The German Aerospace Center's Institute of Space Systems (DLR) is developing a "SpaceLiner" that will fly passengers from Europe to Australia in 90 minutes, or Europe to California in 60 minutes at a speed of 24 Mach, 12 times the speed of Concorde.
The SpaceLiner is a hypersonic suborbital spaceplane concept under development with the support of the EU's European Space Agency's (ESA) FAST 20XX program.
Project coordinators hope the hypersonic "SpaceLiner" will begin operation in 2050. The vehicle will accomplish the "Europe to Australia in 90 minutes" feat with the help of a rocket booster that propels the spaceplane into the Earth's upper atmosphere before gliding back at hypersonic speed to landing.
Space.com reports that Martin Sippel, project co-coordinator of SpaceLiner at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), said the project is still at an early stage, a major challenge being to find a plane design that can withstand the intense heat generated when the plane glides at hypersonic speeds through the upper atmosphere.
Designers hope that new advances in materials, new cooling technologies and heat shielding will help engineers design safeguarding measures to protect the vehicle against the intense heat of hypersonic flight in the upper atmosphere.
Sippel said project managers are expecting to make enough progress with the primary challenges in the next decade to attract project funds in the hope that the vehicle would begin operations by 2050.
The design concept, as currently conceived, is a reusable vehicle that consists of two stages: rocket booster for launch and the passenger-carrying spaceplane. The rocket booster stage provides vertical lift-of in combination with the spaceplane's rocket engines, like the Space Shuttle.
The rocket launch stage which lasts about eight minutes carries the spaceplane to an altitude of about 47 to 50 miles (75 to 80 kilometers), just short of the 62 miles (100-km) altitude considered the edge of space. The rocket then separates from the spaceplane, and after engine cut-ff, the spaceplane follows a suborbital flight cruise-path as it glides back to the Earth at hypersonic speeds of more then 15,0000 mph (25,200 kph).
The SpaceLiner is designed to transport 50 passengers from Australia to Europe in 90 minutes or 100 passengers from Europe to California in 60 minutes.
But passengers will be paying the equivalent of space tourism prices of several thousand dollars. Space.com reports Sippel said: "Maybe we can best characterize the SpaceLiner by saying it's a kind of second-generation space shuttle, but with a completely different task."
The rocket-powered design is unique among hypersonic jet designs. According to Space.com, it features new "air-breathing engine" concepts. Sippel said the concept shares a lot in common with the Space Shuttle as it uses essentially the same proven rocket technology.
European project planners say using proven rocket technology could help hasten the completion of the project and allow the SpaceLiner go into operation "sooner rather than later."
SpaceLiner engineers hope to use a liquid oxygen and hydrogen rocket fuel that leaves only water vapor as exhaust in the atmosphere, presumably an environment friendly option.
The empty rocket stage would return to Earth for reuse after separating from the spaceplane. An aircraft could be used to retrieve the rocket stage and transport to an airfield.
Space.com reports Sippel explained the main thrust of R&D: "We will not try to improve the performance of the engine but would like to have it more reusable."
According to the DLR, it may would take about 25 years to develop the SpaceLiner. The technologies builders will be employing are already available and routinely used in launch vehicle design. Developers are, however, focusing on improving reliability of reusable components to ensure passenger safety in routine flight operations. According to DLR, "studies are underway that place an emphasis on trajectory and performance analysis, structural design, aero(thermo)dynamics, guidance and control, innovating active cooling system as well as safety and abort scenarios are also under investigation."
Other projects being currently run are expected to contribute to the SpaceLiner project. Such projects include the European Union-funded international effort, called the Future High-Altitude High-Speed Transport 20XX (FAST20XX) project, and Project ALPHA, an Aerospace Innovation GmbH effort to launch a space plane from an Airbus A330. FAST 20xx involves researchers from Germany, Austria, Spain, Switzerland, Italy, Belgium, the Netherlands, France and Sweden.
The vehicle will require isolated launch site and careful route planning to prevent sonic booms generated during hypersonic flight speeds from affecting population centers.
But planners say success will depend upon the growth of the space tourism industry being pioneered by companies such as Virgin Galactic.