The results of performance tests with two 40 cm ion optics sets are presented and compared to those of 30 cm ion optics with similar aperture geometries. The 40 cm ion optics utilized both NSTAR and TAG (Thick- Accelerator-Grid) aperture geometries. All 40 cm ion optics tests were conducted on a NEXT (NASA’s Evolutionary Xenon Thruster) laboratory model ion engine. Ion optics performance tests were conducted over a beam current range of 1.20–3.52 A and an engine input power range of 1.1–6.9 kW. Measured ion optics’ performance parameters included near-field radial beam current density profiles, impingement- limited total voltages, electron backstreaming limits, screen grid ion transparencies, beam divergence angles, and start-up transients. Impingement-limited total voltages for 40 cm ion optics with the NSTAR aperture geometry were 60–90 V lower than those with the TAG aperture geometry. This difference was speculated to be due to an incomplete burn-in of the TAG ion optics. Electron backstreaming limits for the 40 cm ion optics with the TAG aperture geometry were 8–19 V higher than those with the NSTAR aperture geometry due to the thicker accelerator grid of the TAG geometry. Because the NEXT ion engine provided beam flatness parameters that were 40–63% higher than those of the NSTAR ion engine, the 40 cm ion optics outperformed the 30 cm ion optics.

This antenna combines a rigid fixed aperture antenna with an auxiliary deployable foam aperture to greatly increase the size of the antenna. The primary improvement over prior art is the use of a polymeric foam as both the structure and the deployment mechanisms used to deploy a large reflective antenna surface. This is an improvement over an inflatable hybrid antenna due for the following reasons: 1. The elimination of an inflation system reduces complexity, risk and mass No pressurant tank or gas generator is required. No plumbing is required No pressure regulation system is required storage system, . No risk of leakage caused by manufacturing defects, stowage and deployment failures, micro-meteoroid or particle impact damage. No need to control the inflation pressure over potentially large temperature variations. No need to rely on a rigidization system which typically involves distributed heaters blanketing and additional power requirements on the vehicle. 2. The use of foam enables the antenna designer to design shapes and configurations not achievable from a stressed skin inflatable system. 3. No power is consumed and no exposure to sunlight is required to stabilize or rigidize the structure once it is deployed. 4. A foam system has higher mechanical damping than an inflated system and this can be a great benefit to large structures especially when used in space.

A new and robust iodine |solid electrolyte| lithium cell has been designed, fabricated and tested. This novel battery system possesses high theoretical capacity and is capable of operation ten to thirty times higher current densities than conventional lithium - iodine cells at room temperature. The specific novelty of this work relates to the development of an approach for the chemical passivation of a commercially supplied solid electrolyte. As received, the solid electrolyte possesses desirable high conductivity, bu undesirable chemical reactivity to lithium, rendering it unusable as an electrolyte in a lithium battery. The chemical reactivity of the high conductivity solid electrolyte was found to be mitigated by the in-situ formation of a thin LiI passivation layer at the anode/electrolyte interface.