Watch live: SpaceX to complete Friday doubleheader with launch for Inmarsat

SpaceX will try to complete a launch doubleheader Friday night with the liftoff of a Falcon 9 rocket from Cape Canaveral with a dual-band, six-ton mobile communications relay station for London-based Inmarsat, hours after launching another Falcon 9 from California with a batch of Starlink internet satellites.

The launch window Friday night at Cape Canaveral opens at 10:59 p.m. EST (0359 GMT Saturday), less than nine hours after a Falcon 9 rocket took off from Vandenberg Space Force Base in California.

Forecasters predict a 75% chance that weather conditions will be acceptable for liftoff of the Falcon 9 rocket Friday night from Florida’s Space Coast. There is a slight chance of rain showers and thunderstorms that could bring thick clouds and cumulus clouds over the launch site.

The Falcon 9’s nine Merlin engines, generating 1.7 million pounds of thrust, will power the 229-foot-tall (70-meter) launcher east from Cape Canaveral to deliver Inmarsat’s new communications satellite into an elongated geostationary transfer orbit stretching more than 20,000 miles (more than 34,000 kilometers) above Earth at its highest point, and as low as 155 miles (250 kilometers) at the point closest to Earth.

The rocket’s upper stage will release the Inmarsat 6 F2 satellite into orbit about 32 minutes after liftoff after two engine firings with its single Merlin engine. The first stage of the Falcon 9, flying for the third time, will return to Earth for landing on a drone ship east of Cape Canaveral in the Atlantic Ocean about eight-and-a-half minutes after launch.

The Inmarsat 6 F2 spacecraft, based on Airbus’s Eurostar 3000 satellite platform, will check in with ground controllers soon after separating from the Falcon 9 rocket. Then the satellite will begin a series of health checks and a partial deployment of its power-generating solar arrays. Once the satellite’s thrusters move the perigee, or low point, of its orbit safely above the atmosphere, ground teams will send commands to a full deployment of the solar arrays and the unfurling of a large 30-foot (9-meter) umbrella-like L-band antenna reflector next week.

Then the satellite will continue reshaping its orbit using the electric propulsion system, which is lighter and more efficient than conventional liquid-fueled maneuvering rockets. The plasma thrusters are positioned on the ends of articulating robotic arms, providing precise pointing as the satellite circularizes its orbit and moves from an inclination of 27 degrees — the drop-off orbit SpaceX will reach with the Falcon 9 — to a position directly over the equator.

With a solar array wingspan as side as a Boeing 767 jetliner and a body the size of a double-decker bus, the Inmarsat 6 F2 spacecraft will be parked in geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the Earth, using a dual-band communications payload provide in-flight WiFi on aircraft, broadband services to ships, and connectivity for U.S. military and other government users.

“It is one of the world’s largest spacecraft in terms of weight and power, but inside of it, I think the thing that makes it unique is all the signal processing that goes on,” said Peter Hadinger, Inmarsat’s chief technology officer.

“It’s an incredibly advanced signal processor that’s capable of forming beams on the Earth and moving them around in real-time, creating channels as we need them, moving the spacecraft’s power to where it’s required on the face of the Earth,” Hadinger told Spaceflight Now in a pre-launch interview. “And that makes it a very capable spacecraft because we can take all the spacecraft’s energy and put it where it’s needed on a moment-by-moment basis.”

Inmarsat 6 F2 is the twin of another satellite, Inmarsat 6 F1, that launched in December 2021 on a Japanese H-2A rocket. Both Inmarsat 6 satellites use electric propulsion for their in-orbit maneuvers, and host L-band and Ka-band communications payloads targeted at different segments in the mobile communications market.

The satellite has 20 steerable wideband Ka-band beams to provide broadband connectivity to airplane passengers and ships at sea, along with the L-band reflector that will open up in space. The L-band antenna and solar panels are stowed against the body of the spacecraft to fit inside the nose cone of SpaceX’s rocket.

