Everything you never knew you wanted to know about the Mercury Project

From RixWiki

Fig 1 - Neck Egress Procedure

Fig 2 - Carpenter Practicing Neck egress

Introduction

The Forward Escape Hatch provided an alternate method of egress to the main side hatch. To egress through the forward escape hatch, the astronaut would remove the right hand portion of the instrument panel, then stand on the couch and open the hatch via a lever. He could then exit the spacecraft through the parachute compartment.

The only astronaut who used this path was Scott Carpenter on the Aurora 7 flight.

Escape Hatch Design

The hatch itself was of the same curvature as the forward pressure bulkhead a circular latching mechanism was used to provide a pressure seal. This design appears to have gone through one revision regarding the latching mechanism on the actuation lever.

Original Design

Fig 3 - Original Hatch Design

Fig 4 - Original Lever Latch Design

Fig 5 - Hatch Seal Detail

The original design is shown in Figures 3, 4, and 5. Note that there was a place to put the safety pin when the hatch was open. The details of how the hatch sealed to the forward pressure bulkhead, shown in Figure 5, did not appear to change throughout the mercury program.

Revised Design

Fig 6 - Revised Hatch Design

Fig 7 - Revised Lever Latch Design

The November 15, 1961 edition of SEDR-104 Mercury Familiarization Manual contains an updated version of the hatch drawing. This design added a spring assembly on the arm latching mechanism, and appears to have done away with the parking spot for the safety pin. Drawings of the revised design are shown in Figures 6, and 7. As noted above, Figure 5 is applicable to both designs

PDF File

I haveprepared a PDF file with the drawing pages from the two editions of SEDR-104 which pertain to the hatch.

Photos

Fig 8 - Aurora 7 Escape Hatch

Figure 8 is a photo of the escape hatch in Aurora 7 note that a careful examination of the curved ribs shows that the hatch is indeed curved.

Fig 9 - MR2 Parachute Compartment

Fig 10 - MA-5 Parachute Compartment

Figures 9 and 10 are views of the outside of the escape hatch through the empty parachute compartment of spacecraft 5 (MR-2) and spacecraft 9 (MA-5) respectively. Note the circular ribbing. This is consistent with the rest of the pressure vessel of the Mercury spacecraft which was constructed of an inner, smooth, sheet metal panel which was welded to an outer beaded panel.

Also note the longitudinal braces connecting the recovery compartment to the small pressure bulkhead, just outside of the circular escape hatch.