PARIS — Europe’s 30-nation meteorological organization Eumetsat said Sept. 11 that it will launch two-second generation satellites on Arianespace Soyuz launches and will consider a third mission with either Soyuz or the future Ariane 6.

Arianespace is contracted to launch Metop-SG A1 and Metop-SG B1, two replacement polar satellites, between 2021 and 2023.

The second-generation system will ultimately consist of six satellites designed and built in pairs of two for at least 21 years of continuous Earth observation.

In an Arianespace press conference here, CEO Stephane Israel said the contract came to the European launch provider competitively, despite being a from European government customer.

Airbus Defence and Space is building the four-ton Metop-SG A1 and Metop-SG B1 satellites on its AstroBus platform. The satellites will operate in a sun-synchronous orbit approximately 800 kilometers above Earth, covering the “mid-morning polar orbit.”

Arianespace is scheduled to launch the third and final first-generation Metop satellite, Metop-C, in the fall of 2018.

Last year Eumetsat decided to shift the orbit of Metop A to keep the now nearly-11 year-old satellite in orbit long enough for Metop-C to start operations in 2019 with some overlap.