Digital converter similar to those flown on OSO series spacecraft in the 1960s. The visible amber-colored potting compound is an electrically neutral insulating sealant that is needed to keep electronics mechanically stable and from arcing and shorting out in the vacuum of space. The circuit converted the analogue output signal from an S-57 ion chamber experiment to a digital signal that was telemetered back to the ground station. The analogue output from most scientific instruments is susceptible to interference and distortion. Data in digital form on the other consists is far less likely to be corrupted. This miniaturized electronic analogue to digital signal converter was developed at GSFC specifically for satellite application. The same design was used on a flown unit that converted the analogue output from the ion chamber electrometer on OSO-3 to 8 bit binary form. This unit was donated to NASM by NASA (GSFC) in 1988.