SpaceX to launch 21 military data-relay satellites for the Space Development Agency on Monday

SpaceX is targeting the early hours of Monday, October 5, to launch 21 data-transport satellites for the Pentagon’s Space Development Agency (SDA) from Vandenberg Space Force Base in California.

The Falcon 9 is scheduled to lift off from Space Launch Complex 4-East at about 1:15 a.m. local time, according to Air & Space Forces Magazine; the Arizona Republic puts the target at 1:17 a.m. PT. A Federal Aviation Administration operations plan advisory lists a backup opportunity the following day if the launch is postponed.

The mission is the fourth of nine planned Tranche 1 batches — and the first to carry Northrop Grumman-built satellites. Once in orbit, the 21 spacecraft will join 63 Tranche 1 satellites built by York Space Systems and Lockheed Martin. Northrop Grumman is on the hook for a further 21 transport satellites and 14 missile-tracking spacecraft.

SDA Director Gurpartap Sandhoo told reporters on an October 1 prelaunch call that scaling production is the constellation’s hardest problem. “It’s one thing to go through launch and early ops of one, two, maybe even three or four satellites. Twenty-one is a completely different ball of wax,” he said.

The 154-satellite Tranche 1 constellation is intended to provide global military tactical communications and missile defence by 2027. SDA hopes to finish the remaining launches and have all Tranche 1 satellites in orbit by late spring 2027.

SpaceX plans to stream the launch on its website from about 10 minutes before liftoff.

Sources: Air & Space Forces Magazine, Arizona Republic