Richard Branson's Virgin Galactic Holdings Inc. became the first space-tourism business to go public as it began trading Monday on the New York Stock Exchange.

The listing, carried out through a merger with a shell investment company that was already trading, secures vital new funding for Branson as the British entrepreneur competes with fellow billionaires Jeff Bezos and Elon Musk in what's been dubbed "the new space race." The deal gives Virgin Galactic a market value of about $2.4 billion, the company said.

Investors are being asked to back a project that's been running for 15 years without yet achieving a first commercial launch, and which came close to folding following a fatal crash during a 2014 test flight.