Northrop Grumman (Norway)

The design and manufacture of Gallium Nitride Monolithic Microwave Integrated Circuits (GaN MMICs) have matured in recent years, yet there is no existing reliability prediction modeling method, like the widely utilized one for Gallium Arsenide (GaAs) MMIC in MIL-HDBK-217. This paper develops and presents a new method for these devices by modifying key parameters in the existing GaAs MMIC standard model to incorporate the improved temperature properties of GaN, and typical activation energy, Ea obtained from accelerated life tests. The resulting model will be an invaluable tool for the reliability modeling of GaN MMICs for device suppliers and customers across all industries.

No abstract available.

For extended mission utility, it is desirable to be able to reprogram on -orbit payloads for new functions not originally envisioned. The basic concept of modifying payloads in orbit is already proven in that software patches and new coding algorithms can be uploaded to payloads years after launch. The goal of this paper is to discuss the option to extend this reprogrammability to payload hardware, using standards and architectures proven in software -defined radio technology. Next generation payloads using these standards can exploit the increasing versatility and density o f modern Field Programmable Gate Arrays and Digital Signal Processing chips to perform new missions that require onboard wideband, real time processing. I. Introduction HIS paper discusses the application of proven software standards and design methodology to enable next generation multifunction payloads. Even though the physics of specific front -end sensors, emitters and associated electronics in the payload must conform to the original mission, the trend is moving toward increasing generalization and digi tal processing onboard, along with more generalized digital control of the front ends . New missions can take advantage of this trend by relying on generalized hardware that is programmed to be mission specific and reprogrammed as missions change . As onbo ard processing bandwidths increase over time, to tens and hundreds of Megahertz, these missions will benefit from the ever -increasing performance of digital technology in field -programmable gate arrays (FPGAs) to achieve their original and future objective s, increasing the payloads’ effectiveness while reducin g size, weight, power and cost. This approach also benefits operationally responsive satellite missions by reducing the serial development cycle, as a result of reusing common hardware and applying pro ven software to the task of on -orbit reconfiguration. Reconfiguring and reprogramming the FPGA -based payload in the field is similar to sending a new software load to an onboard microprocessor. However, the standards for uploading new functionality to a hardware target are not in such a mature form as for software, which use operating systems and monitor programs that can accommodate new program uploads . This paper specifically suggests the use of modern software -defined radio (SDR) standards to be appl ied more widely, to enable management and upgrading of generalized hardware -based, wideband payload functions. Figure 1 shows the generalized block diagram of a reconfigurable payload.

At Northrop Grumman Shipbuilding, a prototype transient thermal tensioning system was installed and successfully demonstrated on a complex test panel design from the Shipboard Applications of Lightweight Structures program.

We report subarcsecond-resolution VLA imaging of four nearby spiral galaxies: IC 342, Maffei II, NGC 2903, and NGC 6946. In each galaxy, compact radio continuum sources are identified in the central ~ 15" x 15" region. These compact sources are responsible for 20 - 30 % of the total emission from the central kpc of the host galaxies at 2 cm, but only ~ 5 - 10 % at 6 cm. More than half of the compact sources appear to be HII regions. The HII regions with rising spectra must be fairly dense (n_i ~ 10^4 cm^(-3)) and are presumably very young. The largest of these HII regions require the excitation of 500 - 800 O stars, within regions of only few parsecs extent. These clusters approach the sizes expected for globular clusters. Thermal free-free emission from compact sources contributes more significantly at 2 cm, while diffuse synchrotron emission dominates at 6 cm. The radio HII regions are found near the centers of giant molecular clouds in projection, and do not have obvious visual counterparts.

Aging surveillance testing was performed in four safety and arming (S&A) devices used in Minuteman II missile systems. The age of the devices was approximately 37 years being typical of the inventory. Testing included nondestructive tests, electrical performance tests, non-operating environments, flight dynamic environments, withdraw tests, and firing tests. Squib circuit condition in the flight dynamics testing was monitored real time by a high sample rate digital data acquisition system. An igniter simulator was integrated with the devices for evaluation of the ignition transfer effectiveness through frangible windows in the igniter. The successful test results support an additional five-year service life extension of the device population. In the investigation of a test set induced inadvertent firing anomaly of one unit, the effect of command voltage level on device performance, electromagnetic interference, and arming/safing under vibration environments were evaluated for the first time and added to the knowledge on the capability and characteristics of the device.