Ranger 4 failed to deploy its solar panels and high-gain antenna due to a stopped main timer in the onboard computer. The spacecraft tumbled through space without telemetry data until it impacted the far side of the Moon on the morning of April 26.
Ranger 4 carried eight thousand six hundred eighty solar cells to generate power for its systems during flight. These cells were designed to unfold automatically but remained folded against the body because the deployment timer malfunctioned.
Ranger 4 impacted the lunar surface on the morning of the 26th of April 1962 after running out of battery power. It became the first American spacecraft to reach another celestial body despite failing to return useful data.
Engineers designed the seismometer capsule with a sawtooth pattern painted on its exterior for thermal protection during the mission. This capsule contained an amplifier and a fifty-milliwatt transmitter capable of operating for thirty days after separating from the main vehicle.