Grumman selected Hamilton Standard to supply the environmental control system for the lunar module. Like AiResearch's unit in the command module, it was a "closed-loop" atmospheric circulation system, using supercritical oxygen and nonregenerative removal of carbon dioxide to provide a pure oxygen atmosphere. The system also had a liquid-circulating network and heat-absorbent panels to maintain a comfortable temperature inside the cabin. By mid-1964, Hamilton Standard had finished the design phase and begun fabrication and testing. Occasional problems arose during development, but none that threatened the manufacture of a successful subsystem.29
United Aircraft Corporation's Pratt & Whitney Aircraft Division, a legendary name in aircraft powerplants, was also a pioneer in research on fuel cells using hydrogen and oxygen as reactants to generate electricity. Grumman picked this firm in July 1963 to develop the power system for the lander. The fuel cell program was laden with technical and managerial problems. Many of the lander's components operated with considerable independence, but the electrical power system had a complex interrelation with virtually every subsystem in the vehicle. The question of how many fuel cell stacks and how many tanks of reactant were needed to meet electrical requirements was, therefore, difficult to answer. In March 1964, Houston approved a three-cell, five-tank arrangement; by summer the fuel cell was in deep technical trouble. NASA and Grumman engineers concluded that it might take more than a year to get the cells working with the other systems properly. The lunar module, which had begun development a year late, did not have the time to spare.
Houston told Grumman in late 1964 to consider substituting batteries for fuel cells, and on 26 February 1965 Bethpage was ordered to make the change. Although the switch was not entirely welcome to the lunar module design team, it caused no appreciable delay. And to some it came as a distinct relief; the beauty of batteries lay in their simplicity, hence their reliability, in contrast to fuel cells. Some of the battery development cost would be offset by the cancellation of the Pratt & Whitney contract.30
29. Wilbert E. Ellis and D. William Morris, Jr., "Lunar Excursion Module Environmental and Thermal Control System Optimization," MSC working paper no. 1102, 8 Jan. 1964; LEM PO, "Problems," 7-13 May 1964; Maynard to Asst. Dep. Mgr., ASPO Syst. Integration, "Review of Apollo Spacecraft Systems Development Specification, . . . Environmental Control System . . . ," 25 May 1963; Maynard to LEM CEB, "LEM Environmental Control System (ECS) redundant equipment cooling," 10 March 1964; Richard E. Mayo to Mgr., ASPO, "Summary report on Hamilton Standard Division for East-Coast Subcontractor Review," 22 Oct. 1964, with encs.; Robert E. Smylie to Chief, Prog. Cont. Off., "Apollo Spacecraft Program Quarterly Status Report No. 9," 14 Oct. 1964, with enc.; MSC Crew Syst. Div. 1964 Annual Status Report; Richard J. Gillen, James C. Brady, and Frank Collier, "Lunar Module Environmental Control Subsystem," AER TN S-296 (MSC-04937), review copy, September 1971.
30. William A. Parker TWX to NASA Hq., Attn.: Brackett, 1 July 1963; Maynard to Decker, "CSM and Gemini Fuel Cell Development Programs," 28 May 1963; Rector to Grumman, Attn.: Mullaney, "Electrical Power Subsystem Fuel Cell Configuration," 20 Dec. 1963; Robert V. Battey memo, "Minutes of the LEM Electrical Power Requirements Meeting, May 5, 1964," 8 May 1964; William R. Dusenbury to LEM PO, "Assessment and recommendation of LEM PGS configuration," 18 March 1964; LEM PO, "Accomplishments," 19-26 March 1964; Rector to Grumman, Attn.: Mullaney, "Electrical Power Generation Section (PGS) Configuration," 23 March 1964; William E. Rice to Chief, PPD, "Report on visit to Pratt and Whitney Aircraft, . . . to attend the Third LEM Fuel Cell Assembly Quarterly Progress Review," 13 July 1964; [Grumman], " 'All Battery' Investigation," 4 Nov. 1964; Clinton L. Taylor TWX to North American, Attn.: James C. Cozad,11 Dec. 1964; Grumman Report No. 25, LPR-10-41, 10 March 1965, pp. 1, 20; E. J. Merrick to Edward B. Hamblett, Jr., "Work Order S64-08, Apollo Electrical Systems Support Survey of Batteries for LEM Application," 30 Oct. 1964, with enc.; Arturo B. Campos, "Lunar Module Electrical Power Subsystem," AER TN S-337 (MSC-05815), review copy, April 1972.