MSC reported that stowage of crew equipment, some of which would be used in both the CM and the LEM, had been worked out. Two portable life support systems and three pressure suits and thermal garments were to be stowed in the CM. Smaller equipment and consumables would be distributed between modules according to mission phase requirements.
At a meeting at MSC, Grumman representatives submitted the cost proposal for LEM test articles LTA-8 and LTA-9, and suggested a testing program for the two vehicles: LTA-8 should be used for restrained integrated systems testing in the altitude propulsion test facilities at the Atlantic Missile Range; LTA-9 should be used for manned atmospheric tethered operation tests. The contractor also recommended an early flight demonstration program to verify the helicopter tether operation potential, which promised greatly increased mission test capability over fixed-base tether facilities. The tether method (helicopter or fixed- base) should be determined after the verification. LTA-8 should be considered as a constraint to LEM-5, and LTA-9 as a constraint to the lunar landing mission.
MSC representatives reviewed Grumman's program for thermal testing for the LEM, to be conducted with the test model 2 (TM-2) vehicle. Because the vehicle's configuration had changed so extensively, the Center canceled the currently planned TM-2 ascent stage and ordered another stage to be substituted. TM-2's descent stage needed only small design changes to make it suitable for the program.
The interrelationships between all major LEM test vehicles, including all test constraints and documentation requirements, were developed. This logic study, prepared by Grumman and forwarded to MSC, stressed the feasibility of alterations in the LEM test program as needed.
Grumman conducted manned drop tests to determine the LEM crew's ability to land the spacecraft from a standing position. All tests were run with the subject in an unpressurized suit in a "hands off" standing position with no restraint system or arm rests.
NASA anticipated five significant milestones for the LEM during the forthcoming year:
MSC's Structures and Mechanics Division and ASPO reviewed the LTA-10 test program to resolve the stop-work imposed upon Grumman. The review resulted in an agreement to have LTA-10 remain in the program with a modified configuration. LTA-10 would be used by North American at Tulsa, Oklahoma, for adapter/LEM modal and separation testing and would consist only of descent stage structure. Subsystems for LTA-10 which were eliminated were the ascent stage, landing gear, ascent propulsion and descent propulsion.
Grumman and Hamilton Standard were exploring various designs for the extravehicular mobility unit. On the basis of some early conclusions, the MSC Crew Systems Division (CSD) recommended that meteoroid and thermal protection be provided by a single garment. Preliminary hypervelocity tests placed the garment's reliability at 0.999. Each would weigh about 7.7 kg (17 lbs), about 2.3 kg (5 lbs) less than the two-garment design. CSD further recommended that the unit be stored either in the LEM's descent stage or in a jettisonable container in the ascent portion.
In the first of a series of manufacturing review meetings at Bethpage, N.Y., it was learned that Grumman's tooling program was behind schedule (caused primarily by engineering changes). Tool manufacturing might recoup much of the lost time, but this process was highly vulnerable to further design changes. Completion of tooling for the ascent stage of LTA-3 was now set for late April, a production delay of about two months.
MSC's Crew Systems Division decreed that the extravehicular mobility unit (EMU) would employ a single garment for both thermal and meteoroid protection. By an earlier decision, the penetration probability requirement had been lowered from 0.9999 to 0.999. This change, along with the use of newer, more efficient materials, promised a substantial lightening of the garment (hopefully down to about 7.7 kg [17 lbs], excluding visors, gloves, and boots). The division also deleted the requirement for a separate meteoroid visor, because the thermal and glare visors provided ample protection against meteoroids as well. Tests by Ling-Temco-Vought confirmed the need for thermal protection over the pressure suit during extravehicular transfer by the LEM crewmen.
At a design review on the VHF radio equipment for the LEM, conducted by RCA, Grumman refused to vote its approval. Grumman's most serious objection centered on thermal loads, which under extreme conditions could far exceed specification limits. RCA thereupon began exploring several approaches, including new materials, relocation of components, and redesigned heat sinks. Grumman was asked to keep MSC well informed on problems, corrective actions, and anticipated impacts.
Crew Systems Division completed evaluation of the three Block II space suits submitted by Hamilton Standard, David Clark, and International Latex. Also, the contractor presented to MSC the results of drop tests with the LEM's support and restraint system.
North American technicians began installing a CM mockup aboard a KC-135 at Wright-Patterson Air Force Base. The structure would be used in a zero-g flight test program (scheduled to begin within a week) to evaluate the Block I space suit re mobility, crew performance, and interfaces with the couch and restraints and with the guidance and navigation station.
Apparently the only available spacecraft-LEM-adapter SLA thermal coating material which would meet the emissivity requirements for LEM flights was 24-carat gold. North American Tulsa, Oklahoma was predicting 18-week and 10-week schedule slips, respectively, for the first two Block 11 SLAs and a $10-12 million cost impact. A meeting would be held at Tulsa January 17 between North American, Grumman, and MSC to determine the course of the action to be taken.
