A huge, highly advanced commercial communications satellite just took to the skies.
The 12,060-pound (5,470 kilograms) Inmarsat-6 F1 is the first of two "I-6" spacecraft that London-based company Inmarsat plans to loft to geostationary orbit, about 22,240 miles (35,790 kilometers) above our planet.
The I-6 pair "are the largest and most sophisticated commercial communications satellites ever launched," Inmarsat representatives wrote in a fact sheet. "Inmarsat's first dual-payload satellites, the I-6s feature both L-band (ELERA) and Ka-band (Global Xpress) payloads."
The I-6 satellites will be compatible with existing terminals for Inmarsat's already-operational ELERA and Global Xpress networks, company representatives said.
The H-2A is Japan's primary medium-lift launcher. The expendable rocket has sent many prominent payloads skyward over the years, including Japan's Hayabusa2 asteroid sample-return mission (in 2014) and the United Arab Emirates' Hope Mars orbiter (in 2020).
Wednesday's launch had originally been targeted for Tuesday (Dec. 21), but concerns about possible bad weather caused a one-day delay.
Editor's note: This story was updated at 12:30 p.m. EST on Dec. 22 with news of successful liftoff.
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.
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Michael Wall is a Senior Space Writer with Space.com and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.