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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 109 records · Page 6

Attitude determination with three-axis accelerometer for emergency atmospheric entry

Two algorithms are disclosed that, with the use of a 3-axis accelerometer, will be able to determine the angles of attack, sideslip and roll of a capsule-type spacecraft prior to entry (at very high altitudes, where the atmospheric density is still very low) and during entry. The invention relates to emergency situations in which no reliable attitude and attitude rate are available. Provided that the spacecraft would not attempt a guided entry without reliable attitude information, the objective of the entry system in such case would be to attempt a safe ballistic entry. A ballistic entry requires three controlled phases to be executed in sequence: First, cancel initial rates in case the spacecraft is tumbling; second, maneuver the capsule to a heat-shield-forward attitude, preferably to the trim attitude, to counteract the heat rate and heat load build up; and third, impart a ballistic bank or roll rate to null the average lift vector in order to prevent prolonged lift down situations. Being able to know the attitude, hence the attitude rate, will allow the control system (nominal or backup, automatic or manual) to cancel any initial angular rates. Also, since a heat-shield forward attitude and the trim attitude can be specified in terms of the angles of attack and sideslip, being able to determine the current attitude in terms of these angles will allow the control system to maneuver the vehicle to the desired attitude. Finally, being able to determine the roll angle will allow for the control of the roll ballistic rate during entry.

Garcia-Llama, Eduardo↗

The NASA Multimission Spacecraft Modular Attitude Control System

This paper describes the design of the Modular Attitude Control Subsystem (MACS) that is incorporated in the NASA Multimission Modular Spacecraft (MMS). The MACS is required to provide precision attitude control for a wide class of spacecraft missions including earth pointing, stellar pointing and solar pointing. The MACS is composed of sensors, actuators and associated electronics. Normally the MACS computational, logic and sequencing functions are performed by an Onboard Computer (OBC) located in the MMS; however, the MACS implements an independent backup safe hold attitude controller to protect against the consequences of an OBC failure. The contents of the paper include a description of the MACS configuration and functional operation. The MACS operational modes and performance requirements are described followed by a discussion of the MACS component characteristics. The paper concludes with a description of the safe hold controller design and typical MACS OBC algorithms.

Murrell, J. W.↗

Apollo experience report: Guidance and control systems: Automated control system for unmanned mission AS-201

The Apollo command module heat shield and Apollo command and service module/Saturn launch vehicle structural integrity were evaluated in an unmanned test flight. An automated control system was developed to provide the mission event sequencing, the real-time ground control interface, and the backup attitude reference system for the unmanned flight. The required mission events, the design logic, the redundancy concept, and the ground-support-equipment concept are described and some development problem areas are discussed. The mission event time line and the real-time ground command list are included to provide an outline of the control system capabilities and requirements. The mission was accomplished with the automated control system, which functioned without flight anomalies.

Holloway, G. F.↗

Thermal control evaluation of a Shuttle Orbiter solar observatory using Skylab ATM backup hardware

A study under the sponsorship of Marshall Space Flight Center (MSFC) established the feasibility to utilize the Skylab Apollo Telescope Mount (ATM) backup hardware for early low cost Shuttle Orbiter solar observation missions. A solar inertial attitude and a seven-day, full sun exposure were baselined. As a portion of the study, a series of thermal control evaluations were performed to resolve the problems caused by the relocation of the ATM to the Shuttle Orbiter bay and resulting configuration changes. Thermal control requirements, problems, the use of solar shields, Spacelab supplied fluid cooling and component placement are discussed.

Class, C. R.↗

Low Yield Nuclear Monitoring Physics Experiment 1 – Integrated Data Acquisition System Design and Initial Observations

The report documents the design of the Integrated Data AcQuisition (IDAQ) system and observations recorded during the first in a series of underground chemical explosions conducted on the Nevada National Security Site (NNSS) in southern Nevada. Experiments are funded as part of Low Yield Nuclear Monitoring (LYNM) research and development within the United States National Nuclear Security Administration NA-22 nuclear non-proliferation program. The series is part of the broader Physical Experiment 1 (PE1) being conducted in and around the P-tunnel facility on the NNSS. Each explosive experiment utilizes several tons of comp-B to generate signals recorded by a broad suite of instrumentation. The IDAQ serves as the backbone for all subsurface instrumentation providing precise time synchronization, remote control, data exfiltration and backup, along with recording several sensing modalities throughout the underground complex that includes ground motion, environmental conditions, and electromagnetic signals.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

