If all goes according to plan, the Falcon 9's first stage will come back to Earth safely, touching down at Vandenberg's Landing Zone 4 just under eight minutes after liftoff.

It will be the second launch and landing for this particular booster, according to a SpaceX mission description (opens in new tab). The rocket previously helped launch a batch of SpaceX's Starlink satellites to orbit.

The Falcon 9's upper stage, meanwhile, will continue carrying the Tranche 0 satellites to orbit. The SpaceX mission description doesn't say when the spacecraft are scheduled to be deployed. That's not terribly surprising; details about national security missions such as this one are often hard to come by.

We do know a bit about the Tranche 0 spacecraft going up today, however. For example, they'll be the first members of the Proliferated Warfighter Space Architecture (PWSA), a constellation the SDA will assemble in low Earth orbit.

"Under the plan, the Space Force will have hundreds of small satellites, with new ones launched every few years to increase resilience and capabilities in orbit," Air and Space Forces Magazine wrote about the PWSA (opens in new tab).

The 10 Tranche 0 satellites cost about $15 million apiece, the magazine added. Eight of the spacecraft going up today will relay data and two will track missiles, though this first set is intended primarily to demonstrate capabilities that future SDA satellites will take operational.

Another Tranche 0 set is expected to launch in June, according to Air and Space Forces Magazine.

"The entire tranche consists of 28 satellites — 20 for data transport and eight for missile tracking," the outlet wrote.