The L-band payload is tailored for lower-bandwidth applications, such as maritime search and rescue, ship and asset tracking, and supply chain management. Inmarsat’s most recent fleet of L-band communications satellites was the Inmarsat 4 series launched between 2005 and 2013, and the two Inmarsat 6 satellites will replace them. Each Inmarsat 6 satellite provides 50% more L-band communications capacity than the entire four-spacecraft Inmarsat 4 fleet.

The Inmarsat 5 satellites, providing Ka-band connectivity through the company’s Global Xpress service, launched between 2013 and 2019.

The two Inmarsat 6 satellites will extend Inmarsat’s narrowband L-band services, used around the world in maritime operations, until around 2040. Inmarsat is planning to launch additional Ka-band satellites in the next few years, including two Ka-band instruments on satellites in a high-inclination orbit to extend broadband coverage over the Arctic. The Arctic mission is slated to launch late this year on another SpaceX rocket from California.

The L-band payload is good for all-weather communications, which is useful in maritime safety. The L-band service can also support commercial drones for disaster response and medical delivers, asset tracking and internet of things applications, and autonomous transportation. The Ka-band payload will be capable of higher-speed connectivity, such as internet services, at speeds of tens or hundreds of megabits per second.

“This spacecraft will be over the Atlantic, and the hotspots that it fills will probably be initially along the East Coast of the United States,” Hadinger said of the I6 F2 mission.

The new Inmarsat satellites, including I6 F2, are crucial for the company’s plans to maintain its market position as constellations of low Earth orbit satellites, like SpaceX’s Starlink fleet and OneWeb’s network, begin operational service to provide broadband internet connectivity. Starlink and OneWeb’s business strategies include serving consumers on land, in the air, and at sea.

Inmarsat was established in 1979 to develop a network of satellites to provide a communications lifeline for maritime safety and distress messages. The maritime safety mission is still part of Inmarsat’s network, but the company has evolved to provide a broader menu of communications services.

“Inmarsat is focused exclusively on mobility,” Hadinger said. “We do not serve residential consumers and fixed businesses so much. Our focus is on the maritime industry, the aviation industry, and governments, with a little bit of portable land requirements thrown in.

“But the majority of things we do are on the move, and that really causes us to focus on frequency bands and satellites which allow us to communicate with small antennas because if you’re going to be on the move, you need to have an antenna that’s buried in the skin of an aircraft or which is on a ship, and these things are rolling and rocking on the way,” Hadinger said. “So all of this has to be tracked and handed off from beam to beam and from satellite to satellite as the user moves around the world.”

Inmarsat plans to launch the Arctic Satellite Broadband Mission later this year, in partnership with Norway and the U.S. Space Force. Then Inmarsat’s GX 7, GX 8, and GX 9 satellites — the next spacecraft to augment the company’s Ka-band network — will launch in late 2024 or early 2025, Hadinger said.

“The I6 spacecraft will be joined by a further five major scale satellites by 2025,” said Rajeev Suri, CEO of Inmarsat. “Each of these has the capability to deliver focused connectivity over a larger region and come with certainty — in resilience, in robustness, in service quality — that is unique to Inmarsat.”

ROCKET: Falcon 9 (B1077.3)

PAYLOAD: Inmarsat 6 F2 communications satellite

LAUNCH SITE: SLC-40, Cape Canaveral Space Force Station, Florida

LAUNCH DATE: Feb. 17, 2023

LAUNCH WINDOW: 10:59 p.m.-12:28 a.m. EST on Feb. 17/18 (0359-0528 GMT on Feb. 18)

WEATHER FORECAST: 75% probability of acceptable weather

BOOSTER RECOVERY: Drone ship “Just Read the Instructions” about 410 miles (665 kilometers) east of Cape Canaveral

LAUNCH AZIMUTH: East

TARGET ORBIT: Geostationary transfer orbit — 155 miles by 21,561 miles (250 by 34,700 kilometers); Inclination of 27 degrees

LAUNCH TIMELINE:

MISSION STATS:

This email address is being protected from spambots. You need JavaScript enabled to view it. the author.

Follow Stephen Clark on Twitter: @StephenClark1.