to ignite dry or soiled cotton. A factor of safety of 10 existed for every test condition.

Suit materials have been carefully selected, as described in Panel Finding 8-1a.

Finding No. a(5)

Finding.—Eighteen electrical circuits in Spacecraft 012 did not adhere completely to wire size/load/circuit protection design criteria.

Determination.-The condition was examined from the standpoint of overheating, and no problem was found to exist.

Responsible Organization.—MSC.

Action. There were 204 circuit breakers in Spacecraft 012. A wire/circuit breaker compatibility study was made to determine the adequacy of protection. A set of stringent ground rules (such as stating that the wire must be capable of carrying continually a current of two times the circuit breaker rating, at an ambient temperature of 150°F and stabilize at less than 500°F) was established. These were purposely stringent rules to eliminate all well protected circuits. More realistic ground rules were used such as actual circuit breaker trip characteristics, wire time/heat rise characteristics, to evaluate those circuits not meeting these original ground rules. Of the 204 circuits, only 18 failed to satisfy the original ground rules. These 18 circuits were further evaluated using the actual circuit breaker and wire characteristics. As a result, these 18 circuits were also judged to be adequately protected.

A complete review of Block II circuits was accomplished and all wiring and circuit breakers changed where necessary to comply with size/load/circuit protection design criteria, as discussed under Panel Finding 9-a8.

Finding No. a (6)

Finding.-Residues of RS89 (inhibited ethylene glycol/water solution) after drying are both corrosive and combustible. RS89 is corrosive to wire bundles because of its inhibitor.

Determination.-Because of the corrosive and combustible properties of the residues, RS89 coolant could in itself provide all of the elements of a fire hazard if leakage occurs onto electrical equipment.

Responsible Organization.—MSC.

Action.-Action has been taken to prevent spillage of water/glycol in Block II spacecraft. This is described under Panel Finding 8-4a. In addition, procedures are being developed to provide a standard method for cleaning water/glycol spills if they should occur. This is described under Panel Finding 2-2.

Finding No. a(7)

Finding.-Water/glycol is combustible, although not easily ignited.

Determination.-Leakage of water/glycol in the cabin increases the risk of fire. Responsible Organization.-MSC.

Action.-Action has been taken to prevent leakage of water/glycol in the cabin as described in Panel Finding 8-4a.

Finding No. a (8)

Finding.-Deficiencies in design, manufacture and quality control were found in the post-fire inspection of the wire installation.

Determination.-There was an undesirable risk exposure which should have been prevented by both the Contractor and the Government.

Responsible Organization.—MSC.

Action. A review of electrical wiring design, fabrication, and installation practices and procedures has been conducted to determine their adequacy. Corrective action was taken where necessary. On spacecraft where wiring was installed and complete, a reinspection was conducted using more stringent acceptance criteria. Corrective action was taken on the deficiencies identified.

On early manned spacecraft, a special wiring design task team was formed to review the wiring modification made as a result of the design changes and ensure the proper fabrication and installation of the wiring modifications in the spacecraft. This task team, made up of representatives from contractor engineering, manufacturing, quality control, and NASA engineering and quality control, reviewed the entire installation area-by-area and recommended modification where necessary.

The actual rework of the harness installation in early manned spacecraft was accomplished with an "overlay harness." After installation of this "overlay harness," the spacecraft was physically inspected and tested to ensure that there

were no shorts from wire-to-wire or from wire-to-ground, and that the wire insulation was not damaged. These tests have been successfully completed and the wiring system accepted by MSC.

An MSC review board chaired by Dr. Gilruth, determined the acceptability of the wiring in early spacecraft.

On all Block II spacecraft the following has been accomplished:

(1) Hard metallic covers have been placed on all wire harnesses on the spacecraft floor as physical protection;

(2) In areas where hard covers are not practical and additional physical protection is needed, single wire wraps and/or harness wraps have been used; (3) Where possible, sharp edges and corners are being removed. If removal is not practical, the edge or corner is provided with a grommet or the harness is provided with additional wraps;

(4) Where possible and practical, combustible material touching the wiring or close to it is being replaced with an acceptable material. In all cases, the criteria specified in ASPO-RQTD-D67-5A are being imposed and any deviations must be reviewed and approved by NASA on an individual basis. Panel Finding 8-1a provides additional information on materials selection and control.

