RAE (Radiation Astronomy Explorer) 1 and 2 were two NASA satellites that investigated low-frequency radio emissions from the Sun and planets as well as from galactic and extragalactic sources. RAE was a subprogram of the Explorer series.

 

spacecraft	date	launch vehicle	launch site	orbit	mass (kg)
Explorer 38	Jul 4, 1968	Delta J	Vandenberg	5,835 × 5,861 km × 120.9°	190
Explorer 49	Jun 10, 1973	Delta 1914	Cape Canaveral	lunar orbit	328

 

RAE-1 (Explorer 38)

The primary objective of RAE-1 was to monitor low-frequency radio signals originating in our solar system. The spacecraft measured the intensity of celestial radio sources, particularly the Sun, as a function of time, direction, and frequency. The onboard experiments consisted of four step-frequency Ryle-Vonberg radiometers, two multichannel total power radiometers, one step frequency V-antenna impedance probe, and one dipole antenna capacitance probe.

 

RAE-2 (Explorer 49)

The primary objective of RAE-2 was to measure low-frequency radio noise from galactic and extragalactic sources and from the Sun, Earth, and Jupiter. It was placed into lunar orbit. The experiment complement consisted of two Ryle-Vonberg radiometers, three swept-frequency burst receivers, and an impedance probe for calibration.