Orbital Keeper - Station Keeping

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Introduction

Orbital Keeper is a Kerbal Space Program (KSP) mod that keeps orbits stable by automatically performing orbit corrections to counter decay-driven orbital lowering.

Automatic station-keeping runs for both loaded and unloaded vessels. Loaded vessels can also be corrected immediately from the UI.

Features

• Automatic station-keeping (loaded / unloaded)
  • Checks orbit drift at a configurable game-time interval and applies corrections for tracked vessels.
  • The scheduler is driven by game time, so checks continue at the configured interval during high warp.
  • Emergency checks run when periapsis decay is approaching a dangerous altitude.
• Safe correction for loaded vessels
  • Loaded vessels receive prograde/retrograde velocity impulses along the current velocity vector, avoiding unstable direct orbital-element rewrites.
  • Manual Correct in the UI applies an immediate correction on demand.
• Per-vessel configuration
  • Set target Ap/Pe/Inclination.
  • Adjust tolerance, check interval, and engine selection mode.
• Resource-aware corrections
  • Consumes propellant and Electric Charge based on required delta-v.
  • Warns when no eligible engine or insufficient resources are available.
  • Unloaded vessels do not model resource connectivity; blockages are ignored.
• Station-keeping lifetime estimate
  • Shows estimated delta-v, propellant use, remaining correction count, maintain time, and nominal correction interval in Flight/Tracking Station.
  • Uses SWAOD public APIs (TryEstimateStationKeepingCadence / TryEstimateCurrentDecayRates); if SWAOD is not installed, this estimate is shown as unavailable.
  • Emergency checks prefer SWAOD's periapsis decay rate (PeriapsisDaDt); storm enhancement is included only when Kerbalism reports an active solar storm.
  • Per-correction delta-v is fixed from the target orbit tolerance band; correction interval and maintain time use target-orbit decay (not the current drifted orbit).
  • Remaining correction count is based on propellant only (EC is not a lifetime limiter).
• VAB/SPH planning estimate
  • Editor window (default Alt + O, hidden by default) estimates craft mass, best engine Isp, fuel budget, and maintain time from target orbit settings before launch.
• RCS thruster support
  • Optional Enable RCS Thrusters toggle in Flight and VAB/SPH UI.
  • RCS burns do not consume the mod's EC-per-delta-v cost; only propellant is charged.
  • In IgnitedOnly mode, the stock RCS action group must be on for loaded vessels.
• Vessel overview
  • View on-orbit/sub-orbit vehicle status, target orbit and accumulated Δv consumption.
• Safety limits
  • Caps maximum correction delta-v and warns if target periapsis is too low.

Compatibility

• ❌ Principia : Not supported.
• ✅ Space Weather & Atmospheric Orbital Decay : Recommended with SWAOD for decay and lifetime estimates.

Dependencies

• Click Through Blocker

Installation

1. Copy the GameData/OrbitalKeeper folder into your KSP installation’s GameData directory.

Usage Guide

Open the UI

• Use the GUI hotkey (default Alt + O) in Flight or Tracking Station.
• If the toolbar button is enabled, click the Orbital Keeper icon in the stock AppLauncher.

Configure a vessel

• Select a vessel, then set target orbit parameters:
  • Apoapsis (Ap), Periapsis (Pe), Inclination.
• Set station-keeping options:
  • Auto-keep toggle, tolerance, check interval, engine mode, RCS toggle, UI font size.
• Click Apply Settings to save.

VAB/SPH planning

• Press Alt + O in the VAB or SPH to open the planning window.
• Pick a body, set target Ap/Pe, tolerance, and check interval, then review craft-side estimates for the current build.
• Toggle Enable RCS Thrusters if the craft relies on RCS for station-keeping.

GUI settings

• Adjust UI font size, hotkey key and modifiers, and toolbar button toggle.
• Per-user GUI settings are saved to GameData/OrbitalKeeper/PluginData/config.xml.

Actions

• Manual Correct applies a correction immediately for the selected vessel.
• Vessel Overview lists tracked vessels and their statuses.
• Remove Keeping clears station-keeping data for the vessel.

Configuration

Difficulty Settings (per save)

When creating or editing a game, configure these under Difficulty Settings → Orbital Keeper. Choosing a global difficulty preset (Easy / Normal / Moderate / Hard) loads the values below; individual fields remain editable.

Difficulty presets

Global config

Other defaults are stored in: GameData/OrbitalKeeper/OrbitalKeeper.cfg

Tolerance Notes

• Ap/Pe use relative ratios, and a correction is needed only when outside 1 ± (tolerance% / 100).
• When target Ap/Pe is very small (< 1 m), use absolute checks instead: |current - target| > 1000m * (tolerance% / 100).
• Inc/Ecc use absolute values with minimum thresholds (Ecc is derived from target Ap/Pe):
  • Inc minimum threshold is 0.5°.
  • Ecc minimum threshold is 0.001.
• Corrections are executed only when the total computed delta-v is greater than 0.01 m/s.

Engine Mode Notes

• IgnitedOnly: selects only engines currently ignited (EngineIgnited = True). For RCS, the stock RCS action group must be enabled on loaded vessels.
• ActiveNotShutdown: selects engines activated and not manually shut down; unignited but staged and not shut down engines are also eligible. RCS modules only need to be enabled.

Performance Note

• The automatic scheduler advances with game time, so checks continue even at high warp (e.g. 10000x) in the Tracking Station. Emergency checks intervene early when periapsis is dropping quickly.
• When enableToolbarButton is enabled, stutters may occur once per second for up to 10 seconds when using JanitorsCloset. Behavior varies by device; if you need JanitorsCloset, you can disable this option.