Precursor Analysis Report: SQL Slammer Worm Infection of Davis-Besse Nuclear Power Plant 2003

The SQL Slammer Worm Infection of Davis-Besse Nuclear Power Plant 2003 Precursor Analysis Report leverages publicly available information about Davis-Besse’s 2003 cyber attack and catalogs anomalous observables for each technique employed in the attack. This analysis is based upon the methodology of the Cybersecurity for the Operational Technology Environment (CyOTE) program. On 25 January 2003, the SQL Slammer worm infected more than 90% of vulnerable hosts and crashed the internet in 10 to 15 minutes, making it one of the fastest spreading worms in history. SQL Slammer is a fileless, memory-resident worm that remotely exploits a stack-based buffer overflow vulnerability on local hosts to intensively scan and rapidly self-propagate across the internet. The worm infected approximately 300,000 unpatched hosts running Microsoft Structured Query Language (SQL) Server 2000 or Microsoft Desktop Engine (MSDE) 2000 with SQL Server Resolution Service. The SQL Slammer worm indirectly infected FirstEnergy’s Davis-Besse nuclear power plant by first infecting a consultant’s company network server and then propagating through an external misconfigured connection into Davis-Besse’s site network. The infection caused major network congestion, slow performance, data overloads, and the inability of local hosts to communicate with each other, which eventually caused a loss of availability and a loss of view when the Safety Parameter Display System (SPDS) and Plant Process Computer (PPC) crashed. At the time of the infection, the plant was already offline, the digital monitoring systems had redundant analog backups, and the plant control and safety functions were not affected, so there were no concerns of a safety breach. However, this incident resulted in many lessons learned and spawned important discussions about cybersecurity’s role in nuclear safety and electric power reliability regulation, policy, and guidance. Researchers and analysts identified 10 unique techniques utilized during the attack with a total of 640 observables using MITRE ATT&CK® for Industrial Control Systems. The CyOTE program assesses observables accompanying techniques used prior to the triggering event to identify opportunities to detect malicious activity. If observables accompanying the attack techniques are perceived and investigated prior to the triggering event, earlier comprehension of malicious activity can take place. Eight of the identified techniques used during Davis-Besse cyber attack were precursors to the triggering event. Analysis identified 596 observables associated with these precursor techniques, 428 of which were assessed to have an increased likelihood of being perceived in the 331 days preceding the triggering event. The response and comprehension time could have been reduced if the observables had been identified earlier. The information gathered in this report contributes to a library of observables tied to a repository of artifacts, data sources, and technique detection references for practitioners and developers to support the comprehension of indicators of attack. Asset owners and operators can use these products if they experience similar observables or to prepare for comparable scenarios.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

Artificial atmosphere control system

Two-gas control system has been developed which uses existing hardware. Three systems are used for control, monitoring, and safety backup. Pure oxygen will be supplied to maintain safe pressure level should something go wrong.

Rebert, D. R.↗

Analysis of the TDRS multiple access system for possible use as an attitude control system sensor

A member of the constellation of TDR satellites (TDRS) has experienced a failure of its prime earth sensor. Failure of the remaining earth sensor could result in the inability of the satellite to control its attitude and provide user services. Loss of the satellite would be a serious event. The multiple access (MA) antenna array on the TDRS has been proposed for use as a backup sensor for the attitude control system. This paper describes our analysis of the performance of the MA array as an interferometer used for accurate attitude determination. A least squares fit of a plane to the MA phase information appears to represent the TDRS body roll and pitch within about 0.1 deg. This is sufficient for SGL pointing and MA and SSA user services. Analytic improvements that include ionospheric correction may yield sufficient accuracy for KSA user services.

Blevins, Bruce Allyn↗

AFTI/F-111 MAW flight control system and redundancy management description

The wing on the NASA F-111 transonic aircraft technology (TACT) airplane was modified to provide flexible leading and trailing edge flaps; this modified wing is known as the mission adaptive wing (MAW). A dual digital primary fly-by-wire flight control system was developed with analog backup reversion for redundancy. This report discusses the functions, design, and redundancy management of the flight control system for these flaps.

