Astrobotic has completed a series of hot-fire tests for its Chakram rotating detonation rocket engine, with additive manufacturing (AM) playing an important role in how the engine was built. The company conducted the tests at NASA Marshall Space Flight Center, where two prototypes ran across eight tests totaling 470 seconds, including a 300-second continuous burn that may be the longest of its kind to date. Of course, the performance stands out, but what really matters here is how the engine was built.