The Atlas 5 rocket launches two SES communication satellites

A United Launch Alliance Atlas 5 rocket lifted off from Cape Canaveral, Florida on Tuesday afternoon and lifted two SES C-band communications satellites into orbit, the second and third in a series of five that will provide television and radio to millions of American homes.

The Atlas 5’s Russian-made RD-180 first-stage engine sprung to life at 5:36 p.m. EDT, followed by the ignition of three Northrop Grumman solid-propellant belt-driven boosters, instantly pushing the 196-foot-tall rocket back away from Pad 41 at the Cape Canaveral Space Station.

Spinning east over the Atlantic Ocean, the Atlas 5 crossed the speed of sound 40 seconds after liftoff, accelerating smoothly while consuming propellant and losing weight.

The three strap boosters burned and fell two minutes after launch and two and a half minutes after that the RD-180 shut down, the first stage fell and the climb to space continued with a only hydrogen- powered by the Aerojet Rocketdyne engine powering the Centaur’s second stage.

The flight plan called for three Centaur engine firings over five and a half hours to place the SES-20 and 21 satellites into a circular geosynchronous orbit, 22,300 miles above the equator. At this altitude, satellites take 24 hours to complete an orbit and therefore appear stationary in the sky, which is ideal for communication stations.

The SES-20 and 21 satellites built by Boeing will join the SES-22 relay station, built by Thales Alenia Space and launched by SpaceX last June. Northrop Grumman is building two more SES satellites, SES-18 and 19, which will launch later this year or early next year.

The sixth in the series, SES-23, is being built by Thales Alenia Space to serve as a ground reserve.

The satellites are the result of a Federal Communications Commission directive to free up the lower end of the C-band spectrum, traditionally used by radio and television relay stations, for use by 5G broadband networks. emerging.

“To meet the FCC’s deadline to release C-band spectrum across the United States, SES has ordered six satellites to provide needed capacity to our existing customers,” the company said in a statement.

The SES-20, 21 and similar satellites will operate in the upper region of the C-band spectrum to make room for 5G transmissions. SES and other existing C-band satellite operators are reimbursed for the cost of building and launching new satellites by companies bidding for slices of 5G spectrum.

Steve Collar, CEO of SES, said the five operational satellites being launched, plus the ground-based spare satellite, will meet the FCC deadline while ensuring continuity for the company’s millions of broadcast customers. .

“These satellites are going to be operational just weeks after launch, which is fantastic,” Collar said of SES-20 and 21.

“They are part of a much larger plan, five satellites that we will launch in order to … implement the plan that we have for spectrum compensation, but also, more specifically, to support the continued services of our customers . and their neighborhoods.”