Larson, Richard R.↗

Using a horizon sensor for Mars observer spacecraft attitude control

A modified earth horizon sensor design is proposed for the Mars Observer mission. The horizon sensor modification are based on Mars horizon radiance profiles. Attention is given to the Mars Observer's attitude control system, whose primary mode is horizon sensor-based and therefore obviates the use of an onboard spacecraft ephemeris; control accuracy of the order of 10 mrad 3sigma/axis is achieved. The attitude control system's second, celestial-backup mode, wich requires greater operational effort, employs an onboard celestial sensor as the spacecraft ephemeris; its control accuracy is of the order of 8 mrad 3sigma/axis.

Langmaier, J. K.↗

The energy footprint of automotive electronic sensors

We discuss how Information and communication technologies (ICT) have emerged as one of the leading technologies to reduce global emissions, particularly in the mobility sector. Automotive electronics, such as sensors/actuators and microcontrollers (commonly known as electronic control units (ECU) which control one or more of the electrical systems or subsystems in a vehicle), play a key role in ICT. Sensors/actuators are key in electronic ICT devices, starting with the data collection and data communication with the internet. The latest two big trends of electrification and automation in vehicles, are projected to increase the use of worldwide automotive sensors from 7.5 billion units in 2017 to 11.0 billion units by the year 2024. A representative state-of-the art automotive sensor system, (i.e., an ultrasonic backup system), including the ECUs controlling the vehicle electrical systems/subsystems, has been considered to estimate the energy footprint in terms of manufacturing and operational energy of global automotive sensors use. A widely used life cycle energy assessment method (i.e., cumulative energy demand) was used as both direct and indirect (including the extraction, manufacturing, and disposal of the raw and auxiliary materials) energy use can be considered for the energy footprint estimation. The embodied manufacturing energy impacts of the system was estimated to be 559 MJ/system, compared to the 417 MJ/system for lifetime system power and additional gasoline use. The share of purchased energy to the embodied energy where the upstream energy isn't included in the former case, is less than 10% and ~ 85% for the component manufacturing and vehicle operation energy uses, respectively. As the purpose of this ultrasonic backup system is to prevent rear crashes, an estimated 1.0 MJ/system is avoided from reduced lifetime vehicular repairs (from an estimated 11% chance of requiring a rear bumper replacement). While all of this is small compared to the overall automotive manufacturing and use energy, the 11 billion automotive sensors expected to be produced in 2024 could require 1540 PJ for manufacturing and those sensors would require an additional 780–1150 PJ for lifetime energy use.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

The STAR computer - A self-testing-and- repairing computer for spacecraft guidance, control, and automatic maintenance

Successful planetary exploration missions have been completed by unmanned Mariner spacecraft, which were designed at the Jet Propulsion Laboratory. Mariner II completed a 109-day flyby mission to Venus on December 14, 1962. This mission was followed by the flyby of Mars and return of 21 historic photographs of its surface by Mariner IV in July 1965. Further successful missions followed: Mariner V to Venus in 1967, Mariners VI and VII to Mars in 1969. In all of these missions, a Central Computer and Sequencer onboard the spacecraft was used to provide on-board control functions, although complete ground backup was also available.

Algirdas Avizienist↗

Design of a dual fault tolerant space shuttle payload deployment actuator

As the Shuttle Transportation System (STS) becomes operational, the number and variety of payloads will increase. The need to deploy these cargo elements will require a variety of unique actuator designs, all of which will have to conform with STS safety policy. For those missions where payload operations extend beyond the payload bay door envelope, this policy deems the prevention of door closure as a catastrophic hazard. As such, it must be controlled by independent, primary and backup methods. The combination of these methods must be two fault tolerant. The design of such an actuator is described. The device consists of a single linear ballscrew with two ballnuts, each bellnut forming an independent actuator using the common ballscrew. The design requirements, concept development, hardware configuration, and fault tolerance rationale are highlighted.

