After it separated from the second stage, the first stage of the Falcon 9 rocket arrested its forward movement, and began falling back toward Earth.
SpaceX launched (and landed!) its Falcon 9 from Vandenberg Air Force Base, which sits just north of Los Angeles. Pacific time. The launch was delayed one day for "pre-flight vehicle checkouts", SpaceX tweeted last week.
A lovely sky show following Falcon 9's launch. Residents in Santa Barbara, Ventura and San Luis Obispo counties may hear sonic booms. SpaceX CEO Elon Musk Reveals Japanese Billionaire Yusaku Maezawa Will Fly Around the Moon on the Big Falcon Rocket.
SpaceX has previously landed first stage rockets on land after Florida launches but has not done so on the West Coast.
According to SpaceX's press release, SAOCOM 1A is carrying an "active instrument consisting of a Synthetic Aperture Radar (SAR), which works in the microwave range of the electromagnetic spectrum, particularly the L-band". The satellite was deployed about 12 minutes after liftoff.
The first stage, meanwhile, flipped around and re-started three of its nine engines to reverse course and head back toward Vandenberg.
Using titanium "grid fins" at the top of the rocket for steering and attitude control, the booster plummeted tail-first toward Vandenberg. Previous rocket landings had taken place on the East Coast.
The 3,500-lb. (1,600 kilograms) SAOCOM-1A satellite was developed by Argentina's national space agency, which is known by its Spanish acronym CONAE. The successful launch marked the company's 17th such mission of the year. SpaceX confirmed as much during its SAOCOM 1A webcast.