Finding No. a(9)

Finding. The environmental control system is plumbed with aluminum tubing in both the water/glycol and oxygen circuits. Joints in the plumbing are made by nickel plating the aluminum and joining the nickel-plated surfaces with a tin-lead solder. Leakage of ECS coolant from these joints has been experienced in the Apollo spacecraft.

Determination.-The design of the soldered joints is inadequate to cope with all the conditions experienced in the spacecraft.

Responsible Organization.-MSC.

Action. The design of soldered joints has been revised to include armoring as described in Panel Finding 8-4a.

Finding No. b(3)

Finding.-Flammability characteristics of non-metallic materials are varied by only a factor of 3 or 4 by diluents in atmospheres containing oxygen at 3 to 5 psi partial pressure.

Determination.-Previous analyses leading to the decision to use 5 psia pure oxygen cabin environment in space are still valid.

Responsible Organization.—MSC.

Action. The fire safety of the reconfigured command module will be established by full-scale mockup tests in a pure oxygen environment as described in Panel Finding 8-1a

It has been reconfirmed by a detailed review of operational requirements that the inflight cabin atmosphere should continue to be oxygen at 5 psia. A 5 psia, 100% oxygen atmosphere in the spacecraft cabin combines the greatest opportunity for mission success with safety for manned operations in space.

However, the command module systems have been modified to be capable of using air, as well as oxygen, as a pressurant on the launch pad in accordance with Apollo Program Directive No. 29, Post-Accident Changes to Apollo CSM and Related Ground Facilities, dated July 6, 1967. This capability will be implemented if the full-scale flammability tests indicate a need to change to an air atmosphere for ground operations. Changes will be effective for all manned spacecraft as authorized by MSC CCA 1319, Revision A, dated May 25, 1967, and include

(1) A sensor to measure suit-to-cabin differential pressure.

(2) Mounting provisions for a cabin gas analyzer to detect air leakage into the suit loop (if air is used as a pressurant).

The risks due to the additional operational requirements of using air on the pad are being controlled by conducting ground tests and developing appropriate crew procedures. Training of the crew in these procedures will be accomplished before the first manned flight test.

Finding No. c(1)

Finding. Sixty seconds are required for unaided crew egress from the Command Module. The hatch cannot be opened with positive cabin pressure above approximately 0.25 psi. The vent capacity was insufficient to accommodate the pressure buildup in the Apollo 204 Spacecraft.

Determination. Even under optimum conditions emergency crew egress from Apollo 204 Spacecraft could not have been accomplished in sufficient time. Responsible Organization.—MSC.

Action. A new hatch has been designed to replace the two-cover hatch system on Block II command modules. The single door is called a "unified hatch" and is made of aluminum with added fiber glass and ablative material. The hatch has flexible thermal seals, a latch and linkage mechanism, hinges, window and a boost-protective hatch cover that swings open on separate hinges. There is a single cabin vent valve for ground testing or cabin purging. The door deployment mechanism contains a counter-balancing device to offset gravity, and a linkage that locks the hatch in full-open position. The door unlatching mechanism can be operated either by the flight crew in less than 3 seconds or by the ground crew for emergency or normal operations in less than 10 seconds.

Ground and flight tests are in progress to qualify the new hatch to assure the following items: (1) effective operation; (2) integrity in the vibration environment encountered during launch and reentry; (3) compatibility with crew requirements including EVA; and (4) integrity during reentry heating. These tests are being conducted on ground test articles, on the thermal vacuum model, and on unmanned Saturn V flights.

This hatch will be incorporated in all manned spacecraft.

Finding No. c(2)

Finding. The access arms to the Command Module in Launch Complexes 34 and 39 contain flammable materials, are removed thirty minutes prior to launch, and their doors open the wrong way for easy egress.

Determination. The access arm could constitute a fire hazard and impose delays to emergency crew egress.

Responsible Organization.-KSC.

