Tech Briefs

Scenario Power Load Analysis Tool (SPLAT) MagicDraw Plug-in

The SPLAT tool could be applied to any project that needs to track time-dependent power consumption; it computes power usage profiles based on modeled component information and scenarios. NASA’s Jet Propulsion Laboratory, Pasadena, California Power consumption during all phases of spacecraft flight is of great interest to the aerospace community. As a result, significant analysis effort is exerted by both system and electrical-domain engineers to understand the rates of electrical energy generation and consumption under many operational scenarios of the system. Previously, no standard tool existed for creating and maintaining a Power Equipment List (PEL) of spacecraft components that consume power, and no standard tool existed for generating power load profiles based on this PEL information during mission design phases. Projects have traditionally either developed ad-hoc spreadsheet-based tools, or adapted complex simulation tools to compute such resource predictions; both of these approaches have significant limitations.

Posted in: Briefs, Power Management

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Wideband, GaN MMIC, Distributed Amplifier-Based Microwave Power Module

The solid-state module operates as a radar, communication, or navigation system. John H. Glenn Research Center, Cleveland, Ohio Historically, the term microwave power module (MPM) has been associated with a small, fully integrated, self-contained radio frequency (RF) amplifier that combines both solid-state and microwave vacuum electronics technologies. Typically, the output power of these MPMs is on the order of about 100 Watts CW over an octave bandwidth. The MPMs require both a solid-state amplifier at the front end and a microwave vacuum electronics amplifier at the back end. However, such MPMs cannot be utilized for communications because the MPMs are not optimized for linearity or efficiency. Also, the MPMs can be very expensive to manufacture, particularly when modules are produced in very small quantities for space applications. Also, a kilovolt (kV) class power supply is required to power the traveling-wave tube amplifier, which is a part of the microwave vacuum electronics.

Posted in: Briefs, Power Management

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Integrated Solar Array Power Management System

Marshall Space Flight Center, Alabama When solar cells are electrically connected to form solar arrays, they are organized into strings. Each string represents a specific number of cells connected in series to produce a specific voltage. The strings are then connected in parallel to add their currents to meet the array power requirement. This requires that the strings have the same voltage. Blocking diodes are used to take out strings with voltage that is too low, resulting in loss of power. When the arrays are mounted to a non-coplanar surface such as a spacecraft body or inflatable structure, many strings will have voltages lower than the rated voltage. This regulator manages the voltage of each string individually so that its power may be used, regardless of its voltage. It does this by converting each string’s energy into a series of high-voltage pulses that charges a reservoir capacitor to one of a set of common voltages used by the spacecraft bus. This allows for use of all of the illuminated strings in producing well-regulated power at pre-programmed voltages.

Posted in: Briefs, Power Management

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High-Energy-Density Solid-State Li-Ion Battery with Enhanced Safety

John H. Glenn Research Center, Cleveland, Ohio High-energy-density and safe rechargeable batteries are required for NASA’s future exploration missions. Lithium-ion (Li-ion) batteries are attractive energy storage systems due to their relatively high energy and power densities. However, the unfavorable side reactions between the electrodes and the liquid electrolyte adversely impact performance. These interfacial reactions are in the form of either anodic oxidation of the electrolyte, or dissolution of the cathode into the electrolyte. As a result, the practical capacity and cycle life of the battery are limited. More importantly, the reactions at the cathode-electrolyte interface pose a serious threat to safety due to the electrolyte decomposition and formation of gaseous products within the cell. In addition, growth of lithium dendrite on the anode can cause cell short circuit and lead to fire or even explosion in the presence of liquid electrolyte.

Posted in: Briefs, Thermal Management

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An On-Demand Gas Generator for CubeSat or Low-Mass Propulsion Systems

This system is applicable to aerospace, automotive, ocean/marine, or limited-resource environments. NASA’s Jet Propulsion Laboratory, Pasadena, California There are difficulties related to storing enough gas to propel a CubeSat within an onboard tank. Currently, a CubeSat requiring a large volume of gas for extended propulsion (outside Earth orbit) would need to store liquefied gases that require heavy-bodied tanks that add significant weight to the spacecraft. Safe storage of gases is difficult and not suited well to the CubeSat platform.

Posted in: Briefs

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Suppression of Unwanted Noise and Howl in a Test Configuration Where Jet Exhaust is Discharged Into a Duct

This method is permanent to a test facility, and does not need to be changed from test to test. John H. Glenn Research Center, Cleveland, Ohio This technology is based on a model-scale experiment simulating a test facility where an engine exhaust is discharged into a duct. Such a configuration sometimes encounters unwanted noise in the form of high-amplitude spectral levels in certain frequency ranges or, in worst cases, a howl that can raise structural concern. The innovation involves placement of a velocity fluctuation damper at the end of the duct. Such a damper is shown to suppress not only the broadband unwanted noise, but also the howl when it occurs. Even though placing the damper on the upstream end of the duct works, the preferred location is the downstream end.

Posted in: Briefs

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Distributed, Fast, Intelligent Infrastructure Health Monitoring System

Improve operation and reduce maintenance costs with intelligent systems. Stennis Space Center, Mississippi NASA needed an innovative solution to conduct system assessments of frameworks and to characterize subsystems of interest. This tool would be required to determine anomalies; examine their causes (root-cause analysis); make predictive statements (prognostics); provide intelligent health monitoring with incremental knowledge for working with unknown scenarios; and provide maintenance support for a complex collection of systems, subsystems, and elements in rocket engine test platforms.

Posted in: Briefs, Electronics & Computers

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