The effects of projectile impact velocity on ejecta fragment size were investigated by striking aluminum alloy 6061-T6 targets with 3.2-mm-diameter aluminum alloy 2017-T4 spheres at velocities ranging from 2 to 6 km/s. The two-stage light-gas gun at the Institute of Space and Astronautical Science (ISAS)/ Japan Aerospace Exploration Agency (JAXA), was used for the experiments. To examine the scattering angles of ejecta, a witness plate (150 mm × 150 mm, 2 mm in thickness) made of copper C1100P-1/4H, with a 30-mm hole in the center, was placed 50 mm in front of the target. The behavior of ejected fragments was observed using a high-speed video camera. The projected areas of ejecta collected from the test chamber after the impact experiments were measured.