SpaceX CRS-18: Launch Countdown Milestones for July 24 Liftoff

The launch of SpaceX’s 18th commercial resupply services mission to the International Space Station for NASA is scheduled for 6:24 p.m. EDT with an instantaneous launch window. The SpaceX Falcon 9 rocket and Dragon spacecraft have been moved to the vertical launch position. Launch coverage will begin at 6 p.m. on NASA Television and the agency’s launch blog.

Meteorologists with the U.S. Air Force 45th Space Wing continue to predict a 30% chance of favorable weather for liftoff. The primary weather concerns are the cumulus cloud rule, lightning rule and attached anvil rule.

Packed with more than 5,000 pounds of research, crew supplies and hardware, the Dragon spacecraft will launch on a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

Mission Timeline (all times approximate)
– 00:38:00     SpaceX Launch Director verifies go for propellant load
– 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
– 00:07:58     Dragon transitions to internal power
– 00:07:00     Falcon 9 begins pre-launch engine chill
– 00:01:00     Command flight computer to begin final prelaunch checks
– 00:01:00     Propellant tanks pressurize for flight
– 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