The Stever Committee, which had been set up on January 12, submitted its report on the civilian space program to NASA. Among the recommendations:
Members of STG presented guidelines for an advanced manned spacecraft program to NASA Centers to enlist research assistance in formulating spacecraft and mission design.
To open these discussions, Director Robert R. Gilruth summarized the guidelines: manned lunar reconnaissance with a lunar mission module, corollary earth orbital missions with a lunar mission module and with a space laboratory, compatibility with the Saturn C-1 or C-2 boosters (weight not to exceed 15,000 pounds for a complete lunar spacecraft and 25,000 pounds for an earth orbiting spacecraft), 14-day flight time, safe recovery from aborts, ground and water landing and avoidance of local hazards, point (ten square-mile) landing, 72-hour postlanding survival period, auxiliary propulsion for maneuvering in space, a "shirtsleeve" environment, a three-man crew, radiation protection, primary command of mission on board, and expanded communications and tracking facilities. In addition, a tentative time schedule was included, projecting multiman earth orbit qualification flights beginning near the end of the first quarter of calendar year 1966.
Stanley C. White of STG outlined at NASA Centers the guidelines for human factors in the advanced manned spacecraft program:
The Apollo Technical Liaison Group for Instrumentation and Communications met at STG and drafted an informal set of guidelines and sent them to the other Technical Liaison Groups:
In preparing background material for the Apollo spacecraft specification at STG, the Apollo Technical Liaison Group for Mechanical Systems worked on environmental control systems, reaction control systems, auxiliary power supplies, landing and recovery systems, and space cabin sealing.
A conference was held at Lewis Research Center between STG and Lewis representatives to discuss the research and development contract for the liquid-hydrogen liquid-oxygen fuel cell as the primary spacecraft electrical power source. Lewis had been provided funds approximately $300,000 by NASA Headquarters to negotiate a contract with Pratt & Whitney Aircraft Division of United Aircraft Corporation for the development of a fuel cell for the Apollo spacecraft. STG and Lewis representatives agreed that the research and development should be directed toward the liquid-hydrogen - liquid-oxygen fuel cell. Guidelines were provided by STG:
STG requested that a program be undertaken by the U.S. Navy Air Crew Equipment Laboratory, Philadelphia, Penna., to validate the atmospheric composition requirement for the Apollo spacecraft. On November 7, the original experimental design was altered by the Manned Spacecraft Center (MSC). The new objectives were:
Representatives of STG visited the Instrumentation Laboratory of MIT for the second monthly progress report meeting on the Apollo spacecraft guidance and navigation contract. A number of technical topics were presented by Laboratory speakers: space sextant visibility and geometry problems, gear train analysis, vacuum environmental approach, midcourse guidance theory, inertial measurement unit, and gyro. The organization of the Apollo effort at the Laboratory was also discussed. A preliminary estimate of the cost for both Laboratory and industrial support for the Apollo navigation and guidance system was presented: $158.4 million through Fiscal Year 1966.
Discussions at the monthly NAA-NASA Apollo spacecraft design review included:
At the monthly Apollo spacecraft design review meeting with NAA, MSC officials directed NAA to design the spacecraft atmospheric system for 5 psia pure oxygen. From an engineering standpoint, the single-gas atmosphere offered advantages in minimizing weight and leakage, in system simplicity and reliability, and in the extravehicular suit interface. Additional Details: here....
A modified method of cooling crew and equipment before launch and during boost was tentatively selected by NAA. Chilled, ground-support-equipment-supplied water-glycol would be pumped through the spacecraft coolant system until 30 seconds before launch, when these lines would be disconnected. After umbilical separation the glycol, as it evaporated at the water boiler, would be chilled by Freon stored in the water tanks.
Air recirculation system components of the command module were rearranged to accommodate a disconnect fitting and lines for the center crewman's suit. To relieve an obstruction, the cabin pressure regulator was relocated and a design study drawing was completed.
The external natural environment of the Apollo spacecraft as defined in the December 18, 1961, Statement of Work had been used in the early Apollo design work. The micrometeoroid, solar proton radiation, and lunar surface characteristics were found to be most critical to the spacecraft design.
