 Around the upper hemisphere of the hydrazine tank was a ring-shaped instrument platform which held the batteries in two packs, two 1.5 W UHF transmitters and diplexers, logic modules for scientific instruments, two command receivers, decoders, a buffer/amplifier, three converters, a telebit, a command box, and most of the scientific instruments.Two dipole UHF antennas protruded from the top of the sphere on either side of the injection rocket nozzle.Two dipole UHF antennas and a long VLF antenna protruded from the bottom of the sphere.