The Boeing built satellites are set for launch on a United Launch Alliance (ULA) Atlas V rocket.

SES ordered the 702 small platform satellites from Boeing in June 2020 as part of its C-band spectrum clearing efforts.

“The delivery of SES-20 and SES-21 marks yet another big milestone for our C-band spectrum clearing project in the U.S.,” commented SES CTO Ruy Pinto.

The satellites went through environmental testing at Boeing’s satellite factory in California, including vibration, thermal vacuum, electromagnetic interference and acoustic testing. The satellites will be in their payload fairings for launch. They have been integrated into a dual-launch configuration platform built by Boeing.

“SES-20 and SES-21 are the first commercial satellites we’ve delivered since the start of the global pandemic,” said Ryan Reid, president of Boeing Satellite Systems International. “It was challenging, but we found ways to be responsive to emerging customer demands and timelines. As a result, we went from contract signing to delivery of two satellites in little over two years.”

Image: Boeing

Atlas V: the workhorse of United Launch Alliance's rocket fleet.

The rocket is a mix of Russian and American technology, using the Russian RD-180 as the rocket's first stage engine, and is one of the most versatile rockets in the world with 20 possible configurations -- though not all variants have flown.

Stats

Height: 58.3 m (191 ft) with payload fairing, 52.4 m (172 ft) with Starliner.

Diameter: 3.81 m (12.5 ft)

Mass: 590,000 kg (1,300,000 lb)

Stages: 2 (3 with Star 48 upper stage)

Developed in the mid- to late-1990s, it is the fifth and last major version of the veteran Atlas rocket, which began flying in 1957.

Lockheed Martin designed and built Atlas V as part of the U.S. government's 1994 initiative to create an Evolved Expendable Launch Vehicle (EELV) for national security missions.

The two companies with EELV rockets -- Lockheed Martin with Atlas V and Boeing with Delta IV -- merged in 2006, creating an effective U.S. market monopoly with United Launch Alliance (ULA).

For years, the U.S. government paid ULA over $800 million annually to maintain their facilities to be ready to launch EELV missions.

Therefore, pricing of the Atlas V has varied greatly over the years, with a basic Atlas V 401 (no boosters and a single-engine second stage) costing anywhere from the high-$90 millions to $163 million USD in the 2000s and early 2010s.

Sweeping price and cost-per-launch figure reductions have occurred since SpaceX began directly competing against ULA in the 2010s.

The Atlas V’s 531 variant costs a minimum of $140 million USD.

While not the cheapest rocket on the market, the Atlas V's safety is unparalleled -- with a 100% mission success rating.

Atlas V 531

This mission will use the Atlas V 531 variant - with a five-meter payload fairing (5), three side-mounted solid rocket boosters (3), and a single engine Centaur upper stage (1).

Of this configuration's previous flights, all have launched Advanced Extremely High Frequency satellites for the U.S. Air Force.

Image: John Kraus for Supercluster

Space Launch Complex 41 (SLC-41) is a significant launch site located at Cape Canaveral Space Force Station (CCSFS) in Florida. Originally built in the 1960s, SLC-41 was designed to support the Titan III and Titan IV rocket programs. Throughout its history, the pad has been used for various missions, including the deployment of military and reconnaissance satellites. A notable launch from SLC-41 was the Cassini spacecraft mission, which began its journey to Saturn in 1997.

In the early 2000s, SLC-41 was repurposed to support the Atlas V rocket, operated by United Launch Alliance (ULA). This transition involved extensive upgrades to the pad’s infrastructure and the installation of new ground support equipment to accommodate the Atlas V. These modifications ensured that SLC-41 could meet the requirements of modern space missions.

Under ULA’s management, SLC-41 has hosted a range of important launches, including the Mars Science Laboratory mission, which successfully landed the Curiosity rover on Mars in August 2012, and the launch of GPS III satellites, enhancing global positioning capabilities. The pad has also supported Boeing's CST-100 Starliner capsule, which is part of NASA’s Commercial Crew Program. The Starliner capsule, designed to transport astronauts to and from the International Space Station, has been launched from SLC-41 to support crewed missions.

Looking to the future, SLC-41 is set to support ULA’s Vulcan Centaur rocket. The Vulcan Centaur is intended to replace the Atlas V and Delta IV rockets, marking a new era in ULA’s launch capabilities with enhanced performance and cost-efficiency. The pad’s infrastructure will be further updated to accommodate this next-generation rocket.