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Dive into the research topics where Binh Q. Le is active.

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Featured researches published by Binh Q. Le.


4th International Energy Conversion Engineering Conference and Exhibit (IECEC) | 2006

The MESSENGER Spacecraft Power Subsystem Thermal Design and Early Mission Performance

C. Jack Ercol; George Dakermanji; Binh Q. Le

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, launched on August 3, 2004, is a NASA spacecraft that will orbit the planet Mercury for a one-year mission. The spacecraft launch mass limitation, combined with the large solar distance variations, impose severe requirements on the spacecraft power and thermal subsystems. The spacecraft is three-axis stabilized. A sunshade protects the spacecraft from the high intensity solar flux. The attitude control maintains the sunshade pointed to the Sun. The solar panels, which are outside the thermal shield, are designed to survive normal Sun incidence at 0.3 AU. The solar panels consist of alternating rows of triple junction cells placed between Optical Solar Reflectors (OSRs). Solar panels thermal control is performed by tilting the panels with increasing solar flux. To minimize the mass of the spacecraft, the structure is made of composite materials. Spacecraft electronic boxes that are high power dissipaters are designed with special thermal vias that conduct the heat directly to diode heat pipes, which transport the heat of the box to thermal radiator panels on the side of the spacecraft behind the sunshade. The MESSENGER spacecraft is on a trajectory to enter Mercury orbit in 2011. The spacecraft is performing as designed.


document analysis systems | 2002

The MESSENGER Power Distribution Unit packaging design

Binh Q. Le; Sharon X. Ling; Larry R. Kennedy; George Dakermanji; Sean C. Laughery

A Power Distribution Unit (PDU) is being developed by The Johns Hopkins University Applied Physics Laboratory for the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft that will orbit the planet Mercury for one Earth year to complete the global mapping and the detailed characterization of the planets exosphere, magnetosphere, surface, and interior. The PDU contains the circuitry for the spacecraft pyrotechnic firing control, power distribution switching, load current and voltage monitoring, fuses, external relay switching, reaction wheel relay selects, and power system relays. It also supports the Inertial Measurement Unit (IMU) reconfiguration, Integrated Electronic Module (IEM) select relays, solar array drives, propulsion thruster firing control, and propulsion latch valve control. To enable the mission to reach the distant planet, significant weight reduction for all spacecraft electronics must be achieved. This requirement has led to an advanced electronic packaging design that begins with component selection, printed wiring board design with very small feature sizes, and a compact interconnection scheme. The significant challenge in the packaging design of the PDU is how to implement state-of-the-art technologies to minimize system weight and meet the stringent reliability required by the MESSENGER power system. This paper will describe the detailed electronic packaging design of the PDU, including the use of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices instead of conventional mechanical relays, high-density printed wiring board designs with blind and buried vias, and a modular packaging design to achieve significant weight reduction.


Lidar Techniques for Remote Sensing II | 1995

Laser rangefinder for the near-earth asteroid rendezvous (NEAR) mission

Timothy D. Cole; Mark T. Boies; Ashruf S. El-Dinary; R. Alan Reiter; Daniel E. Rodriguez; Robert J. Heins; Binh Q. Le; Robert C. Moore; Michael G. Grote; Charles Culpepper; Lee Stillman