Grumman LM thermodynamics studies showed the LM thermal shield would have to be modified because fire-in-the-hole pressures and temperatures had increased. Portions of the LM descent stage would be redesigned, but modification of the descent stage blast deflector was unlikely.
LM test model TM-6 and test article LTA-10 were shipped from Grumman on the Pregnant Guppy aircraft. When the Guppy carrying the LTA-10 stopped at Dover, Del., for refueling, a fire broke out inside the aircraft, but it was discovered in time to prevent damage to the LM test article.
Spacecraft delivery date and ground rule discussions were summarized by MSC ASPO Manager George M. Low in a letter to North American Aviation's Apollo Program Manager Dale D. Myers. Low referred to an April 23 letter from Myers and April 25 talks at Downey, Calif.
Basic was "an MSC ground rule that the first manned flight should be an open-ended mission; and that 2TV-1 (a test spacecraft) would be a constraint on that mission. I also stated that I would like to achieve a delivery date for Spacecraft 101 that is no later than November, 1967, and that all constraining tests on 2TV-1 should be completed one month before the flight of 101. I further stated that the proposed delivery dates for Spacecraft 103 and subsequent spacecraft were not good enough and that we should strive to achieve earlier dates.
"In summary, we did not agree with the basic ground rules stated in your April 23, 1967, letter. These ground rules essentially implied that 101 was to be limited to a six-orbit mission, and to be delivered as early as possible at the expense of all other spacecraft. Instead, we stated that it is NASA's position to achieve a balanced program involving the earliest possible deliveries when all spacecraft are considered and not just the first one."
A further exchange of letters May 8 and 16 reached agreement on target delivery dates and ground rules. Testing of thermal vacuum test vehicle 2TV-1 would be as originally planned except that extravehicular activities would not be included in tests constraining CSM 101. Delivery date was to be October 14. CSM 101 was to be delivered December 8 and would be launched on a Saturn IB to verify system performance. The mission was to be open-ended, up to 10 days, with no LM and no docking or EVA provisions included. New delivery date for CSM 103 was March 23, 1968.
Maxime A. Faget, MSC Director of Engineering and Development, told the ASPO Manager that he had reviewed the LM insulation status and concluded that "the present design is susceptible to degradation from cabin leakage during pressurized conditions. The present insulation design is unacceptable for the lunar landing mission." He agreed with the contractor that design changes were required and specified that the insulation design change should be effective on LM-4 and the changes should be installed for the LTA-8 tests in support of LM-5.
A LM test failed in the Grumman ascent stage manufacturing plant December 17. A window in LM-5 shattered during its initial cabin pressurization test, designed to pressurize the cabin to 3.9 newtons per square centimeter (5.65 pounds per square inch). Both inner and outer windows and the plexiglass cover of the right-hand window shattered when the pressure reached 3.5 newtons per sq cm (5.1 psi). An MSC LM engineer and Corning Glass Co. engineers were investigating the damage and cause of failure.
ASPO Manager George M. Low pointed out to E. Z. Gray of Grumman that in October 1964 NASA had sent a letter to Grumman voicing concern over possible stress corrosion problems. The Grumman reply on October 30 of that year was unsatisfactory when considered in the light of stress corrosion cracks recently found in the LM aluminum structural members. Low asked what Grumman planned to do to make sure that no other potential stress corrosion problems existed in the LM and asked for a reply by January 1968 on how the problem would be attacked.
On December 21, Low wrote a similar letter to Dale D. Myers of North American Rockwell, reminding him of a letter sent by MSC in September 1964. He said that recent stress corrosion problems had been encountered in the LM and asked that North American make a detailed analysis to ensure that not a single stress corrosion problem existed in the CSM or associated equipment. Again, Low asked for a reply by January 15, 1968.
NASA Associate Administrator for Manned Space Flight George E. Mueller directed MSC Director Robert R. Gilruth to establish a task team to investigate why, in light of extreme precautions taken early in the program, the problem of stress corrosion in the LM was being encountered at such a late stage in Apollo. The problem, Mueller stressed, had been discovered at a most critical point in the program - the launch of the first LM was imminent and two subsequent vehicles were already well along in factory checkout. Any resultant slips in the LM program would seriously impact overall Apollo schedules. Gilruth replied he believed that such a team was not required. He affirmed that the reviews undertaken with the contractors in 1964 to guard against just these problems had proved inadequate when judged against present program demands. "The answer simply is that the job was not handled properly on the last go-round."
Rolf Lanzkron and Owen Morris, Chiefs of MSC's CSM and LM Project Engineering Divisions, led a review of the 2TV-1 and LTA-8 (thermal vacuum test article and lunar module test article) thermal vacuum test programs at MSC. Chief concerns expressed during the review centered on the heavy concentration of testing during the summer of 1968, the need for simultaneous operation of test chambers A and B, and the lack of adequately trained chamber operations support personnel for dual testing. The review disclosed that maintenance of testing schedules for LTA-8 was most unlikely, even with a seven-day-a-week work schedule. (The central problem was the large number of open items that had to be cleared before start of the tests.)
