Main page is http://cowlark.com/cowgol/
It used to support the Apollo Guidance Computer used in the Apollo spacecraft, but I had to remove the code generator while rewriting the compiler and I haven’t reworked the AGC backend.
http://cowlark.com/2019-07-20-cowgol-agc/index.html
The author also ported the Fuzix operating system to the Raspberry π pico.
http://cowlark.com/2021-02-16-fuzix-pi-pico/index.html

His tool https://github.com/davidgiven/narcissus to remap keys might be interesting too.
So is his Forth system http://cowlark.com/fforth/

Review of
Eyles, Don. Sunburst and Luminary. Boston: Fort Point Press, 2018. ISBN 978-0-9863859-3-3.

The next blog entry is interesting as well.
https://www.fourmilab.ch/fourmilog/archives/2019-11/001848.html
Crossfield, Albert Scott and Clay Blair. Always Another Dawn. Seattle, CreateSpace, [1960] 2018. ISBN 978-1-7219-0050-3.

Abstract: The Breakthrough Starshot project proposes using radiation-pressure propulsion to send multiple spacecraft in the gram-range mass to interstellar targets. There are numerous engineering challenges to accomplishing this mission, but their project discusses speeds and accelerations previously only discussed for cannon projectiles and particle physics experiments. This article examines the problem from first principles to see if the project is even orders-of-magnitude possible. A preliminary check on their numbers seems to confirm that the project is possible in principle.
https://stkwans.blogspot.com/2012/04/program-66.html is about the Apollo guidance computer.
https://stkwans.blogspot.com/2012/09/a-review-of-adxl345-and-bma180.html

An AGC (Apollo guidance computer) emulator written in C++. The package contains only the emulator.