The near-earth asteroid rendezvous (NEAR) mission is the first of the NASA discovery programs. Discovery-class programs emphasize small, low-cost, quick turnaround space missions that provide significant science returns. The NEAR spacecraft and ground control system are currently being developed and tested at the Applied Physics Laboratory (APL). The NEAR spacecraft will orbit, 433 Eros, possibly the most studied of the near-Earth asteroids. Subsequent to a 3-year cruise, the NEAR spacecraft is inserted into a 50-km-altitude orbit about Eros for 1 year to permit data collection in the infrared, visible, x-ray and gamma-ray regions. One instrument, the NEAR laser rangefinder (NLR), will provide altimetry data useful in characterizing the geophysical nature of Eros. In addition, ranging data from the NLR will support navigation functions associated with spacecraft station-keeping and orbit maintenance. The NLR instrument uniquely applies several technologies for use in space. Our configuration uses a direct-detection, bistatic design employing a gallium arsenide (GaAs) diode-pumped Cr:Nd:YAG laser for the 1.064-micrometer transmitter and an enhanced-silicon avalanche-photodiode (APD) detector for the receiver. Transmitter pulse energy provides the required signal-to-noise power ratio, SNRp, for reliable operation at 50 km. The selected APD exhibited low noise, setting the level achievable for noise equivalent power, NEP, by the receiver. The lithium-niobate (LiNbO3) Q-switched transmitter emits 12-ns pulses at 15.3 mJ/pulse, permitting reliable NLR operation beyond the required 50-km altitude. Cavity aperturing and a 9.3X Galilean telescope reduce beam divergence for high spatial sampling of Eross surface. Our receiver design is an f/3.4 Dall-Kirkham Cassegrain with a 7.62-cm clear aperture -- we emphasized receiver aperture area, Arx, over transmitter power, Pt, in our design based on the range advantage attainable according to the simplified range equation, Rmax equals [(Pt(rho) BArx)/(SNRp NEP)]1/2. Asteroid reflectivity, (rho) B, is estimated to be 0.05 at our wavelength. A reasonable power signal- to-noise ratio for reliable operation, SNRp, was assumed. To minimize our noise equivalent power, NEP, we carefully designed and selected the receiver components. The receiver circuit uses leading-edge detection of the laser backscatter. Our detector circuit is an enhanced-silicon APD hybrid using a video amplifier, an integrating Bessel filter, and a high- speed programmable threshold comparator. We accomplish time-of-flight (TOF) measurements digitally with an APL-designed GaAs application-specific integrated circuit. A radiation-hardened FORTH microprocessor controls range gating, data collection and formatting, and operational modes. Implementation of control and data communications between the spacecraft and rangefinder uses the MIL-STD 1553-bus architecture. Functional testing and calibration indicate exceptional performance; return power levels were reliably detected over several thresholds with 71-dB attenuation, while observed range jitter was equivalent to the resolution determined by the TOF GaAs chip (31.5 cm). This paper discusses NLR performance requirements, design implementation, and qualification testing. It also provides preliminary results from calibration and performance testing.


document analysis systems | 2002

A lightweight Integrated Electronics Module (IEM) packaging design for the MESSENGER spacecraft

Sharon X. Ling; R.F. Conde; Binh Q. Le

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a mission to orbit the planet Mercury. The comprehensive scientific data collected through the one-Earth-year orbital mission phase will allow scientists to study and understand the environment and evolution of the innermost terrestrial planet. The five-year cruise phase and the harsh environment of Mercury orbit pose challenges to the spacecraft subsystem design in terms of balancing an extremely tight mass budget with robust thermal and mechanical designs. The packaging design for a low-cost, lightweight Integrated Electronics Module (IEM) is presented in this paper. The commercial 6U Compact Peripheral Component Interconnect (PCI) Printed Wiring Board (PWB) design has been selected to reduce development cost. Several unique features of the IEM packaging design include using the RAD6000 processor developed by BAE Systems in the Main Processor board, 64-Mb Hyundai TSOPs stacked two-high for 1 GB of SDRAM on the Solid-State Recorder Assembly, and a 32-mm Ceramic Column Grid Array as the PCI Bridge chip. The IEM chassis that accommodates five PWBs is designed with thin-wall aluminum for weight savings, and is fabricated by investment casting for cost savings. Extensive thermal and structural analyses have been performed to ensure that the IEM is capable of surviving and functioning during launch, cruise, and orbit. Environment tests have been conducted on the pre-engineering IEM to validate analytical results.


SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation | 1996

NEAR laser rangefinder light-weight packaging design

Binh Q. Le; Timothy D. Cole; Daniel E. Rodriguez; R. Alan Reiter; Robert C. Moore; Mark T. Boies; Edward D. Schaefer; Lee Stillman; Stephen Krein

The NEAR laser range finder (NLR) design is a compact, light weight design with a high power laser transmitter and a high performance mirror receiver system. One of the main objectives of the NLR is to provide the in-situ distance measurement from the spacecraft to a near earth asteroid. An on board computer will compile this information to provide necessary navigation requirements for the NEAR satellite. Due to the weight budget constraint, the maximum weight limitation of the NLR has been a critical issue from the beginning of the program. To achieve this goal and meet the system design objectives, innovative designs have been implemented in the development of light weight optical, mechanism, and electronic packaging hardware. This paper provides details of the NLR electronic packaging design, thermal and structural designs.


document analysis systems | 2001

Evaluation and implementation of advanced electronic packaging techniques for reliable, cost-effective miniaturized space electronics

Sharon X. Ling; Binh Q. Le; A.L. Lew

Implementing advanced electronic packaging schemes in space electronics design is a desirable, cost-effective way to leverage existing technologies derived from consumer electronics. Demands for faster, better, lighter, and cheaper products have led to many innovative designs in commercial electronics. However, directly using commercially available packaging techniques in space electronics could be extremely risky without careful reliability study and assessment. With many years of experience in developing high-reliability electronics, the Space Department of the Johns Hopkins University Applied Physics Laboratory (JHU/APL) started the process of evaluating, qualifying, and developing commercial advanced packaging techniques for space application with chip-onboard (COB) technology. With our in-house fabrication and coating process, we can improve existing commercial COB technology to survive and function through the entire space mission. We have focused investigations on advanced interconnect methods such as flip-chip technology and high-density printed wiring board implemented with blind and buried microvias.


document analysis systems | 1999

Low-cost miniaturized electronics for space application with chip-on board technology-design, manufacturing and reliability considerations

Binh Q. Le; S.X. Ling; Richard F. Conde; Paul D. Schwartz; A.L. Lew

The shift in emphasis to smaller, better, and cheaper space systems, resulting from the NASA New Millennium Program (NMP) and similar initiatives in DOD-sponsored programs, demands highly innovative designs that cannot be feasibly implemented using conventional electronic packaging techniques. To meet these broad requirements the APL launched an internal research and development initiative to make significant advancements in electronic packaging technology. Among many miniaturization techniques available for design and development, chip-on-board (COB) based on laminated multichip module technology was selected. The technology utilizes a straightforward design concept, that has been simplified through careful review and testing. In the COB technology, both bare dies and conventional packaged devices are mounted on the same substrate with a special coating to protect the circuits from handling, ground testing, and in-orbit environments. The flexibility of COB packaging techniques helps resolving parts shortage, and last-minute part change problems. This paper summarizes the packaging design, development, and fabrication of two miniaturized space systems-the Command and Data Handling In Your Palm (C&DH IYP) and the Miniaturized Scientific Imager (MSI)-using COB technology. The C&DH IYP is a modular system consisting of multiple individual slices that can implement anything from a standalone Instrument Processor, to a Command and Data Handling system, or the entire electronics needed by a spacecraft. The MSI is a narrow-field-of-view visible imager design with a reflective telescope, a single filter, and a charged-couple device (CCD) detector. We demonstrate that mass and volume reduction of a factor of 10 can be achieved with low-cost COB packaging technology.


Archive | 1996

Integrated power source

Ark L. Lew; Joseph J. Suter; Binh Q. Le


Archive | 1997

Integrated power source layered with thin film rechargeable batteries, charger, and charge-control

Ark L. Lew; Joseph J. Suter; Binh Q. Le


Archive | 2002

Ambulatory surface skin temperature monitor

Fredrick M. Wigley; Robert A. Wise; Paul D. Schwartz; Ark L. Lew; David D. Scott; Binh Q. Le

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Ark L. Lew

Johns Hopkins University Applied Physics Laboratory

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Sharon X. Ling

Johns Hopkins University

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Ark L. Lew

Johns Hopkins University Applied Physics Laboratory

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Paul D. Schwartz

Johns Hopkins University Applied Physics Laboratory

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Elbert Nhan

Johns Hopkins University

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Paul D. Schwartz

Johns Hopkins University Applied Physics Laboratory

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David D. Scott

Johns Hopkins University

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Mark T. Boies

Johns Hopkins University

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