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Avionics/Electronics Box Rail Mount System

Marshall Space Flight Center, Alabama There is limited space available to install numerous avionics boxes with the caveat that each box is a line replacement unit (LRU). Access to enable the removal of the boxes is limited, and it is critical that no tools and/or loose parts exist to ensure that no damage is done to aft-located components. Boxes are mounted on pallets and secured by captive screws with a tool. Most installation/removal requires two technicians.

Posted in: Briefs, Electronic Components, Electronics & Computers

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Semiconductor Nanomembrane-Based Flight Sensors and Arrays

These sensor arrays can be used to measure skin friction and pressure. John F. Kennedy Space Center, Florida There are two broad classes of methods for measuring skin friction (or wall shear): indirect and direct. The direct methods generally employ a movable element of the actual surface surrounded by a very small gap and connected to some type of flexure. One then measures the displacement of the movable element or the strain in the flexure to obtain the skin friction force acting on the movable element directly. Some methods of detecting skin friction relied on optical interferometric measurements of the thickness of an oil film applied to a test surface. The motion of the oil due to airflow creates thickness variations that can be associated to the frictional forces acting on the surface. Mapping of the surface over a small area is possible, but practical use of this technique is limited due to contamination of the tunnel by the free-flowing oil.

Posted in: Briefs, TSP, Electronic Components

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Dual I²C and SPI Slave Core for FPGA and ASIC Implementations

Goddard Space Flight Center, Greenbelt, Maryland The I2C/SPI Verilog core consists of a combined register transfer logic (RTL) Verilog code for a general-purpose I2C and serial-to-parallel interface (SPI) slave for implementations targeting field programmable gate arrays (FPGAs) and application specific integrated circuits (ASICs). The core was developed as part of the radiation hardened digital-to-analog converters’ 10-bit (RH-DAC10) and 12-bit (RH-DAC12) ASICs. The core contains both an I2C and SPI slave cores that share all inputs/outputs, and is selectable by setting a single input. The I2C portion uses an asynchronous design and does not require a continuous clock to operate, thus reducing the dynamic power consumption. The core serves as a baseline that can be tailored to any application requiring I2C and SPI slave interfaces. The core has been implemented and verified in both a commercial FPGA and a custom, radiation-hardened ASIC in a commercial CMOS (complementary metal-oxide semiconductor) 0.25-μm process, where the I2C and SPI were tested at 1 MHz and 50 MHz, respectively.

Posted in: Briefs, TSP, Electronics & Computers

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Automated Break-Out Box for Use with Low-Cost Spacecraft Integration and Test

Goddard Space Flight Center, Greenbelt, Maryland Electrical checkout and testing is a critical part of the overall space integration and test flow. Verifying proper harness and connector signal interfaces is key to ensuring component health and overall system functionality. Break-out boxes (BOBs) are used to give test personnel access to electrical signals for probing, voltage injection, isolation checks, safe-to-mate checks, and voltage/current measurements, and comparing to expected results. Currently, this involves manually attaching multimeters and oscilloscopes to banana jacks on the BOB, taking measurements, and comparing to expected results.

Posted in: Briefs, TSP, Electronic Components

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Radiation-Hardened 10BASE-T Ethernet Physical Interface (PHY)

Goddard Space Flight Center, Greenbelt, Maryland The EXPRESS Logistics Carrier (ELC) system was built by NASA Goddard for installation on the International Space Station (ISS). Four ELC systems are on ISS. Each ELC site includes two data nodes. The ELC requirements call for a radiation-hardened 10BASE-T Ethernet interface at each data node. The requirement for ELC was to support a full receive version of the interface, and only to provide a link pulse to the attached payloads on the transmit side of the interface. Further development required a full duplex version of a radiation-hardened 10BASE-T Ethernet interface to support the SpaceCube program.

Posted in: Briefs, TSP, Electronic Components

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Radiation-Hardened, Quad 12-Bit Digital-to-Analog Converter ASIC

This circuit incorporates science-driven features based on applications in a realistic space environment. Goddard Space Flight Center, Greenbelt, Maryland This radiation-hardened, compact, low-power, quad 12-bit digital-to-analog converter (DAC) application specific integrated circuit (ASIC) incorporates science-driven features based on applications in a realistic space environment such as threshold setting, current bias circuits, and general-purpose DC voltage generation. It is based on a previous 10-bit DAC that exhibited excellent test results, presenting the possibility of a 12-bit design.

Posted in: Briefs, TSP, Electronic Components

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Automated Generation of Failure Modes and Effects Document from a Simple SysML Model

NASA’s Jet Propulsion Laboratory, Pasadena, California This software queries a model of system in the MagicDraw program and uses that information to create an Excel spreadsheet that represents a basic FMEA (Failure Modes and Effects Analysis). It automates the generation of an FMEA; the user only has to open MagicDraw, then run this plugin to produce an Excel spreadsheet.

Posted in: Briefs, TSP, Electronic Components, Software

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