MSC reported that Apollo training requirements planning was 40 percent complete. The preparation of specific materials would begin during the first quarter of 1964. The crew training equipment included earth launch and reentry, orbital and rendezvous, and navigation and trajectory control part-task trainers, which were special-purpose simulators. An early delivery would allow extensive practice for the crew in those mission functions where crew activity was time-critical and required development of particular skills. The mission simulators had complete mission capability, providing visual as well as instrument environments. Mission simulators would be located at MSC and at Cape Canaveral.
The valves of the command module (CM) environmental control system were modified to meet the 5.0 psia oxygen operating requirements. All oxygen partial pressure controls were deleted from the system and the relief pressure setting of 7 +/- 0.2 psia was changed to 6 +/- 0.2 psia. The CM now could be repressurized from 0 to 5.0 psia in one hour.
Proposed designs for view port covers on the crew-hatch window, docking ports, and earth landing windows were prepared by NAA. Design planning called for these port covers to be removed solely in the space environment. (Crew members would not use such windows during launch and reentry phases.) NAA,
MSC Director Robert R. Gilruth reported to the MSF Management Council that tests by Republic Aviation Corporation, the U.S. Air Force School of Aerospace Medicine SAM at Brooks Air Force Base, Tex., and the U.S. Navy Air Crew Equipment Laboratory (ACEL) at Philadelphia, Pa., had established that, physiologically, a spacecraft atmosphere of pure oxygen at 3.5 newtons per square centimeter (five pounds per square inch absolute (psia)) was acceptable. During the separate experiments, about 20 people had been exposed to pure oxygen environments for periods of up to two weeks without showing adverse effects. Two fires had occurred, one on September 10 at SAM and the other on November 17 at ACEL. The cause in both cases was faulty test equipment. On July 11, NASA had ordered North American to design the CM for 3.5 newtons per square centimeter (5-psia), pure-oxygen atmosphere.
In the first of a series of reliability-crew safety design reviews on all systems for the CM, North American examined the spacecraft's environmental control system (ECS). The Design Review Board approved the overall ECS concept, but made several recommendations for further refinement. Among these were:
MSC awarded a $3.69 million contract to the Radio Corporation of America
RCA Service Company to design and build two vacuum chambers at MSC. The facility was used in astronaut training and spacecraft environmental testing. using carbon arc: lamps, the chambers simulated the sun's intensity, permitting observation of the effects of solar heating encountered on a lunar mission. At the end of July, MSC awarded RCA another contract (worth $3,341,750) for these solar simulators.
MSC awarded a $67,000 contract to The Perkin-Elmer Corporation to develop a carbon dioxide measurement system, a device to measure the partial carbon dioxide pressure within the spacecraft's cabin. Two prototype units were to be delivered to MSC for evaluation. About seven months later, a $249,000 definitive contract for fabrication and testing of the sensor was signed.
MSC announced the beginning of CM environmental control system tests at the AiResearch Manufacturing Company simulating prelaunch, ascent, orbital, and reentry pressure effects. Earlier in the month, analysis had indicated that the CM interior temperature could be maintained between 294 K (70 degrees F) and 300 K (80 degrees F) during all flight operations, although prelaunch temperatures might rise to a maximum of 302 K (84 degrees F).
A meeting was held at North American to define CM-space suit interface problem areas. Demonstrations of pressurized International Latex suits revealed poor crew mobility and task performance inside the CM, caused in part by the crew's unavoidably interfering with one another.
Other items received considerable attention: A six-foot umbilical hose would be adequate for the astronaut in the CM. The location of spacecraft water, oxygen, and electrical fittings was judged satisfactory, as were the new couch assist handholds. The astronaut's ability to operate the environmental control system (ECS) oxygen flow control valve while couched and pressurized was questionable. Therefore, it was decided that the ECS valve would remain open and that the astronaut would use the suit control valve to regulate the flow. It was also found that the hand controller must be moved about nine inches forward.
MSC reported that two portable life support systems would be stowed in the LEM and one in the CM. Resupplying water, oxygen, and lithium hydroxide could be done in a matter of minutes; however, battery recharging took considerably longer, and detailed design of a charger was continuing.
