Translation Hand Controller

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The Translation Hand Controller (THC) provides the capability of manual commanding simultaneous accelerations along the spacecraft axes, that means translational manoevers. It is also used to initiate several transfer commands, to transfer the spacecraft control from CMC to SCS control for example. The real THC is basically a kind of joystick, but with some significant differences. The main functions are simulated by using a joystick or Orbiter's controls configured with the Launchpad Configuration Options, for some functions the panel is used.

Quickstart Mode

In Quickstart Mode the THC isn't used, but the CSM RCS is controlled by Orbiter directly as for example in the Delta-glider including the navmodes (killrot etc.), external control by MFDs etc. So this article applies in Virtual AGC Mode only, but optionally Orbiter control can be disabled with the Launchpad Configuration Options for Quickstart Mode, too.

Panel switches

Location of THC switches

In order to use the THC it needs to be powered, which is done by switching the TRANS CONTR PWR switch A to the upper position[1].

Additionally to the translational movements the real THC may be rotated clockwise or counterclockwise. This isn't done with an external joystick, but with a small "bitmap THC" B in the lower left corner of the main panel.

  • The clockwise switch (CW) will transfer spacecraft control from CMC to SCS. It may also transfer control between certain submodes within the SCS, see the Service Propulsion System for example.
  • The redundant counterclockwise switches (CCW) provides for a manual abort initiation during the launch phase. A signal is fed to the master sequence controller, a SECS component, which initiates other about functions.

Joystick support

The axes of the real THC[2]

Translational control is provided by a joystick or Orbiter's controls as configured with the Launchpad Configuration Options. Unlike the RHC the axes of the real THC are different to the axes of a joystick. The following table shows how the joystick axes are related to the translational movements with respect to the astronaut in the spacecraft:

Joystick Spacecraft
Push forward ("pitch down") Move Down
Pull backward ("pitch up") Move up
Push left ("roll left") Move left
Push right ("roll right") Move right
Turn left ("yaw left") Move backward
Turn right ("yaw right") Move foreward

The last two axes assignments (foreward/backward) are not intuitive and different to the real THC, also not all joysticks have a yaw axis. Because of this additionally the POV "Hat" Switch can be used:

Joystick Spacecraft
POV foreward ("0°") Move foreward
POV backward ("180°") Move backward
  1. The TRANS CONTR PWR switch receives power from the SCS CONTR/AUTO MNA/B circuit breakers on panel 8 [I]
  2. Apollo Command Module News Reference. 1968. North American Aviation. PDF [CSMNEWSREF]

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