This is really interesting but I find myself puzzling that even a PC wasn't available instead? Heck, SPARCstation 1 (a truly lovely system) was introduced in '89. I had an older Sun 3 on my desk in '88 coming previously from an employer where I had a personal terminal attached to a VAX 8600 running Unix.
Was NASA requiring its engineers to work frozen in 1968, having to submit punched decks, so a calculator was such a step up?