John P. Bryant, of the Flight Operations Division's (FOD) Mission Analysis Branch (MAB), reported to FOD that the branch had conducted a rough analysis of the effects of some mission constraints upon the flexibility possible with lunar launch operations. (As a base, MAB used April and May 1968, called "a typical two-month period.") First, Bryant said, MAB used the mission rules demanded for the Apollo lunar landing (e.g., free-return trajectory; predetermined lunar landing sites; and lighting conditions on the moon - "by far the most restrictive of the lot"). Next, MAB included a number of operational constraints, ones "reasonably representative of those expected for a typical flight," but by no means an "exhaustive" list:
"The consequences," Bryant concluded, "of imposing an ever-increasing number of these flight restrictions is obvious - the eventual loss of almost all operational flexibility. The only solution is . . . (a) meticulous examination of every constraint which tends to reduce the number of available launch opportunities," looking toward eliminating "as many as possible."
North American incorporated an automatic radiator control into the CM's environmental control system to eliminate the need for crew attention during lunar orbit.
Recent load analysis at North American placed the power required for a 14-day mission at 577 kilowatt-hours, a decrease of about 80 kilowatt-hours from earlier estimates.
North American presented to MSC the results of a three-month study on radiation instrumentation. Three general areas were covered: radio-frequency (RF) warning systems, directional instrumentation, and external environment instrumentation. The company concluded that, with the use of an RE system, astronauts would receive about two hours' notice of any impending solar proton event and could take appropriate action. Proper orientation of the spacecraft could reduce doses by 17 percent, but this could be accomplished only by using a directional detection instrument. There was a 70 percent chance that dosages would exceed safe limits unless such an instrument was used. Consequently North American recommended prompt development.
Despite the contractor's findings, MSC concluded that there was no need for an RE warning system aboard the spacecraft, believing that radiation warning could be handled more effectively by ground systems. But MSC did concur in the recommendation for a combined proton direction and external environment detection system and authorized North American to proceed with its design and development.
All production drawings for the CM environmental control system were released. - AiResearch Manufacturing Company reported the most critical pacing items were the suit heat exchanger, cyclic accumulator selector valve, and the potable and waste water tanks.
MSC and the U.S. Air Force Aerospace Medical Division completed a joint manned environmental experiment at Brooks Air Force Base, Tex. After spending a week in a sea-level atmospheric environment, the test subjects breathed 100 percent oxygen at 3.5 newtons per square centimeter (5 psi) at a simulated altitude of 8,230 meters (27,000 feet) for 30 days. They then reentered the test capsule for observation in a sea-level environment for the next five days. This experiment demonstrated that men could live in a 100 percent oxygen environment under these conditions with no apparent ill effects.
MSC directed North American to redesign the CM environmental control system compressor to provide 0.283 cubic meters (10 cubic feet) of air per minute to each space suit at 1.8 newtons per square centimeter (3.5 psi), 16.78 kilograms (37 pounds) per hour total.
North American completed the first of a series of simulations to evaluate the astronauts' ability to perform attitude change maneuvers under varying rates and angles. Subjects were tested in a shirtsleeve environment and in vented and pressurized International Latex Corporation state-of-the-art pressure suits. The subjects had considerable difficulty making large, multi-axis attitude corrections because the pressurized suit restricted manipulation of the rotational hand controller.
Heavy black deposits were discovered on the environmental control system (ECS) cold plates when they were removed from boilerplate 14. Several pinholes were found in the cold plate surfaces, and the aluminum lines were severely pitted. This was, as ASPO admitted, a matter of "extreme concern" to the ECS design people at North American, because the equipment had been charged with coolant for only three weeks. This evidence of excessive corrosion reemphasized the drawbacks of using ethylene glycol as a coolant.
ASPO deleted the requirement for LEM checkout during the translunar phase of the mission. Thus the length of time that the CM must be capable of maintaining pressure in the LEM (for normal leakage in the docked configuration) was reduced from 10 hours to three.
Because of the redesign of the portable life support system that would be required, MSC directed Grumman and North American to drop the "buddy system" concept for the spacecraft environmental control system (ECS) umbilicals. The two LEM crewmen would transfer from the CM while attached to that module's umbilicals. Hookup with the LEM umbilicals, and ventilation from the LEM ECS, would be achieved before disconnecting the first set of lifelines. MSC requested North American to cooperate with Grumman and Hamilton Standard on the design of the fetal end of the umbilicals. Also, the two spacecraft contractors were directed jointly to determine umbilical lengths and LEM ECS control locations required for such transfer.
Crew Systems Division (CSD) was proceeding with procurement of an inflight metabolic simulator in response to a request by Systems Engineering Division. The simulator would be used to support the LEM mission for SA-206 and would be compatible for use in the CM. Responsibility for the project had been assigned to the Manager of the LEM Environmental Control System Office. It was projected that the Statement of Work would be completed by January 15, 1965; the proposals evaluated by April 1; the contract awarded by June 1, 1965; the prototype delivered by April 1, 1966, with two qualified simulator deliveries by July 1, 1966.
