Hypersonic 'SpaceLiner' to Fly Passengers in 2050

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.

SpaceLiner's European project planners say their reliance upon proven rocket technology could allow their vehicle to fly sooner rather than later. They plan to use liquid oxygen and hydrogen rocket propellants so that the rocket engines leave only water vapor and hydrogen in the atmosphere. (Video: How DARPA's HTV-2 Hypersonic Bomber Test Works)

"We will not try to improve the performance of the engine but would like to have it more reusable," Sippel told TechNewsDaily.

The empty rocket stage from SpaceLiner would return to Earth immediately after launch in preparation for reuse. An aircraft could grab the rocket stage in midair, tow it toward an airfield and release it for an autonomous gliding landing.

But big challenges remain before SpaceLiner can take off. Researchers first must finalize a design shape capable of surviving the intense heat created by gliding at hypersonic speeds through the upper atmosphere. New cooling technologies and improved heat shielding for SpaceLiner's wing "leading edge" could help in that case.

Launching like a rocket rather than taking off like an aircraft means SpaceLiner would remain restricted to suitable launch sites with uninhabited areas down range. The SpaceLiner also would need a careful flight path during its final landing approach - the "sonic boom" shock that accompanies aircraft traveling faster than the speed of sound can damage buildings on the ground at low altitudes.

"The profile of the vehicle is very similar to a rocket-propelled vehicle," Sippel explained. "We only have a small corridor in which we can fly safely and economically."

SpaceLiner's design will make use of study results from a FAST20XX (Future High-Altitude High-Speed Transport 20XX) project funded by the European Union and backed by researchers from Germany, Austria, Spain, Switzerland, Italy, Belgium, the Netherlands, France and Sweden. It can also draw lessons from upcoming efforts such as Project ALPHA by Aerospace Innovation GmbH - a space plane that aims to launch in midair from an Airbus A330 aircraft.

But future success ultimately depends upon the success of space tourism efforts by companies such as Virgin Galactic. If enough people prove willing to pay top dollar for suborbital flights as part of their travels around the world, Sippel envisions a fleet of SpaceLiners eventually making 10 to 15 flights per day.

This article originally appeared on TechNewsDaily.

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An artist impression of the SpaceLiner during booster separation.

Reader's Choice: Favorite Space Story of 2012

As 2012 rolls to a close, we can look back at an incredible 12 months of space exploration. Could this be one of the most profound years in space history? It might just be, but as we throw out our old calendars and replace them with ones marked "2013" (while avoiding doomsday in the process)* we look forward to another groundbreaking year in space that (who knows?) might be even more historic. So here are the top 10 space stories as chosen by our readers. Over 30 nominations were rounded up by Discovery News writers, bloggers and editorial staff, and the final 10 were voted on and ranked by you via Twitter, Facebook and Tumblr. Here they are in descending order, counting down to #1, the favorite space story of the year. And so we begin, on Mars, in 1976... *(This will be the ONLY reference to the idiotic "Maya doomsday" pseudoscience that plagued an otherwise outstanding year of

real science!

)

10: Mars Viking Robots 'Found Life' (April 12, 2012)

When NASA's Viking landers touched down on the Red Planet's surface in 1976, little did mission scientists realize that they'd be triggering a controversy that would resurface 36 years later. After reanalysis of the experiments carried out by the twin landers, an international team of mathematicians and scientists concluded that the mission may have detected microscopic life in the Martian soil. Read more.

9: Milky Way Crammed With 100 Billion Alien Worlds? (Jan. 11, 2012)

There's exoplanets EVERYWHERE! And according to new estimates, our galaxy is positively

crammed full

of alien worlds orbiting other stars. This new (and rather exciting) estimate was arrived at by astronomers from the Space Telescope Science Institute (STScI) in Baltimore, Md., and the PLANET (Probing Lensing Anomalies NETwork) collaboration. Needless to say, the ramifications of the search for alien worlds are huge, so when we think about 100 billion of them, surely one or two may host life? Might there even be a Earth 2.0? Fingers crossed. Read more.

8: Curiosity Landing: What's With All the Peanuts? (Aug. 15, 2012)

What was with NASA's crazy peanut-eating frenzy just before the Mars Science Laboratory touched down on Aug. 5? The NASA Jet Propulsion Laboratory scientists and engineers couldn't get enough of the salty snack! As it turned out, just before the one-ton rover began its incredibly exciting entry, descent and landing (dubbed the not-so-subtle "Seven Minutes of Terror"), the outbreak of peanut consumption was down to a long-standing tradition dating back to the 1964 Ranger 7 mission. Read more.

7 (tied): Organics Discovered on Mercury (Nov. 29, 2012)

Poor old Mercury. It's small, barren and uninteresting.

Wait!

