The stretched lens array (SLA) [spacecraft solar power]

At IECEC 2001, this team presented a paper on the new stretched lens array (SLA), including its evolution from the successful SCARLET array on the NASA/JPL Deep Space 1 spacecraft. Since that conference, the SLA team has made significant advances in SLA technology, including component-level improvements, array-level optimization, space environment exposure testing, and prototype hardware fabrication and evaluation. This paper describes the evolved version of the SLA, highlighting recent improvements in the lens, solar cell, photovoltaic receiver, rigid panel structure, and complete solar array wing. In addition to excellent durability in the space environment, the near-term SLA will provide outstanding wing-level performance parameters: 180 W/kg specific power; 300 W/m/sup 2/ power density; 300 V operational voltage; 85% savings in cell area (cm/sup 2//W) and cell-related cost ($/W) compared to planar arrays; 9 kW/m/sup 3/ stowed power at launch.     

Space solar array reliability: A study and recommendations

Providing reliable power over the anticipated mission life is critical to all satellites; therefore solar arrays are one of the most vital links to satellite mission success. Furthermore, solar arrays are exposed to the harshest environment of virtually any satellite component. In the past 10 years 117 satellite solar array anomalies have been recorded with 12 resulting in total satellite failure. Through an in-depth analysis of satellite anomalies listed in the Airclaim's Ascend SpaceTrak database, it is clear that solar array reliability is a serious, industry-wide issue. Solar array reliability directly affects the cost of future satellites through increased insurance premiums and a lack of confidence by investors. Recommendations for improving reliability through careful ground testing, standardization of testing procedures such as the emerging AIAA standards, and data sharing across the industry will be discussed. The benefits of creating a certified module and array testing facility that would certify in-space reliability will also be briefly examined. Solar array reliability is an issue that must be addressed to both reduce costs and ensure continued viability of the commercial and government assets on orbit.     

POWOW: power without wires: a SEP concept for space exploration

Electric propulsion has emerged as a cost-effective solution to a wide range of satellite applications. Deep Space 1 successfully demonstrated electric propulsion as the primary propulsion source for a satellite. The POWOW concept is a solar-electric propelled spacecraft capable of significant cargo and short trip times for traveling to Mars. It would enter aerosynchronous orbit and from there, beam power to surface installations via lasers. The concept has been developed with industrial partner expertise in high efficiency solar cells, advanced concentrator modules, innovative arrays, and high power electric propulsion systems. The latest version of the spacecraft, the technologies used, and trip times to Mars are presented. The POWOW spacecraft is a general purpose solar electric propulsion system that uses new technologies that are directly applicable to commercial and government spacecraft with power levels ranging from a LEO power level of 4 kW up to GEO spacecraft about 1 MW. The system is modular, expandable, and amenable to learning curve cost projection methods     

InAsP cells for solar thermophotovoltaic applications

High temperature wide band gap InAsP cells have been specifically designed and fabricated for operating temperatures up 250°C to match with selective emitters operating near 1 μm in a TPV system. An important assumption is that the emitters can be heated up to the range of 1400 K to 2000 K by either solar concentrators or some other heat source. The efficiency of a selective emitter, which can be selected depending on the emitter operating temperatures, will be significantly higher than either a blackbody or a graybody emitter. The key for the TPV success is that the match between the band gap and selective emission must occur at the cell operating temperature. An appropriate cell band gap needs to be carefully selected; so when the band gap shrinks at the operating temperature, the desired match can be achieved. In this paper, two types of InAsP cells were investigated for this concept. The performance of these cells at elevated temperature and energy conversion efficiency are reported in this paper     

Space power-whats old is new again

The nation is presently seeking smaller and faster space missions that cost less. Furthermore, there is pressure to spin off technologies into the commercial sector as well as spin in technologies to the space program. In this environment, ideas that were dismissed in the past have come to the forefront again. This paper discusses high performance photovoltaic devices, solar dynamic systems, new batteries and power management and distribution schemes. Spin offs of power technologies are impacting aeronautical, terrestrial and naval applications as well. It is believed that interactions with terrestrial commercial industries will lead to deeper understanding of how to reduce space costs as well as increasing quality and reliability