Explorer 36 was a gravity-gradient stabilized, solar cell powered spacecraft that carried electronic and geodetic instrumentation.

The objectives of the spacecraft were to optimize optical station visibility periods and to provide complementary data for inclination-dependent terms established by the Explorer 29 (GEOS 1) gravimetric studies.

[7] Laser corner reflectors, composed of 322 fused quartz cubes with silvered reflecting surfaces, were used for determining the spacecraft range and angle.

The cubes, which were mounted on fiberglass panels on the bottom rim of the spacecraft, provided a total reflecting area of 0.18 m2.

The reflectors conserved the narrow beamwidth of incoming light and provided a maximum signal to the ground almost exactly to where it originated.

Reflected light received by ground telescopes was amplified by a photomultiplier tube that converted the optical impulse to an electrical signal.

Although the principal function of the magnetometer was to serve as an attitude sensor, a very limited amount of scientifically useful data on fluctuations in the range 0.03 to 3.0 cps were obtained through use of a filter.

[10] The optical beacon system, used for geometric geodesy studies, consisted of four xenon 670-watts (1580 candle-second/flash) Flashtubes housed in reflectors.

[11] This instrument consisted of an Electrostatic deflection device and channeltron detector intended to measure electrons in the energy range 2 to 10 keV.

[12] The Doppler technique of timing and measuring the frequency shift of radio transmissions from a moving spacecraft was used to help establish the structure of the Earth's gravitational field to an accuracy of approximately five parts in 100 million.

The system, which operated on 2271-MHz (receiver) and 1705-MHz (transmitter), utilized an antenna mounted on the Earth-facing portion of the spacecraft.