Scrub that last bit. The planet closest to the sun is ANYTHING but uninteresting. One of the latest crazy-cool discoveries to come from the NASA MESSENGER probe currently in orbit about the planet is that the pockmarked surface doesn't only host water ice inside its most shady craters, it also has a layer of organic compounds over the top. But what does that mean for the history of the solar system? Read more.

7 (tied): Voyager 1 Detects Weirdness at Solar System Edge (Oct. 30, 2012)

We love weird things at Discovery News, and it appears our readers do too. This latest "weird" thing to come from the epic Voyager 1 mission concerns some fascinating physics right at the edge of our solar system's heliosphere -- aptly known as the "heliopause." The 35 year-old spacecraft is currently ploughing towards interstellar space at a rapid pace and has detected some rather odd magnetic behavior out there. But what does it mean? Read more.

6: The Transit of Venus 2012 (June 5, 2012)

2012 marked the last time that we will see Venus pass across the disk of the sun for over 100 years (from Earth, in any case). The historic event was marked by a momentous international celebration of the transit. I even had the opportunity to represent Discovery News as co-host for the Astronomers Without Borders (AWB) live webcast from the summit of the world famous Mount Wilson, Calif. It really was a once-in-a-lifetime experience that saw the world join in a celebration of astronomy and celestial mechanics. Johannes Kepler would be proud. Read More.

5: Super-Earth Discovered in Star's Habitable Zone (Nov. 7, 2012)

The day when an Earth-sized world is discovered orbiting its star within the "habitable zone" will be a profound day. We already know that there is a preponderance of small exoplanets in our galaxy, but do any have all the right stuff to be called a "second Earth"? So far, we haven't found "that" exoplanet, but we're getting close. Take HD40307g, for example. It orbits inside its star's habitable zone... but it's at least seven times more massive than our planet. It's a "super-Earth." It may not be Earth 2.0, but exoplanet hunters may not be that far off... Read More.

4: Neil Armstrong, Apollo Legend, Has Died (Aug. 25, 2012)

This year also saw the death of a legend. After complications stemming from a cardiovascular procedure, Apollo 11 commander Neil Armstrong passed away on Aug 25 at the age of 82. In a statement, Armstrong's family made a simple request: "Honor his example of service, accomplishment and modesty, and the next time you walk outside on a clear night and see the moon smiling down at you, think of Neil Armstrong and give him a wink." Read more.

3: Red Bull Stratos Skydive (Oct. 14, 2012)

Call it the mother of all marketing stunts or a historic human achievement -- it was both. The Red Bull Stratos mission saw Austrian daredevil Felix Baumgartner jump from an altitude of 128,000 ft, smashing Joe Kittinger's 52-year high-altitude dive record. So profound was the record attempt, Discovery Channel interrupted its scheduled programming to allow Discovery News to cover event live. The international media was also hooked. And when Baumgartner stepped into the void... the world's collective heart skipped a beat and we all cheered when we saw that parachute open. Red Bull may give you wings, but it also remembers to pack a parachute. Read more.

2. Particle 'Consistent' With Higgs Boson Discovered (July 4, 2012)

One of the main objectives for the Large Hadron Collider (LHC) -- most definitely the grandest, most complex and expensive piece of lab kit ever conceived -- is to hunt down "the last piece" of the Standard Model of physics. What that basically means is that should the LHC find evidence for the Higgs boson (named after Prof. Peter Higgs, one of the key physicists who formulated the mechanism that mediates mass in matter), science has the answer to everything! Well, not quite, but these first detections of something that looks like the Higgs does mean that decades of physics theory have been (just about) nailed down. In a nutshell, it's a very exciting era for all physics disciplines, as the Higgs helps us understand how the Universe works. Read more.

1. Touch Down! Mars Rover Curiosity Lands (Aug. 6, 2012)

After surviving the "seven minutes of terror," the dust settled in Gale Crater and a nuclear-powered wheeled robot started taking pictures of its new home. Of course, that new home was Mars and the rover, "Curiosity." The first photos were grainy hazcam pics, shown here, of the crater's plain and rover shadow. As luck would have it, Discovery News' Irene Klotz, Amy Shira Teitel and myself were physically at JPL, Curiosity's mission control in Pasadena, Calif., to cover the event live. It was a night to remember. The landing of NASA's Mars Science Laboratory in August began what is shaping up to be a paradigm shift in how the red planet is explored. Building on the incredible successes of the landers and rovers that have come before it (in fact, Mars Exploration Rover Opportunity still rolls on, eight years after landing), Curiosity is the most sophisticated robot we've ever sent to another world. But it was that dramatic landing on the morning of Aug. 6 (ET) that captivated the world, kicking off many years of scientific discovery. Read more.

MORE: Reader's Choice: Favorite Space Story of 2011 Reader's Choice: Favorite Space Story of 2010