Model Takes the Heat for the Space Shuttle
Could a surface anomaly on the space shuttle pose a danger to the vehicle and its crew on landing? NASA has a way of finding out while the shuttle is in orbit. A small molded space shuttle model in the NASA exhibit at EAA AirVenture in Oshkosh, Wis., can be coated with a thermal reactive finish that reveals any hot spots caused by air friction during re-entry.
Image right: NASA uses ceramic models like the space shuttle shown by technician Johnny Ellis to map skin temperatures on high-speed aerospace craft. Ellis brought the model to AirVenture in Oshkosh, Wis. from the Langley Research Center in Virginia. (Photo by Frederick A. Johnsen)
When space shuttle mission STS-121 orbited Earth earlier this month, inspection of the shuttle in flight revealed a small piece of gap filler material protruding from its normal position. NASA engineers quickly configured a small thermographic space shuttle model with a surface irregularity where the real shuttle had the protruding material. While the shuttle crew orbited overhead, NASA used the heat-sensitive model to verify that the material would not cause that portion of the shuttle to overheat on re-entry. This good news meant the crew would not have to spend a valuable space walk repairing the material, but could concentrate on other important scheduled duties.
The model flies in a NASA wind tunnel that can generate temperatures higher than 1,000 degrees Fahrenheit. In these conditions the special coating, when viewed under ultraviolet light, reveals rainbow colors that are calibrated to different temperature ranges. The model is made from a ceramic material because unlike metal, ceramic does not expand under heat. Unlike older thermal test models that had limited locations for mechanical temperature sensors, the coated ceramic models reveal temperature variations over their entire surface.
NASA uses heat-predictive wind tunnel models to forecast the degree of punishment other future aerospace vehicles can expect to encounter. These and other fascinating aerospace research and development tools can be viewed in the NASA exhibit’s craftsman area at AirVenture July 23-30, staffed by NASA specialists happy to explain the tools of their trade. A piece of genuine space shuttle heat resistant tile is in the NASA AirVenture exhibit. Ask NASA’s Johnny Ellis, and he might let you hold it.
By Frederick A. Johnsen
NASA Public Affairs