Stress corrosion and window problems in the LM had been resolved, NASA Associate Administrator for Manned Space Flight George E. Mueller advised the Administrator in his weekly progress report. By a thorough analysis of the entire structure of the spacecraft, a team of engineers at Grumman had determined that widespread stress corrosion on the vehicle was highly unlikely. Also, inspection of more than 1,400 individual parts on exposed surfaces of lunar module test article LTA-3 and LMs 3 through 8 had failed to discover a single instance of stress corrosion cracking, and thus no major changes would be made to the structure of the spacecraft.
Regarding the window problem (a window had blown out during a routine pressure test of LM-5 on December 17, 1967), Mueller stated that the windows on the LM were made from the strongest glass ever used on manned spacecraft. The most important factor, he said, was to avoid scratches on the window surface. Accordingly, Grumman and MSC had instituted a new acceptance test procedure to be conducted at Bethpage immediately before installation, after which the windows would remain fully protected. The LM-5 window failure had been caused by a defect in the body of the glass. Grumman subsequently planned to pressure-test all LM windows at 17.2 newtons per square centimeter (25 pounds per square inch). Normal operating pressure was 4.0 newtons per sq cm (5.8 psia).
MSC Director Robert R. Gilruth observed that the Engineering and Development Directorate would be conducting two thermal-vacuum test programs during the next several months, following the April 9 shipment of the Block II thermal vacuum test article 2TV-1 to MSC from Downey. (The second test article was the LM counterpart, LTA-8.) Both programs were of major importance, Gilruth told his organization. However, because the 2TV-1 test program directly supported - and constrained - the first manned Apollo mission, he said that, in the event of any conflict between the two test programs, 2TV-1 had clear priority.
NASA Associate Administrator for Manned Space Flight George E. Mueller recommended to the Administrator several alternative uses for the LM-2 vehicle, since that spacecraft was no longer destined for flight. (The successful LM-1 flight during the Apollo 5 mission in January had obviated the need for a second such unmanned flight.) Mueller suggested that LM-2 be used for nondestructive tests and for documentary photography. Additional drop tests with the craft, he said, would enhance confidence in the strength of the LM to withstand the impact of landing on the moon, with all subsystems functioning. (The LM drop test program using Lunar Test Article 3, Mueller said, would verify the LM structure itself; however, LTA-3 contained no operational subsystems, wiring, or plumbing and therefore could not verify the total flight vehicle.) Among several other possible uses for the vehicle examined but rejected, Mueller cited modifying the craft into a manned configuration for Apollo or using it for an early Apollo Applications flight. LM-2 was unsuitable for both these alternatives, he stated, because of the extensive structural modifications needed to make it a flightworthy Apollo spacecraft - and the attendant disruption of vehicle flow within the Grumman production line - and because of the many fire-proofing changes that would be required. The launch vehicle (SA-206), LM adapter, and protective shroud were to be placed in storage for further Saturn tests if needed.
ASPO Manager Low informed Apollo Program Director Phillips of several changes in the LM vibration testing program. Before beginning the series of tests, he told Phillips, red line values were established on critical components that were not to be exceeded. However, because of the most recent test effort on LM-2, which resulted from the pogo problem experienced during the flight of Apollo 6, Low was forced to authorize vibration testing beyond the red line values initially set for the spacecraft. This action, in turn, forced an inspection and possible refurbishment of LM-2 to make it available for an unmanned flight, should such a second unmanned LM test mission be required. He then cited MSC's future plans for LM-2:
Two NASA investigation boards had reported that loss of attitude control caused the May 6 accident that destroyed lunar landing research vehicle No. 1, NASA announced. Helium in propellant tanks had been depleted earlier than normal, dropping pressure needed to force hydrogen peroxide propellant to the attitude-control lift rockets and thrusters. Warning to the pilot was too late for him to take necessary action for landing. The boards called for improvements in LLRV and LLTV design and operating practices and more stringent control over flying programs. No bad effects on the Apollo lunar landing program had been found and no changes were recommended for the LM.
The LM-11 midsection assembly collapsed in the assembly jig during the bulkhead prefitting stage of construction at Grumman. The structure buckled when the bulkheads, which had just been prefitted and drilled, were removed to permit deburring the drilled holes. Jig gates that were supposed to hold up the assembly were not in position, nor was the safety line properly installed. The structure was supported by hand. Damage to the skin of the structure was not severe, although a small radius bend was put in one of the upper skins.
The fifth and final drop test of LM-2 was made on May 7. The first four drop tests had been made to establish the proper functioning of all LM systems after a lunar landing. The fifth test was made to qualify the functioning of the pyrotechnics after landing. On May 8, the final test, physically separating the ascent stage, was conducted.