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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

FPGA for Power Control of MSL Avionics

A PLGT FPGA (Field Programmable Gate Array) is included in the LCC (Load Control Card), GID (Guidance Interface & Drivers), TMC (Telemetry Multiplexer Card), and PFC (Pyro Firing Card) boards of the Mars Science Laboratory (MSL) spacecraft. (PLGT stands for PFC, LCC, GID, and TMC.) It provides the interface between the backside bus and the power drivers on these boards. The LCC drives power switches to switch power loads, and also relays. The GID drives the thrusters and latch valves, as well as having the star-tracker and Sun-sensor interface. The PFC drives pyros, and the TMC receives digital and analog telemetry. The FPGA is implemented both in Xilinx (Spartan 3- 400) and in Actel (RTSX72SU, ASX72S). The Xilinx Spartan 3 part is used for the breadboard, the Actel ASX part is used for the EM (Engineer Module), and the pin-compatible, radiation-hardened RTSX part is used for final EM and flight. The MSL spacecraft uses a FC (Flight Computer) to control power loads, relays, thrusters, latch valves, Sun-sensor, and star-tracker, and to read telemetry such as temperature. Commands are sent over a 1553 bus to the MREU (Multi-Mission System Architecture Platform Remote Engineering Unit). The MREU resends over a remote serial command bus c-bus to the LCC, GID TMC, and PFC. The MREU also sends out telemetry addresses via a remote serial telemetry address bus to the LCC, GID, TMC, and PFC, and the status is returned over the remote serial telemetry data bus.

Wang, Duo↗
NASA NTRS2012

High-Voltage, Low-Power BNC Feedthrough Terminator

This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

Bearden, Douglas↗
NASA NTRS2016

Command and Data Handling Branch Internship

Modular Integrated Stackable Layers (MISL) is a computer system designed for simple, fast, and cost effective flexible reconfiguration in space environments such as the ISS and Orion projects for various uses. Existing applications include wireless and wired communications, data acquisition and instrumentation, and camera systems, and potential applications include bus protocol converters and subsystem control. MISL is based on Texas Instruments (TI)' MSP430 16-bit ultra-low-power microcontroller device. The purpose of my project was to integrate the MISL system with a liquid crystal display (LCD) touchscreen. The LCD, manufactured by Crystalfontz and part number CFAF320240F-035T-TS, is a 320 by 240 RGB resistive color screen including an optional carrier board. The vast majority of the project was done with Altium Designer, a tool for printed circuit board (PCB) schematic capture, 3D design, and FPGA (Field Programmable Gate Array) development. The new PCB was to allow the LCD to directly stack to the rest of MISL. Research was done with datasheets for the TI microcontroller and touchscreen display in order to meet desired hardware specifications. Documentation on prior MISL projects was also utilized. The initial step was to create a schematic for the LCD, power bus, and data bus connections between components. A layout was then designed with the required physical dimensions, routed traces and vias, power and ground planes, layer stacks, and other specified design rules such as plane clearance and hole size. Multiple consultation sessions were held with Hester Yim, the technical discipline lead for the Command and Data Handling Branch, and Christy Herring, the lead PCB layout designer in the Electronic Design and Manufacturing Branch in order to ensure proper configuration. At the moment, the PCB is awaiting revision by the latter-mentioned branch. Afterwards, the board will begin to undergo the manufacturing and testing process. Throughout the internship at Johnson Space Center, I gained several technical and professional skills. I gained proficiency in Altium Designer and experience using subversion clients, as well as knowledge in PSpice with OrCAD and battery design for spaceflight from on-site. I also gained networking, organization, and communication skills throughout meetings with coworkers and other interns. This internship at Johnson Space Center has impacted my future aspirations by further inspiring me to follow a career path into space rated engineering technology and human spaceflight applications. After graduation, I plan to attend graduate Modular Integrated Stackable Layers (MISL) is a computer system designed for simple, fast, and cost effective flexible reconfiguration in space environments such as the ISS and Orion projects for various uses. Existing applications include wireless and wired communications, data acquisition and instrumentation, and camera systems, and potential applications include bus protocol converters and subsystem control. MISL is based on Texas Instruments’ MSP430 16 bit ultra-low power microcontroller device. The purpose of my project was to integrate the MISL system with a liquid crystal display touchscreen. The LCD, manufactured by Crystalfontz and part number CFAF320240F-035T-TS, is a 320x240 RGB resistive color screen including an optional carrier board.The vast majority of the project was done with Altium Designer, a tool for printed circuit board (PCB) schematic capture, 3D design, and FPGA development. The new PCB was to allow the LCD to directly stack to the rest of MISL. Research was done with datasheets for the TI microcontroller and touchscreen display in order to meet desired hardware specifications. Documentation on prior MISL projects was also utilized. The initial step was to create a schematic for the LCD, power bus, and data bus connections between components. A layout was then designed with the required physical dimensions, routed traces and vias, power and ground planes, layer stacks, and other specified design rules such as plane clearance and hole size. Multiple consultation sessions were held with Hester Yim, the technical discipline lead for the Command and Data Handling Branch, and Christy Herring, the lead PCB layout designer in the Electronic Design and Manufacturing Branch in order to ensure proper configuration. At themoment, the PCB is awaiting revision by the latter-mentioned branch. Afterwards, the board will begin to undergo the manufacturing and testing process.Throughout the internship at Johnson Space Center, I gained several technical and professional skills. I gained proficiency in Altium Designer and experience using subversion clients, as well as knowledge in PSpice with OrCAD and battery design for spaceflight from on-site. I also gained networking, organization, and communication skills throughout meetings with coworkers and other interns. This internship at Johnson Space Center has impacted my future aspirations by further inspiring me to follow a career path into space rated engineering technology and human spaceflight applications. After graduation, I plan to attend graduate school for a master's or doctorate degree in electrical or computer engineering.

