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This presentation will include information about Double Data Rate (DDR) technology, NASA Electronic Parts and Packaging (NEPP) tasks and their purpose, collaborations, a roadmap, NEPP partners, results to date, and future plans.
The electrician pictured is installing a General Electric Ground Fault Interrupter (GFI), a device which provides protection against electrical shock in the home or in industrial facilities. Shocks due to defective wiring in home appliances or other electrical equipment can cause severe burns, even death. As a result, the National Electrical Code now requires GFIs in all new homes constructed. This particular type of GFI employs a sensing element which derives from technology acquired in space projects by SCI Systems, Inc., Huntsville, Alabama, producer of sensors for GE and other manufacturers of GFI equipment. The sensor is based on the company's experience in developing miniaturized circuitry for space telemetry and other spacecraft electrical systems; this experience enabled SCI to package interruptor circuitry in the extremely limited space available and to produce sensory devices at practicable cost. The tiny sensor measures the strength of the electrical current and detects current differentials that indicate a fault in the functioning of an electrical system. The sensing element then triggers a signal to a disconnect mechanism in the GFI, which cuts off the current in the faulty circuit.
The goal of this technology is to provide improved calibration and measurement sensitivity to the Soil Moisture Active Passive Mission (SMAP) radiometer. While RF switches have been used in the past to calibrate microwave radiometers, the switch used on SMAP employs several techniques uniquely tailored to the instrument requirements and passive remote-sensing in general to improve radiometer performance. Measurement error and sensitivity are improved by employing techniques to reduce thermal gradients within the device, reduce insertion loss during antenna observations, increase insertion loss temporal stability, and increase rejection of radar and RFI (radio-frequency interference) signals during calibration. The two legs of the single-pole double-throw reference switch employ three PIN diodes per leg in a parallel-shunt configuration to minimize insertion loss and increase stability while exceeding rejection requirements at 1,413 MHz. The high-speed packaged diodes are selected to minimize junction capacitance and resistance while ensuring the parallel devices have very similar I-V curves. Switch rejection is improved by adding high-impedance quarter-wave tapers before and after the diodes, along with replacing the ground via of one diode per leg with an open circuit stub. Errors due to thermal gradients in the switch are reduced by embedding the 50-ohm reference load within the switch, along with using a 0.25-in. (approximately equal to 0.6-cm) aluminum prebacked substrate. Previous spaceflight microwave radiometers did not embed the reference load and thermocouple directly within the calibration switch. In doing so, the SMAP switch reduces error caused by thermal gradients between the load and switch. Thermal issues are further reduced by moving the custom, highspeed regulated driver circuit to a physically separate PWB (printed wiring board). Regarding RF performance, previous spaceflight reference switches have not employed high-impedance tapers to improve rejection. The use of open-circuit stubs instead of a via to provide an improved RF short is unique to this design. The stubs are easily tunable to provide high rejection at specific frequencies while maintaining very low insertion loss in-band.
During the Apollo program, unique ALSEP (Apollo Lunar Surface Experiments Package) stations were deployed and left on the surface for long term data collection. Powered by a SNAP-27 electrical power source, the packages continued to transmit useful data until September 30, 1977 (the end of the Fiscal year and termination of the budget). The instruments were varied but included an active seismic experiment (ASE), charged particle experiments, magnetometer experiment, micro-meteoroide/bolide detection experiments. Only only one, the Laser Ranging Retro-Reflector (LRRR) was continued to be used to the present day due to the passive nature of the device. After a dearth of data during an absence of 50 years, is it possible to restart similar packages using the advances in nano-sat technologies? An innovation effort is proposed that would first look at a 2U nano-sat package evolving to an eventual radio-isotope powered system that could be either part of a lunar lander or as an independent package. In the first phase, the packages would only survive during the Lunar day. In a second phase, the later radio-isotope options would place the surface packages in a semi-dormant mode during the Lunar night cycle. Communication capability developed in the TechEdSat-n flight series (UHF, S, X and optical bands) would help to independently close the link and potentially explore IoT devices that were powered only in the sunlight. In addition, limited mobility in the form factor of a nano-rover might also greatly extend the utility of such packages while adding evolutionary capability - and finally continue where the Apollo program was forced to leave off.
