Atlas 5 launches Amazon Leo satellites

WASHINGTON — An Atlas 5 launched the latest set of satellites for Amazon’s broadband constellation April 4 as the company seeks to accelerate deployment of its spacecraft.

An Atlas 5 551 rocket lifted off from Cape Canaveral Space Force Station in Florida at 1:46 a.m. Eastern. The rocket completed deployment of its payload of 29 Amazon Leo satellites into low Earth orbit 37½ minutes after liftoff.

The launch was the fifth flight of operational Amazon Leo (previously known as Project Kuiper) satellites on Atlas 5 rockets. This was the first, though, to carry 29 satellites, as the previous four launches each carried 27.

Amazon said March 23 it worked with United Launch Alliance to add more satellites to Atlas 5 launches, which it accomplished through “detailed engineering work” and the use of a higher-performing version of the RL10C engine that powers Atlas’s Centaur upper stage.

ULA said the launch, which it called LEO 5, carried the most satellites of any Atlas mission and was also the heaviest payload, but the companies did not disclose the total mass of the payload.

Amazon is under pressure to accelerate the deployment of its 3,232-satellite constellation. With this launch, the company has launched 241 satellites, but it is far short of the 1,616 satellites it needs to have in orbit to reach the milestone in its Federal Communications Commission license to have half the constellation deployed by July.

The company filed a request with the FCC in January to either extend that deadline by two years or waive it, citing delays in the launch vehicles contracted to deploy most of the constellation: Arianespace’s Ariane 6, Blue Origin’s New Glenn and ULA’s Vulcan Centaur. Amazon launched its first satellites on Ariane 6 in February while neither New Glenn nor Vulcan has launched any Amazon Leo satellites.

Most Amazon Leo satellites have been launched on Atlas 5 rockets as well as three SpaceX Falcon 9 vehicles, and Amazon noted in its FCC request it has purchased an additional 10 Falcon 9 launches. There are three remaining Atlas 5 launches for Amazon.

Amazon said March 23 it is working to double the cadence of launches to more than 20 missions a year as New Glenn and Vulcan begin launching Amazon Leo satellites. Each Vulcan launch will be able to carry at least 40 satellites while New Glenn will carry 48 or more satellites at a time. The company expects to fly more than 32 satellites on later Ariane 6 launches once that vehicle switches to more powerful solid boosters.

The launch was the first for ULA since a Feb. 12 launch of a Vulcan Centaur for the U.S. Space Force. That launch suffered an issue with one of its solid rocket boosters that did not prevent the rocket from successfully deploying the payload but has paused future launches of the vehicle.

Space Force officials said at a March 25 hearing that they are preparing alternative plans for launching some upcoming payloads assigned to Vulcan given that the vehicle may be grounded for several months.

ULA’s next launch will also be an Atlas 5 mission for Amazon Leo, currently scheduled for no earlier than April 27. Another Amazon Leo launch on Ariane 6 is scheduled for April 28.