NASA's dream of a space plane could finally become reality

• Space planes could become a reality if one company achieves its goal.
• Radian Aerospace has plans to test its Radian One space plane over the next few years.
• Radian's model differs from multi-stage rockets and could be a cheap alternative to space travel.

One company is reviving a decades-old NASA idea to build a reusable space plane that could shuttle people and small payloads to space for cheap.

In the 1990s, NASA looked into developing a space plane prototype called X-33, but it scrapped the mission in 2001 citing technical issues.

Seattle-based Radian Aerospace is now trying to finish what NASA started by building Radian One, a space plane that will be fully reusable up to 100 times and could carry up to five astronauts at a time.

Livingston Holder, who was the program manager of X-33 for NASA, is the company's chief technology officer and is overseeing the new effort.

Holder told CNN that enough has changed since 2001 to make creating a space plane a more realistic goal.

"We've got composite materials that are lighter, tougher and can take a larger thermal range than we had back then," he said. "And propulsion is better than anything we had, in terms of how efficiently it burns propellant and how much the systems weigh."

The company raised nearly $28 million to build Radian One in 2022 and told CNN that it plans to test a scale model this year.

Why we need space planes

Demand for launching things into space — like satellites, which make everything from weather forecasting to GPS possible — is only increasing.

Rockets remain the best option for doing that, even though they're "terribly inefficient and expensive," according to NASA.

A typical rocket consists of multiple stages that are expensive to build and often discarded after one use.

Companies like SpaceX have revolutionized rocket technology and reduced costs with fleets of reusable rockets, like the Falcon 9.

But space planes, which require less fuel and no rocket stages, could offer another cheap, and more comfortable, alternative to space travel.

How Radian One could offer a cheap and comfortable ride to space

Unlike a rocket, which launches vertically, the concept for Radian One uses a rocket-powered sled.

The sled would carry the plane along a two-mile-long rail, accelerating it to a speed of 537 miles per hour, and then launching it toward space.

The plane would then fly the rest of the way with its own engines. Using the sled to reach launch speed reduces the amount of fuel that the space plane itself needs to carry, according to Radian's website.

This airline-like ascent would be a more comfortable ride for passengers, according to Radian. The company also hopes that it could reduce the cost of spaceflight.

It's unclear by how much, but for some idea, NASA hoped that its X-33 space plane would reduce the cost of sending a pound of payload into orbit from $10,000 to $1,000.

Radian One wouldn't be a replacement for all rockets, though.

Radian's space plane would be capable of carrying smaller payloads into space making it the equivalent of a pickup truck, he told CNN. Traditional rockets, Holder said, will likely remain for heavier payloads, making them the 18-wheelers in this analogy.

A full-size plane won't take to the skies until 2028, and even then, the company doesn't expect it to reach orbit just yet. But, if successful, Radian One could eventually present a cheap option for a growing segment of space travel.