Tubular Extendible Lock-Out Composite Boom (STELOC)

Advancement of high power and high specific power arrays and large robust arrays are both listed as critical requirements in NASA's technology roadmap. Advanced arrays are required to enable scaling up to 350 kW systems for interplanetary missions using solar electric power (SEP). While increased efficiencies of PV cells and power distribution will contribute to a portion of this power increase, very large arrays with very stiff support structures will be necessary to reach powers in the hundreds of kilowatts. In addition, large arrays which are structurally and dynamically durable under deployed conditions will require stiff, stable deployable structures to carry the deployed load and provide deployment forces. The stiff, lightweight STELOC booms provide the efficient structural performance necessary to achieve both very large arrays and robust deployed arrays. Therefore, successful achievement of the objectives defined for this program can provide a significant capability to NASA and NASA contractors to aid in the development of a SEP spacecraft tug or SEP for deep space missions. And in the near term, the 10cm twin-boom STELOC mast will enable robust 30 kW array systems for an SEP demonstrator or other high power missions.

Power systems compromise nearly 30% of a spacecraft's mass on average, thus improvements in specific power (W/kg) will enable either a reduction in spacecraft mass or an increase in capabilities. Near term Air Force satellite missions require more capable solar arrays with more total power on the same or smaller platforms. This includes enabling the GPS III Dual Launch variant which can leverage significant cost savings, and overcoming power challenges for Advanced EHF and classified missions. More powerful arrays must also have better specific power, decreased stowage volume and increased deployed stiffness in order to maintain other performance parameters of the spacecraft. Flexible blanket solar arrays can provide all these improvements by eliminating the heavy, bulky honeycomb panels used for conventional arrays. The STELOC boom will enable flexible arrays with all these qualities that could save $50 million per satellite and more than $1.5 Billion for a notional 30 satellite constellation of the GPS III Dual Launch Variant. The next-generation solar arrays being designed by Lockheed Martin are also intended for use on commercial geostationary satellites. Larger arrays will enable more transponders per spacecraft. Solar electric propulsion variants with high power, very stiff arrays can arrive on orbit more quickly and provide longer lifetimes. All these benefits translate to higher total revenues per spacecraft. More »