)