The Falcon 9 first stage booster landed in the center of LZ-4, SpaceX's landing pad at Vandenburg Air Force Base.
SAOCOM 1A 3,000-kilogram satellite built by INVAP and this deployment was done in conjunction with Argentina's space agency with the objective of radar-imaging the earth.
Aside from the stir it caused among the locals, the launch was a huge success for SpaceX.
As The Verge noted, SpaceX hasn't been making sea landings by choice.
The rocket's first - and reusable - stage landed successfully, marking the first West Coast landing for a booster.
Landing and refurbishing first-stage boosters is key to SpaceX's plans to decrease launch costs.
The second stage continued the flight to the satellite into a sun-synchronous orbit.
The satellite is the first of two for Argentina's space agency, Comision Nacional de Actividades Espaciales, and will work in conjunction with a constellation of Italian space agency satellites. The spacecraft will set up shop 385 miles (620 kilometers) above Earth and scrutinize the planet using a Synthetic Aperture Radar (SAR) instrument. The mission's main objective is to collect soil moisture information.
The satellite is the first of two that will be used for emergency management and for land monitoring.
That almost identical satellite will launch in "the near future", also on a Falcon 9, according to the mission narrator for the Saocom-1A webcast.