The launch phase begins when the spacecraft transfers to internal power on the launch pad and ends when the spacecraft is declared stable, healthy, and ready to accept commands and the launch telemetry has been played back. The launch telemetry tells engineers exactly what happened during the launch.

The Mars Science Laboratory launch strategy will provide for a launch window of extended duration in order to accommodate any minor hardware problems, short-term weather delays at the launch pad, and launch holds caused by potential collisions with objects in Earth orbit. The specifics of the daily launch windows for the Mars Science Laboratory, which will fly on an ATLAS V 541 launch vehicle , are now being analyzed.

The major activities in this mission phase include:

• the liftoff and boost phase of the launch;
• insertion into a circular parking orbit;
• a coast period followed by additional launch vehicle burns necessary to inject the spacecraft onto a trajectory to Mars;
• separation of the spacecraft from the launch vehicle;
• initial acquisition by the Deep Space Network;
• verification of the initial spacecraft health and operating conditions; and,
• the verified execution of a minimal set of post-launch commands.