NAA engineers began preliminary layouts to define the elements of the command module (CM) configuration. Additional requirements and limitations imposed on the CM included reduction in diameter, paraglider compatibility, 250 pounds of radiation protection water, redundant propellant tankage for the attitude control system, and an increase in system weight and volume. Additional Details: here....
NAA decided to retain the inward-opening pull-down concept for the spacecraft crew hatch, which would use plain through bolts for lower sill attachment and a manual jack-screw device to supply the force necessary to seat and unseat the hatch.
Concurrently, a number of NAA latching concepts were in preparation for presentation to NASA, including that of an outward-opening, quick- opening crew door without an outer emergency panel. This design, however, had weight and complexity disadvantages, as well as requiring explosive charges.
NAA's evaluation of the emergency blow-out hatch study showed that the linear-shaped explosive charge should be installed on the outside of the command module, with a backup structure and an epoxy-foam-filled annulus on the inside of the module to trap fragmentation and gases. Detail drawings of the crew hatch were prepared for fabrication of actual test sections.
Robert R. Gilruth, Director of MSC, presented details of the Apollo spacecraft at the Institute of the Aerospace Sciences meeting in Seattle, Wash. During launch and reentry, the three-man crew would be seated in adjacent couches; during other phases of flight, the center couch would be stowed to permit more freedom of movement. The Apollo command module cabin would have 365 cubic feet of volume, with 22 cubic feet of free area available to the crew: "The small end of the command module may contain an airlock; when the lunar excursion module is not attached, the airlock would permit a pressure-suited crewman to exit to free space without decompressing the cabin. Crew ingress and egress while on earth will be through a hatch in the side of the command module."
The establishment of a basic command module (CM) airlock and docking design criteria were discussed by NAA and NASA representatives. While NASA preferred a closed-hatch, one-man airlock system, NAA had based its design on an open-hatch, two-man airlock operation.
Another closed-hatch configuration under consideration would entirely eliminate the CM airlock. Astronauts transferring to and from the lunar excursion module would be in a pressurized environment constantly.
Apollo Spacecraft Project Office requested NAA to perform a study of command module-lunar excursion module (CM-LEM) docking and crew transfer operations and recommend a preferred mode, establish docking design criteria, and define the CM-LEM interface. Both translunar and lunar orbital docking maneuvers were to be considered. The docking concept finally selected would satisfy the requirements of minimum weight, design and functional simplicity, maximum docking reliability, minimum docking time, and maximum visibility.
The mission constraints to be used for this study were :
Elimination of the requirement for personal parachutes nullified consideration of a command module (CM) blowout emergency escape hatch. A set of quick-acting latches for the inward-opening crew hatch would be needed, however, to provide a means of egress following a forced landing. The latches would be operable from outside as well as inside the pressure vessel. Outside hardware for securing the ablative panel over the crew door would be required as well as a method of releasing the panel from inside the CM.
North American made a number of changes in the layout of the CM:
The second prototype space suit was received by MSC's Crew Systems Division. Preliminary tests showed little improvement in mobility over the first suit. On October 24-25, a space suit mobility demonstration was held at North American. The results showed that the suit had less shoulder mobility than the earlier version, but more lower limb mobility. Astronaut John W. Young, wearing the pressurized suit and a mockup portable life support system (PLSS), attempted an egress through the CM hatch but encountered considerable difficulty. At the same time, tests of the suit-couch- restraint system interfaces and control display layout were begun at the Navy's Aviation Medical Acceleration Laboratory centrifuge in Johnsville, Pa. Major problems were restriction of downward vision by the helmet, extension of the suit elbow arm beyond the couch, and awkward reach patterns to the lower part of the control panel. On October 30-November 1, lunar task studies with the suit were carried out at Wright-Patterson Air Force Base in a KC-135 aircraft at simulated lunar gravity. Mobility tests were made with the suit pressurized and a PLSS attached.
North American completed its initial phase of crew transfer tests using a mockup of the CM/LEM transfer tunnel. Subjects wearing pressure suits were suspended and counterbalanced in a special torso harness to simulate weightlessness; hatches and docking mechanisms were supported by counterweight devices. The entire tunnel mockup was mounted on an air-bearing, frictionless table. Preliminary results showed that the crew could remove and install the hatches and docking mechanisms fairly easily.
