Seven astronauts are poised to launch into space today aboard NASA’s shuttle Endeavour today with fairly straightforward monikers, though why its pilot goes by “Scorch” is up for grabs.

STS-118 shuttle pilot Charlie Hobaugh, a lieutenant colonel in the U.S. Marine Corps, goes by the call sign “Scorch” and isn’t telling any tales on the hot name’s genesis.

“You know, you’re the third reporter to ask me that and the third guy I probably won’t tell,” Hobaugh told me leading up to today’s launch attempt.

Hobaugh did concede that his call sign stems from his days flying vertical takeoff and landing Harrier jets in the Marine Corps, but more than that he’s mum.

“I usually say sometimes a call sign sounds a lot better when you don’t know where it came from,” Hobaugh says.

The rest of Endeavour’s crew have intuitive names or nicknames. Commander Scott Kelly and mission specialists Tracy Caldwell and Rick Mastracchio seem to prefer their given names, while teacher-turned-astronaut Barbara Morgan is frequently referred to as ‘Barb.’

Rounding out the crew are Benjamin Alvin Drew, Jr., who goes by Alvin or Al, and the Canadian Space Agency’s Dafydd “Dave” Williams.

UPDATE: So a day after launch it has become clear that Tracy Caldwell does indeed have a nickname. You’ll hear astronauts call her “TC” during space-to-ground chats.

So stick that in your back pocket when you’re listening to NASA’s live coverage on NASA TV which, incidentally, you can find along with SPACE.com’s blow-by-blow mission updates by clicking here.