The satellite world is undergoing a massive upheaval. Thanks to advancements in computing and new manufacturing techniques, even spacecraft with the most critical responsibilities are becoming smaller and more inexpensive. As a result, satellite owners are building them faster and in greater quantities than ever before. Launch service providers like Virgin Orbit are working to build vehicles that can match this rapid evolution — which means they must continuously explore and implement new techniques, tools and materials.
Like other high-profile pioneers of this new commercial space race (SmarTech Publishing dedicated a full report to AM for space applications), including the likes of Space X and Blue Origin, Virgin Orbit has been printing key parts of its rocket engines for some time: they were among the first private space companies to recognize additive manufacturing as a great enabler. Similarly, the engineers at NASA’s Marshall Space Flight have been working with AM for decades. Now both teams have put their heads together for a mutually beneficial project partnership, or Space Act Agreement.
The project’s joint goal is to study the use of additive manufacturing to build multimetallic combustion chambers. Combustion chambers are a crucial component of all rocket engines. It’s here that the propellants mix and ignite, generating incredibly high pressure and temperature before accelerating past the speed of sound as they exit the nozzle. The punishing operating environment makes combustion chambers one of the most difficult engine parts to develop while keeping manufacturing time short and cost low.
The benefit of developing multimetallic parts, as Virgin Orbit is doing for its own engines, is that you can take advantage of their distinct properties (such as strength or thermal conductivity) to create a more robust, higher performing end product. The problem is developing such parts can be an excruciatingly slow process. Powerful tools, like hybrid additive-subtractive manufacturing LASERTEC 65 systems from DMG Mori, in use at Virgin Orbit, can go a long way toward accelerating the process.
Virgin Orbit obtained one of the first hybrid additive-subtractive manufacturing machines in the world through a partnership with DMG Mori. This technology can save months in production cycles, reducing the time to craft an engine thrust nozzle by an order of magnitude.
Virgin Orbit engineers used this hybrid machine to modify combustion chambers designed by NASA. The chamber’s geometry was unchanged from the traditionally manufactured design, but the engineers were able to build it more quickly and out of different materials. An extensive hotfire test campaign then proved that the unit could hold up under realistic operational conditions, and in fact matched the performance of a traditionally manufactured unit.
Virgin Orbit is taking the lessons learned from this partnership and incorporating them into its own manufacturing development. Reaching its production goals will likely mean an order of magnitude reduction in both cost and lead time for its engines — and it will be thanks in part to the work done with the Marshall Space Flight Center.