Updated Feb. 7 at 12:05 a.m. Eastern after payload separation.

WASHINGTON — A Soyuz rocket launched 34 small broadband satellites for OneWeb Thursday from the Baikonur Cosmodrome in Kazakhstan, marking the beginning of a multi-launch campaign for the company.

The Russian rocket, whose launch was arranged by European launch provider Arianespace, lifted off at 4:43 p.m. Eastern on a mission lasting three hours and 45 minutes.

The first two OneWeb’s spacecraft deployed about an hour and 10 minutes after liftoff. The rest deployed in groups of four about once every 20 minutes, with Soyuz’s Fregat upper-stage engine conducting brief firings in between each deployment. Arianespace confirmed all satellites separated in a news release issued around 9:41 p.m. Eastern.

The Soyuz upper stage used a dispenser supplied by Ruag Space to release the satellites at 450 kilometers. From there, each 150-kilogram satellite will use onboard electric propulsion to climb to their 1,200-kilometer operational orbit.

The launch expands OneWeb’s constellation of low Earth orbiting satellites to 40, following a Soyuz launch last February that carried six satellites.

Adrian Steckel, OneWeb’s chief executive, told SpaceNews the company has another batch of 34 satellites launching from Baikonur in March before the company plans to take a monthlong break to implement spacecraft software and hardware changes. After that pause, OneWeb plans to launch once in May and once in June before potentially shifting out of a monthly launch cadence, he said.

Steckel said OneWeb still plans to achieve global coverage by the end of 2021. The company is building its satellites in Florida through a joint venture with Airbus Defence and Space called OneWeb Satellites.

Counting Thursday’s launch, OneWeb plans to conduct a total of 17 or 18 Soyuz launches and one Ariane 6 launch with Arianespace to orbit 588 satellites before the end of next year, Steckel said. After those launches, OneWeb will pause again before deciding a schedule for launching 60 spares, completing the 648-satellite first-generation constellation, he said.

Arianespace is launching the vast majority of OneWeb’s first-generation constellation using Soyuz rockets from Europe’s Guiana Space Center in South America and Russia’s Baikonur and Vostochny Cosmodromes. Thursday’s OneWeb launch is Arianespace’s first mission from Baikonur in seven years, and marks the 50 Soyuz launch the Evry, France-based company has provided.