Stay up late tonight to watch Europe's Ariane 6 rocket launch its 1st pair of Galileo navigation satellites

Europe's towering Ariane 6 rocket is gaining momentum in the heavy-lift launch market as the vehicle gears up for its fifth flight.

The first pair of Galileo navigation satellites to launch on an Ariane 6 are scheduled to liftoff from Europe's Spaceport in Kourou, French Guiana on Wednesday (Dec. 17) at 12:01 a.m. EST (0501 GMT; 2:01 a.m. local time in Kourou).

Galileo Launch 14 (L14) will send the spacecraft pair to join 26 other active satellites in the constellation, which is Europe's equivalent to the Global Positioning System (GPS) used by the United States. The launch will be broadcast live by Arianespace, which operates the Ariane 6, and livestreamed here,on Space.com tonight (Dec. 16) beginning at 11:35 p.m. EST (0435 GMT on Dec. 17).

The L14 satellites are scheduled to deploy about 3 hours and 20 minutes after liftoff and will then spend three days unfolding their solar arrays and running checks on critical systems. The two satellites will then enter a four-month drift and positioning phase before settling into their final orbital position to begin operation.

The Galileo constellation circles Earth at an altitude of 14,429 miles (23,222 kilometers). To date, most of the 1,610-pound (730 kilograms) spacecraft have been launched aboard Europe's Ariane 5, which retired in 2023, or the Russian-built Soyuz rocket, an arrangement that Europe ended following Russia's invasion of Ukraine in February 2022.

Europe tapped SpaceX's Falcon 9 to fly Galileo satellites after the invasion, but now that Ariane 6 is operational, the continent can loft those missions without depending on outside launch providers.

This will be the fifth-ever launch of the Ariane 6, which completed four successful flights over the past year, with its most recent lifting off just over a month ago.