Acceptance testing was completed at Downey, California, on three principal systems trainers for the CSM (the environmental control, stabilization and control, and electrical power systems). The trainers were then shipped to Houston and installed at the site, arriving there December 8. They were constructed under the basic Apollo Spacecraft contract at a cost of $953,024.
Engineering and medical experts of the Crew Systems Division reviewed dumping helium from the CM's gas chromatograph into the cabin during reentry or in a pad abort. Reviewers decided that the resultant atmosphere (9.995 kilonewtons (1.45 psi) helium and 31.349 kilonewtons (4.55 psia) oxygen) posed no hazard for the crew. Systems Engineering Division recommended, however, that dump time be reduced from 15 minutes to three, which could readily be done.
OMSF asked MSC to provide NASA Headquarters with a statement of "the minimum definition of meteoroid environment in cislunar space" which would be necessary for confidence that Apollo could withstand the meteoroid flux. The "desirable degree of definition" was also requested. This material was to be used as inputs to the current cislunar Pegasus studies being conducted by OMSF.
ASPO established radiation reliability goals for Apollo. These figures would be used to coordinate the radiation program, to define the allowable dosages, and to determine the effect of radiation on mission success. The crew safety goal (defined as the probability of a crewman's not suffering permanent injury or worse, nor his being incapacitated and thus no longer able to perform his duties) was set at 0.99999. The major hazard of a radiation environment, it was felt, was not the chance of fatal doses. It was, rather, the possibility of acute radiation sickness during the mission. The second reliability goal, that for success of the mission (the probability that the mission would not be aborted because of radiation environment), was placed at 0.98.
These values, ASPO Manager Joseph F. Shea emphasized, were based on the 8.3-day reference mission and on emergency dose limits previously set forth. They were not to be included in overall reliability goals for the spacecraft, nor were they to be met by weight increases or equipment relocations.
MSC questioned the necessity of using highly purified (and expensive) fuel-cell-type oxygen to maintain the cabin atmosphere during manned ground testing of the spacecraft. The Center, therefore, undertook a study of the resultant impurities and effect on crew habitability of using a commercial grade of aviation oxygen.
MSC's Systems Engineering Division (SED) requested support from the Structures and Mechanics Division in determining the existence or extent of corrosion in the coolant loops of the SM electrical power subsystem (EPS) and the CM and LEM environmental control subsystems (ECS), resulting from the use of water glycol as coolant fluid. Informal contact had been made with W. R. Downs of the Structures and Mechanics Division and he had been given copies of contractor reports and correspondence between MSC, North American, and MIT pertaining to the problem. The contractors had conflicting positions regarding the extent and seriousness of glycol corrosion.
SED requested that a study be initiated to:
MSC announced a realignment of specialty areas for the 13 astronauts not assigned to forthcoming Gemini missions (GT 3 through 5) or to strictly administrative positions:
Charles A. Bassett - operations handbooks, training, and simulators
Alan L. Bean - recovery systems
Michael Collins - pressure suits and extravehicular activity
David R. Scott - mission planning and guidance and navigation
Clifton C. Williams - range operations, deep space instrumentation, and crew safety.
Donn F. Eisele - CSM and LEM
William A. Anders - environmental control system and radiation and thermal systems
Eugene A. Cernan - boosters, spacecraft propulsion, and the Agena stage
Roger B. Chaffee - communications, flight controls, and docking
R. Walter Cunningham - electrical and sequential systems and non-flight experiments
Russell L. Schweickart - in-flight experiments and future programs.
After extensive analysis, Crew Systems Division recommended that the "shirtsleeve" environment be kept in the CM. Such a design was simpler and more reliable, and promised much greater personal comfort than wearing the space suit during the entire mission.
ASPO requested the Structures and Mechanics Division (SMD) to study the problem of corrosion in the coolant loops of the CM's environmental control system, and to search for effective inhibitors. Current efforts at North American to lessen corrosion included improved hardware and operating procedures, but stopped short of extensive redesigning; and it would be some time before conclusive results could be expected. Early in May, Owen E. Maynard, chief of the Systems Engineering Division, directed SMD immediately to begin its search for inhibitors. If by July 1966 the corrosion problem remained unresolved, SMD could thus recommend stopgap measures for the early spacecraft.
