Ready to book your satellite launch online?

After decades of building commercial airliners, Boeing is now developing something that looks like a plane and sometimes acts like a plane — but is not a plane.

The company’s latest invention is instead a spaceplane. The Phantom Express, as it is known, would perform like one of the many jets in Boeing’s vast fleet, landing on a runway with a 737-like wingspan, able to take off quickly on demand — just fuel up and go. But instead of carrying passengers, it would launch satellites into orbit. And if all goes to plan, soon it would be able to fly to the stratosphere 10 times in 10 days under a test program funded by the Defense Advanced Research Projects Agency (DARPA).

Fast and affordable access to space has long been a sci-fi fantasy, but now it is also the goal of the Pentagon, the intelligence community and an increasing number of businesses, particularly when it comes to delivering a new generation of satellites over the Earth.

Several firms are working on flying on a weekly, if not daily basis, making a once-rarefied event as routine as commercial air travel. Some are even allowing customers to order a launch online — just enter the number and mass of your satellites, and the orbital inclination, as if choosing toppings on a pizza delivery.

“We’re trying to bring the knowhow from our Boeing commercial aircraft folks on turning around large, complex machines in a very short amount of time,” said Steven Johnston, the director of launch for Boeing’s Phantom Works division.

The market for these new launches is being driven by a revolution in satellite technology that is dramatically reducing their size. Just as computers have gone from massive mainframes to hand-held devices, satellites have shrunk from the size of garbage trucks to that of shoe boxes. To meet the potential demand, there are more than 40 small launch vehicles in development around the world, said Phil Smith, a space analyst at Bryce Space and Technology, a consulting firm. But given the cost and risk of space travel, he warned that not all of them will endure.

“There is a rush to address this perceived demand, and only a handful will survive,” he said.

One company that spotted the early potential for frequent flight is SpaceX, the rocketmaker founded by tech billionaire Elon Musk. SpaceX has launched 16 times this year, more than many space-going nations, and Musk has said SpaceX’s goal is to launch more and faster in the coming years.

The new satellites have many potential uses. Companies such as OneWeb and SpaceX want to put up hundreds, if not thousands, of small satellites that would beam the internet to every corner of the Earth.

Others see possibilities for new weather satellites and eyes-in-thesky to monitor the health of the planet. That’s what got Peter Beck to start Rocket Lab. His company is developing a small rocket called Electron that had a test launch earlier this year in New Zealand.

Instead of relying on a couple dozen weather satellites, “what would happen if we replaced them with 300 state-of-the-art technology satellites to take the true pulse of the planet?” Beck said. “You’d leapfrog an order of magnitude in your understanding of the planet.”

Planet, a San Francisco-based company, has already launched 190 small satellites for Earth monitoring, and it has 10 more scheduled to go soon.

U.S. national security officials, meanwhile, have long been dependent on space for the GPS signals that guide precision weapons, communication for soldiers on the battlefield and spying on the enemy.

Under the DARPA program, Boeing’s Phantom Express “is intended to really revolutionize space access by making recurring reusable launch operations aircraftlike,” Boeing’s Johnston said.

The company’s spaceplane would launch vertically, while carrying another rocket, space-shuttle-like, on its back. Once aloft, the piggybacking rocket would detach and then shoot off into orbit, and the spaceplane would land on a runway, ready to fly again. The company hopes to demonstrate that it can fly to as high as 150,000 feet repeatedly — 10 times in 10 days — by 2020.

Companies such as Vector and Rocket Lab, which have already had test launches of their vehicles that are designed for even smaller payloads, seem closer to operation. Rocket Lab, which uses a 3-D printer to make a large portion of its engines, has another test flight scheduled later this year and already has enough customers to launch once a month for nearly two years, Beck said.

His company would charge $5 million a launch, which it heralds as “a drastic cost reduction” compared to competitors.