JPL (or, rather, Caltech) maintains a blanket policy that the copyright to all JPL-owned software remains with Caltech, although they do permit software (on a case-by-case basis, as approved by the tech transfer office) to be open-sourced: https://ott.jpl.nasa.gov/software

In this case, the linked software definitely isn't public domain and it's most likely not open source (since this wasn't an approved release through JPL/Caltech). Also, given that the linked software's running on a spacecraft, distributing it might be in violation of federal law (thanks to ITAR/EAR-- spacecraft and related articles are on the US Munitions List).