SpaceX Targets Monday for 21 SDA Data Satellites

So basically: SpaceX is targeting Monday, Oct. 5, for a Falcon 9 launch of 21 Space Development Agency data satellites from Vandenberg. Liftoff is targeted for 1:17 a.m. PT, which is 4:17 a.m. ET. If it slips, Tuesday is 1:08 a.m. PT, or 4:08 a.m. ET.

The load

SpaceX says this is the fourth of nine Tranche 1 missions it will fly for the SDA. The 21 satellites are the fourth orbital plane of the Proliferated Warfighter Space Architecture.

That network is a mesh of satellites in low Earth orbit, linked optically. SpaceX says it is meant for military tactical communications and for missile warning, indication, and tracking. The page does not name who built the 21 satellites.

The rocket

The booster is on its sixth flight. SpaceX says it has already flown NROL-179, an earlier SDA mission labeled SDA-T1TL-E, and three Starlink missions. After separation it is planned to land at Landing Zone 4 at Vandenberg.

The webcast is supposed to start about 10 minutes before liftoff. SpaceX also says people in Santa Barbara, San Luis Obispo, and Ventura counties might hear one or more sonic booms, depending on the weather.

My take

This is not a crew flight and it is not a secret box with no description. SpaceX has said what the plane is for and how many satellites are on it. What it has not said is which company built them. Monday morning is a data-transport launch. The useful check after liftoff is whether all 21 get to that plane, not whether the booster sticks the landing.