SYSTEMS DATA BOOK.
Flown on Apollo 13, a schematic from the LM Systems Data Book, a single folding sheet, 36 by 10 ½ inches, with an "RCS MECH" (Reaction Control System Mechanical) tab.
Accompanied by a Typed Letter Signed by Fred Haise, which reads in part: "Accompanying this letter is a folded sheet ... carried on the flight of Apollo 13 during April 11 to 17, 1970 ... This particular sheet is the Reaction Control System Mechanical Schematic for the Lunar Module. It illustrates the RCS rocket engines with their corresponding fluid flow lines from the fuel and oxidizer tanks. The helium pressurization lines are also shown ... The 16 engines shown were 100 pound thrust rocket engines mounted in groups of four on the Ascent Stage of the LM.
We could monitor the performance of these engines with dual indicator meters which provided readings on temperature, tank pressure, and the remaining fuel and oxidizer quantities. Our instrument panel also had eight 'talk back' switches that would show 'gray' if the valves to the engine pairs were open, 'barber pole' if the valves were closed, and 'red' if the values had failed. Similar type of indicators were also used for the SOV (Main Shutoff Valve) and ASC (Ascent) fuel and oxidizer tank valves. In addition, signal flow for the RCS Caution and RCS 'A' and 'B' Warning lights are shown.
I have inscribed and signed the schematic with: 'Carried to the moon on Apollo 13, Fred Haise, Apollo 13 LMP' near the bottom center of the sheet."
The sheet has annotations in red ink, written by Fred Haise prior to the Apollo 13 launch to remind the crew what spacecraft axis translation would be lost pending which RCS system, A or B.
