Test & Measurement

Automated Table Lookup Solution Algorithm of the Optimal Powered Descent Guidance for Planetary Landing

NASA’s Jet Propulsion Laboratory, Pasadena, California A novel automated table lookup method is developed to compute the near-fuel-optimal powered descent guidance trajectories, in real-time, for planetary soft landing. The main advantage of this algorithm is that it can be executed autonomously in milliseconds without performing iterative numerical computations to obtain the solution of the optimization problem. The key enabling idea behind this approach is to store, in a lookup table, a number of optimal trajectories that have been computed on the ground for a systematically chosen set of initial conditions. In flight, a near-fuel-optimal trajectory is computed for the actual initial condition by interpolating between these pre-computed trajectories. The lookup method requires only a small, predetermined number of basic algebraic operations. Moreover, this method guarantees that the interpolated solutions are in a prescribed neighborhood of the true optimal solutions.

Posted in: Articles, Briefs, Aeronautics, Aviation, Test & Measurement

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Computation of Wing Deflection and Slope from Measured Strain

Patent-pending methodology computes detailed wing loads during actual flight. Armstrong Flight Research Center, Edwards, California A lightweight, robust fiber-optic system is the technology behind a new method to compute wing deflection and slope from measured strain of an aircraft. This state-of-the-art sensor system is small, easy to install, and fast, and offers the first-ever means of obtaining real-time strain measurements that can accurately determine wing deflection and slope during flight. Such measurements are particularly useful for real-time virtual displays of wing motion, aircraft structural integrity monitoring, active drag reduction, active flexible motion control, and active loads alleviation.

Posted in: Articles, Briefs, Aeronautics, Aviation, Motion Control, Measuring Instruments

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A Continuous-Flow, Microfluidic, Microwave-Assisted Chemical Reactor

The reactor uses a directed 60-GHz source, which may require far less power to observe the same reactivity profiles. NASA’s Jet Propulsion Laboratory, Pasadena, California In industrial synthetic chemistry laboratories, reactions are generally carried out using batch-mode methodologies, stepwise reactions, and purifications to generate a final product. Each step has an associated yield of both the reaction itself and of the final purification that is largely dependent on the procedure being used, and the scientist carrying out the procedure. Continuous-flow reactors are one way of streamlining the process. Furthermore, microwave-enhanced, or microwave-assisted, chemistry has been demonstrated to aid in many of these areas; however, scaling has been a traditional problem with this technique.

Posted in: Articles, Briefs, TSP, Instrumentation, Physical Sciences, RF & Microwave Electronics, Test & Measurement

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High-Resolution Data Acquisition System Enables Reliable Engine Parameter Measurements

Obtaining accurate measurements is critical for improving vehicle component performance and overall system reliability. HBM, Inc., Marlborough, Massachusetts Data acquisition plays a critical role in improving vehicle component performance and overall system reliability. Measuring engine parameters, including engine cranking speed and the mechanical condition of the engine, requires high-resolution data acquisition equipment.

Posted in: Articles, Briefs, Instrumentation, Data Acquisition, Measuring Instruments, Test & Measurement

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Guarded Flat Plate Insulation Test Cryostat

Features include high testing rate and high data quality. John F. Kennedy Space Center, Florida The guarded flat plate insulation test cryostat (Cryostat-500) is a boil-off calorimeter comprising a flat-bottom test apparatus for measuring the absolute thermal performance of an insulation test article. Typical dimensions allow accepting test specimens 200 mm in diameter by up to 30 mm thick. The test chamber is guarded by a second cryogen chamber to prevent parasitic heat loads. System insulation materials provide additional thermal stability for testing over a wide range of environmental conditions. The cold-mass assembly can be configured for rigid or soft materials, with or without compressive loads.

Posted in: Articles, Briefs, Instrumentation, Data Acquisition, Test & Measurement

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Imaging Technique Could Detect Acoustically “Invisible” Cracks

It has long been understood that acoustic nonlinearity is sensitive to many physical properties including material microstructure and mechanical damage. The lack of effective imaging has, however, held back the use of this important method. Currently, engineers are able to produce images of the interior of components using ultrasound, but can only detect large problems such as cracks.

Posted in: News, Imaging, Test & Measurement

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Webb Telescope’s Heart Survives Deep-Freeze Test

After 116 days of being subjected to extremely frigid temperatures like those in space, the heart of the James Webb Space Telescope, the Integrated Science Instrument Module (ISIM) and its sensitive instruments, emerged unscathed from the thermal vacuum chamber at NASA’s Goddard Space Flight Center.

Posted in: News, Aerospace, RF & Microwave Electronics, Measuring Instruments, Monitoring, Test & Measurement

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