Orbit MFD

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Revision as of 13:24, 21 July 2023 by Arvil (talk | contribs) (Orbit MFD)
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Orbit is an MFD mode which is included in the Orbiter Space Flight Simulator. This mode displays a graphic representing a central body, the orbit of the pilot's ship, and the orbit of a target body, and also includes orbital parameters and elements of those orbits. The pilot can select Orbit from the MFD mode selection page.

Orbit MFD displays the osculating orbits at the current epoch (its 2-body orbit) with respect to a celestial body. The orbital parameters may change over time due to perturbations from other gravity sources, nonspherical gravity, atmospheric drag, and thruster action, etc. Any celestial body in the current session can be selected as the reference body.

Orbital elements and graphic display is displayed in one of two frames of reference, Ecliptic (ECL) or Equatorial (EQU) by selecting the FRM button or Shift+F. The current frame is displayed on the top line of the MFD display near the right corner.

Any celestial body may be selected as the reference body by selecting the REF button or Shift+R, displaying a pop-up window where the pilot may select the reference body. Selecting the NT button or Shift+A will autoselect the reference body having the highest gravitational influence on the ship.

The display may project a plane to be projected onto the MFD display by selecting PRJ or Shift+P. Four planes may be selected: Ecliptic (ECL), Equatorial (EQU), the focus ship (SHP), or target ship or celestial body (TGT).

Distance from the focus body may be displayed from the center of the body, indicated by Rad, ApR, PeR, or from the altitude of the mean radius of the body, indicated by Alt, ApA, PeA, by selecting the DTS button or Shift+D.

The orbit of a target ship or body orbiting the same body as the pilot's ship may be selected with the TGT button or Shift+T. The NT button or Shift+N turns off the target orbit and data.

Selecting the HUD button or Shift+H will set the HUD to Orbit MFD mode and copy the orbit reference object.

Key Options
MFD button Keypress Description
AR Shift+A Autoselect the reference body.
DST Shift+D Toggle planetocentric distance or altitude above mean radius
FRM Shift+F Toggle frame of reference
(ecliptic or reference object equator)
HUD Shift+H Set HUD to Orbit mode and copy the current MFD orbit reference object
MOD Shift+M Toggle display mode
(reference frame, ship's orbital plane, target orbital frame)
will show central body with ship's orbit and target orbit if selected; orbital data; both
NT Shift+N No target orbit
PRJ Shift+P Toggle projection mode of orbit
(reference frame, ship's orbital plane, target orbital plane
REF Shift+R Select new reference object (celestial object) or orbital data
TGT Shift+T Open popup menu to select a target


MFD display components
!Parameter Nomenclature Description
SMa Semimajor axis longest semi-diameter of the orbit
Periapsis + Apoapsis
SMi Semiminor axis shortest semi-diameter of the orbit
PeR
PeA
Periapsis Radius
Periapsis Altitude
Lowest point of the orbit
ApR
ApA
Apoapsis Radius
Apoapsis Altitude
Highest point of the orbit
Rad
Alt
Radius
Altitude
Radius from the center of the body
Altitude from body mean radius
Ecc Eccentricity Circularity of the orbit (0-1)
T Orbit Period Time in seconds for one orbit
PeT Periapsis Time Time in seconds until the next Periapsis
ApT Apoapsis Time Time in seconds until the next Apospsis
Vel Velocity Velocity of the ship or target in km/sec
Inc Inclination Angle (°) at which orbit deviates from the ecliptic or equator
LAN Longitude of the Ascending Node Angle in degrees (°) of the orbit from the Vernal Equinox
LPe Longitude of Periapsis Angle (°) along the reference plane from the Vernal Equinox to the Periapsis
AgP Argument of Periapsis Angle (°) from the ascending node to the periapsis
TrA True Anomaly Angle (°) from the Periapsis to the ship's or target's location along the orbit
TrL True Longitude Angle (°) of the longitude of the ship's or target's position from the ecliptic
MnA Mean Anomaly Angle (°)
MnL Mean Longitude