'Cosmos'

"Cosmos: A Spacetime Odyssey" aired on Fox and other networks. (Fox)

Facing a supernova of TV rivals, Fox's "Cosmos: A Spacetime Odyssey" launched with a solid 8.5 million viewers from 10 networks Sunday night, according to Nielsen. 

The heavily promoted, 13-part science documentary series, featuring astrophysicist host Neil deGrasse Tyson touring the universe in a CGI spaceship, arrives more than three decades after Carl Sagan's "Cosmos: A Personal Voyage" debuted on PBS

"Cosmos" marks an unusual roll-out for TV, and not just because it's a science program from a major broadcaster in prime time, but also because it was simulcast across a variety of outlets, including Fox, National Geographic Channel, FX and sports channels. 

PHOTOS: 'Cosmos: A Spacetime Odyssey' series premiere

On the big Fox broadcast network, the reboot drew 5.8 million viewers overall and a rating of 2.1 among  18-to-49-year-old viewers, a key demographic, and even though that's less-than-stellar numbers for a broadcast premiere, it's a good start for an educational program on a busy TV night. The 10-network 18-49 rating was a 2.9. 

The 9 p.m. telecast, which began with a taped introduction by President Obama, faced heavy broadcast and cable competition, including the premiere of ABC's "Resurrection," AMC's "The Walking Dead" and HBO's "True Detective" finale. "Resurrection" averaged 13.3 million viewers, while "Walking Dead" scored an audience of 12.7 million and "True Detective" delivered 3.5 million, according to Nielsen. 

The new "Cosmos" was written by Sagan's widow Ann Druyan and Steven Soter, both of whom were collaborators on the original series. They teamed with "Family Guy" creator Seth MacFarlane, who is an executive producer on the show.

Fox is projecting that 40 million people worldwide will watch the premiere this week. 

ALSO:

PHOTOS: Biggest box office flops of 2013

TV ratings: CBS wins with 'Big Bang' as 'Idol' hits another low

'300: Rise of an Empire' tops 'Mr. Peabody' at box office

ryan.faughnder@latimes.com

Twitter: @rfaughnder