Today, the Mars Science Laboratory flight team begins executing its procedure for entry, descent and landing (EDL), and the spacecraft begins its sequence of autonomous activities leading to the landing this coming weekend. These activities include enabling needed components and setting final parameters. In addition, the schedule over the next several days includes opportunities to update parameters for the autonomous software controlling events during EDL. If needed, these updates can fine-tune the spacecraft’s autonomous controls for its descent through the atmosphere. Some parameters give the spacecraft’s onboard computer knowledge about where the vehicle is relative to Mars. Others may be updated based on observations by NASA’s Mars Reconnaissance Orbiter spacecraft of Mars’ variable atmospheric conditions in this week before landing.