A hypersonic "SpaceLiner" would whisk up to 50 passengers from Europe to Australia in 90 minutes. The futuristic vehicle would do so by riding a rocket into Earth's upper atmosphere, reaching 24 times the speed of sound before gliding in for a landing.
Many challenges still remain, including finding the right shape for the vehicle, said Martin Sippel, project coordinator for SpaceLiner at the German Aerospace Center. But he suggested the project could make enough progress to begin attracting private funding in another 10 years and aim for full operations by 2050.
The current concept includes a rocket booster stage for launch and a separate orbiter stage to carry passengers halfway around the world without ever making it to space. Flight times between the U.S. and Europe could fall to just over an hour if the SpaceLiner takes off — that is, if passengers don't mind paying the equivalent of space tourism prices around several hundred thousand dollars.
"Maybe we can best characterize the SpaceLiner by saying it's a kind of second-generation space shuttle, but with a completely different task," Sippel said.
SpaceLiner passengers would have eight minutes to experience the rocket launch before they reached an altitude of about 47 to 50 miles (75 to 80 kilometers). That falls short of the 62-mile (100-km) boundary considered the edge of space, but even a suborbital flight would allow SpaceLiner to glide back to Earth at hypersonic speeds of more than 15,000 mph (25,200 kph).
The rocket-powered design stands out compared with other proposed hypersonic jets, which feature new air-breathing engine concepts. European aerospace giant EADS previously unveiled a hypersonic jet concept that would rely mainly upon air-breathing ramjets to reach cruising speeds of Mach 4 — faster than the supersonic Concorde's Mach 2 performances but far slower than the SpaceLiner's Mach 24 goal.