resulting in a TRL-6 design. Ion thruster DART demonstrated the NEXT gridded ion thruster, a type of solar electric propulsion. It was powered by solar arrays to generate the ~3.5 kW needed to power the NASA Evolutionary Xenon Thruster–Commercial (NEXT-C) engine. Early tests of the ion thruster revealed a reset mode that induced higher current (100 A) in the spacecraft structure than expected (25 A). It was decided not to use the ion thruster further as the mission could be accomplished without it, using conventional thrusters fueled by the 110 pounds of hydrazine onboard. However, the ion thrusters remained available if needed to deal with contingencies, and had DART missed its target, the ion system could have returned DART to Dimorphos two years later. Secondary spacecraft The Italian Space Agency (ASI) contributed a secondary spacecraft called LICIACube (Light Italian CubeSat for Imaging of Asteroids), a small CubeSat that piggybacked with DART and separated on 11 September 2022, 15 days before impact. It acquired images of the impact and ejecta as it drifted past the asteroid. LICIACube communicated directly with Earth, sending back images of the ejecta after the Dimorphos flyby. LICIACube is equipped with two optical cameras, dubbed LUKE and LEIA. Effect of the impact on Dimorphos and Didymos The spacecraft hit Dimorphos in the direction opposite to the asteroid's motion. Following the impact, the orbital speed of Dimorphos therefore dropped slightly, which reduced the radius of its orbit around Didymos. The trajectory of Didymos was also modified, but in inverse proportion to the ratio of its mass to the much lower mass of Dimorphos. The actual velocity change and orbital shift depended on the topography and composition of the surface, among other things. The contribution of the recoil momentum from the impact ejecta produces a poorly predictable "momentum enhancement" effect. Before the impact, the momentum transferred by DART to the largest remaining fragment of the asteroid was estimated as up to 3–5 times the incident momentum, depending on how much and how fast material would be ejected from the impact crater. Obtaining accurate measurements of that effect was one of the mission's main goals and will help refine models of future impacts on asteroids. The DART impact excavated surface/subsurface materials of Dimorphos, leading to the formation of a crater and/or some magnitude of reshaping (i.e., shape change without significant mass loss). Some of the ejecta may eventually hit Didymos's