 The seismometer (code-named "Tonto") was encased in the lunar capsule along with an amplifier, a 50 mW transmitter, voltage control, a turnstile antenna, and six silver-cadmium batteries capable of operating the lunar capsule transmitter for 30 days, all designed to land on the Moon at 130 to 160 km/h (80 to 100 mph).The radar altimeter would be used for reflectivity studies, but was also designed to initiate capsule separation and ignite the retrorocket.Preparation for Ranger 3 was complicated by developmental issues with the Agena B stage, which had failed to operate correctly on Rangers 1-2.