F´ (or F Prime) is a software framework for the rapid development and deployment of embedded systems and spaceflight applications. Originally developed at NASA’s Jet Propulsion Laboratory, F´ is open-source software that has been successfully deployed for several space applications. It has been used for but is not limited to, CubeSats, SmallSats, instruments, and deployable.

Brief description of a failed attempt to install the virtual AGC
from https://www.ibiblio.org/apollo/ on a Raspberry π 4 running Raspian.

GMAT is designed to model, optimize, and estimate spacecraft trajectories in flight regimes ranging from low Earth orbit to lunar applications, interplanetary trajectories, and other deep space missions. Analysts model space missions in GMAT by first creating resources such as spacecraft, propagators, estimators, and optimizers.

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

Information about visual satellite observation.

Simulation of the Apollo Guidance Computer (AGC) and its display/keyboard (DSKY).

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

Interesting articles about amateur satellites.

Time lapse video taken from the ISS.