Action.-Service structures and umbilical towers are being modified to improve emergency personnel and crew evacuation capability. Changes were authorized to be made on LC-34 on April 21, 1967 and include

(1) Reconfiguring the environmental chamber (EC) adapter hood to provide a flatter egress path from the spacecraft to the EC;

(2) Eliminating the step at each end of the Apollo access arm;

(3) Incorporating two-way swinging doors on the Apollo access arm and on the access arm cab;

(4) Providing smoke removal ventilation in the Apollo access arm cab; (5) Changing the arm retraction sequence to rotate the arm to a park position near the latch position at T-30 minutes to permit quick return to the command module. At T-4 minutes the arm will be swung to the stowed position;

(6) Incorporating fire-resistant materials inside the Apollo access arm. Effectivity for LC-34 is for the first manned spacecraft. The operational ready date is early in 1968. Effectivity for LC-39 is for the first manned Apollo/Saturn V flight. The operational ready date is in the second quarter of 1968.

Finding No. d(1)

Finding The control circuit from the Command Pilot developed a condition of continuous keying during the test.

Determination.-An anomaly existed in the spacecraft communication system. Responsible Organization.-MSC.

Action. The continuous keying that occurred was thoroughly reviewed by continuity measurements on wiring and associated control circuits. No specific malfunction could be identified. The Block II design is such that if this same anomaly occurred, it would not affect the other crew members.

Finding No. d(2)

Finding. During the Apollo 204 test, difficulty was experienced in communicating from ground to Spacecraft and among ground stations.

Determination. The ground system design was not compatible with operational requirements.

Responsible Organization.—KSC.

Action.-The ground communications system has been reviewed in detail and improvements are being made to ensure reliable communications between all test elements. Specific equipment modifications include

(1) For Launch Complex 34:

(a) Undesirable coupling in the astronaut communications panels has been eliminated and duplex communications to the spacecraft umbilical cable have been provided with minimum use of VOX devices;

(b) Headset frequency response has been improved and its efficiency raised;

(c) Central testing facilities are being added to permit continuous monitoring of circuit quality;

(d) Continuous recordings of critical voice communication loops will be provided.

Effectivity is for the first manned spacecraft and the operational ready date is the second quarter of 1968. Additional changes made to this launch complex ground communications system are described in Panel Finding 9-d(2).

(2) For Launch Complex 39:

(a) Evaluations are currently being made of Launch Complex 39 communications based on the changes being incorporated in Launch Complex 34;

(b) Effectivity for all changes to the LC-39 ground communications system will be for the first manned Apollo/Saturn V flight.

(3) Procedural changes to be made for all launch complexes:

(a) Reduction in the number of stations on critical communication loops;

(b) Inspection and verification by test of system configuration and operational readiness before each major space vehicle test;

(c) Provision for knowledgeable communications system engineers to be on duty during all major space vehicle tests.

These procedures will be used to support all manned flights from both LC-34 and LC-39.

The ground communications system will be capable of meeting all operational requirements to support manned flights from all launch complexes.

Panel No. 10

Finding No. 10

ANALYSIS OF FRACTURE AREAS

Finding. Several aluminum tubes were parted at soldered joints at unions. Determination.-The soldered aluminum joints at unions will fail if the solder is raised to its melting point of approximately 360°F. The soldered aluminum joints at unions were not adequate for the temperatures attained during the fire. Responsible Organization.-MSC.

Action.-The soldered aluminum joints are being armor plated to eliminate leakage, as described in Panel Finding 9-a(7).

Panel No. 11

Finding No. 13

MEDICAL ANALYSIS

Finding.-The Environmental Control System contains activated charcoal, which, if heated, will produce CO.

Determination.—It is the opinion of Panel 5 that heating of the CO2 canister occurred late in the progress of the fire after significant levels of CO were already present in the cabin atmosphere, and after at least one suit had failed.

Responsible Organization. MSC.

Action.-CO from this source can only constitute a hazard after an intense fire has progressed for a sufficient period to overheat the activated charcoal in the environment control system.

