2.2 Orbit

The Orbit MFD displays a list of elements and parameters which characterize the ship’s orbit around a central body, as well as a graphical representation. In addition, a target object (ship orbital station or moon) orbiting the same central body can be selected, whose orbital parameters will then be displayed as well.

The parameters of the current orbit can be displayed in the list mode are:

• SMa - semi-major axisIn geometry, the semi-major axis (also semimajor axis a applies to ellipses and hyperbolas. Ellipse The semi-major axis of an ellipse is one half of the major axis running from the center, through a focus, and to the edge of the ellipse. The major axis is
• SMi - semi-minor axisIn geometry, the semi-minor axis (also semiminor axis applies to ellipses and hyperbolas. Ellipse The semi-minor axis of an ellipse is one half of the minor axis, running from the center, halfway between and perpendicular to the line running between the f
• PeD - periapsis distance
• ApD - apopasis distance
• Rad - radial distance
• Ecc - eccentricityMathematics In mathematics, eccentricity is a parameter associated with every conic section, see Conic section#Eccentricity. It can be thought of as a measure of how much the conic section deviates from being circular. In particular, The eccentricity of a
• T- orbit periodThe orbital period is the time it takes a planet (or another object) to make one full orbit. There are several kinds of orbital periods for objects around the Sun: The sidereal period is the time that it takes the object to make one full orbit around the
• PeT - time to periapsis passage
• ApT - time to apopasis passage
• Vel - velocityVelocity (symbol: v is a vector measurement of the rate and direction of motion. The scalar absolute value ( magnitude) of velocity is speed. Velocity can also be defined as rate of change of displacement or just as the rate of displacement, depending on
• Inc – inclinationInclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planet's equator or the ecliptic), stated in degrees.
• LAN - longitude of ascending node
• Lpe longitude of periapsis
• AgP - argument of periapsis
• TrA - true anomaly
• TrL - true longitude
• MnA - mean anomaly
• MnL - mean longitude

In graphic mode Orbit mode MFD projects relative view of following parameters:

• Periapsis
• Apoapsis
• Ascending node
• Descending node
• Radius vector

G-field contribution is a parameter displayed at the bottom of the MFD in both modes that provides information about How it works:

Select key: SHIFT-O

Available in Orbiter (sim) standard distribution

2.3 VOR/VTOL

VOR/VTOL is primarily used for planetary surface flight and vertical takeoff/landing.

How it works: MFD features multitude of altitude and airspeed readouts.

• DIST: distance in [m] and DIR: direction of slaved NAV transmitter
• HSPD: horizontal and VSPD: vertical airspeed component [m/s]
• ALT: altitude [m] and Target indicator which shows the horizontal location of the slaved NAV transmitter.

Select key: SHIFT-

Available in Orbiter (sim) standard distribution

2.4 Horizontal Situation Indicator

HSI MFD is primarily used for surface navigation and instrument landing.

How it works:

Select key: SHIFT-L

Available in Orbiter (sim) standard distribution

2.5 Docking

Docking MFD is used during final approach to dock with another vessel or orbital station. The layout is similar to the Landing MFD.

How it works: MFD supports three different modes:

• IDS mode
• Visual mode
• Direct target selection

Select key: SHIFT-D

Available in Orbiter (sim) standard distribution

2.6 Surface

Surface MFD assists in flight close to planetary surfaces.

How it works:

Select key: SHIFT-S

Available in Orbiter (sim) standard distribution

2.7 Map

Map MFD shows a surface map of a planet or moon, including all available surface bases and can be used to guide Orbiteers in their approach to bases. How it works:

Select key: SHIFT-M

Available in Orbiter (sim) standard distribution

2.8 Align orbital plane

Align orbital plane MFD is used to calculate maneuvers necessary to rotate the orbital plane in space so that it corresponds with some target plane, e.g. the orbital plane of another object.

How it works: The instrument contains the relevant orbital elements (inclination and longitude of the ascending node) of the current and target orbits. It also shows the relative inclination (angle between the two planes), the angles of the current radius vector towards ascending and descending nodes, the time to intercept the next node, and the predicted required thruster burn time. See section 15.3 on how to use this MFD mode.

Select key: SHIFT-A

Available in Orbiter (sim) standard distribution

2.9 Synchronise orbit

Synchronise orbit MFD helps with catching up with an orbiting body once the orbital planes have been aligned (e.g. using Align orbital plane MFD .

How it works:

Select key: SHIFT-V

Available in Orbiter (sim) standard distribution

2.10 Transfer

How it works:

Select key: SHIFT-X

Available in Orbiter (sim) standard distribution

2.11 TransX

Developed by long-time community contributor Duncan Sharpe the TransX MFD (known also as Xtransfer) is an advanced navigation tool that enables Orbiteers to plan and fly complex trips across the Solar system. It is also the first third-party MFD that is included in the Orbiter (sim) standard distribution of Orbiter.

