The new system is Office 365 and all employees are *required* to use
Lookout on their Windows and Mac systems as an MUA using a badge for
authentication. Given that, I'm pessimistic there is an open way to
access NASA email. Linux users currently have a waiver to continue using
IMAP, but that will go away once NASA IT finds a solution. It is likely
to be a dictated MUA (as with the Mac and Windows) rather than a general
mechanism.
Geez, you really should be more up-to-date on the mailing list :-)
I can't promise this will work for you, but this message might be
helpful:
https://lists.nongnu.org/archive/html/nmh-workers/2019-05/msg00029.html
--Ken