The Flight Projects Division (FPD) proposed a change in the checkout procedure at Merritt Island (KSC). The idea, drawn from Gemini, would eliminate checkout at the environmental control system (ECS) facility. Basically, FPD's plan was to transport the mated CSM directly from the Operations and Checkout Building to the altitude chamber, where the ECS would be tested. Officials at North American approved the new procedure, and FPD requested the Checkout and Test Division to study its feasibility.
NASA hired the U.S. Navy's Air Crew Equipment Laboratory (ACEL) to study several physiological aspects of pure-oxygen environments. Primarily, ACEL's study would try to determine: (1) whether known effects (such as lung collapse) could somehow be reversed; and (2) whether such environments enhanced respiratory infections.
Illustrative of continuing design and managerial problems, MSC and North American representatives attempted to resolve thermal problems with the Block II environmental control system (ECS), primarily the ECS radiator. The week-long talks were fruitless. MSC's arguments and supportive evidence notwithstanding, the contractor steadfastly opposed the water-glycol approach, favoring a nonfreezing liquid (Freon). MSC, similarly, was hardly satisfied with North American's intransigence and less so with the company's effort and performance. "A pertinent observation," reported Crew Systems Division, "is that . . . it will be extremely difficult to complete any other development in support of Block II schedules unless their (North American's) attitude is changed."
ASPO Manager Joseph F. Shea informed North American, Grumman, and Bell Aerosystems Company that NASA's Associate Administrator for Manned Space Flight, George E. Mueller, had requested a presentation on the incompatibility of titanium alloys and nitrogen tetroxide and its impact on the Apollo Program, this to be done at the NASA Senior Management Council meeting on December 21.
In light of recent failures of almost all titanium tanks planned for use in the Apollo Program when exposed to nitrogen tetroxide under conditions which might be encountered in flight, the matter was deemed to be of utmost urgency.
A preliminary meeting was scheduled at NASA Headquarters on December 16 and one responsible representative from each of the prime contractors and subcontractors was requested to be present. Prior to the December 16 meeting, it would be necessary for each organization to complete the following tasks:
Robert C. Duncan, Chief of MSC's Guidance and Control Division, revealed that recent discussions between himself, NASA Associate Administrator for Manned Space Flight George E. Mueller, and ASPO Manager Joseph F. Shea had resulted in a decision to continue both radar and optical tracking systems into the hardware development phase. It was also agreed that some specific analytical and hardware homework must be done. The hardware action items were being assigned to Robert A. Gardiner and the analytical action items to Donald C. Cheatham.
The primary objective was to design, develop, and produce rendezvous sensor hardware that was on time and would work, Duncan said; second, that "we must have a rendezvous strategy which takes best advantage of the capability of the rendezvous sensor (whichever type it might be)."
The greatest difficulty in reducing operating laboratory equipment into operating spacecraft hardware occurred in the process of packaging and testing for flight. This milestone had not been reached in either the radar or the optical tracker programs.
Duncan said, "We want to set up a 'rendezvous sensor olympics' at some appropriate stage . . . when we have flight-weight equipment available from both the radar contractor and the optical tracker contractor. This olympics should consist of exposing the hardware to critical environmental tests, particularly vibration and thermal-cycling, and to operate the equipment after such exposure." If one or the other equipment failed to survive the test, it would be clear which program would be continued and which would be canceled. "If both successfully pass the olympics, the system which will be chosen will be based largely upon the results of the analytical effort. . . . If both systems fail the olympics, it is clear we have lots of work to do," Duncan said.
As a result of a fire in the environmental control system (ECS) unit at AiResearch Co., a concerted effort was under way to identify nonmetallic materials as well as other potential fire problems. MSC told North American Aviation it appeared that at least some modifications would be required in Block I spacecraft and that modifications could be considered only as temporary expedients to correct conditions that could be more readily resolved in the original design. MSC requested that North American eliminate or restrict as far as possible combustible materials in the following categories in the Block II spacecraft:
Apollo Program Director Samuel C. Phillips told Mark E. Bradley, Vice President and Assistant to the President of The Garrett Corp., that "the environment control unit, developed and produced by Garrett's AiResearch Division under subcontract to North American Aviation for the Apollo spacecraft was again in serious trouble and threatened a major delay in the first flight of Apollo." Additional Details: here....
