Re-entry from space is challenging because of many factors, including heat.
Marcos Fernandez-Tous, assistant professor in the department of space studies at the University of North Dakota, details how a new trajectory may help cool things down.
Assistant professor of space technology, I teach courses on rocket propulsion and hypersonic aerodynamics at the University of North Dakota. Between 2001 and 2016 I have been working in the aeronautical industry in Europe between Madrid and Brussels. Experience in research projects management and development. M.S. in Aerospace Engineering (Polytechnic University of Madrid, 2001) and PhD in Space Sciences (University of North Dakota, 2022).
Damage in the Heat Shield of the ORION Capsule
Off the coast of Baja California, the sea sparkles around the USS Portland as Navy officials scan the sky. Suddenly, a glowing spot appears, growing into the Orion capsule hurtling back from a 25-day mission to the Moon. After traveling over 270,000 miles, Orion reenters Earth’s atmosphere at 27,000 mph, deploying parachutes before splashing into the ocean. But as the capsule is hoisted aboard the ship, cracks on its heat shield raise concerns.
The heat shield, critical for protecting future astronauts, endured reentry temperatures of 5,000°F. As Orion skimmed the atmosphere, the friction generated a glowing sheath of charged particles called plasma. To withstand such high temperatures, the shield is designed to sacrifice material through melting and evaporation, preventing the heat from reaching the inner structure of the capsule. But the Orion shield, inherited from Apollo-era designs, was showing unexpected damage.
NASA determined that during Orion’s skip-guidance reentry, heat flow had been underestimated. As the surface was exposed to the plasma, the resin melted and receded exposing the fiberglass, that produced a black structure called char. The shield released the gases from the resin, but as Orion ascended briefly, the resin froze again, trapping heat and gas inside the structure. On its final descent, the gases expanded before they could be released, causing surface cracks and damaging the protective char layer.
Artemis II mission will be designed with a modified reentry trajectory to prevent the accumulation of heat inside. With Artemis III, NASA plans to implement new manufacturing methods, producing a more permeable structure. Will it still be hot outside during reentry? It sure will. But the astronauts will be kept in a cozy space all the way through splashdown when, rocked by the gentle waves, will just need to wait for another amphibious transport dock to bring them home.
Read More:
Space Studies Propulsion Lab (SSPL) – University of North Dakota
