The Orbit Flight Dynamics Officer has a large number of displays that are part of normal operations.

Since there are so many possible things that happen during the course of a mission, once the Shuttle makes it to orbit, there are an equally complex and large number of displays that help the FDO do the job!

Specializations in the Orbit FDO position, including the Deploy FDO and Rendezvous FDO certifications, would require the use of more specific displays than a normal Spacelab or other “non-dynamic” mission.

This section of displays gives some insight into some of the possible tools available to the Orbit, Deploy, or Rendezvous FDO!

Feel free to contact me if you have any questions about anything you see here!

Checkout Monitor

This display (“Checkout” for short) is an at-a-glance snapshot overview of a state vector at any given time from any given source.

The FDO uses this display to see a number of trajectory parameters specific to the orbit, including apogee/perigee heights, position/velocity information, and much more! There are several variations of this display (shown in the Aries Mean-of-1950, or M50, coordinate system): M50, True-of-Date Rotating (TDR), and J2K.

Given the wealth of trajectory information available on this one screen, it is one of the most used and most valuable sources of information for the FDO.

Detailed Maneuver Table

The DMT provides the FDO with tons of information about a specific planned (or executed!) maneuver.
Time of Ignition (TIG), specific maneuver targets (in several possible Powered Explicit Guidance – PEG – modes), burn attitude, body-fixed Velocity-to-Go (VGO), and resultant apogee/perigee data are shown in the center “PAD” section.

Other information about the burn and the state vector information used to compute it are shown around the PAD section.

Since the FDO is primarily responsible for computing and monitoring the execution of burns, this is also one of the most important displays for the FDO.

Relative Motion Plot

RelMo provides a graphic representation of the relative motion between two vehicles, a “chaser” (usually the Shuttle) and the “target” (ISS, HST, or some other free-flying vehicle or payload).

The origin is target-centered, and the plot of the chaser is projected onto an X-Z (downrange-radial) plot with respect to the target.

This gives the FDO an at-a-glance view of how the two vehicles will be moving with respect to each other in space.

This particular example shows a fairly nominal Day-of-Rendezvous scenario with the Orbiter less than one orbit away from the Terminal Initiation (or Ti) burn that will start the direct course for rendezvous operations.

ONAV Orbital Status

This legacy, completely-digital, display was one of the FDO’s most-used information screens in the “old MCC”. It was usually referred to by its display ID # (i.e., “MSK549”).

The amount of information shown on this one summary display could be overwhelming to a new trainee in The Trench, but over time the FDO would develop a scan pattern that allowed for a rapid evaluation of the health of “all things Trajectory”.

An evaluation of the onboard state vectors, compared to the ground ephemeris, allows the FDO to determine, quickly, if the Shuttle’s computers had a solid knowledge of where the vehicle was.

Other, onboard navigation-specific information on this display allows the FDO to watch over the crew as they executed maneuvers, typed in keyboard commands, and performed other Shuttle activities specific to Trajectory Operations.


Like MSK549, the Rendezvous/Proximity Operations Procedures display (RNDZ/PROX OPS PROC, or MSK1888), is another legacy, completely-digital, display brought over from the “old MCC”.

It, too, has a large amount of data displayed in one summary screen.

Its primary original use was targeted for rendezvous and Prox Ops phases (thus the name, duh!), but a number of Orbit FDOs prefer it to MSK549 for data presentation

Trajectory Profile Status

Another legacy display provided the FDO with a one-stop-shop view of specific details on each of his four vehicle ephemerides and those of the three TDRS satellites (for acquisition and pointing purposes).

EPH 1 is almost always used as the “prime” Orbiter ephemeris, with the “best maneuver plan”, weight profile, and state vectors contained there.

EPH 3 is, when applicable, the deploy or rendezvous target ephemeris.

EPH 2 and 4 are used for planning purposes. They allow the FDO to perform an number of “what-if” analyses, without disturbing the other MCC processors and timers that were driven from data provided by the prime Orbiter and Target ephemerides.

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The space exploration advocacy website of Roger Balettie, former Flight Dynamics Officer in NASA’s Space Shuttle Mission Control Center.

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The Flight Dynamics Officer (FDO, pronounced “fido”) is a Flight Controller in the Mission Control Center responsible for the overall trajectory, or flight path, of the Space Shuttle and all related payloads or other space-bound vehicles associated with the Shuttle.

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"Houston… Tranquility Base here. The Eagle has landed."

Since 1965, the Mission Control Center (MCC) has been the nerve center for America’s manned space program.


Space- and NASA-based blog entries.

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50 Years

50 Years

The Artemis I mission occurred 50 years after Apollo 17. What will it take to not have this happen again?

13 Minutes – a podcast review

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“13 Minutes to the Moon” – an excellent BBC podcast focusing on the behind-the-scenes heroes of Apollo 11 and Apollo 13.



It’s been 40 years since the launch of STS-1, and the excitement of that day never faded.