In a New Year's blog posting, Virgin Galactic founder Richard Branson says October's fatal breakup of the SpaceShipTwo rocket plane led him to question whether he should continue with his multimillion-dollar space travel venture.

He said the Oct. 31 crash, which killed one test pilot and injured the other pilot, affected him deeply as he flew to California's Mojave Air and Space Port in California to meet with the SpaceShipTwo team.

"I found myself questioning seriously for the first time, whether in fact it was right to be backing the development of something that could result in such tragic circumstances. In short — was Virgin Galactic and everything it has stood for and dreamt of achieving, really worth it?"I got a very firm answer to that question immediately when I landed in Mojave. From the designers, the builders, the engineers, the pilots and the whole community who passionately believed — and still believe — that truly opening space and making it accessible and safe is of vital importance to all our futures."

Branson and the rest of the team are pressing on with the Virgin Galactic venture, which has signed up about 700 customers to take suborbital space trips at a cost of as much as $250,000 a seat. A second SpaceShipTwo plane is under construction, and work is proceeding as well on Virgin Galactic's LauncherOne system for sending small satellites into orbit.

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Virgin Galactic's pilots took WhiteKnightTwo, the wide-winged airplane that's designed to carry SpaceShipTwo up for launch, out for a practice flight "just before people started trickling out to spend time with their families for the holidays," Will Pomerantz, the company's vice president for special projects, told NBC News.

Investigation continues

Meanwhile, the National Transportation Safety Board is continuing its investigation of the incident, which marks the first in-flight fatality suffered by a commercial spaceflight effort.

The NTSB said an onboard video showed that co-pilot Michael Alsbury, who died in the crash, prematurely pulled a lever that unlocked SpaceShipTwo's wing-feathering brake system. That action was taken seconds after the plane lit up its rocket motor, and just moments before the catastrophic breakup.

SpaceShipTwo pilot Pete Siebold, who survived the crash with injuries, told investigators he was unaware that the feathering system was unlocked early. The NTSB quoted Siebold as saying that he "was extracted from the vehicle as a result of the breakup sequence and unbuckled from his seat at some point before the parachute deployed automatically."

NTSB investigators have not yet laid out their conclusions about the cause of the crash, or their recommendations for Virgin Galactic's future operations. That's expected to take months longer. Virgin Galactic CEO George T. Whitesides told NBC News in November that the NTSB's recommendations would be factored into the plan for SpaceShipTwo 2.0.

In his New Year's retrospective, Branson gave a nod to Alsbury and Siebold as well as to Virgin Galactic's customers.

"When this story is told in years to come, I believe alongside the bravery of Mike and the incredible tale of Pete’s survival will stand the story of the commitment, loyalty and passion of the world's first private astronauts," Branson wrote. "And so Virgin Galactic goes on, with an unwavering commitment to safety and a renewed sense of purpose."

NBCUniversal has established a multi-platform partnership with Virgin Galactic to track the development of SpaceShipTwo.