The first manned flight of the Apollo CSM, the Apollo C category mission, was planned for the last quarter of 1966. Numerous problems with the Apollo Block I spacecraft resulted in a flight delay to February 1967. The crew of Virgil I. Grissom, Edward H. White II, and Roger B. Chaffee, was killed in a fire while testing their capsule on the pad on 27 January 1967, still weeks away from launch. The designation AS-204 was used by NASA for the flight at the time; the designation Apollo 1 was applied retroactively at the request of Grissom's widow.
A TWX from NASA Headquarters to MSC, MSFC, and KSC ordered checkout and launch preparation of AS-501 to proceed as planned, except that the CM would not be pressurized in an oxygen environment pending further direction. If AS-501 support, facility, or work force should conflict with the activities of the AS-204 Review Board, the Board would be given priority.
A meeting at MSC considered fire detection systems and fire extinguishers. Participants were G. M. Low, K. S. Kleinknecht, A. C. Bond, J. N. Kotanchik, J. W. Craig, M. W. Lippitt, and G. W. S. Abbey. Craig and Lippitt had visited Wright Field, Ohio, and from their findings the following conclusions were reached:
CM mockup tests by the Structures and Mechanics Division at the MSC Thermochemical Test Area had shown that significant burning occurred in oxygen environments at a pressure of 11.4 newtons per square centimeter (16.5 psia). The tests, in which most of the major crew bay materials had been replaced by Teflon or Beta cloth, consisted of deliberately igniting crew bay materials sequentially in two places. The Division recommended that operation with oxygen at 11.4 newtons in the crew compartment be eliminated and that either air or oxygen at 3.5 newtons per sq cm (5 psia) be used. In reply, the ASPO Manager pointed out that "Dr. Gilruth has indicated a strong desire to avoid the use of air on the pad which requires subsequent spacecraft purges. Accordingly, we should maintain the option of launching with a pure oxygen cabin environment until such time as additional tests indicate it would not be feasible."
ASPO Manager George Low told Charles A. Berry, MSC Director of Medical Research and Operations, that it had been determined there was no suitable substitute for water glycol as a coolant and it would continue to be used in the Apollo spacecraft. Low recognized that it was "essential that the effects of any possible glycol spill be well defined and that procedures be established to avoid any hazardous conditions." He asked Berry's office to define the limits of exposure for glycol spills of varying quantities and for recommendations concerning cabin purge in the event of a spill. Low also wondered, assuming development of a smelling agent, if it would be possible to determine the concentration of water glycol by the strength of the smell in the spacecraft. Berry's office replied June 22 that it was working with Crew Systems Division to identify an odor additive for leak detection. They would begin a program to establish a safe upper limit for human exposure to ethylene glycol and had asked the National Academy of Sciences Committee on Toxicity for information. Animal exposure tests probably would be necessary; if they were needed, a test plan would be submitted before July 1.
Dale D. Myers, Apollo CSM Manager for North American Aviation, Inc., requested a meeting with ASPO Manager George M. Low and ASPO CSM Manager Kenneth S. Kleinknecht to resolve issues concerning materials replacement and objectives for boilerplate tests. In reply, on July 6, Low said that Kleinknecht had conducted a complete review of flammable materials since receipt of Myers' June 28 letter and that a number of telephone conversations had been held on the subject. MSC recommended that the insulation on the environmental control unit be covered with nickel foil and that silicone-rubber wire-harness clamps could possibly be covered with a combination of "Laddicote" and nitroso rubber. Plans were for the boilerplate mockup tests to use an overloaded wire in a wire bundle as an ignition source. At Myers' suggestion, MSC was also looking into the use of electric arcs, or sparks, as a possible ignition source. Low said: "As you know, our goal in the mockup tests will be to demonstrate that any fire in a 6 psi (4.1 newtons per square centimeter) oxygen atmosphere extinguishes itself. . . . If we can demonstrate that in the 6 psi oxygen atmosphere a fire would spread very slowly so that the crew could easily get out of the spacecraft while on the pad . . . , then I believe that we should also be satisfied."
CSM flammability mockup testing was discussed at a program review. It was pointed out that boilerplate testing was being conducted at Downey and that an all-up test should not be performed until all individual tests were completed and the final configuration was completely established.
