Virgin Galactic's SS2 brings commercial spaceflight closer to reality (pictures)

Virgin Galactic's SpaceShipTwo (SS2) successfully sailed to supersonic speeds with the aid of a rocket engine for the second time on Thursday.

Here's a close-up shot of the SS2 during its first rocket-powered flight back in April. The hybrid rocket motor has thus far pushed the aircraft to 69,000 feet and Mach 1.43, or more than 1,000 mph, over the course of 20 seconds of use.

The ultimate goal is to keep the rocket burning for 70 seconds until SS2 hits 2,500 mph and a max altitude of 364,000 feet.

SpaceShipTwo, designed and manufactured by aerospace pioneers Scaled Composites, is carried to roughly 46,000 feet by another Scaled Composites vehicle, White Knight Two. When it's released, it kicks on the rocket motor with an astounding burst of orange and white.

The motor -- a hybrid rocket engine fueled by hydroxyl-terminated polybutadiene (HTBP) and nitrous oxide -- provides 60,000 pounds-force (270 kN) of thrust.

White Knight Two, seen here at right, after launching SpaceShipTwo. The rocket-powered spacecraft goes supersonic within eight seconds.

Designed by aerospace company Scaled Composites -- who also designed SpaceShipTwo, SpaceShipOne, and the original White Knight -- White Knight Two is a twin-boom aircraft with two jet engines per hull and a wingspan similar to a Boeing B-29 Superfortress.

It is roughly three times larger than the original White Knight and will be used to allow commercial spaceflight passengers to test the feelings of weightlessness; the White Knight Two will provide a few seconds of the sensation as opposed to the SpaceShipTwo's five minutes.

SpaceShipTwo, though twice as large as its predecessor, retains much of the same design and technology, which originally earned Virgin Galactic and Scaled Composites the $10 million Ansari X prize in 2004. The material used is a graphite/epoxy carbon composite.

At roughly 8 a.m. local time in the heart of California's Mojave Desert on Thursday, White Knight Two carried the spacecraft SpaceShipTwo -- in a combination aerial vehicle seen here -- to 46,000 feet before SS2 disengaged and began flying on its own.

The eight-seater SS2 -- designed for two pilots and six passengers -- then kicked on its hybrid rocket motor for 20 seconds, twice as long as the initial rocket-powered test flight. The thrust pushed the vehicle to 69,000 feet and a max speed of Mach 1.23, or approximately 1,090 mph.