NASA's Rail-Launched Scramjet Spacecraft Concept

Emerging Technologies May Fuel Revolutionary Launcher

As NASA studies possibilities for the next launcher to the stars, a team of engineers from Kennedy Space Center and several other field centers are looking for a system that turns a host of existing cutting-edge technologies into the next giant leap spaceward.

This artist's concept shows a potential design for a rail-launched aircraft and spacecraft that could revolutionize the launch business. Early designs envision a 2-mile-long track at Kennedy Space Center shooting a Mach 10-capable carrier aircraft to the upper reaches of the atmosphere. then a second stage booster would fire to lift a satellite or spacecraft into orbit. 

 Different technologies to push a spacecraft down a long rail have been tested in several settings, including this Magnetic Levitation (MagLev) System evaluated at NASA's Marshall Space Flight Center. Engineers have a number of options to choose from as their designs progress.

NASA Engineers Propose Combining a Rail Gun and a Scramjet to Fire Spacecraft Into Orbit | Popular Science

The system calls for a two-mile- long rail gun that will launch a scramjet, which will then fly to 200,000 feet. The scramjet will then fire a payload into orbit and return to Earth. The process is more complex than a rocket launch, but engineers say it’s also more flexible. With it, NASA could orbit a 10,000-pound satellite one day and send a manned ship toward the moon the next, on a fraction of the propellant used by today’s rockets.

Scramjet - Wikipedia, the free encyclopedia

A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing combustion jet engine in which the combustion process takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to forcefully compress and decelerate the incoming air before combustion (hence ramjet), but whereas a ramjet decelerates the air to subsonic velocities before combustion, airflow in a scramjet is supersonic throughout the entire engine. This allows the scramjet to efficiently operate at extremely high speeds: theoretical projections place the top speed of a scramjet between Mach 12 and Mach 24, which is near orbital velocity. The fastest air-breathing plane is a SCRAM jet design, the NASA X-43a which reached Mach 9.8. For comparison, the second fastest [1] manned airbreathing aircraft, the SR-71 Blackbird, has a cruising speed of Mach 3.2.[2]