Ariane 62 | Galileo L15 (FOC FM28 & FM31)

### Ariane 62 Set to Bolster Europe's Galileo Constellation with L15 Mission

On December 31, 2026, the European Space Agency (ESA) is scheduled to launch the Ariane 62 rocket from the Guiana Space Centre in Kourou, French Guiana, carrying the Galileo L15 mission. This flight will deploy two Full Operational Capability (FOC) satellites, designated FM28 and FM31, into medium Earth orbit. As part of Europe's ambitious Galileo global navigation satellite system (GNSS), this mission represents a critical step in maintaining and expanding the constellation's capabilities amid growing demands for precise positioning, navigation, and timing services worldwide.

The primary objective of the Galileo L15 mission is to reinforce the Galileo network, which currently consists of over 20 operational satellites. These FOC satellites, built by OHB System AG in Germany with navigation payloads from Surrey Satellite Technology Ltd. in the UK, are designed to provide highly accurate location data with meter-level precision for civilian users and centimeter-level accuracy for authorized services. Each satellite weighs approximately 730 kilograms and operates at an altitude of about 23,222 kilometers in a near-circular orbit. Their payloads include advanced atomic clocks—hydrogen masers and rubidium clocks—that ensure timing accuracy to within nanoseconds, essential for applications ranging from autonomous vehicles and precision agriculture to search-and-rescue operations. By adding FM28 and FM31, the mission aims to enhance signal redundancy, improve global coverage, and support the system's open service, encrypted public regulated service, and commercial high-accuracy offerings. This launch will help Galileo achieve full constellation strength, targeting 30 satellites by the late 2020s, thereby rivaling established systems like the U.S. GPS and Russia's GLONASS.

At the heart of this mission is the Ariane 62 launch vehicle, a two-stage rocket developed by ArianeGroup under ESA's oversight. Standing 63 meters tall with a diameter of 5.4 meters, the Ariane 62 features a Vulcain 2.1 main engine on its cryogenic core stage, fueled by liquid hydrogen and oxygen, delivering 1,370 kN of thrust. It is augmented by two P120C solid rocket boosters, each providing 4,650 kN of thrust during the initial ascent. The upper stage, powered by the Vinci engine with 180 kN of restartable thrust, enables precise orbital insertions. With a liftoff mass of around 530 tons, the Ariane