Mercury Retro-pack
Project Mercury’s goal was simple. Get a man into orbit and bring him back. Safely. Preferably in that order. And to see how long-term weightlessness would affect him, mentally and physically. Would his eye’s focus? Could he swallow any foods? What would happen to his circulatory system?
This image depicts the center of the Mercury’s retro-pack. It had 3 small solid fuel engines which would fire off in sequence. Afterwards the straps (the three narrow strips) would be released, letting the pack drift away.That was the plan. However, on John Glenn’s flight a light on the ground indicated that his heat shield was loose. (When nearing splashdown, the heat-shield would be dropped by about a foot, uncovering an inflatable landing bag that would cushion the impact.) Glenn was commanded to keep the retro pack on just in case the readings were true, it might hold the heat-shield on. As it turned out, the indicator was at fault and Glenn’s spacecraft worked normally. And Glenn was rather upset when they withheld that information from him at first.