A series of oxygen purge system (OPS) transfer runs were conducted in the Water Immersion Facility at MSC. Preliminary reports indicated the results of the tests were highly satisfactory, but an assessment of pad abort procedures following several runs in the Apollo Mission Simulator were not so promising. Further work and study in this area was in progress.
ASPO Manager George M. Low issued instructions that the changes and actions to be carried out by MSC as a result of the AS-204 accident investigation were the responsibility of CSM Manager Kenneth S. Kleinknecht. The changes and actions were summarized in Apollo Program Directive No. 29, dated July 6, 1967.
Plans were to use 100-percent oxygen in the CSM cabin during prelaunch operations for manned flights but, since flammability tests of the CSM were not finished, the possibility existed that air might be used instead of pure oxygen. Therefore, contingency plans would be developed to use air in the cabin during the prelaunch operations so that a change would not delay the program.
The MSC Director of Engineering and Development pointed out that a fullscale CSM would soon be tested to evaluate the hazard of fire propagation both in orbit (cabin atmosphere of oxygen at pressure of 3.8 newtons per square centimeter - 5.5 pounds per square inch absolute) and on the pad (oxygen at 11.4 newtons per sq cm-16.5 psia). There was a reasonable probability that the CSM might qualify in the first but not the second case. In such event, it was proposed that the prelaunch cabin atmosphere be changed from 100-percent oxygen to a mixture of 60-percent oxygen and 40percent helium or to a mixture of 60-percent oxygen and 40-percent nitrogen. This proposal was made on the assumption that those mixtures at 11.4 newtons per sq cm would not offer more of a fire hazard than 100percent oxygen at 3.8 newtons. It was also assumed that these mixtures would be physiologically suitable after being bled down to orbital pressure without subsequent purging or being enriched with additional oxygen. Structures and Mechanics Division (SMD) was requested to make flammability tests to determine the relative merit of the two mixtures and to outline a minimum test program to provide confidence that the mixed gas atmosphere might be considered equivalent to oxygen at 3.8 newtons.
ASPO Manager George M. Low advised Apollo Program Director Samuel C. Phillips that, in accordance with an action item resulting from the spacecraft environmental testing review at MSFC on January 10, he was reexamining the design, fabrication, and inspection of all interconnecting systems of the spacecraft to determine what further steps might be taken to ensure the integrity of those systems. Low had requested William Mrazek of MSFC to direct this effort, using a small task team to review the design of all spacecraft wiring and plumbing systems, their fabrication, and quality assurance and inspection techniques.
Apollo Program Director Samuel C. Phillips wrote ASPO Manager George M. Low setting forth a strategy for announcing selection of a prelaunch atmosphere for the spacecraft. Because the decision undoubtedly would draw much public attention, Phillips said, it was important that the decision be based on comprehensive study and be fully documented to explain the rationale for the decision both to NASA's management and to the general public. Foremost, he said, that rationale must include a clear statement of physiological requirements for the mission and for aborts. Secondly, it must also cover flammability factors in cabin atmosphere selection. Finally, the decision rationale must explain engineering factors related to hardware capability and crew procedures, as well as operational factors and how they affected the choice of atmosphere during prelaunch and launch phases of the mission.
ASPO Manager George Low appointed Douglas R. Broome to head a special task team to resolve the problem of water requirements aboard the Apollo spacecraft. For some six months, Low noted, numerous discussions had surrounded the question of water purity requirements and loading procedures. Several meetings and reviews, including one at MSC on January 16 and another at KSC on February 13, had failed to resolve the problem, and Low thus instructed Broome's team to reach a "final and definite agreement" on acceptable water specifications and loading procedures. Much unnecessary time and effort had been expended on this problem, Low said, and he expected the team "to put this problem to rest once and for all."
The MSC Flammability Review Board met to assess results of the CSM flammability tests conducted on boilerplate 1224. The Board unanimously recommended using a 60-percent-oxygen and 40-percent-nitrogen atmosphere in the spacecraft cabin during launch, but continued use of a pure oxygen atmosphere at pressure of 4.1 newtons per square centimeter (6 pounds per square inch) during flight. Members concluded that this mixed-gas environment offered the best protection for the crew on the pad and during launch operations, while still meeting physiological and operational requirements. During the final stages of the flammability test program, tests had indicated that combustion characteristics for the 11-newtons-per-sq-cm (16-psi), 60-40 atmosphere and for the 4.1-newton pure oxygen atmosphere were remarkably similar. Also, full-scale trials had demonstrated that in an emergency the crew could get out of the spacecraft quickly and safely.
