On August 22 at 22:13 UTC, Arianespace and its affiliate, Starsem, launched a Soyuz 2.1b/Fregat from the Baikonur Cosmodrome in Kazakhstan. Onboard the Soyuz were 34 satellites for the OneWeb 9 mission. It was the 1,944th Soyuz launch since its first in 1957.
This launch was delayed by one day due to an abort moments before engine ignition on the first attempt, which is highly unusual for a Soyuz rocket. The abort was due to the rocket’s ground system seeing something it didn’t like in the final count and calling a hold, something that can happen to any rocket.
The rocket’s Fregat upper stage conducted several engine burns over the course of two and a half hours and then inserted the 34 satellites into their target orbits in several groups. This marks 288 satellites launched of a planned constellation of 648 OneWeb internet satellites, making the constellation about 44% complete.
Arianespace press release
Starsem press release