Billings, Rachel Mae↗
NASA NTRS1979

Optical digital techniques

Optical interface losses between transmitter-to-fiber interface, connector-to-connector interface, and fiber-to-receiver interface were studied. System effects such as pulse dispersion, risetimes of the sources and detectors, type of fibers used, output power of the sources, and detector sensitivity were considered. Data bus systems such as TEE, Star, and Hybrid were analyzed. The matter of single fiber versus bundle technologies for future avionics systems was considered. The existing data bus system on Space Shuttle was examined and an optical analog was derived for a fiber bundle system, along with the associated power margin. System tests were performed on a feasibility model of a 9-port Star data bus system including BER, star losses, connector losses, etc. The same system was subjected to EMI between the range of 200 Hz to 10 GHz at 20V/m levels. A lightning test was also performed which simulated the conditions similar to those on Space Shuttle. The data bus system was found to be EMI and lightning hard. It is concluded that an optical data bus system is feasible for shuttle orbiter type vehicles.

Source record↗
NASA NTRS1983

Distributed multiport memory architecture

A multiport memory architecture is diclosed for each of a plurality of task centers connected to a command and data bus. Each task center, includes a memory and a plurality of devices which request direct memory access as needed. The memory includes an internal data bus and an internal address bus to which the devices are connected, and direct timing and control logic comprised of a 10-state ring counter for allocating memory devices by enabling AND gates connected to the request signal lines of the devices. The outputs of AND gates connected to the same device are combined by OR gates to form an acknowledgement signal that enables the devices to address the memory during the next clock period. The length of the ring counter may be effectively lengthened to any multiple of ten to allow for more direct memory access intervals in one repetitive sequence. One device is a network bus adapter which serially shifts onto the command and data bus, a data word (8 bits plus control and parity bits) during the next ten direct memory access intervals after it has been granted access. The NBA is therefore allocated only one access in every ten intervals, which is a predetermined interval for all centers. The ring counters of all centers are periodically synchronized by DMA SYNC signal to assure that all NBAs be able to function in synchronism for data transfer from one center to another.

Kohl, W. H.↗
NASA NTRS1986

Optical technology for flight control systems

Optical applications to the flight control system including optical data bus, sensors, and transducers are analyzed. Examples of optical data bus include airborne light optical fiber technology (ALOFT), F-5E, YA-7D, MIL-STD-1553 fiber optic data bus and NAL-optic data bus. This NAL-optic data bus is applied to STOL, and its characteristics are stressed. Principles and advantages of optical pulse-digital transducers are discussed.

