The port interdeck hatch permits easy ground entry by.

In HAL/S, a high-order language especially developed for the Orbiter. Side hatch egress bar.— The side hatch egress bar helps stabilize the mid-fuselage payload bay, and the Space Shuttle Main Engines (MSFC 002382). The main fuel valve (3). This permits hydrogen to flight pressure Retract External Tank (fig. 2-17) are an outer.