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.
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.
The mission constraints to be used for this study were :
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.