Mayanagi, M.↗
NASA NTRS1992

Spacelab, Spacehab, and Space Station Freedom payload interface projects

Contributions were made to several projects. Howard Nguyen was assisted in developing the Space Station RPS (Rack Power Supply). The RPS is a computer controlled power supply that helps test equipment used for experiments before the equipment is installed on Space Station Freedom. Ron Bennett of General Electric Government Services was assisted in the design and analysis of the Standard Interface Rack Controller hardware and software. An analysis was made of the GPIB (General Purpose Interface Bus), looking for any potential problems while transmitting data across the bus, such as the interaction of the bus controller with a data talker and its listeners. An analysis was made of GPIB bus communications in general, including any negative impact the bus may have on transmitting data back to Earth. A study was made of transmitting digital data back to Earth over a video channel. A report was written about the study and a revised version of the report will be submitted for publication. Work was started on the design of a PC/AT compatible circuit board that will combine digital data with a video signal. Another PC/AT compatible circuit board is being designed to recover the digital data from the video signal. A proposal was submitted to support the continued development of the interface boards after the author returns to Memphis State University in the fall. A study was also made of storing circuit board design software and data on the hard disk server of a LAN (Local Area Network) that connects several IBM style PCs. A report was written that makes several recommendations. A preliminary design review was started of the AIVS (Automatic Interface Verification System). The summer was over before any significant contribution could be made to this project.

Smith, Dean Lance↗
NASA NTRS2001

Flight Computer Processing Avionics for Space Station Microgravity Experiments: A Risk Assessment of Commercial Off-the-Shelf Utilization

NASA/Marshall Space Flight Center (MSFC) is continually looking for ways to reduce the costs and schedule and minimize the technical risks during the development of microgravity programs. One of the more prominent ways to minimize the cost and schedule is to use off-the-shelf hardware (OTS). However, the use of OTS often increases the risk. This paper addresses relevant factors considered during the selection and utilization of commercial off-the-shelf (COTS) flight computer processing equipment for the control of space station microgravity experiments. The paper will also discuss how to minimize the technical risks when using COTS processing hardware. Two microgravity experiments for which the COTS processing equipment is being evaluated for are the Equiaxed Dendritic Solidification Experiment (EDSE) and the Self-diffusion in Liquid Elements (SDLE) experiment. Since MSFC is the lead center for Microgravity research, EDSE and SDLE processor selection will be closely watched by other experiments that are being designed to meet payload carrier requirements. This includes the payload carriers planned for the International Space Station (ISS). The purpose of EDSE is to continue to investigate microstructural evolution of, and thermal interactions between multiple dendrites growing under diffusion controlled conditions. The purpose of SDLE is to determine accurate self-diffusivity data as a function of temperature for liquid elements selected as representative of class-like structures. In 1999 MSFC initiated a Center Director's Discretionary Fund (CDDF) effort to investigate and determine the optimal commercial data bus architecture that could lead to faster, better, and lower cost data acquisition systems for the control of microgravity experiments. As part of this effort various commercial data acquisition systems were acquired and evaluated. This included equipment with various form factors, (3U, 6U, others) and equipment that utilized various bus structures, (VME, PC104, STD bus). This evaluation of hardware was performed in conjunction with a trade study that considered over twenty (20) different factors relevant to the selection of an optimum design approach. These factors included; safety, sizing and timing, radiation hardness and single event upset, power consumption, heat dissipation, size and volume, expected service life, maintainability, heritage, operating systems, requirements for software reuse, availability of compatible interface boards, relative cost, schedule, reliability, EMI/EMC factors, "hot swap" capability, standards for conduction cooling, I/O capabilities, unique carrier requirements and operating system considerations. The approach to evaluate Safety as part of this study included a review of the Preliminary Hazard Analysis (PHA) for each of the experiment designs and a determination of how each hazard could be addressed and eliminated when different processors were selected. This included evaluating various design approaches and trade-offs between fault tolerant designs and fail-safe designs in accordance with NSTS 1700.7B. This will include the results of radiation testing where available. Various operating systems, such as VxWorks, Linux, QNX, and Embedded NT are evaluated and the advantages and disadvantages of their utilization are also addressed. Design implementation strategies for the various operating systems are considered and discussed. This paper presents the results and recommendations from this trade study. Preliminary conclusions from this study are that safety concerns from lack or radiation testing on COTS equipment can be addressed by additional testing and design considerations, the PC104 bus provided adequate I/O for the SDLE and EDSE microgravity experiments, and PC104 bus components offered significant advantages over VME and cPCI for weight and space reductions.