Teske, D. R.↗

An Overview of the NASA F-18 High Alpha Research Vehicle

This paper gives an overview of the NASA F-18 High Alpha Research Vehicle. The three flight phases of the program are introduced, along with the specific goals and data examples taken during each phase. The aircraft configuration and systems needed to perform the disciplinary and inter-disciplinary research are discussed. The specific disciplines involved with the flight research are introduced, including aerodynamics, controls, propulsion, systems, and structures. Decisions that were made early in the planning of the aircraft project and the results of those decisions are briefly discussed. Each of the three flight phases corresponds to a particular aircraft configuration, and the research dictated the configuration to be flown. The first phase gathered data with the baseline F-18 configuration. The second phase was the thrust-vectoring phase. The third phase used a modified forebody with deployable nose strakes. Aircraft systems supporting these flights included extensive instrumentation systems, integrated research flight controls using flight control hardware and corresponding software, analog interface boxes to control forebody strakes, a thrust-vectoring system using external post-exit vanes around axisymmetric nozzles, a forebody vortex control system with strakes, and backup systems using battery-powered emergency systems and a spin recovery parachute.

Bowers, Albion H.↗

Galileo spacecraft power management and distribution system

The Galileo PMAD (power management and distribution system) is described, and the design drivers that established the final as-built hardware are discussed. The spacecraft is powered by two general-purpose heat-source-radioisotope thermoelectric generators. Power bus regulation is provided by a shunt regulator. Galileo PMAD distributes a 570-W beginning of mission (BOM) power source to a user complement of some 137 load elements. Extensive use of pyrotechnics requires two pyro switching subassemblies. They initiate 148 squibs which operate the 47 pyro devices on the spacecraft. Detection and correction of faults in the Galileo PMAD is an autonomous feature dictated by requirements for long life and reliability in the absence of ground-based support. Volatile computer memories in the spacecraft command and data system and attitude control system require a continuous source of backup power during all anticipated power bus fault scenarios. Power for the Jupiter Probe is conditioned, isolated, and controlled by a Probe interface subassembly. Flight performance of the spacecraft and the PMAD has been successful to date, with no major anomalies.

Detwiler, R. C.↗

Magnetic control systems for large spacecraft with applications to space telescope

Magnetic control systems for large space vehicles offer the advantage of a simple, reliable, low cost augmentation to the primary control system. When used for momentum management, a magnetic torque source offers a long life and noncontaminant environment when compared to a mass expulsion torque source. These qualities make such systems suitable for employment with the Space Telescope, which is a long life, high performance vehicle with optics and scientific instruments which would be degraded by contamination due to mass expulsion products. The various applications of magnetic systems on the Space Telescope are considered. The future trend in magnetic control of large space vehicles lies in providing a known three axis reference for backup operations, such as recovery of the primary control mode.

Dougherty, H.↗

Control Room Training for the Hyper-X Program Utilizing Aircraft Simulation

The NASA Dryden Flight Research Center flew two Hyper-X Research Vehicles and achieved hypersonic speeds over the Pacific Ocean in March and November 2004. To train the flight and mission control room crew, the NASA Dryden simulation capability was utilized to generate telemetry and radar data, which was used in nominal and emergency mission scenarios. During these control room training sessions, personnel were able to evaluate and refine data displays, flight cards, mission parameter allowable limits, and emergency procedure checklists. Practice in the mission control room ensured that all primary and backup Hyper-X staff were familiar with the nominal mission and knew how to respond to anomalous conditions quickly and successfully. This paper describes the technology in the simulation environment and the mission control center, the need for and benefit of control room training, and the rationale and results of specific scenarios unique to the Hyper-X research missions.

Lux-Baumann, Jessica R.↗

Control Room Training for the Hyper-X Project Utilizing Aircraft Simulation

The NASA Dryden Flight Research Center flew two Hyper-X research vehicles and achieved hypersonic speeds over the Pacific Ocean in March and November 2004. To train the flight and mission control room crew, the NASA Dryden simulation capability was utilized to generate telemetry and radar data, which was used in nominal and emergency mission scenarios. During these control room training sessions personnel were able to evaluate and refine data displays, flight cards, mission parameter allowable limits, and emergency procedure checklists. Practice in the mission control room ensured that all primary and backup Hyper-X staff were familiar with the nominal mission and knew how to respond to anomalous conditions quickly and successfully. This report describes the technology in the simulation environment and the Mission Control Center, the need for and benefit of control room training, and the rationale and results of specific scenarios unique to the Hyper-X research missions.

Lux-Baumann, Jesica↗