Apollo 11 LM descent chart to tranquility base

LM Descent Monitoring Chart - Sheet 2, 16 July 1969 Launch Date – Landing Site No. 2 and LM Descent Monitoring Chart - Sheet 3A, 16 July 1969 Launch Date – Landing Site No. 2. Both first editions. 11 by 77 inches.

The two descent charts are identical to the Lunar Orbiter based photography charts carried by Neil Armstrong and Buzz Aldrin inside Lunar Module (LM) Eagle. In this case, sheets 2 and 3A are combined to create a continuous chart over six feet long with numerous lunar land mark locations identified in bold black wording. These land marks include Apollo, Sidewinder and Diamondback Rilles, Cat’s Paw, Boot Hill, Mt. Marilyn (for Apollo 8 and 13 Astronaut James Lovell’s wife), Weatherford (Oklahoma) and Faye Ridge (for Apollo 10 Astronaut Tom Stafford’s home town and wife).

Both sheets have the planned descent path marked with a solid white line down the middle of the chart. Sheet two plots the 4, 3, 2 and 1 minute marks before the start of the LM’s descent engine burn to lower Armstrong and Aldrin to the surface. That burn starts at the letters listed as “PDI” (for Power Descent Initiation), and plots the increasing time marks of the engine burn at 20 second intervals. Sheet 3A begins at the PDI 3 minute mark and continues to the landing ellipse. The actual complete PDI burn was over twelve and half minutes, about 30 seconds more than planned due to rough terrain encountered by the crew which required Neil Armstrong to fly longer down range to find an acceptable landing spot. Real time communications with the crew indicated that they had less than 30 seconds of fuel remaining in Eagle at lunar touchdown.

Related lots: 121, 122, 124, 125