SEATTLE – In the booming commercial space business, ventures founded by tech billionaires Jeff Bezos, Elon Musk and Paul Allen are reinventing the most expensive aspect: launching spacecraft into orbit.

All three are intent on tapping the Seattle region’s aerospace and software talent, and all three speak in visionary terms.

“Earth — this blue planet — in all its beauty, is just our starting point,” Amazon Chief Executive Bezos says on the Blue Origin website. “Now is the time to open the promise of space to all.”

In April, Blue Origin successfully tested its New Shepard rocket. It’s also partnering with Boeing and Lockheed to design American rocket engines that will replace the current Russian engines on government launches.

Bezos has gathered a 350-strong engineering team at Blue Origin headquarters just outside Seattle.

Serial entrepreneur Musk, who made his fortune as a co-founder of PayPal and reinvented the car at Tesla Motors, formed SpaceX to pursue his ambition to colonize Mars.

Already he has muscled his way into the heavy rocket market formerly dominated by Boeing and Lockheed Martin.

And SpaceX has just opened an office in the Seattle area where a team expected to grow to hundreds of engineers will design an ambitious satellite constellation.

Chuck Beames, president of Microsoft founder Allen’s Vulcan Aerospace, says his boss perceives a business tipping point “analogous to the PC industry in its infancy.”

Later this year, it plans to roll out from a hangar in the California desert the biggest airplane ever built, designed to carry a rocket under its wing and shoot it into space from 30,000 feet.

The premise for all three companies is that launch vehicles must be reusable so that getting to space becomes dramatically cheaper. That could revolutionize the sector by encouraging start-ups to develop new space-based applications.

Blue Origin

Rob Meyerson, who in the 1990s worked at ­Kistler Aerospace — the reusable-rocket pioneer that went bankrupt after the dot-com bubble killed off its satellite-maker customers — is now president of Bezos’ Blue Origin.

In April the company launched the first developmental flight of its New Shepard vehicle, blasting an empty crew capsule capable of holding six people to a test altitude of 58 miles then returning it safely to Earth by parachute.

The plan to land the rocket itself back on the ground near the launch site failed when the hydraulic system lost pressure. Yet Bezos was undeterred, promising in a statement “to fly again soon.”

Meyerson said the company is also getting ready for the next step — orbital spaceflight. “We’re already designing our orbital launch vehicle that is many times New Shepard’s size.”

SpaceX

Founded in 2002, SpaceX has already slashed the cost of space access.

Caceres said the launch of a Boeing Delta IV Heavy rocket to launch a big military satellite costs $350 million or more. A Lockheed Atlas V launch for smaller payloads costs at least $150 million.

SpaceX, by contrast, lists its Falcon 9 rocket launches at about $70 million, he said.

After Musk dropped a lawsuit attempting to force the issue, the Air Force last month granted SpaceX certification for national-security missions — ending the monopoly on military launch contracts long held by the Boeing/Lockheed joint venture.

Vulcan Aerospace

Vulcan Aerospace’s concept is to launch space rockets into orbit from 30,000 feet up.

The idea is to make launches more routine, substituting an airport for a launchpad and costing only as much as the jet fuel to fly two 747s from Seattle to Los Angeles, according to Beames.

Vulcan’s giant carrier plane, now taking shape inside a hangar in Mohave, Calif., is called ­Stratolaunch.

The main structure features twin fuselages — each roughly the size of a 747 jumbo jet.

A huge wing stretches across the top — the wingspan of 385 feet is about the length of a football field, including the end zones. The payload-carrying booster rocket will be slung under that wing, between the two fuselages.

With the Stratolaunch’s novel shape, Vulcan will almost certainly run into hard-to-predict problems once the plane flies. Despite that, Vulcan has used Boeing engineers only as consultants, reflecting a typical tech-industry bias against established players.

That spirit of pioneering innovation comes with risks.

Richard Branson’s Virgin Galactic suborbital-space-tourism project is based on a precursor to the Stratolaunch concept and operates the technology under license from Vulcan.

The deadly in-flight breakup last October of Virgin’s SpaceShipTwo rocket plane — which killed one of the two pilots on board — served as “a cold, hard reminder that this can be a dangerous business,” Beames said.

Unlike Blue Origin and SpaceX, privately funded Vulcan hasn’t received any government contracts.

Its strategy has already undergone several changes, and right now what will be strapped under that huge wing is not clear.

Originally, SpaceX was to provide the booster rocket; Vulcan then switched to relying on rocket-maker Orbital ATK.

As recently as last fall, Beames spoke about a plan to put a human-crewed spacecraft developed by Sierra Nevada on the tip of the Orbital booster rocket.

But now that human spaceflight plan is shelved, along with Orbital’s planned rocket.

Beames said Orbital’s rocket “was not hitting the economic sweet spot to generate revenue,” so Vulcan has reopened the design plan and is “evaluating over 70 different launch vehicle variants.”

This shift won’t affect the timetable for flying the carrier plane, he said, but it could mean “maybe a little delay” in the plans to use it to launch spacecraft into orbit.

Launching a manned spacecraft will be even further out, “in 10 years,” he said.

Meanwhile, said Beames, Vulcan has decided to diversify beyond the Stratolaunch project by investing in other space companies. It put money into Seattle-based Spaceflight this spring and is actively searching for more candidates.

As for direct Vulcan Aerospace employment, Beames declined to say how many engineers the company has in Seattle but predicted, “It’ll likely double in the next year or two.”

Though in 2011 Vulcan had said its space unit headquarters would be in Huntsville, Ala., Beames said it’s now firmly established in Seattle.

“Paul [Allen] wanted a closer, more personal leadership on it,” said Beames. “All future work … will be run out of Vulcan Aerospace here in Seattle.”