 The micrometeorite detector and sun scanner were mounted on the sphere.The difference between the payload of Pioneer P-30 and the earlier Pioneer P-3 was the replacement of the TV facsimile system on P-3 with a scintillation spectrometer to study the Earth's (and possible lunar) radiation belts, mounted on the instrument platform, and a plasma probe mounted on the sphere to measure energy and momentum distribution of protons above a few kilovolts to study the radiation effect of solar flares.The total mass of the science package including electronics and power supply was roughly .