Midcourse guidance for return from the moon to a geographically fixed landing site
Midcourse guidance system for return from moon to geographically fixed landing site
RETURN-TO-EARTH PHASE↗
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Postflight Evaluation of Atlas-Centaur AC-6 (Launched August 11, 1965)
The sixth Atlas Centaur vehicle (AC-6) was successfully launched from the Eastern T e s t Range, Complex 36B, on August 11, 1965, at 0931:04.430 EST. A 2084-pound dynamic model of the Surveyor payload was placed in a simulated lunar transfer trajectory. Vehicle systems operated satisfactorily and all the flight objectives were accomplished. Lift-off within 4 seconds of the window opening demonstrated the launch-on-time capability of the vehicle were accurately compensated for by the Centaur guidance system. the Surveyor model into a near-perfect lunar transfer trajectory would have resulted in an impact of the moon without a midcourse correction. To hit the precise target area on the lunar surface, the required correction would have been 4.25 meters per second, which is well within the spacecraft capability. Normal thrust and impulse levels were obtained with both the A t l a s and Centaur propulsion systems. However, a sizeable thrust overshoot on startup of the Centaur engines has not been resolved. A propellant-utilization system used for the first time on the Centaur, accurately controlled the fuel and oxidant consumption. The turnaround and retrothrust maneuver were performed without incident. Relatively high longitudinal modal excitations and lateral payload excitations were obtained at lift-off; these high perturbations are believed t o be related t o the launcher holddown arms. Nominal temperatures were recorded for both the external vehicle skin and the payload compartment; however, abnormally low temperatures were measured in the forward equipment area, which may have resulted from leakage of cold helium purge gas. All vehicle electrical systems performed satisfactorily; the only difficulty with the RF systems was obtained with the C-band transponder. of the vehicle instrumentation yielded valid data. The AC-6 vehicle was constructed with several new lightweight designs including the forward bulkhead, thrust barrel, interstage adapter and tank skin thickness reduction from 0.016 t o 0.014 inch. No deficiencies were observed in any of these new structural elements.
Source record↗
Analytical Evaluation of a Method of Midcourse Guidance for Rendezvous with Earth Satellites
A digital-computer simulation was made of the midcourse or ascent phase of a rendezvous between a ferry vehicle and a space station. The simulation involved a closed-loop guidance system in which both the relative position and relative velocity between ferry and station are measured (by simulated radar) and the relative-velocity corrections required to null the miss distance are computed and applied. The results are used to study the effectiveness of a particular set of guidance equations and to study the effects of errors in the launch conditions and errors in the navigation data. A number of trajectories were investigated over a variety of initial conditions for cases in which the space station was in a circular orbit and also in an elliptic orbit. Trajectories are described in terms of a rotating coordinate system fixed in the station. As a result of this study the following conclusions are drawn. Successful rendezvous can be achieved even with launch conditions which are substantially less accurate than those obtained with present-day techniques. The average total-velocity correction required during the midcourse phase is directly proportional to the radar accuracy but the miss distance is not. Errors in the time of booster burnout or in the position of the ferry at booster burnout are less important than errors in the ferry velocity at booster burnout. The use of dead bands to account for errors in the navigational (radar) equipment appears to depend upon a compromise between the magnitude of the velocity corrections to be made and the allowable miss distance at the termination of the midcourse phase of the rendezvous. When approximate guidance equations are used, there are limits on their accuracy which are dependent on the angular distance about the earth to the expected point of rendezvous.
Eggleston, John M.↗
Study of automatic and manual terminal guidance and control systems for space shuttle vehicles. Volume 1: Sections 1 through 3
The results of a study to analyze, design, and evaluate guidance and control systems are presented that start at an altitude of about 100,000 feet and bring the unpowered space shuttle orbiters to a precision horizontal landing. The systems under consideration included fully automatic versions which involve no pilot participation as well as various manual configurations that provide combinations of displays and control augmentation which permit the pilot to control the vehicle to a successful landing. Two classes of vehicles were studied: the low cross range or straight-wing orbiter and the high cross range or delta-wing (delta body) orbiter. The recommended navigation, guidance and control system is shown to be compatible with realistic physical constraints that would exist in space shuttlecraft and to be consistent with the 1971 avionics equipment state of the art. Aircraft capable of aerodynamically simulating the various candidate space shuttlecraft in their unpowered, terminal area descent were investigated, and flight test recommendations, including system mechanizations, are made.
Osder, S.↗
Space telescope astrometry
A description of instruments used for astrometric observations are examined with special emphasis on the Fine Guidance Systems of the space telescope. The telescope consists of a 2.4 meter diameter primary and a secondary figured to the Ritchey-Chretien design that yields a f/24 focal plane. The function of the FGS is to keep the total guidance jitter within the ST requirement of + or - 0.0007 rms, and to maximize the probability of finding suitable guide stars with the available 210 arcmin. Attention is given to the focal plane arrangement and to the ray paths and output images from the Koester's prisms. Some projected scientific uses of the space telescope are given as well as beneficial areas of close cooperation between the space telescope and the ESA.
Van Altena, W.↗
Development of STOLAND, a versatile navigation, guidance and control system
STOLAND has been developed to perform navigation, guidance, control, and flight management experiments in advanced V/STOL aircraft. The experiments have broad requirements and have dictated that STOLAND be capable of providing performance that would be realistic and equivalent to a wide range of current and future avionics systems. An integrated digital concept using modern avionics components was selected as the simplest approach to maximizing versatility and growth potential. Unique flexibility has been obtained by use of a single, general-purpose digital computer for all navigation, guidance, control, and displays computation.
