SpaceX is preparing to launch the latest pair of Galileo spacecraft for the European Union’s navigation satellite constellation.

The mission marks the second time that Galileo satellites will launch from U.S. soil, following the so-called L-12 mission, which flew on another Falcon 9 rocket back in April 2024. Liftoff of the L-13 mission from pad 40 at Cape Canaveral Space Force Station is set for 6:50 p.m. EDT (2250 UTC).

Spaceflight Now will have live coverage beginning about an hour prior to liftoff.

Heading into the launch opportunity, the 45th Weather Squadron forecast just a 40 percent chance of favorable weather at liftoff. The booster recovery weather risk was also noted as “moderate” on a scale of low-moderate-high.

“Several factors are in play for the weather this week. Primarily an area of low pressure spinning off the southeast U.S. coastline will gradually move onshore near South Carolina by Tuesday afternoon,” meteorologists wrote. “This circulation pattern, along with several waves of upper-level vorticity will help generate convergent bands of clouds and associated showers rotating through most of Florida into Tuesday.

“Additionally, expect west coast seabreeze convection to make its way across Florida nearing the spaceport Tuesday afternoon further enhancing possibilities for showers and thunderstorms.”

The Falcon 9 first stage booster supporting this mission, tail number B1067 in the SpaceX fleet, will be launching for a 22nd time. It previously supported two astronaut missions to the International Space Station (Crew-3 and Crew-4), two cargo mission to the ISS (CRS-22 and CRS-25) and 12 Starlink missions.

About 8.5 minutes after liftoff, B1067 will land on the SpaceX droneship, ‘Just Read the Instructions.’ This is a shift from the last time SpaceX launched a pair of Galileo satellites back in April.

“During the Galileo L12 mission earlier this year, the Falcon 9 booster was expended to provide the additional performance needed to deliver the payload to its orbit,” SpaceX wrote on its website. “Data from that mission informed subtle design and operational changes, including mass reductions and trajectory adjustments, that will allow us to safely recover and reuse this booster.

“Falcon 9 is ready to safely deliver Galileo L13 to orbit and return to the droneship in the Atlantic Ocean.”

While SpaceX said it fully intends to recover B1067, the company is hedging its bets given the challenges of landing with this flight profile.

“The booster reentry trajectory will result in higher heating and dynamic pressure on the booster than many of our historical landings. Although the reentry conditions are on the higher end of past missions, they are still acceptable,” SpaceX wrote. “This landing attempt will test the bounds of recovery, giving us valuable data on the design of the vehicle in these elevated entry conditions.

“This in turn will help us innovate on future vehicle designs to make our vehicles more robust and rapidly reusable while expanding into more challenging reentry conditions.”

Galileo expansion

The Galileo satellites preparing to launch are the latest in the constellation, following the deployment of satellites numbers 29 and 30 back in April. The satellites are managed and operated by the European Union Agency for the Space Programme (EUSPA) on behalf of the EU.

Earlier this month, the EUSPA confirmed that the L12 satellites completed on-orbit commissioning and officially joined the constellation on Sept. 5. The satellites are in medium Earth orbit about 23,200 km (14,416 mi.) above Earth.

“These two new satellites strengthen Galileo’s position as the world’s most accurate positioning system,” said EUSPA Executive Director Rodrigo da Costa in a statement. “With the European Commission, EUSPA and ESA collaborating closely, Galileo goes beyond just satellites; it stands as proof of our united dedication to innovation, security, and progress. Each addition not only improves availability and navigation robustness for over 4 billion users but also reinforce new market opportunities for European businesses, SMEs, and entrepreneurs.”

The satellites each weigh 2.3 tons (4,600 lbs.) and have an expected 15-year lifespan, according to manufacturer, Airbus. The two satellites launching as part of the L13 mission, 31 and 32 (FMs 26 and 32).