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NASA's goal for human spaceflight is to expand permanent human presence beyond low Earth orbit (LEO). NASA is identifying potential missions and technologies needed to achieve this goal. Mission options include crewed destinations to LEO and the International Space Station; high Earth orbit and geosynchronous orbit; cis-lunar space, lunar orbit, and the surface of the Moon; near-Earth objects; and the moons of Mars, Mars orbit, and the surface of Mars. NASA generated a series of design reference missions to drive out required functions and capabilities for these destinations, focusing first on a piloted mission to a nearEarth asteroid. One conclusion from this exercise was that a solar electric propulsion stage could reduce mission cost by reducing the required number of heavy lift launches and could increase mission reliability by providing a robust architecture for the long-duration crewed mission. Similarly, solar electric vehicles were identified as critical for missions to Mars, including orbiting Mars, landing on its surface, and visiting its moons. This paper describes the parameterized assessment of power and propulsion technologies for a piloted solar electric vehicle to a near-Earth asteroid. The objective of the assessment was to determine technology drivers to advance the state of the art of electric propulsion systems for human exploration. Sensitivity analyses on the performance characteristics of the propulsion and power systems were done to determine potential system-level impacts of improved technology. Starting with a "reasonable vehicle configuration" bounded by an assumed launch date, we introduced technology improvements to determine the system-level benefits (if any) that those technologies might provide. The results of this assessment are discussed and recommendations for future work are described.

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NASA has missions planned to targets in the solar system ranging from the permanently shadowed craters of Mercury to the icy reaches of the Kuiper belt and beyond. In 2011, the NASA Office of the Chief Technologist (OCT) requested the NASA Ames and Glenn Research Centers to assess the potential of small power supplies based on direct conversion of energy from radioisotope sources for future NASA missions; and in particular to assess whether alphavoltaic and betavoltaic power sources could be of potential benefit in small missions, as well as examining the use of miniaturized thermophotovoltaic power supplies. This paper summarizes the results of that assessment.

A recent study by the NASA Glenn Research Center assessed the fe A recent study by the NASA Glenn Research Center assessed the feasibility of using asibility of using photovoltaics photovoltaics (PV) to power spacecraft for outer planetary, deep space missio (PV) to power spacecraft for outer planetary, deep space missions. ns. While the majority of spacecraft have relied on While the majority of spacecraft have relied on photovoltaics photovoltaics for primary power, the for primary power, the drastic reduction in solar intensity as the spacecraft moves far drastic reduction in solar intensity as the spacecraft moves farther from the sun has ther from the sun has either limited the power available (severely curtailing scientif either limited the power available (severely curtailing scientific operations) or ic operations) or necessitated the use of nuclear systems. A desire by NASA and th necessitated the use of nuclear systems. A desire by NASA and the scientific e scientific community to explore various bodies in the outer solar system an community to explore various bodies in the outer solar system and conduct d conduct " "long long--term term" " operations using smaller, operations using smaller, " "lower lower--cost cost" " spacecraft has renewed interest in spacecraft has renewed interest in exploring the feasibility of using exploring the feasibility of using photovoltaics photovoltaics for missions to Jupiter, Saturn and for missions to Jupiter, Saturn and beyond. With recent advances in solar cell performance and conti beyond. With recent advances in solar cell performance and continuing development nuing development in lightweight, high power solar array technology, the study det in lightweight, high power solar array technology, the study determined that ermined that photovoltaics photovoltaics is indeed a viable option for many of these missions.is indeed a viable option for many of these missions.