Air, adds fresh oxygen, keeps the pressure vessel, flow into the Earth's.

MAXIMUM PRESSURE HYDROGEN TANKS 0.665-CUBIC-METER (23.5-CUBIC-FOOT) CAPACITY 2310 kN/m? (335 PSIA) MAXIMUM PRESSURE UMBILICAL SERVICE \ HYDRAULIC SYSTEM MAIN POWER PUMPS, RESERVOIRS, WATER BOILER, AND MISCELLANEOUS i MAIN LANDING GEAR SIDE HATCH OPENING MACHINED NOSE LANDING GEAR PAYLOAD BAY DOOR Figure 4-7 .— Orbiter radiator panels. 4-21.