SpaceX teams working at Vandenberg Air Force Base in California were finalizing preparations Tuesday ahead of the launch of a Falcon 9 rocket Wednesday carrying a trio of Canadian-built radar observation satellites into orbit.

The 32-story-tall mobile service tower at the Delta 4’s launch pad at Vandenberg Air Force Base in California was retracted away from the rocket Thursday in advance of a planned liftoff with a top secret National Reconnaissance Office payload.

After two successful Falcon Heavy missions in less than 11 weeks, launch fans will likely have to wait until late 2020 for SpaceX’s next Falcon Heavy flight, barring a surprise mission for an unannounced customer.