Physicsless part
Some parts within the game are listed as having a small mass, but in the config file a flag is set "PhysicsSignificance = 1". This has the effect that in flight physics calculations such as mass and drag are not calculated for that part. However, as of KSP 1.0.2, the part mass is instead added to the parent part, so that the vessel mass is increased appropriately even if the part itself is ignored for the physics simulation.
When constructing a craft, the root part can't be such a part.
Behaviour
A craft with only physicsless parts starts to oscillate after a short time and then starts to destroy itself. But this is usually not possible because the root part is always not a physicsless part. The game can change the property on the fly, because when a new root part after decoupling would be physicsless the game removes that special status.
List of physicsless parts
Parts with PhysicsSignificance = 1 as of 1.0.2
- 2HOT Thermometer
- Atmospheric Fluid Spectro-Variometer
- BZ-52 Radial Attachment Point
- Communotron 16
- Communotron 88-88
- Cubic Octagonal Strut
- Double-C Seismic Accelerometer
- EAS-4 Strut Connector
- FL-A5 Adapter
- FTX-2 External Fuel Duct
- GRAVMAX Negative Gravioli Detector
- Illuminator Mk1 (spot)
- Illuminator Mk2 (wide)
- LY-01 Fixed Landing Gear
- LY05 Steerable Landing Gear
- O-10 MonoPropellant Engine
- Octagonal Strut
- OX-STAT Photovoltaic Panels
- Pegasus I Mobility Enhancer
- Place-Anywhere 7 Linear RCS Port
- PresMat Barometer
- RV-105 RCS Thruster Block
- Small Hardpoint
- Telus-LV Bay Mobility Enhancer
- Telus Mobility Enhancer
- TR-38-D (Size 3 decoupler)
- Vernor Engine
- Z-100 Rechargeable Battery Pack
- Z-400 Rechargeable Battery
Note that several parts, such as the LT-2 Landing Strut, have PhysicsSignificance = 0 in its part.cfg. This does nothing, and the part behaves as normal.
See also
- “Kerbal Space Program - Your Physics Have No Power Over Me!” by Scott Manley
