WASHINGTON — An Ariane 6 with upgraded solid rocket boosters successfully launched three dozen Amazon Leo satellites June 17 as ESA weighs options for increasing the vehicle’s launch rate.

The Ariane 64 rocket lifted off from the European spaceport at Kourou, French Guiana, at 8:21 a.m. Eastern. The liftoff was delayed by about a half-hour because of an unspecified issue detected about a minute before the planned liftoff.

The rocket carried 36 Amazon Leo broadband satellites that were deployed by the Ariane 6 upper stage into low Earth orbit starting 1 hour and 26 minutes after liftoff. The satellite deployments were completed 25 minutes later.

The mission, designated VA269 by Arianespace and LE-03 by Amazon, was the third Ariane 6 launch this year, all for Amazon. It was the first, though, to use upgraded P160C solid rocket boosters. Those boosters provide increased thrust compared with the P120C boosters used on previous Ariane 6 launches, increasing the rocket’s payload capacity to LEO by more than two metric tons.

That allowed this mission to carry 36 Amazon Leo satellites, whereas the prior launches in February and April each carried 32. That is the most Amazon Leo satellites on a single launch to date, including Atlas 5 and Falcon 9 missions, and the payload is the heaviest launched on an Ariane 6.