This is well written article. It does not wander into irrelevancies. I learned lots of new things. It had fun anecdotes. It was short. Regarding the "set numbe

This is well written article. It does not wander into irrelevancies. I learned lots of new things. It had fun anecdotes. It was short. Regarding the "set number of heartbeats", David Scott mentions it while they were training for Gemini in "Two Sides of the Moon". Neil had a physically less demanding role in the mission and chose to train less hard. Great book, recommended.