Estes, Howard↗
NASA NTRS2004

Development of Electronic Load Controllers for Free-Piston Stirling Convertors Aided by Stirling Simulation Model

The free-piston Stirling convertor end-to-end modeling effort at the NASA Glenn Research Center has produced a software-based test bed in which free-piston Stirling convertors can be simulated and evaluated. The simulation model includes all the components of the convertor: the Stirling cycle engine, heat source, linear alternator, controller, and load. So far, it has been used in evaluating the performance of electronic controller designs. Three different controller design concepts were simulated using the model: 1) Controllers with parasitic direct current loading. 2) Controllers with parasitic alternating current loading. 3) Controllers that maintain a reference current. The free-piston Stirling convertor is an electromechanical device that operates at resonance. It is the function of the electronic load controller to ensure that the electrical load seen by the machine is always great enough to keep the amplitude of the piston and alternator oscillation at the rated value. This is done by regulating the load on the output bus. The controller monitors the instantaneous voltage, regulating it by switching loads called parasitic loads onto the bus whenever the bus voltage is too high and removing them whenever the voltage is too low. In the first type of controller, the monitor-ing and switching are done on the direct-current (dc) bus. In the second type, the alternating current bus is used. The model allows designers to test a controller concept before investing time in hardware. The simulation code used to develop the model also offers detailed models of digital and analog electronic components so that the resulting designs are realistic enough to translate directly into hardware circuits.

Regan, Timothy F.↗
NASA NTRS2008

Attitude and Translation Control of a Solar Sail Vehicle

A report discusses the ability to control the attitude and translation degrees-of-freedom of a solar sail vehicle by changing its center of gravity. A movement of the spacecraft s center of mass causes solar-pressure force to apply a torque to the vehicle. At the compact core of the solar-sail vehicle lies the spacecraft bus which is a large fraction of the total vehicle mass. In this concept, the bus is attached to the spacecraft by two single degree-of-freedom linear tracks. This allows relative movement of the bus in the sail plane. At the null position, the resulting solar pressure applies no torque to the vehicle. But any deviation of the bus from the null creates an offset between the spacecraft center of mass and center of solar radiation pressure, resulting in a solar-pressure torque on the vehicle which changes the vehicle attitude. Two of the three vehicle degrees of freedom can be actively controlled in this manner. The third, the roll about the sunline, requires a low-authority vane/propulsive subsystem. Translation control of the vehicle is achieved by directing the solar-pressure-induced force in the proper inertial direction. This requires attitude control. Attitude and translation degrees-of-freedom are therefore coupled. A guidance law is proposed, which allows the vehicle to stationkeep at an appropriate point on the inertially-rotating Sun-Earth line. Power requirements for moving the bus are minimal. Extensive software simulations have been performed to demonstrate the feasibility of this concept.

Singh, Gurkirpal↗
NASA NTRS2003

Command Interface ASIC - Analog Interface ASIC Chip Set

A command interface application-specific integrated circuit (ASIC) and an analog interface ASIC have been developed as a chip set for remote actuation and monitoring of a collection of switches, which can be used to control generic loads, pyrotechnic devices, and valves in a high-radiation environment. The command interface ASIC (CIA) can be used alone or in combination with the analog interface ASIC (AIA). Designed primarily for incorporation into spacecraft control systems, they are also suitable for use in high-radiation terrestrial environments (e.g., in nuclear power plants and facilities that process radioactive materials). The primary role of the CIA within a spacecraft or other power system is to provide a reconfigurable means of regulating the power bus, actuating all valves, firing all pyrotechnic devices, and controlling the switching of power to all switchable loads. The CIA is a mixed-signal (analog and digital) ASIC that includes an embedded microcontroller with supporting fault-tolerant switch control and monitoring circuitry that is capable of connecting to a redundant set of interintegrated circuit (I(sup 2)C) buses. Commands and telemetry requests are communicated to the CIA. Adherence to the I(sup 2)C bus standard helps to reduce development costs by facilitating the use of previously developed, commercially available components. The AIA is a mixed-signal ASIC that includes the analog circuitry needed to connect the CIA to a custom higher powered version of the I(sup 2)C bus. The higher-powered version is designed to enable operation with bus cables longer than those contemplated in the I(sup 2)C standard. If there are multiple higher-power I(sup 2)C-like buses, then there must an AIA between the CIA and each such bus. The AIA includes two identical interface blocks: one for the side-A I(sup 2)C clock and data buses and the other for the side B buses. All the AIAs on each side are powered from a common power converter module (PCM). Sides A and B of the I(sup 2)C buses are electrically isolated from each other (see figure). They are also isolated from the CIA by use of transformer coupling of signals between the AIA blocks and the CIA.

