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Meet the company that wants to replace rockets with space shuttles
Called the X-33, it was based on a concept called SSTO — or “single stage to orbit”. The SSTO eliminates rocket stages in conventional spaceflight—in which rockets containing engines and fuel are jettisoned during ascent to reduce weight—in favor of a single, fully reusable spacecraft.
The X-33 was designed to launch vertically like a rocket but land on a runway like an airplane, with the goal of reducing the cost of sending a pound (about 450 grams) of payload to orbit from $10,000 ( around R$56,000) to just US$1,000 (around R$5,600).
However, the program was canceled in 2001 due to technical difficulties, adding to a list of similar projects that did not come to fruition.
“I was leading the X-33 program, and we gave up on it because our assessment was that it would cost more than we were willing to spend, and we were at the limit of our technological capabilities to actually do it,” says Livingston Holder, an aerospace engineer, former USAF astronaut and X-33 program manager, and now CTO of Radian Aerospace, a Seattle-based company he co-founded in 2016 to revive the SSTO dream.
“Things have changed drastically since the X-33 — we have composite materials that are lighter, stronger and can withstand a greater thermal range than we had back then. And the propulsion is better than anything we had, in terms of how efficiently it burns propellant and how much the systems weigh,” he says.
The product of this updated technology is Radian One, a new space plane that will replace vertical launch with a very unusual system — a rocket-powered sled.
Wasted internships
To escape Earth's gravity and reach orbit, a rocket needs to reach a speed of about 28,000 km/h, according to Jeffrey Hoffman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology and a former NASA astronaut who flew on five Space Shuttle missions.