- Concept Led By: N/A
- Companies Involved: Lockheed Martin, Boeing, Northrop Grumman, General Electric, Airbus, & More
During the 1960s and 1970s, several companies and engineers proposed plans to NASA and other space agencies to make spacecraft designs using hypersonic planes. Of course, a hypersonic plane is anything that can reach or surpass Mach-5. Basically, they move faster or at the speed of sound. Yet early hypersonic planes were not exactly useful and were often dealing with several technical limitations at the time. Safety concerns were so high that most space agencies, especially NASA, refused to consider anything utilizing hypersonic plane concepts.
Why do we consider hypersonic planes for spacecraft designs? Early on, these planes were able to go above the clouds and reach near-space boundaries. The notable boundary here is called the Kármán line, which planes are unable to cross because they use engines that burn air. There is no oxygen in space, so hypersonic plane designs could never take us to real space. However, this is likely to change soon. Two experimental planes (SpaceShipOne and North American X-15) use rocket engines rather than jet engines, allowing them to burn liquid fuel instead of air. We will likely be seeing these in use before too long.