This is a half-scale model of the Magnetic Field Satellite, also known as Magsat. The model was built at the Applied Physics Laboratory of The Johns Hopkins University, the manufacturer of the original satellite. The model is currently displayed at NASM in the Exploring the Planets gallery.

The Magsat project was a joint effort by NASA and the U.S. Geological Survey. It was the first spacecraft designed specifically to provide information on the near-earth magnetic field and crustal anomalies. The bus of the flight object was fabricated with spare hardware from the Small Astronomical Satellite (SAS-C) program. Its appearance is marked by four windmill-like solar panels and a long scissors-type boom that carries the magnetometer sensor. The latter trailed 6 meters behind the bus in flight to minimize possible interference from other equipment. The satellite was launched from Vandenberg on October 30, 1979, into a near-polar orbit on a Scout vehicle.