Many of the micromachines under consideration require computer support, indeed, one of the appeals of this technology is the ability to intermix mechanical, optical, analog, and digital devices on the same substrate. The amount of computer power is rarely an issue, the sticking point is the complexity of the software required to make effective use of these devices. Micromachines are the nano-technologist's equivalent of 'golden screws'. In other words, they will be piece parts in larger assemblages. For example, a nano-satellite may be composed of stacked silicon wafers where each wafer contains hundreds to thousands of micromachines, digital controllers, general purpose computers, memories, and high-speed bus interconnects. Comparatively few of these devices will be custom designed, most will be stock parts selected from libraries and catalogs. The novelty will lie in the interconnections. For example, a digital accelerometer may be a component part in an adaptive suspension, a monitoring element embedded in the wrapper of a package, or a portion of the smart skin of a launch vehicle. In each case, this device must inter-operate with other devices and probes for the purposes of command, control, and communication. We propose a software technology called 'weaves' that will permit large collections of micromachines and their attendant computers to freely intercommunicate while preserving modularity, transparency, and flexibility. Weaves are composed of networks of communicating software components. The network, and the components comprising it, may be changed even while the software, and the devices it controls, are executing. This unusual degree of software plasticity permits micromachines to dynamically adapt the software to changing conditions and allows system engineers to rapidly and inexpensively develop special purpose software by assembling stock software components in custom configurations.
Vacuum Microelectronic devices can be described as vacuum transistors or micro-miniature vacuum tubes, as one chooses. The fundamental reason behind this new technology is the very large current densities available from field emitters, namely as high as 10(8) A/sq cm. Array current densities as high as 1000 A/sq cm have been measured. Total electron transit times from source to drain for 1 micron feature size devices have been predicted to be about 150fs. This very short transit time implies the possibility of submillimeter wave transmitters and rectennas in devices which can operate with reasonably high voltages and which are small in size and are lightweight. In addition, they are expected to be extremely radiation hard and very temperature insensitive. That is, they are expected to have radiation hardness characteristics similar to vacuum tubes, and both the high temperature and low temperature limits should be determined by the package. That is, there should be no practical intrinsic temperature or carrier freezeout problems for devices based on metals or composites. But the technology is difficult to implement at the present time because it is based on 300 to 500 angstrom radius field emitters which must be relatively uniform. There is also the need to understand the non-equilibrium transport physics in the near-surface regions of the field emitters.
A practical method of applying a parylene (paraxylene) coating to hybrid microcircuit devices was developed for the prevention of circuit malfunctions existing prior to package sealing or formed upon exposure to the service environment. It was found that paralene and an associated primer (if used) had generally little or no adverse effect on the active and passive elements of typical hybrid microcircuits. Exceptions were related to high frequency circuitry, low resistivity thick film resistors, and highly sensitive PIN diodes. Advantages of the use of the coating included increased dielectric strength and increased interconnection bond strength. Coating service life in nitrogen or nitrogen with low levels of oxygen as a contaminant is shown to be in excess of 1000 hours at 150 C and can be projected to be in excess of 5000 hours at 125 C.
The author has identified the following significant results. The DAM package is an integrated set of manual procedures, computer programs, and graphic devices designed for efficient production of precisely registered and formatted maps from digital LANDSAT multispectral scanner data. The software can be readily implemented on any Univac 1100 series computer with standard peripheral equipment. This version of the software includes predefined spectral limits for use in classifying and mapping surface water.
The package is an integrated set of manual procedures, computer programs, and graphic devices designed for efficient production of precisely registered and formatted maps from digital LANDSAT multispectral scanner (MSS) data. The software can be readily implemented on any Univac 1100 series computer with standard peripheral equipment. This version of the software includes predefined spectral limits for use in classifying and mapping surface water for LANDSAT-1, LANDSAT-2, and LANDSAT-3. Tape formats supported include X, AM, and PM.
Low noise and linearity of charge-coupled devices (CCD's) combined with optical waveguide components in hybrid, integrated chip package. Concept used to measure laser flux in fiber-gyro application using sensing fibers that range from several to several tens of kilometers in length. Potential applications include optical delay measurement and linear detector of light flux emanating from fiber-optic waveguides.
The process and mechanism involved in producing glass microballoons (GMBs) of acceptable quality for laser triggered inertial fusion through use of glass jet levitation and manipulation are considered. The gas jet levitation device, called sonic pumps, provides positioning by timely and appropriate application of gas mementum from one or more of six sonic pumps which are arranged orthogonally in opposed pairs about the levitation region and are activated by an electrooptical, computer controlled, feedback system. The levitation device was fabricated and its associated control systems were assembled into a package and tested in reduced gravity flight regime of the NASA KC-135 aircraft.
