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(CNN) -- It's the biggest countdown for NASA since the shuttle era ended in 2011. The space agency's new Orion spacecraft is scheduled to lift off on an uncrewed test flight at 7:05 a.m. ET Thursday from Space Launch Complex 37 at Cape Canaveral, Florida.

"We haven't had this feeling in awhile, since the end of the shuttle program," Mike Sarafin, Orion flight director at Johnson Space Center, said in a preflight briefing on Wednesday. He said it's the beginning of something new: exploring deep space.

Orion looks like a throwback to the Apollo era, but it is roomier and designed to go far beyond the moon: to an asteroid and eventually to Mars.

"It is, I think, consistent with those -- the beginning of shuttle and beginning of Apollo," said Mark Geyer, NASA Orion program manager. "I think it's in the same category."

Orion -- NASA's next giant leap

Orion -- NASA's next giant leap

Orion -- NASA's next giant leap

Orion -- NASA's next giant leap

Orion -- NASA's next giant leap

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NASA 'go' for its next giant leap