Special Coverage

Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research

Support for Diagnosis of Custom Computer Hardware

The Coldfire SDN Diagnostics software is a flexible means of exercising, testing, and debugging custom computer hardware. The software is a set of routines that, collectively, serve as a common software interface through which one can gain access to various parts of the hardware under test and/or cause the hardware to perform various functions. The routines can be used to construct tests to exercise, and verify the operation of, various processors and hardware interfaces. More specifically, the software can be used to gain access to memory, to execute timer delays, to configure interrupts, and configure processor cache, floating-point, and direct-memory-access units.

Posted in: Briefs, Electronics & Computers, Computer software and hardware, Diagnostics, Test procedures

Providing Goal-Based Autonomy for Commanding a Spacecraft

A computer program for use aboard a scientific- exploration spacecraft autonomously selects among goals specified in high-level requests and generates corresponding sequences of low-level commands, understandable by spacecraft systems. (As used here, “goals” signifies specific scientific observations.) From a dynamic, onboard set of goals that could oversubscribe spacecraft resources, the program selects a non-oversubscribing subset that maximizes a quality metric. In an early version of the program, the requested goals are assumed to have fixed starting times and durations. Goals can conflict by exceeding a limit on either the number of separate goals or the number of overlapping goals making demands on the same resource.

Posted in: Briefs, TSP, Information Sciences, Automatic pilots, Computer software and hardware, Spacecraft guidance, Logistics

Dynamic Method For Identifying Collected Sample Mass

G-Sample is designed for sample collection missions to identify the presence and quantity of sample material gathered by spacecraft equipped with end effectors. The software method uses a maximum-likelihood estimator to identify the collected sample’s mass based on onboard force-sensor measurements, thruster firings, and a dynamics model of the spacecraft. This makes sample mass identification a computation rather than a process requiring additional hardware.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Computer software and hardware, Test equipment and instrumentation, Spacecraft, Vehicle dynamics

Optimal Planning and Problem-Solving

CTAEMS MDP Optimal Planner is a problem- solving software designed to command a single spacecraft/rover, or a team of spacecraft/ rovers, to perform the best action possible at all times according to an abstract model of the spacecraft/rover and its environment. It also may be useful in solving logistical problems encountered in commercial applications such as shipping and manufacturing.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Spacecraft guidance, Logistics, Manufacturing processes, Materials handling

Attitude-Control Algorithm for Minimizing Maneuver Execution Errors

A G-RAC attitude- control algorithm is used to minimize maneuver execution error in a spacecraft with a flexible appendage when said spacecraft must induce translational momentum by firing (in open loop) large thrusters along a desired direction for a given period of time. The controller is dynamic with two integrators and requires measurement of only the angular position and velocity of the spacecraft. The global stability of the closed-loop system is guaranteed without having access to the states describing the dynamics of the appendage and with severe saturation in the available torque.

Posted in: Briefs, Information Sciences, Mathematical models, Attitude control, Booster rocket engines, Spacecraft

Grants Document-Generation System

The Grants Document- Generation System (GDGS) software allows the generation of official grants documents for distribution to the appropriate parties. The documents are created after the selection and entry of specific data elements and clauses. GDGS is written in Cold Fusion that resides on an SQL2000 database and is housed on-site at Goddard Space Flight Center. It includes access security written around GSFC’s (Goddard Space Flight Center’s) LIST system, and allows for the entry of Procurement Request information necessary for the generation of the resulting Grant Award.

Posted in: Briefs, Information Sciences, Computer software and hardware, Documentation, Financial management

Precipitation-Strengthened, High-Temperature, High-Force Shape Memory Alloys

Shape memory alloys capable of performing up to 400 °C have been developed for use in solidstate actuator systems.

Shape memory alloys (SMAs) are an enabling component in the development of compact, lightweight, durable, high-force actuation systems particularly for use where hydraulics or electrical motors are not practical. However, commercial shape memory alloys based on NiTi are only suitable for applications near room temperature, due to their relatively low transformation temperatures, while many potential applications require higher temperature capability. Consequently, a family of (Ni,Pt)1–xTix shape memory alloys with Ti concentrations x ≤ 50 atomic percent and Pt contents ranging from about 15 to 25 at.% have been developed for applications in which there are requirements for SMA actuators to exert high forces at operating temperatures higher than those of conventional binary NiTi SMAs. These alloys can be heat treated in the range of 500 °C to produce a series of fine precipitate phases that increase the strength of alloy while maintaining a high transformation temperature, even in Ti-lean compositions.

Posted in: Briefs, TSP, Materials, Sensors and actuators, Heat treatment, Alloys, Smart materials

Heat-Storage Modules Containing LiNO3•3H2O and Graphite Foam

Heat capacity per unit volume has been increased.

A heat-storage module based on a commercial open-cell graphite foam (PocoFoam or equivalent) imbued with lithium nitrate trihydrate (LiNO3•3H2O) has been developed as a prototype of other such modules for use as short-term heat sources or heat sinks in the temperature range of approximately 28 to 30 °C. In this module, the LiNO3•3H2O serves as a phase-change heat-storage material and the graphite foam as thermally conductive filler for transferring heat to or from the phase-change material. In comparison with typical prior heat-storage modules in which paraffins are the phase-change materials and aluminum fins are the thermally conductive fillers, this module has more than twice the heat-storage capacity per unit volume.

Posted in: Briefs, Materials, Energy storage systems, Heating, ventilation, and air conditioning systems (HVAC), Foams, Graphite

Improved Relief Valve Would Be Less Susceptible to Failure

Opening force and, hence, opening piston speed would be reduced.

The balanced-piston relief valve with side vented reaction cavity has been proposed as an improved alternative to a conventional high- pressure, high-flow relief valve. As explained below, the proposed valve would be less susceptible to failure.

Posted in: Briefs, Mechanical Components, Mechanics, Product development, Valves, Pistons

Using Composite Materials in a Cryogenic Pump

Shaft speed is increased and conductive leakage of heat is reduced.

Several modifications have been made to the design and operation of an extended-shaft cryogenic pump to increase the efficiency of pumping. In general, the efficiency of pumping a cryogenic fluid is limited by thermal losses (the thermal energy that the pump adds to the fluid). The sources of the thermal losses are pump inefficiency and leakage (conduction) of heat through the pump structure. Most cryogenic pumping systems are required to operate at maximum efficiency because the thermal energy added to the fluids by the pumps is removed by expensive down-stream refrigeration equipment. It would be beneficial to reduce thermal losses to the point where the downstream refrigeration equipment would not be necessary.

Posted in: Briefs, Mechanical Components, Mechanics, Thermal management, Composite materials, Pumps

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