Home

Active Layer Optimization in Ultra-Thin, Surface-Parallel, Deformable Mirrors

This method enables low-cost, lightweight, active mirrors with a large dynamic range and improved actuation characteristics. NASA’s Jet Propulsion Laboratory, Pasadena, California A design methodology was developed that optimizes the performance of active mirrors. Patterns of parameterized ellipsoidal actuators are overlaid onto the mirror, and then numerically optimized to improve performance of the mirror in optical modes that are typically difficult to correct, while also improving performance in other optical modes.

Posted in: Tech Briefs, Photonics, Optics, Articles, Briefs

Read More >>

Monolithic Dual Telescope for Compact Biaxial Lidar

Goddard Space Flight Center, Greenbelt, Maryland A document discusses the Ultra Compact Cloud Physics Lidar, a biaxial lidar with a narrow receiver field of view. It requires tight optical alignment between the transmitter and receiver paths while flying on various aircraft over various temperatures and in the presence of vibration. To achieve optical crossover as close to the lidar as possible, the transmit and receive telescopes must be built very closely to each other.

Posted in: Tech Briefs, Physical Sciences, Photonics, Articles, Briefs, TSP

Read More >>

Passive Aerosol Cloud Suite

High-accuracy polarization measurements can be made with high angular density across full images. Goddard Space Flight Center, Greenbelt, Maryland The Passive Aerosol Cloud Suite (PACS) is an imaging polarimeter that employs wide field-of-view (FOV) optics to obtain a highly accurate polarimetric signal across an image with hyperangle, multiangle views. PACS is designed to measure the array of parameters necessary to retrieve aerosol and cloud microphysical characteristics. The final goal of PACS is a flight model able to compete for a position on the Aerosol-Cloud-Ecology (ACE) Decadal Survey mission or other space-based platforms, but adaptations of the basic technology to airborne and ground-based applications are anticipated.

Posted in: Tech Briefs, Photonics, Optics, Articles, Briefs, TSP

Read More >>

Differential Nonlinearity in Analog Measurements

By: Jon Titus, Sealevel Systems, Inc. Q: In a previous answer you noted, "... most applications require linearity but not absolute precision..." What does that mean?

Posted in: Test & Measurement, White Papers, Briefs

Read More >>

Radiation Hard By Design (RHBD) Electronics

Under certain conditions, a false signal will be absorbed and a correct signal will be generated. Goddard Space Flight Center, Greenbelt, Maryland Current RHBD electronics are limited to speeds that approximate 250 MHz, regardless of the electronic process. The fact that determines the final speed is based on the nature of the current SEU (single-event upsets) radiation-tolerant latches, and the data flow between the latches through combinational logic.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Detecting Loss of Configuration Access of Reprogrammable FPGA Without External Circuitry

This innovation makes use of the clearing of distributed memory that results from configuration refreshes. Langley Research Center, Hampton, Virginia The configuration of the reprogrammable field-programmable gate array (FPGA) currently on the market is very susceptible to single event upset when it operates in radiation environments. The current state-of-the-art approach is to refresh the configuration while the FPGA is operating. When using this approach, it is essential to detect the loss of configuration access while the FPGA is operating in a radiation environment, allowing the system to initiate a configuration access recovery.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Micro-Coil Spring Interconnection for Ceramic Grid Array Packaged Integrated Circuits

This interconnection method extends the useful life of ceramic area array integrated circuits. Marshall Space Flight Center, Alabama This method of interconnecting ceramic integrated circuits to organic printed circuit boards (PCBs) is designed to substantially increase the life of the interconnections. This is accomplished by providing a means of compensating for the shear stresses produced by thermal excursions as a result of the large mismatch of coefficients of thermal expansion between the integrated circuit and the printed circuit board.

Posted in: Semiconductors & ICs, Briefs

Read More >>