In November of 2020, NASA concluded a series of 23 hot-fire tests of an experimental rocket engine with two 3D printed components: a combustion chamber and a nozzle made of a high-strength alloy that can withstand hydrogen embrittlement. We will talk about how they managed to do so and how it’s related to llamas.
Over the course of ten days, a group of NASA engineers was conducting 23 hot-fire tests that lasted 280 seconds in total. They gained data regarding pressure and temperature in the chamber and integrated coolant channels and calculated the performance and overall fuel efficiency.
“This 3D printed technology is a game-changer when it comes to reducing total hardware manufacturing time and cost. These hot-fire tests are a critical step in preparing this hardware for use in future Moon and Mars missions.”, — comments Tom Teasley, a test engineer at Marshall Space Flight Center.
The parts were made using the Direct Energy Deposition (DED) technology of 3D printing. The combustion chamber is made of copper alloy, while the nozzle is made of iron-nickel superalloy that is resistant to atomic hydrogen that decreases the plasticity of the steels and alloys that come in contact.
A similar additive manufacturing technology named Direct Metal Deposition (shown on the picture below) is being perfected by Russian scientists and engineers from the Institute of Laser and Welding Technologies (ILWT) with the plans of being used in both aerospace and shipbuilding and ship repair fields. Usually, a laser spray head is mounted to an industrial robotic hand that will “grow” large-sized objects.
The conducted tests are a part of the Long-Life Additive Manufacturing Assembly (LLAMA) project that aims to integrate additive manufacturing of the components of rocket and space technologies created for new Moon exploration missions.