Tech Briefs

Cyclops: the Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS)

Lyndon B. Johnson Space Center, Houston, Texas The Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS), also known as “Cyclops,” deployed the largest satellite ever from the International Space Station (ISS) on November 28, 2014. The satellite, SpinSat, a Naval Research Laboratory (NRL)/Department of Defense Space Test Program (DoD STP) satellite, is pioneering the utilization of electronically controlled solid propellant thrusters as well as acquiring vital atmospheric density data. It is a spherical satellite 22 inches in diameter, weighing 115 pounds, and will remain in orbit for over two years.

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Vacuum-Jacketed Cryogenic Flex-Through

John F. Kennedy Space Center, Florida A vacuum-jacketed, cryogenic flex hose was designed with an integrated flange to be able to pass through a vacuum chamber wall. This design increases the quality of the cryogenic fluid at the exit of the hose (i.e., more liquid, less vapor) by extending the hose vacuum-jacket through the chamber wall, where usually a non-insulated fluid fitting would be required.

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Normally-Closed Zero-Leak Valve with a Magnetostrictive Actuator

The valve can be used wherever normally closed valves are required. Goddard Space Flight Center, Greenbelt, Maryland A hermetically sealed, normally closed (NC) zero-leak valve has been developed. Prior to actuation, the valve isolates the working fluid in the upstream volume from the downstream volume with a parent metal seal. The valve utilizes the magnetostrictive alloy Terfenol-D for actuation. This alloy experiences a phenomenon known as magnetostriction, i.e., a gross elongation, when exposed to a magnetic field. This elongation fractures the seal within the wetted volume of the valve, opening the valve permanently and establishing fluid flow. The required magnetic field is generated by redundant coils concentric to the Terfenol, but isolated from the working fluid. The response time for this phenomenon to occur and subsequently for actuation is on the order of milliseconds. The wetted volume consists of entirely parent-metal 6Al-4V titanium, compatible with all storable propellants, helium, nitrogen, argon, isopropyl alcohol, and argon. When coupled with the parent metal seal, this design gives the valve internal and external leak rates of zero.

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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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