Bieber ... IN ... SPAAACE! Singer Booked On Virgin Galactic

0606-justin-bieber-space-virginFerraris apparently aren't fast enough for Justin Bieber .... 'cause the singer has just been booked on a ROCKETSHIP DESTINED FOR SPACE ... so says Virgin Galactic honcho Richard Branson

Branson himself confirmed that Biebs and manager Scooter Braun are on the V.G. manifest, tweeting this morning: "Great to hear @justinbieber & @scooterbraun are latest @virgingalactic future astronauts. Congrats, see you up there!"

Branson's venture just completed its first rocket-powered test last month, and the company is planning to start commercial flights next year -- plenty of time for Bieber to order a tacky, blinged-out astronaut suit.

Tickets reportedly start around $250k ... but it's unclear if JB is paying for the ride himself ... or if the trip will be comped.

No word on when Bieber is scheduled for lift off.