When spacecraft reenter, they need a heat shield to protect them from the immense friction and heat of speeding through the atmosphere. Usually, these are rigid structures, but ULA plans to use an inflatable heat shield to protect the engines of their Vulcan rocket and recover them for reuse. They’ll be testing out that type of heat shield next month.
This Low-Earth Orbit Flight Test of an Inflatable Deorbiter (LOFTID), a joint test between ULA and NASA, is scheduled to take place on November 1. It will launch as a secondary payload on an Atlas V launching out of Vandenberg Space Force Base.
The primary payload of the mission is launching JPSS-2 – a weather satellite for the National Oceanic and Atmospheric Administration and NASA. The rocket is in the 401 configuration, and it is set to be the final Atlas V to launch out of Vandenberg. Future Atlas launches, such as project Kuiper and crewed Starliner launches, are all set to launch from SLC-41 at Cape Canaveral Space Force Station in Florida.
The world of spaceflight is moving more and more towards reusability. While SpaceX and Blue Origin have plans for full reusability with Starship and New Glenn, ULA is following a unique approach. They are, instead, opting for “SMART reuse.” Rather than spending the extra fuel to land the entire rocket (decreasing payload capacity), they eventually plan to separate the engine from the first stage to recover the engines. Engines are more than half the cost of the first stage, and ULA is purchasing the BE-4 engines from Blue Origin, so recovering and reusing them could help reduce cost.
SMART reuse stands for Sensible Modular Autonomous Return Technology, and for this recovery to work the engines will need to be protected from the forces of reentry. This inflatable heat shield is essential for that. The heat shield needs to be small enough and light enough to fit in the small section of the rocket with the engines during launch, but needs to be large enough to totally protect them on return.
In addition to the potential for this test to help prove inflatable heat shields for engine recovery, it is possible inflatable heat shields serve an essential role landing on Mars. And inflatable heat shield removes the size limitation of a rocket’s fairings – allowing a larger heat shield to slow down a payload even further as it enters the atmosphere. “That translates into allowing not only heavier payloads, but also landing at higher altitudes.”
The shield test will take place after the deployment of the primary payload. “LOFTID rides below JPSS-2 in the payload stack and is packed within a bag 7.4 feet (2.3 meters) tall and 4.3 feet (1.3 meters) in diameter.” Despite this small package, it will deploy to nearly 20 feet wide and 6 feet tall. Splashing down off the coast of Hawaii, the data gathered during this test will help the teams understand the stress that Vulcan’s engine reentry system will undergo.