Apollo abort modes

Houston's announcements of the current abort mode and the spacecraft commander's acknowledgements were among the few things said on the radio link during the first minutes of flight.

If the rocket failed during the first phases of the flight, the Emergency Detection System (EDS) would automatically give the command to abort.

(Preparation for a pad abort is seen in Apollo video footage: five minutes before launch, the umbilical arm connecting to the CM retracts and swings clear of the rocket.

During the abort, the main pitch control motors move the CM out of the flight path of the possibly exploding rocket.

After the LES main motor moves the CM away from the rocket, the tower would deploy canards (small wings at the tip).

[note 1] From 30.5 km (100,000 ft) until the LES is jettisoned, pitching the CM-LES combination over into the CM-forward position would still be necessary, but in the now thin air the canards are useless.

Should the S-IVB fail, the Service Module engine can place the CSM into Earth orbit to perform an Earth-orbit mission.

In the event of an early S-IVB shutdown, the CSM RCS thrusters would be used to insert the entire stack (including the docking adapter) into orbit.