Spacex stopped the launch of its Falcon 9 rocket just 2 seconds before liftoff. The next opportunity for SpaceX to fly is Saturday evening, though a launch date has n’t been confirmed yet.

This will be the fourth GPS satellite of its kind to launch in the last three years, and the third one to be launched by SpaceX.

Gps III sv04 will become one of the 31 primary GPS satellites in orbit. Part of a new block of GPS III spacecraft intended to slowly replace the current GPS vehicles.

The GPS III satellites are meant to be more user-friendly for civilians. The satellites sport a new’civil signal’ that allows them to more easily communicate with other satellite navigation systems in space.

In the meantime, five more GPS III satellites are in production. Three of them are fully built and undergoing tests. Lockheed Martin says the fifth satellite is ready to go.

The launch is scheduled for 9:43pm et, on top of SpaceX’s Falcon 9 rocket from the Cape Canaveral Air Force station in Florida. Spacex still plans to recover the Falcon 9 following the flight and will attempt to land the rocket on one of the company’s floating drone ships in the Atlantic Ocean.

Rockets on the East coast have struggled to launch this week. Three separate vehicles have experienced delays due to weather issues and weather problems.