These four pale-blue Grumman booklets are Lunar Module training study guides, marked “For Training Purposes Only” and signed V. / Vincent Maietta: Lunar Module Radar (February 1967, prepared by William Barber A7141), Environmental Control Subsystem (Course 30515), Communications Subsystem, and Propulsion and RCS (Course 30217). They are contractor classroom material for the Apollo LM, the Grumman vehicle that would land on the Moon, and they treat the machine as four interlocking systems rather than one spacecraft. The propulsion guide’s fuel page specifies Aerozine 50 for all LM engines: about 51.5% hydrazine (N₂H₄), 47.5% unsymmetrical dimethylhydrazine (UDMH), and at most 1% water. It is colorless to clear yellow, with colorless vapors and an ammonia or “fishy” odor. It is hypergolic with nitrogen tetroxide, so the two ignite on contact, and it can also ignite if contaminated with metallic oxides. It is not shock-sensitive and can be stored indefinitely if sealed, but it is extremely hygroscopic and spoils fast in air. Freezing point is given as 21°F, boiling point 170°F. The hazards section treats fuel and oxidizer together: corrosive to tissue, capable of severe burns and systemic effects, eye contact that can blind, and fumes that cause cough, nausea, chest pain, and shortness of breath, with longer exposure able to kill. First aid is copious water flush, clothing off, eyes flushed 15 minutes, then medical care. The December 1965 chart (T30207-112, Figure 2) ranks propellant pairs by specific impulse. Liquid hydrogen with liquid fluorine sits at the top, about 410 seconds, with liquid hydrogen / LOX near 395. Ammonia / fluorine is about 340; solid propellants are listed around 260–300. Closer to what the LM actually flew, Aerozine 50 with nitrogen tetroxide is charted near 310, hydrazine / N₂O₄ near 290, and the kerosene (RP-1) pairs with nitric acid, hydrogen peroxide, or N₂O₄ cluster around 260–280. The chart is a menu of performance versus practicality; Grumman took the storable, hypergolic middle option so the descent and ascent engines needed no igniter and could restart in vacuum. The descent-stage schematic shows how that choice was plumbed. Helium, including a supercritical He bottle and a gaseous-helium supply, pressurizes the tanks through regulators, filters, a fuel/helium heat exchanger, and burst disks. Oxidizer tanks and fuel tanks sit in parallel paths, each with shutoff valves, check valves, explosive valves, temperature and pressure transducers, and low-level / quantity sensors. Trim orifices balance flow into the engine. Fill, drain, flush, purge, vent, and test ports, plus vacuum-sensing reference ports, are the ground interfaces; disconnect symbols mark what separates at staging. The drawing is the operational skeleton behind the fuel page: pressurize with helium, keep the hypergolics apart until the valves open, then let contact in the engine do the ignition. Taken together, the four guides are a 1965–67 snapshot of how Grumman taught the LM: radar and communications to find and talk to the Command Module, environmental control to keep the crew alive, and a helium-fed Aerozine 50 / N₂O₄ propulsion and RCS system chosen for storability and reliable restart on the way down and back up.