A LM prelaunch atmosphere selection and repressurization meeting was held at MSC, attended by representatives of MSC, MSFC, KSC, North American Rockwell, and Grumman. The rationale for MSC selection of 100 percent oxygen as the LM cabin launch atmosphere was based on three factors: use of other than 100 percent oxygen in the LM cabin would entail additional crew procedural workloads at transposition and docking; excessive risk to crew due to depletion of the CM emergency oxygen consumables would be added; and it would require use of 2.7 kilograms of onboard CM oxygen. Two problems were identified with use of 100 percent oxygen in the LM cabin at launch: LM cabin flammability on the pad and LM venting oxygen into the SLA during boost. If air were used in the LM cabin at launch and the LM vent valve opened during boost, the full CM stored-oxygen capacity would be required to pressurize the LM and LM tunnel for umbilical mating. For a lunar mission, this situation would be similar to that before lunar orbital insertion, but would subject the crew to a condition of no stored oxygen for an emergency. For an earth-orbital mission this situation would be objectionable because CM stored oxygen would be lacking for an emergency entry into the atmosphere.
ASPO documented its reasons for using nitrogen rather than helium (as the Air Force had done) as the diluent in the Apollo spacecraft's cabin atmosphere, in response to a suggestion from Julian M. West of NASA Hq. Aaron Cohen, Assistant Chief of the MSC Systems Engineering Division, recounted that the Atmosphere Selection Task Team had addressed the question of nitrogen versus helium (regardless of percentage) and had rejected helium because of uncertainty of the compatibility of spacecraft equipment with helium. Further, helium presented the same physiological problems as did nitrogen, and whatever flammabilities advantages helium possessed were extremely small. For all these reasons, Cohen explained, the team had early elected to concentrate on nitrogen- mixed atmospheres.
Eberhard F. M. Rees, Director of the Special Task Team at North American Rockwell, spearheaded a design review of the CM water sterilization system at Downey, Calif. (The review had resulted as an action item from the March 21 Configuration Control Board meeting in Downey.) Rees and a team of North American engineers reviewed the design of the system and test results and problems to date. Chief among performance concerns seemed to be compatibility of the chlorine solution with several materials in the system, maximum allowable concentration of chlorine in the water supply from the medical aspect, and contamination of the system during storage, handling, and filling. Assuming North American's successful completion of qualification testing and attention to the foregoing action items, said Rees, the system design was judged satisfactory.
NASA Hq. confirmed oral instructions to MSC and KSC to use 60 percent oxygen and 40 percent nitrogen to pressurize the Apollo CM cabin in prelaunch checkout operations and during manned chamber testing, as recommended by the Design Certification Review Board on March 7 and confirmed by the NASA Administrator on March 12. This instruction was applicable to flight and test articles at all locations.
A meeting at MSC with Irving Pinkel of Lewis Research Center and Robert Van Dolah of the Bureau of Mines reviewed results of boilerplate 1224 tests at 11.4 newtons per square centimeter (16.5 pounds per square inch) in a 60-percent-oxygen and 40-percent-nitrogen atmosphere. Additional Details: here....
Flammability tests of the Sony tape/voice recorder were made to determine if the recorder met crew-cabin use requirements. Testing was by electrical overloads of nichrome wire ignitors in an atmosphere of 100 percent oxygen at 4.3 newtons per square centimeter (6.2 psia). Post-test evaluations indicated that flammability requirements had been met, since ignitions were self-extinguishing and only localized internal damage occurred.
The ASPO Manager for the command and service modules expressed belief that costs could be reduced and others avoided by the effective use of agency resources in many areas. However, he pointed out that the very nature of the program - that is, one operating in a research and development atmosphere - would result in higher costs than would a mass-production program.
Christopher C. Kraft, Jr., MSC Director of Flight Operations, suggested that an in-house review reevaluate the Apollo secondary life support system, because of its complexity and cost of development, and at the same time reexamine the possibilities of an expanded oxygen purge system using identical concepts.
North American Rockwell announced that William B. Bergen, who had been serving as president of North American's Space Division, would become a corporate vice president with the title Group Vice President - Aerospace and Systems. This was one of a number of key organizational steps taken since January to improve and strengthen the North American management structure in response to significant changes that had occurred in the aerospace environment.