ASPO decided upon transfer through free space as the backup mode for the crew's getting from the LEM back to the CM if the two spacecraft could not be pressurized. North American had not designed the CM for extravehicular activity nor for passage through the docking tunnel in a pressurized suit. Thus there was no way for the LEM crew to transfer to the CM unless docking was successfully accomplished. ASPO considered crew transfer in a pressurized suit both through the docking tunnel and through space to be a double redundancy that could not be afforded.
After reviewing the requirement for extravehicular transfer (EVT) from the LEM to the CM, MSC reaffirmed its validity. The Center already had approved additional fuel for the CM, to lengthen its rendezvousing range, and modifications of the vehicle's hatch to permit exterior operation. The need for a greater protection for the astronaut during EVT would be determined largely by current thermal tests of the pressure suit being conducted by NASA and Hamilton Standard. While the emergency oxygen system was unnecessary during normal transfer from one vehicle to the other, it was essential during EVT or lunar surface activities.
Officials from North American and the three NASA centers most concerned (MSFC, KSC, and MSC) discussed the environmental umbilical arrangement for the CM. The current configuration hampered rapid crew egress and therefore did not meet emergency requirements. This group put forth several alternative designs, including lengthening the umbilical hood and relocating the door or hatch.
MSC's Assistant Director for Flight Operations, Christopher C. Kraft, Jr., told ASPO Manager Joseph F. Shea that postlanding operational procedures require that recovery force personnel have the capability of gaining access into the interior of the CM through the main crew hatch. This was necessary, he said, so recovery force swimmers could provide immediate aid to the crew, if required, and for normal postlanding operations by recovery engineers such as spacecraft shutdown, crew removal, data retrieval, etc.
Kraft said the crew compartment heatshield might char upon reentry in such a manner as to make it difficult to distinguish the outline of the main egress hatch. This potential problem and the necessity of applying a force outward to free the hatch might demand use of a "crow bar" tool to chip the ablator and apply a prying force on the hatch.
Since this would be a special tool, it would have to be distributed to recovery forces on a worldwide basis or be carried aboard the spacecraft. Kraft requested that the tool be mounted onboard the spacecraft in a manner to be readily accessible. He requested that the design incorporate a method to preclude loss of the tool - either by designing the tool to float or by attaching it to the spacecraft by a lanyard.
A North American layout of the volume swept by the CM couch and crewmen during landing impact attenuation showed several areas where the couch and or crewmen struck the CM structure or stowed equipment. One area of such interference was that the center crewman's helmet could overlap about four inches into the volume occupied by the portable life support system (PLSS) stowed beneath the side access hatch. The PLSS stowage was recently changed to this position at North American's recommendation because the original stowage position on the aft bulkhead interfered with the couch attenuation envelope. The contractor was directed by MSC to explain this situation.
MSC Director of Flight Crew Operations Donald K. Slayton pointed out to ASPO Manager Joseph F. Shea that LM-to-CSM crew rescue was impossible. Slayton said
MSC submitted requirements to KSC that TV signals from cameras inside the LM and CM be monitored and recorded during manned hazardous tests, with hatch open or closed, and tests in the Vehicle Assembly Building, launch pads, and altitude chambers. A facility camera was to monitor the propellant-utilization gauging system during propellant loading. MSC specified that the field of view of the TV camera should encompass the shoulder and torso and portions of the legs of personnel at the normal flight stations in both the CM and the LM.
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.
ASPO Manager George Low, commented on control of Apollo spacecraft weight. Following the January 1967 spacecraft fire at Cape Kennedy, there had been substantial initial weight growth in the CSM. This was attributed to such items as the new CSM hatch, the flammability changes, and the additional flight safety changes. In mid-1967 the CSM weight stabilized and from then on showed a downward trend. The LM weight stabilized in mid1968 and since that time had remained fairly constant. Conclusions were that the program redefinition had caused a larger weight increase than expected, but that once the weight control system became fully effective, it was possible to maintain a weight that was essentially constant. Low told Caldwell C. Johnson, Jr., of the MSC Spacecraft Design Division that the weight control was in part due to Johnson's strong inputs in early 1968. Johnson responded, "Your control of Apollo weight growth has destroyed my reputation as a weight forecaster - but I'm rather glad."
Microscopic examination of dust particles collected from the spacecraft after the Apollo 10 mission and of samples collected from the inside of nine garments worn by the Apollo 10 astronauts confirmed preliminary findings that the itching experienced by the astronauts was due to the insulation in the tunnel hatch of the command module. Additional Details: here....