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The Extravehicular Mobility Unit (EMU) used by astronauts during space walks is powered by an 11-cell, silver-zinc battery. The present battery is certified for 6 cycles with a minimum discharge requirement of 7 hours above 16.0 volts at a 3.8 Amp load. Its certified wet-life is 170 days. Operational requirements for the International Space Station (ISS) led to a design capable of 32 cycles over a 425 day wet-life. Other battery parameters including capacity, rate capability, weight, volume, safety and the need for continuing compatibility with the EMU and the Space Shuttle charger dictate that the new battery will also be silver-zinc.

Future space missions will feature extensive EVA operations. In order to avoid the expendables and logistics penalties associated with recharging the EMU's oxygen supply bottles on the ground, a High Pressure Oxygen Recharge System (HPORS), is being developed for use aboard the Space Station. The HPORS will be an electrolysis system capable of providing oxygen at up to 6000 psia without the use of a mechanical compressor, using only the facilities that will be available on board the Space Station (electrical, nitrogen and water). The Hamilton Standard HPORS will be based on a solid polymer electrolyte system which has already demonstrated thousands of hours of performance at 3000 psia in an oxygen generating plant for military applications. The program includes testing of various water feed modes, operating temperatures and current densities in order to optimize the system size, weight and power consumption.