Launch Day Arrives for NASA’s SpaceX Demo-2

Countdown clocks are ticking toward the launch of a new era in human spaceflight. With today’s scheduled launch of NASA’s SpaceX Demo-2 mission at the agency’s Kennedy Space Center in Florida, American astronauts will once again launch on American spacecraft from American soil to the International Space Station. Liftoff of the SpaceX Falcon 9 rocket and Crew Dragon spacecraft carrying NASA astronauts Robert Behnken and Douglas Hurley is targeted for 4:33 p.m. EDT from Kennedy’s historic Launch Complex 39A.

Don’t miss a minute of today’s events. Follow the countdown live starting at 12:15 p.m. EDT on NASA Television, on the web at http://www.nasa.gov/live and here on the blog.

Behnken and Hurley are spending the morning in the Astronaut Crew Quarters inside Kennedy’s Neil Armstrong Operations and Checkout Building, where they’ll sit down for a preflight meal five hours prior to launch. The crewmates will receive a weather briefing at approximately 12:15 p.m., then begin suiting up in the crew quarters’ Suit Room around 12:30 p.m.

Here’s an overview of the countdown milestones ahead:

-04:15:00       Crew weather brief
-04:05:00       Crew handoff
-04:00:00       Suit donning and checkouts
-03:22:00       Crew walk out from Neil Armstrong Operations and Checkout Building
-03:15:00       Crew transportation to Launch Complex 39A
-02:55:00       Crew arrives at pad
-02:35:00       Crew ingress
-02:20:00       Communication check
-02:15:00       Verify ready for seat rotation
-02:14:00       Suit leak checks
-01:55:00       Hatch close
-00:45:00       SpaceX Launch Director verifies go for propellant load
-00:42:00       Crew access arm retracts
-00:37:00       Dragon launch escape system is armed
-00:35:00       RP-1 (rocket grade kerosene) loading begins
-00:35:00       1st stage LOX (liquid oxygen) loading begins
-00:16:00       2nd stage LOX loading begins
-00:07:00       Falcon 9 begins engine chill prior to launch
-00:05:00       Dragon transitions to internal power
-00:01:00       Command flight computer to begin final prelaunch checks
-00:01:00       Propellant tank pressurization to flight pressure begins
-00:00:45       SpaceX Launch Director verifies go for launch
-00:00:03       Engine controller commands engine ignition sequence to start
-00:00:00       Falcon 9 liftoff

The Demo-2 mission will serve as an end-to-end flight test to validate the SpaceX crew transportation system, from launch to docking to splashdown. It is the final flight test for the system to be certified for regular crew flights to the station as part of NASA’s Commercial Crew Program.