The remote sensing research and technology to be used in the development of future NASA missions are discussed, with consideration given to earth sciences, planetary sciences, solar physics, and astrophysics. The remote sensing missions planned in the four application areas, their payload packages, and the particular instruments that will make up these packages are described. The advanced technologies to be used include systems and devices that address the detection of radiation in the radio, microwave, millimeter wave, submillimeter wave, IR, visible, UV, X-ray, and gamma-ray parts of the spectrum, including supporting technologies, such as optics, liquid cryogen transfer systems, and 'smart' sensors.
A conceptual design for a microstrip phased array with monolithic microwave integrated circuit (MMIC) amplitude and phase controls is described. The MMIC devices used are 20 GHz variable power amplifiers and variable phase shifters recently developed by NASA contractors for applications in future Ka band advanced satellite communication antenna systems. The proposed design concept is for a general NxN element array of rectangular lattice geometry. Subarray excitation is incorporated in the MMIC phased array design to reduce the complexity of the beam forming network and the number of MMIC components required. The proposed design concept takes into consideration the RF characteristics and actual phyical dimensions of the MMIC devices. Also, solutions to spatial constraints and interconnections associated with currently available packaging designs are discussed. Finally, the design of the microstrip radiating elements and their radiation characteristics are examined.
Magnetic thermometers are appealing at temperatures below about 0.1 Kelvin, because the avoid the noise self-heating problems associated with resistive thermometers. In practical, metallic dilute electronic thermometers add the advantages of chemical stability, high thermal conductivity, and easy in heat sinking work we describe a palladium-iron thermometer which was designed to be small and conveniently packaged and optimized for use at temperatures down to 0.05 Kelvin. The device showed Curie-Weiss behavior above about 0.06 Kelvin, and we achieve 41 nK/ square root of z temperature resolution at a temperature of 49 mK. We describe the design and operation of this thermometers and present the test results.
Future space exploration missions will need to use less logistical supplies if humans are to live for longer periods away from our home planet. Anything that can be done to reduce initial mass and volume of supplies or reuse or recycle items that have been launched will be very valuable. Reuse and recycling also reduce the trash burden and associated nuisances, such as smell, but require good systems engineering and operations integration to reap the greatest benefits. A systems analysis was conducted to quantify the mass and volume savings of four different technologies currently under development by NASA fs Advanced Exploration Systems (AES) Logistics Reduction and Repurposing project. Advanced clothing systems lead to savings by direct mass reduction and increased wear duration. Reuse of logistical items, such as packaging, for a second purpose allows fewer items to be launched. A device known as a heat melt compactor drastically reduces the volume of trash, recovers water and produces a stable tile that can be used instead of launching additional radiation protection. The fourth technology, called trash ]to ]supply ]gas, can benefit a mission by supplying fuel such as methane to the propulsion system. This systems engineering work will help improve logistics planning and overall mission architectures by determining the most effective use, and reuse, of all resources.
Future space exploration missions will need to use less logistical supplies if humans are to live for longer periods away from our home planet. Anything that can be done to reduce initial mass and volume of supplies or reuse or recycle items that have been launched will be very valuable. Reuse and recycling also reduce the trash burden and associated nuisances, such as smell, but require good systems engineering and operations integration to reap the greatest benefits. A systems analysis was conducted to quantify the mass and volume savings of four different technologies currently under development by NASA s Advanced Exploration Systems (AES) Logistics Reduction and Repurposing project. Advanced clothing systems lead to savings by direct mass reduction and increased wear duration. Reuse of logistical items, such as packaging, for a second purpose allows fewer items to be launched. A device known as a heat melt compactor drastically reduces the volume of trash, recovers water and produces a stable tile that can be used instead of launching additional radiation protection. The fourth technology, called trash-to-gas, can benefit a mission by supplying fuel such as methane to the propulsion system. This systems engineering work will help improve logistics planning and overall mission architectures by determining the most effective use, and reuse, of all resources.
The methods, techniques, and devices used in testing various electrical and electronic apparatus are presented. The items described range from semiconductor package leak detectors to automatic circuit analyzer and antenna simulators for system checkout. In many cases the approaches can result in considerable cost savings and improved quality control. The testing of various electronic components, assemblies, and systems; the testing of various electrical devices; and the testing of cables and connectors are explained.
Thermal fatigue life testing of various electronic packaging technologies is being performed by the Reliability Technology Group at the Jet Propulsion Laboratory.