Improved Heat Shield Protects Next-Gen Reusable Spacecraft from Heat of Reentry

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Oak Ridge National Laboratory and Sierra Space Corporation have successfully developed a new heat shield to protect the next generation of reusable spacecraft during reentry. The new heat shield is inspired by 1980s Space Shuttle technology.

In the aerospace industry, the most difficult thing to get spacecraft back safely to Earth is the atmosphere, which serves as the shell of air around Earth to protect humans from cosmic rays and the meteors that constantly rain down on Earth. Not only that, it also burns up satellites whose orbits have decayed in case they haven’t been equipped with special protection.

The most common type of heat shield used today is made of phenol plastic. First launched in the 1950s, these heat shields protect returning spacecraft by what is called ablative shielding. To deal with the heat caused by a craft hitting the atmosphere at ultrasonic speed, it vaporizes the plastic and carries the heat away before it causes damage.

As it works by destroying the shield, it can only be used one time and has a very limited service life. Over time, a replacement solution was developed for NASA’s Space Shuttle in the 1980s. The Shuttle was equipped with a heat shield that was made of a vast array of ceramic silicon carbide tiles. It works by absorbing the heat and very slowly releasing it.

However, these tiles also had some major disadvantages. More than 24,000, six-by-six-inch (15-by-15-cm) silica-fiber tiles had to be applied to the undersurface of the Shuttle. In addition, each one had to be made by hand using molds and heating them to 2,350 °C (4,262 °F). During its operation, these tiles not only had a nasty tendency to come loose and fall off but were also very fragile.

Meanwhile, the new tiles use a combination of silicon carbide and carbon fibers that provide protection, high strength, and stable flight dynamics. 

Moreover, new manufacturing techniques also help to make these tiles much less labor-intensive to produce. As a result, they created a new generation of heat shields based on the one from the 1980s when NASA made five launches of the Shuttle a year, to a new version that could bear five launches per day.

The new tiles are now used on the Sierra Space Dream Chaser, the first winged commercial space plane designed to transport crew and cargo to low-Earth orbit.

Ashton Henning