The quantity of charcoal contained in each canister is very small and is used to absorb a variety of noxious and toxic gaseous compounds. Charcoal can be beneficial in absorbing combustion by-products when ambient temperatures are not excessively high.

The primary means of reducing this type of secondary fire effect will be through the limitation of basic nonmetallic materials and thus reducing the probability of a high-temperature fire. This is described in Panel Finding 8-1a.

Finding No. 14

Finding. The distribution of CO in various organs indicates that circulations stopped rather abruptly when high levels of carboxyhemoglobin reached the heart. Determination.-Loss of consciousness was due to cerebral hypoxia due to cardiac arrest, due to myocardial hypoxia. Factors of temperature, pressure and

environmental concentrations of carbon monoxide, carbon dioxide, oxygen and pulmonary irritants were changing at extremely rapid rates. It is impossible to integrate these variables, on the basis of available information with the dynamic physiological and metabolic conditions they produced in order to arrive at a precise statement of time when consciousness was lost and when death supervened. The combined effect of these environmental factors dramatically increased the lethal effect of any factor by itself. It is estimated that consciousness was lost between 15 and 30 seconds after the first suit failed. Chances of resuscitation decreased rapidly thereafter and were irrevocably lost within four minutes. Responsible Organization.-MSC.

Action.-The reduction of combustible materials in the spacecraft will materially reduce the concentration of toxicants, but will not eliminate the hazard completely. Emergency breathing oxygen has been provided to prevent inhalation of toxic fumes during a fire. Operational procedures and suit ECS integrity are being reexamined to minimize the hazard to the crewman. Occupants normally assigned to duty in the White Room or other high-risk areas will be properly trained in rescue and resuscitation procedures and will be supported by professional medical personnel stationed near by. Training and practice will be regularly scheduled and all emergency procedures will be reviewed before the conduct of any test determined to be hazardous.

CCA 1361 dated April 17, 1967, to Contract NAS9-150 implements guidelines for reduction of flammable materials. Additional description can be found in Panel Finding 8-1a. All changes will be effective before manned testing.

Finding No. 15

Finding. All three suits were breeched by fire to some degree.

Determination.-The suits were not capable of providing crew protection in a fire of this intensity.

Action.-Block II suits are different in detail design than the suits used during Block I (Spacecraft 204). However, these also would not (as originally configured) provide crew protection from a fire of the intensity of the 204 accident. Thus, the "Finding and Determination" statements are applicable to Block II suits.

Redesign of the outer layers of Block II suits has been accomplished to use less flammable materials. The Nomex outer layer of thermal meteoroid garment (TMG) has been changed to Beta fabric. Internal alternating layers of the superinsulation (thermal layers) have been changed from aluminized mylar film to aluminized H-film (Kapton). The TMG configuration (multilayer cross section) is designed to provide thermal protection, micrometeoroid protection, and limited flame impingement protection (45 seconds at 1800° F without degradation of the innermost bladder layer of the pressure garment).

RECP 7E152 defining the TMG configuration and identifying it as an integral part of the suit assembly was approved by the spacecraft program manager. Implementation was by Change Order No. 79 to International Latex Corporation, Contract NAS9-6100, issued on July 13, 1967.

All nonmetallic materials in the suit will again be reviewed by a materials selection review board in accordance with the instructions of MSC-A-D-66-3 Revision A, and by the program manager as required by Apollo Program Directive No. 29, Paragraph 3. Additional details on this review board are found in Panel Finding 8-1a.

Effectivity of the TMG with the redesigned cover layers will be for all future flight and training suits.

Finding No. 21

Finding. It was not possible from biomedical and environmental data to accurately construct a time line of environmental conditions or crew activities during this emergency.

Determination.-Available environmental and biomedical instrumentation cannot be considered optimum for a potentially hazardous test or for flight. Responsible Organization.MSC.

Action.-TV coverage will be provided for all hazardous testing in the command module and lunar module. Simultaneous continuous biomedical telemetry will be provided, selective from each astronaut, from all three crew members n the command module. Direction to provide simultaneous continuous telemetry from all crew members in the spacecraft was given to NAR in CCA 1482 dated June 19, 1967. TV coverage will be provided for all manned hazardous testing in the command module.