Magazine

A model predictive control (MPC) algorithm that differs from prior MPC algorithms has been developed for controlling an uncertain nonlinear system. This algorithm guarantees the resolvability of an associated finite-horizon optimal-control problem in a receding horizon implementation. Given...

A report describes recent accomplishments of a continuing effort to develop the vapor-phase catalytic ammonia removal (VPCAR) process for recycling wastewater for consumption by humans aboard a spacecraft in transit to Mars. The VPCAR process is implemented by a system of highly integrated...

Five reports address different aspects of development of tethers to be deployed from spacecraft in orbit around the Earth. The first report discusses proposed optoelectronic tracking of retroreflective objects located at intervals or of retroreflective coats along the entire length of a tether to measure...

A report presents a design concept for an instrumented robotic vehicle (rover) to be used on a future mission of exploration of the planet Mars. The design incorporates a nuclear fission power system to provide long range, long life, and high power capabilities unachievable through the use of...

A paper presents an algorithm to initialize a formation of N distributed spacecraft in deep space. Such formations will enable variable-baseline interferometers in future NASA missions designed to study the structure and origin of the universe. The algorithm described in the paper reflects some...

A paper describes direct numerical simulations (DNSs) of three-dimensional mixing-layer flows undergoing transition to turbulence; the mixing layers may or may not be laden with evaporating liquid drops. In contrast to most studies in this field, the...

The Portion Marking Verification Tool (PMVT) software automates the process of regulatory document marking. This tool assists users in meeting the mandated requirements for portion marking in sensitive or classified documents. By utilizing PMVT, portion marking can be up to 200–400% faster than traditional review...

A flexible, platform microencapsulation technology can be applied to actives from water soluble to water insoluble materials at the 20–35% range; loading levels of up to >50% have been achieved for some actives. The microcapsules protect the actives from environmental conditions, and can be designed to release...

Thin-film technologies are sought for dye-sensitized solar cells that are flexible and printable on a plastic substrate; amorphous silicon/microcrystalline silicon tandem solar cells and textured TCO glass; and copper-indium- gallium-selenide solar cells that are flexible and printable on a plastic or stainless...

Organic antimicrobial chemistries are needed to act as natural preservatives for a variety of beverages. They must be safe, stable, colorless, odorless, and tasteless at the concentration necessary to act as a preservative, and be effective at low concentrations (below 1%). They must extend the overall lifetime...

A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beam-steering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space...