Social media went into a frenzy in Southern California Sunday night after odd lights appeared to cross the evening sky.
The launch lit up the sky across San Diego and locals flooded KSWB with photos and questions about what they'd just seen overhead.
But, no need to fear. While many people's first instinct was to think aliens were en route, it was, in fact, a SpaceX rocket launch.
It's the very first time SpaceX (or anyone) has successfully landed a rocket on the West Coast.
The SpaceX mission, masterminded by billionaire Elon Musk, marks the 62nd flight of the Falcon 9, a rocket created to land back on Earth so it can be used again.
The reusable booster assembly makes the use of rockets more affordable for a wide range of customers across the globe.
SpaceX has flown boosters back to land after launches from Florida but has yet to do so in California.
If the mission goes according to plan, Sunday night will mark SpaceX's first landing of this sort on the West Coast.
On Twitter, SpaceX founder and CEO Elon Musk said it "wouldn't be subtle".
SAOCOM 1A carries a high-resolution instrument called a synthetic aperture radar that will be used for emergency management during disasters and for land monitoring.
Two minutes later, the second stage engine shut down as planned and two-and-a-half minutes after that, the SAOCOM 1A satellite was released into the planned polar orbit.
As the biggest antenna in space for a civil mission, its main goal is to gather soil moisture information.
The satellite will be operated by Argentina's space agency, known as the National Commission on Space Activites or by its Spanish-language acronym, CONAE.
Its name is short for Satelite Argentino de Observacion Con Microondas.