The sphere was internally gold-plated, and externally covered with an aluminum deposit coated with silicon oxide of sufficient thickness to provide thermal control for the instrumentation.

As the satellite circled Earth, two photocells, located at the focus of two optical telescopes aimed in diametrically opposite directions, measured the intensity of sunlight reflected from clouds (about 80%), from land masses (15 to 20%), and from sea areas (5%).

Separate solar batteries turned on a recorder only when the Earth beneath the satellite was in sunlight and about 50 minutes of data per orbit were obtained.

[12] Because of its symmetrical shape, Vanguard 2 was selected by the experimenters for use in determining upper atmospheric densities as a function of altitude, latitude, season, and solar activity.

By measuring the rate and timing of orbital shifts, the relevant atmosphere's parameters could be back-calculated knowing the body's drag properties.

Initial Naval Research Laboratory (NRL) proposals for Project Vanguard included conical satellite bodies; this eliminated the need for a separate fairing and ejection mechanisms, and their associated weight and failure modes.

The payload weight savings, from reduced size as well as decreased instrumentation in the early satellites, was considered acceptable for the initial launches.

[15][14] After the scientific mission ended, both Vanguard 2 and the upper stage of the rocket used to launch the satellite became derelict objects that would continue to orbit Earth for many years.