They may all be unpaid for this; copyright belongs to one man rather than being a work of the US government. It looks like a project from their spare time and retirement.
This is a collaboration and international labor of love, with people hailing from Australia, England, and Canada. Go visit nasa.gov at top-level and see how the design changes, and the NASA logos are used.
These pages carry the Apollo insignias, and "last modified: November 2017".