The LM DPS DE GCC test, + 40:00 years

Today is the 40th anniversary of the first firing of a throttleable rocket in space. The Apollo 5 flight (aka 1968-007A, aka AS-204, aka 03106) had a mission patch but no astronauts to wear it. The flight was an unmanned test of the systems that would land man on the moon. In a high altitude test simulating a moon landing, the LM (Lunar Module) DPS (Descent Propulsion System) DE (Descent Engine) GCC (Guidance Control Computer) was supposedly programmed to fire the rocket for 39 seconds. It started then stopped after 4. Realizing this was a bug (not the obvious order of magnitude one confusing 4 secs for 40, it was actually related to slower than expected fuel tank pressurization), MC (Mission Control) took over and the burn and 4 followups were done by humans.

While bugs are expected in tests, the NASA MMs (Mission Managers) seemed a little generous declaring the mission was a TS (Total Success). This sounds like BS (backup subsystems) would have been useful. Given the incredible cost of buillding and programming (CCs) custom computers back then, maybe they thought they had money to burn. Actually, they did. After two days, the 2 parts of the LM burnt as they descended back to Earth.

Read more of the story here . If you hadn't already guessed, not all the acronyms above are real. The real ones can be checked here