DART Launch Day
Events
All times are in EST unless otherwise
stated.
Unlike other rocket launches, the Pegasus XL launch vehicle is carried aloft by an L-1011 Carrier Aircraft and released from the plane's underbelly at a designated "drop" point and time. For Pegasus launches, launch time is considered the "drop" time, or the time when the Pegasus is released from the aircraft.
Several key countdown events will occur during live launch countdown.
Approximately 2 hours before takeoff of the L-1011 Carrier Aircraft and its payload, the ground communications and power are disconnected between the aircraft and the Hot Pad portion of the runway.
About half an hour later, if tower clearance has been granted, the L-1011 rolls to the end of the runway and the chase plans are notified.
At L-1:03 hours, the Ground Launch Team is polled to determine if the L-1011 is ready for takeoff. If all team members report a "go," the aircraft takes off minutes later.
Thirty-six minutes before the drop, the carrier aircraft begins a turn, under flying the drop point. About ten minutes later, the L-1011 pilot reports any turbulence, winds or clouds.
At L-12 minutes, the spacecraft is running on its own internal power. The final weather briefing occurs about eight minutes before the drop.
Five minutes before launch, the launch team is polled to determine final launch readiness. The terminal count begins one minute later at L-4 minutes.
In the final 90 seconds before Pegasus peforms the drop, the pilot acquires the necessary launch heading and the Pegasus' fin battery is activated at L-45 seconds.
Ten seconds before the drop, the Launch Conductor gives the official "go" for launch. When the clock ticks down to T-0, the Pegasus is released from the L-1011 aircraft.
|
