WASHINGTON — European launch provider Arianespace completed its final launch of the year Dec. 19, sending the French spy satellite CSO-1 into orbit on a Soyuz ST-A rocket.

The launch, delayed by one day due to high-altitude winds above the Guiana Space Center, took place at 11:37 a.m. Eastern, with satellite separation occurring one hour later.

The year-end mission was the 20th Soyuz rocket to launch from the Guiana Space Center since Arianespace began offering a Europeanized version of the Russian workhorse rocket.

CSO-1 is the first of three Composante Spatiale Optique (Optical Space Component) satellites the French government intends to launch over the next few years.

The high-resolution optical and infrared satellite is the first in a trio that replaces France’s Helios-2A and -2B surveillance satellites. Germany, Sweden and Belgium will, through partnership with France, also have access to CSO imagery.

France’s space agency CNES and defense procurement agency DGA led the satellite program, with prime contractor Airbus Defence and Space building the 3,565-kilogram satellite and Thales Alenia Space providing the imaging payload. CSO-1 will operate in an 800-kilometer sun-synchronous orbit and is expected to last at least 10 years.

The second CSO satellite, CSO-2, is scheduled for a Soyuz launch in 2020 to a 480-kilometer orbit for a closer view of specific targets. The third satellite, CSO-3, is scheduled for a 2021 launch on an Ariane 6, and will join CSO-1 in the higher orbit to boost the system’s revisit times.

11 launches for 2018

Arianespace completed 11 launches this year, the same as 2017, but fell short of the 14 launches it projected for 2018.

At least two missions initially planned for this year slipped in 2019 because the satellites were not ready for launch. OneWeb, opting to run more satellite tests on the ground before deploying its early satellites, ultimately pushed back its planned Soyuz launch from May to February. A five-month delay with the European Space Agency’s wind-mapping satellite Aeolus from March to August had a knock-on effect on the other two Vega rocket missions planned for 2018, pushing the launch of Italy’s Prisma Earth-observation satellite into 2019.

Arianespace had also expected to launch India’s GSAT-31 and Arabsat’s Hellas-Sat-4/SaudiGEOsat-1 on an Ariane 5 by the end of 2018. A company spokesman did not respond to questions submitted Dec. 17 about the reason for the delay.

The last-minute withdraw by the Indian Space Research Organisation in April of its GSAT-11 satellite for additional checks in India caused a reshuffling of Arianespace’s manifest. Fleet operator Intelsat, who was ISRO’s co-passenger for what was supposed to be a May mission, was in the unique position of being able rebook the Intelsat-38/Azerspace-2 satellite with another Intelsat-Ariane 5 mission that launched in September. ISRO’s GSAT-11 launched on an Ariane 5 in December with the Korea Aerospace Research Institute’s GEO-Kompsat-2A weather satellite.

Arianespace launched six Ariane 5 heavy-lift rockets, three medium-lift Soyuz rockets and two Vega light-lift rockets this year. The last five missions all occurred within two months.