Thanks to Dan at hpmuseum.org’s forum, here’s a significant addition to this blog. The HP-41 was used by german astronaut Ernst Messerschmid for importing voltmeter readings in Spacelab D1.
Here’s the text from Deutsches Museum:
D1-SPACELAB Mission, 1985
Walcher Elektronik GmbH, Kirchheim, 1985
Hewlett-Packard, USA, 1984
The voltmeter is an instrument for measuring voltage and temperature. It contains an analog-to-digital converter that feeds the measured values to the calculator for processing. The calculator is a slightly modified standard HP 41 calculator.
Astronaut Ernst Messerschmid devised this voltmeter to be used for experiments in materials science aboard the 1985 German D1 mission.
Additional pictures taken by Dan at the Deutsches Museum: