Fig. 1
From: Recovery and validation of Mars ionospheric electron density profiles from Mariner 9
An example of the microfilmed images of Mariner 9 radio occultation data available from the NSSDC. This image is the first of a set of three that displays radial distances, electron densities, plasma scale heights, and inferred plasma temperatures for the ingress occultation on revolution 1. This image covers radial distances of 3644 to 3762 km (the topside ionosphere) and the complete set of three images covers radial distances of 3492 to 3762 km