Development of a New Prototype of a Thermal Screen

Rui Wu, the creator of the prototype, and a few professors from the University of Manchester, published this article in the Acta Astronautica to inform the public about the development of new heat shield prototype for future spaceships. Wu is in Manchester’s School of Mechanical, Aerospace and Civil Engineering.

Rui Wu, a student at the University of Manchester, developed a prototype for a flexible heat shield. It’s lightweight, cost effective, and can be folded, so that it’s easy to store. “Spacecraft for future missions must be larger and heavier than ever before, meaning that heat shields will become increasingly too large to manage,” said Rui Wu (Wu, 2018). Wu believes that his invention could help with future research and recovery expeditions. Because this new heat shield would be more cost effective than the current ones, Wu says that it may help the U.S to make a future expedition to Mars.

This prototype uses centrifugal force to accomplish the same thing as the current heat shields we use for spaceships. The force causes the material to stiffen, when it’s in use, making it sturdy. It spins like the seed of the samara tree, when deployed. This causes drag, so that the spacecraft can slow down, and not catch on fire. When the rocket re-enters earth’s atmosphere, the air around it can heat up to 10000 C, but the spaceship doesn’t burn up because of the heat shield on the front of it. This newer skirt shaped heat shield will be less expensive and will be self-regulating, unlike the current heat shields used on spaceships.

When it is partially deployed, it causes a higher roll torque then when its fully deployed. Once fully deployed, it causes a low roll torque, which helps stabilize the spin rate. Rui Wu also created an origami paper model of his spinning heat shield, so that he could test it. It was able to be folded down into a smaller form, like he had designed it to. The material becomes stiffer because of centrifugal forces in the first stage of deployment, and in the second stage, it fully deploys. The ridges and indents on the spinning heat shield are what cause the roll torque.

Rui Wu used a numerous amount of equations to figure out how to build this prototype. Some of these equations include spin rate, pitching frequency, oscillation frequency, and thermal transmission. He also combined several well-known scientific formulas into extremely complicated equations so that he could solve for things such as deployment moments at off equilibrium conditions, using sine and cosine. In order for him to be able to know if his prototype will work without having to try it on a spacecraft, he had to use these equations to scientifically prove it will. On page nine of the article, Rui Wu even states that he uses equations to make sure everything will work. “To avoid resonance, the structural natural frequency of the flexible second stage must not overlap with the spin rate and the aerodynamic pitching frequency. In this section, those three frequencies are analytically assessed and the former two are also analyzed by FE simulations.” (Wu, 2018, p.9) By using equations to build this prototype, Wu is presenting good science.

Rui Wu also uses scientific facts to explain why and how he designed his spinning heat shield. He used centrifugal force to help design his prototype. Centrifugal force is a force that acts out, away from the center, of a spinning object. So, he made his prototype move in a circular motion, so that centrifugal forces would act on it and help slow the spaceship down.

When the heat shield is fully deployed, the skirt shaped structure spins and fills with air, creating drag. The slower that the spaceship enters a new atmosphere, the less likely it will catch on fire. For example, if a match is slowly scraped on the box, it won’t catch on fire. If it is quickly scraped along the box, it will catch on fire almost immediately. The same applies to a spacecraft in a way. The heat shield needs to be able to slow the spacecraft down as well as protect it from high temperatures, so that it won’t catch on fire. So, Wu designed a structure, based on this scientific fact, that would created enough drag to slow a spacecraft down to a safe speed when entering a new atmosphere.

Past explorations have contributed to several scientific developments, such as cell phone technology, anti-icing for aircraft safety, and advancements in medicine, just to name a few. For example, with this lightweight and easily storable spinning heat shield, we could make future trips to Mars. We have never been able to send astronauts to Mars. We have only seen pictures of Mars from satellites and robots. We would be able to say that we were the first country to send astronauts to Mars and gather data by hand, as opposed to relying on space robots.

It is said that the first person to travel to Mars is alive at this moment. For me, personally, that’s exciting. We have never been able to step foot on a planet. Astronauts have been able to walk on the moon, but never a planet. It would be interesting to hear about what was found on Mars by astronauts during my lifetime. I am confident that successful technological advances regarding spinning heat shield development will re-open such ambitious space endeavors.