Select key: SHIFT-

Available in Orbiter (sim) standard distribution or at Orbiter Mars – Duncan Sharpe's Orbiter site

2.11.1 Evolution and updates

The MFD is still under active development, and new versions are released every few months and can be downloaded directly from author’s site.

2.12 Ascent profile (custom MFD mode)

How it works:

Select key: SHIFT-

Available in Orbiter (sim) standard distribution

3 Other third-party MFDs

Thanks to MFD API published first in Orbiter release XXXXX it is possible for third-party add-on developers to create their own custom-built MFDs. The MFDs can be shipped as a stand-alone .DLL libraries (modules) that require activation in Orbiter Launchpad before they can be used.

Over last two years a large number of MFDs has been published ranging from complex and powerful (like advanced TransX MFD by Duncan Sharpe ) to less elaborate but still useful (like WinAmp MFD or IRC MFD or even Minibar MFD).

Some of the third-party MFDs are assigned specific key combinations for the activation. This may result frequently in conflicts.

3.1 Interplanetary MFD

Created by Jarmo "Jarmonik" Nikkanen Interplanetary MFD (also called I-MFD) serves similar fuctions as TransX - as an aid in interplanetary navigation and support for complex space maneuvers.

How it works: I-MFD calculates orbits using xxx It features Solar system map, course planning tool, orbit-ejection tool as well as TEI-burn and planet approach program and aero-brake program. I-MFD has a high speed numerical trajectory calculator supporting planet-to-planet perturbated trajectories. Trajectories are not limited in a ellipses and hyperbolas and can be plotted around multiple references.

Select key: SHIFT-

Available at: Interplanetary MFD page

3.2 BaseSync

How it works:

Select key: SHIFT-

Available at: []

3.3 Reentry

How it works:

Select key: SHIFT-

Available at: []

3.4 Fuel transfer

How it works:

Select key: SHIFT-

Available at: []

3.5 IRC

Created by Toni Ylisirnio IRC MFD is a first-generation multiplayer IRC plugin for Orbiter that allows communication between Orbiteers.

How it works:

Select key: SHIFT-

Available at: []

3.6 MultiOrb

Created by David "dh219/Hendo" Henderson MultiOrb MFD is a second-generation multiplayer plugin. It allows for connection with other clients in the Orbiter IRC network (orbiterirc.no-ip.com:6667) and automatically sends and receives telemetry from other online Orbiteers. MultiOrb is backwards compatible with IRCMFD, adds extra functionality but doesn't support IRC chat. This limitation will be hopefully rectified in next version (third generation?)

How it works: MultiOrb MFD is sending periodic telemetry updates to other Orbiteers MultiOrb MFDs and thus makes their systems aware of each other ships. MultiOrb physics engine then extrapolates movement of respective ships from those updates. In case one of the Orbiteers time-accelerates or is thrusting (rotation, linear or indeed main and retro), there is an inherent difference (error) on connected Orbiteers' machines until they are able to exchange telemetry updates again. MultiOrb therefore sends telemetry only after the end of every burn or maneuver, but not at the end of every time-acceleration switch.

Select key: SHIFT-2

Available at: AIBS

3.7 WinAmp

Created by Matt Weidner WinAmp MFD allows for playing .MP3 and other files supported by Winamp 2 player.

How it works: MFD acts as an interface for controlling a running instance of Winamp 2 (Winamp 3 is not supported).

Select key:

Available at: AVSIM

3.8 BurnTimeCalc

Contributed by David "dh219/Hendo" Henderson BurnTimeCalc (BTC) is a simple MFD that allows precise determination of beginning of an engine burn during the propulsive maneuver . It is supposed to be used in conjunction with other MFDs to calculate the delta v required for a given maneuver (e.g. Trans MFD or TransX MFD).

How it works: BTC assumes that delta V required for a particular maneuver is already known (e.g. computed by TransX or other MFD). After it is entered using MFD keys, MFD displays time to periapsis and count-down to beginning of the engine burn . User is supposed to start burning when count-down display reaches 0. End of burn should be determined using other MFD.

Limitations According to the creator, BTC is limited by following assumptions:

• engine burn is achieved using main engines at 100% throttle,
• all main engines have the same Isp,
• multistage burns are not allowed.

Although BTC uses simple first-order approximation of the mass decrease of vessel, it should be relatively accurate for most of the propulsive maneuvers.

Select key: SHIFT-T

Available at AIBS

Source: available via anonymous CVS at http://sourceforge.net/projects/projectganymede/ Sourceforge's ProjectGanymede

3.9 Orbiter MiniBar

Created by David "dh219/Hendo" Henderson Orbiter MiniBar MFD is allegedly one of the least "serious" MFDs in Orbiter community. On the other hand who can say a bar can be dispensable during a half-year trek to Mars?

Select key: SHIFT-B

Available at: AIBS

3.10 See also

• Orbiter (sim)
• Orbiter (sim) standard distribution

3.11 External links

Orbiter (sim)

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