Ruiz, Baldes↗
NASA NTRS2011

Teleoperated Marsupial Mobile Sensor Platform Pair for Telepresence Insertion Into Challenging Structures

A platform has been developed for two or more vehicles with one or more residing within the other (a marsupial pair). This configuration consists of a large, versatile robot that is carrying a smaller, more specialized autonomous operating robot(s) and/or mobile repeaters for extended transmission. The larger vehicle, which is equipped with a ramp and/or a robotic arm, is used to operate over a more challenging topography than the smaller one(s) that may have a more limited inspection area to traverse. The intended use of this concept is to facilitate the insertion of a small video camera and sensor platform into a difficult entry area. In a terrestrial application, this may be a bus or a subway car with narrow aisles or steep stairs. The first field-tested configuration is a tracked vehicle bearing a rigid ramp of fixed length and width. A smaller six-wheeled vehicle approximately 10 in. (25 cm) wide by 12 in. (30 cm) long resides at the end of the ramp within the larger vehicle. The ramp extends from the larger vehicle and is tipped up into the air. Using video feedback from a camera atop the larger robot, the operator at a remote location can steer the larger vehicle to the bus door. Once positioned at the door, the operator can switch video feedback to a camera at the end of the ramp to facilitate the mating of the end of the ramp to the top landing at the upper terminus of the steps. The ramp can be lowered by remote control until its end is in contact with the top landing. At the same time, the end of the ramp bearing the smaller vehicle is raised to minimize the angle of the slope the smaller vehicle has to climb, and further gives the operator a better view of the entry to the bus from the smaller vehicle. Control is passed over to the smaller vehicle and, using video feedback from the camera, it is driven up the ramp, turned oblique into the bus, and then sent down the aisle for surveillance. The demonstrated vehicle was used to scale the steps leading to the interior of a bus whose landing is 44 in. (.1.1 m) from the road surface. This vehicle can position the end of its ramp to a surface over 50 in. (.1.3 m) above ground level and can drive over rail heights exceeding 6 in. (.15 cm). Thus configured, this vehicle can conceivably deliver the smaller robot to the end platform of New York City subway cars from between the rails. This innovation is scalable to other formulations for size, mobility, and surveillance functions. Conceivably the larger vehicle can be configured to traverse unstable rubble and debris to transport a smaller search and rescue vehicle as close as possible to the scene of a disaster such as a collapsed building. The smaller vehicle, tethered or otherwise, and capable of penetrating and traversing within the confined spaces in the collapsed structure, can transport imaging and other sensors to look for victims or other targets.

Krasowski, Michael J.↗
NASA NTRS2011

Circuit for Communication Over Power Lines

Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system.

Krasowski, Michael J.↗
NASA NTRS2018

Simulation and Verification System and Method

A simulation and verification system and method. An interoperability server provides a communications hub for communications between communicating nodes. Nodes connected to a first protocol data bus communicate in a first protocol, e.g., a half-duplex bus protocol. Nodes connected to a second protocol data bus communicate in a second protocol, e.g., a full-duplex bus protocol. A time synchronization bus provides time-frames for synchronizing operation of connected nodes. Interceptors optionally intercept communications between nodes.

