{"id":11245,"date":"2022-10-05T22:59:56","date_gmt":"2022-10-05T14:59:56","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/atlas-5-rocket-completes-high-altitude-tandem-satellite-delivery-for-ses\/"},"modified":"2022-10-05T22:59:56","modified_gmt":"2022-10-05T14:59:56","slug":"atlas-5-rocket-completes-high-altitude-tandem-satellite-delivery-for-ses","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/atlas-5-rocket-completes-high-altitude-tandem-satellite-delivery-for-ses\/","title":{"rendered":"Atlas 5 rocket completes high-altitude tandem satellite delivery for SES"},"content":{"rendered":"
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United Launch Alliance\u2019s Atlas 5 rocket climbs off pad 41 Tuesday at Cape Canaveral Space Force Station with the SES 20 and SES 21 television broadcasting satellites. Credit: Michael Cain \/ Spaceflight Now \/ Coldlife Photography<\/figcaption><\/figure>\n

Running a few days late after a delay caused by Hurricane Ian, an Atlas 5 rocket built by United Launch Alliance thundered off a launch pad at Cape Canaveral Tuesday and soared to an altitude of nearly 22,000 miles to deploy two commercial television broadcasting satellites for the commercial operator SES.<\/p>\n

The Atlas 5 launcher lit its Russian-built RD-180 main engine in the final seconds of a smooth countdown Tuesday. As the countdown clock struck zero, three strap-on solid rocket boosters supplied by Northrop Grumman ignited to propel the 196-foot-tall (59.7-meter) rocket off the pad at Cape Canaveral Space Force Station, Florida.<\/p>\n

The main engine and boosters combined to generate nearly 2 million pounds of thrust as the Atlas 5 darted through scattered clouds and arced downrange toward the east from Florida\u2019s Space Coast. The Atlas 5 powered through the speed of sound in 40 seconds, and jettisoned its three solid rocket booster casings nearly two minutes into the flight. About 90 seconds later, the rocket released its nose cone to shed weight on the climb into space.<\/p>\n

The kerosene-fueled RD-180 main engine shut off more than four minutes into the flight, and the Atlas 5\u2019s first stage separated to fall into the Atlantic Ocean. Then the rocket\u2019s hydrogen-fueled Centaur upper stage got to work with a series of three burns by its Aerojet Rocketdyne RL10 engine.<\/p>\n

The Centaur upper stage\u2019s first burn placed the mission\u2019s two commercial communications payloads \u2014 SES 20 and SES 21 \u2014 into a parking orbit a few hundred miles above Earth. A second RL10 engine firing propelled the the rocket and the tandem satellites into an oval-shaped transfer orbit with its highest point, or apogee, stretching to an altitude of nearly 22,000 miles (35,000 kilometers).<\/p>\n

After the second Centaur burn, the rocket coasted through space for five hours before reigniting for a final maneuver to reshape the orbit to a more circular path around Earth, and nudge the satellites closer to the final operating position over the equator.<\/p>\n

Then the Centaur upper stage sent commands to release the satellites one at a time. The SES 20 satellite deployed first from the upper position on the dual-payload stack, followed by separation of SES 21 at 11:54 p.m. EDT (0354 GMT), more than six hours after departure from Cape Canaveral.<\/p>\n

The satellites were injected directly into an orbit just below geosynchronous altitude, where their motion around Earth will match the rate of the planet\u2019s rotation, completing one lap around the equator every 24 hours.<\/p>\n

The launch Tuesday was the first commercial Atlas 5 mission to head directly to a near-geosynchronous orbit. The trajectory requires a lengthy coast phase, and additional battery capacity and other upgrades to the Centaur upper stage. Atlas 5 rockets have deployed payloads directly into similar orbits near geosynchronous altitude on four previous missions for the U.S. military.<\/p>\n

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Three strap-on solid-fueled boosters and a core stage RD-180 main engine combined to generate nearly 2 million pounds of thrust at liftoff. Credit: Alex Polimeni \/ Spaceflight Now<\/figcaption><\/figure>\n

The SES 20 and 21 satellites are nearly identical, and were manufactured by Boeing in El Segundo, California. Each satellite uses all-electric propulsion for in-orbit maneuvers, and were built on Boeing\u2019s 702SP satellite platform.<\/p>\n

The Atlas 5\u2019s guidance computer aimed to release the two spacecraft in a circular orbit roughly 21,750 miles (about 35,000 kilometers), just below geostationary altitude, at an inclination angle of 1.9 degrees to the equator. ULA said the Atlas 5 rocket\u2019s Centaur upper stage delivered the satellites to an on-target orbit, and SES confirmed both spacecraft were alive and healthy following launch.<\/p>\n

After separating from the Atlas 5\u2019s Centaur upper stage, SES 20 and 21 will unfurl their solar panels and run through post-launch checkouts. They will use plasma thrusters to fine-tune their orbits and slide into their operating positions in geostationary orbit.<\/p>\n

SES 20 will maneuver into a position along the equator at 103 degrees west longitude, while SES 21 will head for 131 degrees west longitude. Both satellites will provide C-band television and radio broadcast services over the United States. SES 20 and 21 are part of a program to redirect television communications services to a different part of the C-band spectrum, following the Federal Communications Commission\u2019s decision in 2020 to clear 300 megahertz of spectrum for the roll-out of 5G mobile connectivity networks.<\/p>\n

The FCC auctioned U.S. C-band spectrum \u2014 previously used for satellite-based video broadcast services to millions of customers \u2014 to 5G operators, which are paying satellite operators like SES through multibillion-dollar compensation agreements. SES and Intelsat, another large geostationary satellite operator, purchased new C-band broadcasting satellites to function in the narrower swath of spectrum.<\/p>\n

In 2020, SES ordered six new C-band satellites, including a spare, and Intelsat procured seven C-band satellites. SES says the new C-band satellites will enable the broadcast of digital TV services to nearly 120 million homes in the United States.<\/p>\n

\u201cWe\u2019re excited to support our commercial partner SES in their C-band transition efforts to meet the FCC\u2019s objective to deploy 5G service across the U.S. Their mission aligns with our mission to connect the world and these capabilities will enable uninterrupted commercial services to many Americans,\u201d said Gary Wentz, ULA vice president of government and commercial programs, in a statement.<\/p>\n

SES launched their first new C-band satellite as part of the program in June on a SpaceX Falcon 9 rocket. Later this week, following the Atlas 5 launch for SES, SpaceX is scheduled to launch another pair of similar C-band television broadcast satellites from Cape Canaveral for Intelsat.<\/p>\n