A space shuttle-era main engine is defying the expectations of many critics as it undergoes a series of daily test firing to prove its reusability.
The Aerojet Rocketdyne AR-22 engine has no new hardware in it aside from minor modifications and is apart of a series of tests for Boeing’s plans to develop a reusable lower stage vehicle that can take over a ton of material into orbit.
As the engine continues to exceed expectations, other systems are undergoing critical inspections and reviews, which will culminate in full spacecraft assembly in in 2019.