Outer planet satellite return missions using in situ propellant production

In situ production of oxygen and oxygen with hydrogen for utilization as return propellant from the Galilean satellites has been investigated. Europa has emerged as the preferred landing sight because of the availability of water ice and its surface temperature. When oxygen is used with methane transported from earth, a Europa sample return mission requires 4000 kg less estimated earth launch mass than a vehicle using space storable propellant. Neither methane nor oxygen require active refrigeration at Europa. When oxygen and hydrogen are both utilized to form the primary sample return propellant, the required processor mass increases, but the estimated earth launch mass requirement is reduced by an additional 550 kg.