Combined energy production and waste management in manned spacecraft utilizing on-demand hydrogen production and fuel cells

• Reaction of activated aluminum powder and water generates hydrogen on-demand.
• Hydrogen can be generated on-board a manned spacecraft using waste water and urine.
• Application of the hydrogen in fuel cells yields electric energy and fresh water.
• This hydrogen technique enables improved safety, compactness, and waste management.
• It may be used for back-up power systems and hydrogen source for extended mission.

Energy supply and waste management are among the most significant challenges in human spacecraft. Great efforts are invested in managing solid waste, recycling grey water and urine, cleaning the atmosphere, removing CO2, generating and saving energy, and making further use of components and products. This paper describes and investigates a concept for managing waste water and urine to simultaneously produce electric and heat energies as well as fresh water. It utilizes an original technique for aluminum activation to react spontaneously with water at room temperature to produce hydrogen on-site and on-demand. This reaction has further been proven to be effective also when using waste water and urine. Applying the hydrogen produced in a fuel cell, one obtains electric energy as well as fresh (drinking) water. The method was compared to the traditional energy production technology of the Space Shuttle, which is based on storing the fuel cell reactants, hydrogen and oxygen, in cryogenic tanks. It is shown that the alternative concept presented here may provide improved safety, compactness (reduction of more than one half of the volume of the hydrogen storage system), and management of waste liquids for energy generation and drinking water production. Nevertheless, it adds mass compared to the cryogenic hydrogen technology. It is concluded that the proposed method may be used as an emergency and backup power system as well as an additional hydrogen source for extended missions in human spacecraft.