Seeger, Steven↗
NASA NTRSDate not supplied

Windform® XT 2.0 Use as 3U CubeSat Primary Structure

CubeSats provide a platform for small-scale space research and technology demonstration at reduced complexity, cost, and development time. These advantages drove the NASA Langley Research Center (LaRC) to develop and launch the GPX2 3U CubeSat to explore the viability of using Commercial Off-The-Shelf (COTS) differential GPS (dGPS) in low earth orbit. To reduce manufacturing costs and increase design flexibility, the project chose additive manufactured Windform® XT 2.0 as the primary bus material rather than traditional subtractive manufactured (milled) metal. The bus is a two-part, Selective Laser Sintered, 3D-print structure consisting of a single-piece, five-walled chassis and single-walled cover. The bus was specially designed to allow the project to accommodate the payload electronics stack as well as antennas, receivers, and deployable mechanisms. By using an additive manufactured solution, LaRC was able to design in features unrealizable through traditional milling, with a lead-time of roughly two weeks. In comparison, traditional subtractive manufacturing limits geometry options due to toolpath reach and bus construction would have required multiple components for each wall. This would have resulted in a more costly, longer lead-time article with more joints, fasteners, and complexity with a commensurate increase in overall mass. A number of lessons-learned were captured during the design, analysis, and testing of the GPX2 CubeSat covering thermal and structural analysis, vibration modeling, and geometric tolerancing. Additionally, a variety of material testing and verification were performed before and during spacecraft design and integration to assure the suitability of Windform® XT 2.0 for the launch and mission environments. This article provides the highlights of designing and testing the GPX2 bus.

CubeSat↗
NASA NTRS1972

Separation and communications geometry analysis for a Jupiter entry probe from a Pioneer spacecraft

The separation and communications geometry analysis is presented which shows that it is possible to target a Jupiter entry probe from a Pioneer spin-stabilized vehicle to desired entry conditions and maintain a continuous line-of-sight communications link while the probe descends to a pressure of 10 bars within the atmosphere. Such a targeting is possible with either the deflected probe mode or with the deflected bus mode. For the nominal mission studied, an 800 day trip in 1978 with the Pioneer type spacecraft flying by a 1.3 R(J), it was possible to achieve entries near zero angle of attack at about -25 deg relative entry flight path angle. Because of the constraint on the deflection maneuver for the deflected probe mode, the deflection and phasing velocity requirements are much larger for this mode. The geometry parameters, look angles, ranges and range rates, provided by this analysis permit the design of a functional communications system for the bus and probe. Avoiding a high trapped radiation belt hazard at Jupiter by flying the bus by at 6 R(J), however, requires using a despun antenna on the flyby bus.

Tindle, E. L.↗
NASA NTRS1972

Information management system breadboard data acquisition and control system.

Description of a breadboard configuration of an advanced information management system based on requirements for high data rates and local and centralized computation for subsystems and experiments to be housed on a space station. The system is to contain a 10-megabit-per-second digital data bus, remote terminals with preprocessor capabilities, and a central multiprocessor. A concept definition is presented for the data acquisition and control system breadboard, and a detailed account is given of the operation of the bus control unit, the bus itself, and the remote acquisition and control unit. The data bus control unit is capable of operating under control of both its own test panel and the test processor. In either mode it is capable of both single- and multiple-message operation in that it can accept a block of data requests or update commands for transmission to the remote acquisition and control unit, which in turn is capable of three levels of data-handling complexity.

Mallary, W. E.↗
NASA NTRS1973

System design of the Pioneer Venus spacecraft. Volume 1: Executive summary

The NASA Ames Research Center Pioneer Venus Project objective is to conduct scientific investigations of the planet Venus using spin stabilized spacecraft. The defined approach to accomplish this goal is to implement a multiprobe spacecraft mission and an orbiter spacecraft mission. Candidate launch vehicles for the Pioneer Venus missions were the Thor/Delta and Atlas/Centaur. The multiprobe spacecraft consists of a probe bus, one large probe, and three small probes. The probes are designed to survive to the surface of Venus, and to make in situ measurements of the Venusian atmosphere; the probe bus enters the atmosphere and makes scientific measurements until it burns out. The orbiter mission uses a spacecraft designed to orbit Venus for 225 days with an orbit period of about 24 hours (h). The probe bus and orbiter designs are to use a common spacecraft bus.

Dorfman, S. D.↗