Hypersonic Speed refers to speeds of Mach 5 and above. Mach speed refers to the speed of sound. Thus when you talk about a craft travelling at hypersonic speed, it’s likely to be travelling at least five times the speed of sound. Needless to say the craft would have to be able to withstand a great deal of pressure.

Finding a material that would survive regular hypersonic speed travel is the first challenge that scientists face. So far carbon nano tubes have been used in planes for their strength and ability to withstand heat. They have proved stronger than steel, however scientists at the Binghamton University say that boron nitride nano tubes are the construction material of the future.

Boron nitride nano tubes or BNNTs are currently being manufactured solely by NASA. They are lightweight and able to withstand great pressure. While carbon nano tubes stay stable at temperatures up to 400 degrees Celsius, BNNTs stay stable till 900 degrees Celsius.

Unfortunately the production of BNNTs costs $1,000 per gram. This makes it a very expensive proposition for using in construction of a aircraft. While science experiments with the material will continue to see if hypersonic speeds can be reached in a craft made out of this material, it’s prohibitive price will not translate easily to commercial application. We may still be waiting a while to experience commercial hypersonic speed travel.