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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Long-duration life tests of slip ring capsule assemblies for inertial guidance platforms

Eight slip ring capsules, each having 80 or 100 circuits, were operated for time periods ranging from 14,300 hours to 24,700 hours. The test mode simulated the motion of gimbal axes of the Saturn inertial guidance the platform in an organic free nitrogen environment. Computer-compiled noise data (approximately 45,000 recordings) were graphed as a function of test time and position within the capsules and as extreme probability distributions. Greater than ninety-nine percent of the noise measurements for the capsules with sufficient lubrication were less than 10 milliohms. Capsules with glass dielectrics did not perform significantly differently than those with filled epoxy dielectrics. The initial wear mode of prow formation was followed by rider wear. After 10 to the 8th power wipes, ring wear depth did not exceed the surface finish and the radial rider wear depth was less than 13 microns.

Cole, S. R.↗
NASA NTRS1987

Optical alignment of Centaur's inertial guidance system

During Centaur launch operations the launch azimuth of the inertial platform's U-accelerometer input axis must be accurately established and maintained. This is accomplished by using an optically closed loop system with a long-range autotheodolite whose line of sight was established by a first-order survey. A collimated light beam from the autotheodolite intercepts a reflecting Porro prism mounted on the platform azimuth gimbal. Thus, any deviation of the Porro prism from its predetermined heading is optically detected by the autotheodolite. The error signal produced is used to torque the azimuth gimbal back to its required launch azimuth. The heading of the U-accelerometer input axis is therefore maintained automatically. Previously, the autotheodolite system could not distinguish between vehicle sway and rotational motion of the inertial platform unless at least three prisms were used. One prism was mounted on the inertial platform to maintain azimuth alignment, and two prisms were mounted externally on the vehicle to track sway. For example, the automatic azimuth-laying theodolite (AALT-SV-M2) on the Saturn vehilce used three prisms. The results of testing and modifying the AALT-SV-M2 autotheodolite to simultaneously monitor and maintain alignment of the inertial platform and track the sway of the vehicle from a single Porro prism.

Gordan, Andrew L.↗
NASA NTRS1988

In-flight inertial guidance alignment

This work reports on an extension of a recent work by Goshen-Meskin and Bar-Itzhack (1988). That work dealt with the observability analysis of inertial-navigation systems during in-flight alignment. The work was confined to the analysis of altitude damped systems; hence, the error model considered was a two-channel model. The present work deals with an undamped three-channel error model. An analysis similar to the previous one is carried out. It is shown that it is possible to fully observe, and thus estimate, all the states of the system. This is in contrast to the previous two-channel system, in which it is impossible to fully observe and estimate all the states of the system. The conclusions of the analysis presented in this paper are verified through covariance simulation which yields identical results.

Bar-Itzhack, I. Y.↗
NASA NTRS1982

Less-Costly Inertial Guidance

Two gyroscopes mounted in gimbals yield signals that allow calculation of velocity, position and altitude of an aircraft. The mass lowers center of gravity of gimbal-and-gyro assembly to below the intersection of their axes. Combination acts as a two-axis pendulum. Rate signals from the leveling gyroscope are integrated, amplified, and fed to gimbal torquers to restore pendulum to alinement with local vertical.

Merhav, S. J.↗
NASA NTRS1976

Astrodynamics 1975; Conference, Nassau, Bahamas, July 28-30, 1975, Technical Papers

Articles are grouped under four headings: (1) dynamics and control of satellites; (2) satellite mission analysis; (3) Aeros-B and Symphonie satellite engineering problems; (4) optimization and control techniques applied to solar space heating and cooling of buildings. Topics covered include: communications and earth survey satellite systems, a system of two counter-orbiting satellites measuring GRT-predicted nodal drag, statistical mechanics studies of the spatial density function of orbiting space junk, attitude control of satellites, nutation dampers, low thrust inertial guidance and ascent inertial guidance, a shuttle-launched multi-comet intercept mission, preflight and in-flight analysis of the Atmosphere Explorer (AE-C) satellite, and launch-encounter strategy for the Mariner 1977 Jupiter-Saturn mission. Individual items are announced in this issue.

Powers, W. F.↗
NASA NTRS1991

An integrated autonomous rendezvous and docking system architecture using Centaur modern avionics

The avionics system for the Centaur upper stage is in the process of being modernized with the current state-of-the-art in strapdown inertial guidance equipment. This equipment includes an integrated flight control processor with a ring laser gyro based inertial guidance system. This inertial navigation unit (INU) uses two MIL-STD-1750A processors and communicates over the MIL-STD-1553B data bus. Commands are translated into load activation through a Remote Control Unit (RCU) which incorporates the use of solid state relays. Also, a programmable data acquisition system replaces separate multiplexer and signal conditioning units. This modern avionics suite is currently being enhanced through independent research and development programs to provide autonomous rendezvous and docking capability using advanced cruise missile image processing technology and integrated GPS navigational aids. A system concept was developed to combine these technologies in order to achieve a fully autonomous rendezvous, docking, and autoland capability. The current system architecture and the evolution of this architecture using advanced modular avionics concepts being pursued for the National Launch System are discussed.

Nelson, Kurt↗
NASA NTRS1966

Guidance and control engineering.

Guidance and control technology examining inertial guidance systems, Apollo space system, gyros, accelerometers and computers

INERTIAL GUIDANCE↗
NASA NTRS1974

A systems concept of the vestibular organs

A comprehensive model of vestibular organ function is presented. The model is based on an analogy with the inertial guidance systems used in navigation. Three distinct operations are investigated: angular motion sensing, linear motion sensing, and computation. These operations correspond to the semicircular canals, the otoliths, and central processing respectively. It is especially important for both an inertial guidance system and the vestibular organs to distinguish between attitude with respect to the vertical on the one hand, and linear velocity and displacement on the other. The model is applied to various experimental situations and found to be corroborated by them.

Mayne, R.↗
NASA NTRS1972

Improved guidance hardware study for the scout launch vehicle

A market survey and evaluation of inertial guidance systems (inertial measurement units and digital computers) were made. Comparisons were made to determine the candidate systems for use in the Scout launch vehicle. Error analyses were made using typical Scout trajectories. A reaction control system was sized for the fourth stage. The guidance hardware to Scout vehicle interface was listed.

Schappell, R. T.↗