Reentry Vehicle Technology

Atmospheric reentry is the process where vehicles that are outside the atmosphere of a planet can enter the atmosphere and reach the planetary surface intact. Usually this process requires methods to protect against aerodynamic heating. Many technologies have been developed to enable reentry in to the atmosphere. The ablative heat shield is one technology. The purpose of the ablative heat shield is to dissipate the heat away from the spacecraft during its reentry.

The objective of this paper is to compare the different materials used to create the ablative heat shield and compare it to other forms of heat shield technology. There are some materials that work better for an ablative heat shield than others. For example, carbon phenolic is an effective ablative material but it has a high density which is undesirable. SLA-561V is the material used in all the 70 degree sphere-cone entry vehicles sent by NASA to Mars. SLA stands for "Super Light weight Ablator.” SLA-561V is not applicable for reentry vehicles like the Apollo-CM because this material can only handle a heat flux of up to 225W/cm2, and the Apollo-CM reentry vehicle, for lunar return, can get a heat flux of around 497 W/cm2. There are many more materials used in reentry vehicle technology, like Phenolic Impregnated Carbon Ablator (PICA), Silicone Impregnated Reusable Ceramic Ablator (SIRCA), and Reinforced Carbon Carbon (also called RCC or carbon-carbon), which will also be discussed and compared in this paper. The significance of these materials is that it makes space travel possible. The practicality of space travel is dependent on the protection of the spacecraft, which makes reentry vehicle technology a vital part of space travel.