I'll post this here in the science group. Apollo 11's desent to the moon

with added comments from NASA officials.

http://www.hq.nasa.gov/alsj/a11/a11.landing.html

102:44:45 Aldrin: 100 feet, 3 1/2 down, 9 forward. Five percent (fuel remaining). Quantity light.

[Fjeld - "The quantity light latched at 102:44:31, and indicated that 5.6% of the original propellant load remained. This event started a 94-second countdown to a 'Bingo' fuel call which meant 'land in 20 seconds or abort.' So if the count gets down to zero, Neil will have 20 seconds to land, if he thinks he can get down in time. Otherwise, he will have to abort immediately. If you're 50 feet up at 'bingo fuel' with all of your horizontal rates nulled and are coming down to a good spot, you could certainly continue to land. With your horizontal rates nulled at 70 to 100 feet, it would be risky to land - perhaps giving you a landing at the limiting load of the landing gear. At anything over 100 feet, you'd punch the abort button, say goodbye to the moon, and stew for the rest of your life!"]

[The Descent Quantity Light - labeled DES QTY - is one of a group of twenty warning lights ( 94k ) at the top of Panel 1, which is to the right of the CDR's window. In a 2006 exchange of e-mails, Frank O'Brien indicated that these warning lights were amber on the simulators at the Cradle of Aviation Museum; Ed Mitchell confirmed that they were amber on the flight LMs; and Dave Scott added, "Probably amber. 'Red was for emergencies'. We spent considerable time with the contractors defining the color, title, and placement of C&W lights"]

I am so proud to be a geek.