Young, L. S.↗
Review of AIDS development
The operation and implementation of the aircraft integrated data system AIDS are described. The system is described as an engineering tool with strong emphasis on analysis of recorded information. The AIDS is primarily directed to the monitoring of parameters related to: the safety of the flight; the performance of the aircraft; the performance of the flight guidance system; and the performance and condition of the engines. The system provide short term trend analysis on a trend chart that is updated by the flight engineer on every flight that lasts more than 4 flight hours. Engine data prints are automatically presented during take-off and in the case of limit excedance, e.g., the print shows an automatically reported impending hotstarts on engine nr. 1. Other significant features are reported.
Vermeulen, H. C.↗
The Space Telescope
The Space Telescope is a NASA program intended to launch a long-lived 2.4 meter astronomical observatory in 1983. It will contain optical and pointing systems producing a resolution of at least 0.1 arc seconds over periods of 10 hours. This capability will allow a new regime of imaging astronomical observations to be undertaken from below Lyman-alpha to the millimeter wavelength range. The optical, optical metering structure, pointing and guidance system, and control system will be described.
Odell, C. R.↗
Earth-Moon Cycler Mission Design for Lunar Logistics
One of the key functions of the Artemis program is to drive a sustainable approach to manned Lunar exploration. Current planning takes steps to achieve this through the development of Gateway and a Human Landing System. However, establishing and maintaining a supply chain to and from the Gateway and the Lunar south pole requires a more robust and sustainable approach to logistics. This paper explores the benefits that an Earth-Moon cycler may provide to lunar logistics by removing the necessity for large and often expensive rockets in lieu of more frequent but smaller missions. Furthermore, such a cycler can open up possibilities for lunar cargo return which is currently only fulfilled by Orion's limited return capability. The Earth-Moon cylcer offers a platform for power, thermal systems, guidance, navigation, and control, as well as communications which can open opportunities for the growing market of commercial satellites. This work explores the available families of Earth-Moon cyclers with an inclination near 90° with respect to the Moon, and the capabilities such a notional system can offer to desirable locations in cis-lunar space.
Cycler↗
A METHOD OF DETERMINING THE SOURCE OF ERRORS IN GUIDANCE MEASUREMENTS AND THE RESULTANT ERRORS IN EARTH-FIXED COMPONENTS
Analysis of guidance system errors resulting from initial misalignments of both the accelerometer and stabilizing gyros, the drift of the stabilized element during flight and errors in measuring the vehicle motions
GUIDANCE (MOTION)↗
Space shuttle GN and C equation document no. 23: Energy dissipation rate guidance for approach phase
The approach guidance routine for taking the space shuttle orbiter from the entry phase of approximately 100,000 feet to the start of the final landing maneuver is discussed. The approach guidance system is a closed feedback loop scheme. The vehicle energy is managed by controlling the rate at which energy is dissipated during a straight in approach. The spacecraft performance during each segment of the approach flight is analyzed. Equations of motion are developed to describe the spacecraft guidance and flight path.
Elias, A.↗
Study of basic requirements for a navigation, guidance, and control system for an unmanned lunar landing vehicle Final summary report
Sensor requirements for spaceborne navigation, guidance, and control system for unmanned lunar landing vehicle
GUIDANCE SENSOR↗
Miniature Optical Wide-Angle-Lens Startracker (Mini-OWLS)
This paper provides a brief overview of the design considerations and the current status of the Miniature Optical Wide-Angle Lens Startracker Program. Mini-OWLS offers a revolutionary alternative to the conventional startracker. It is a small, lightweight, low cost, high performance startracker that can be used in a variety of applications including calibration and alignment of Inertial Measurement Units (IMU's) Mini-OWLS makes use of a strap down design incorporating Holographic Optical Elements (HOES) in place of conventional optics. HOES can be multiplexed so that the same aperture can be used for multiple separate optical paths looking in several directions simultaneously without startracker rotation. Additionally, separate Schmidt corrector plates are not required to compensate for spherical aberration. The optical assembly, or what would normally be considered as the telescope, is less than 20 cc in volume, weighs less than 55 grams, and contains the equivalent of three individual telescopes. Each one has a 4 deg Field of View (FOV) with a field of regard of 48 square degrees. Mini-OWLS has a bandwidth of approximately 300 nm in or near the visible wavelength. The projected resolution of the startracker is 5 to 10 arcseconds, depending on the centroiding algorithm used. The Mini-OWLS program was initiated last year and represents a miniaturized version of a similar design for aeronautical applications. The contract is managed by Wright Laboratory, Air Force Systems Command, Wright-Patterson AFB, Ohio, with funding from the Strategic Defense Initiative Organization through Eglin AFB. The initial phase of the program is to build and test a development unit. The second phase is to integrate the startracker with the Charles Stark Draper Laboratory Micromechanical Inertial Guidance System (MIGS) and the Signal Processing Packaging Design (SPPD) being developed by Texas Instruments. The preliminary design review was conducted in November 1991. Three-axes prototype telescope assemblies have been built and design evaluation tests initiated.
Miller, Rick↗
Demonstration of Land and Hold Short Technology at the Dallas-Fort Worth International Airport
A guidance system for assisting in Land and Hold Short operations was developed and then tested at the Dallas-Fort Worth International Airport. This system displays deceleration advisory information on a head-up display (HUD) in front of the airline pilot during landing. The display includes runway edges, a trend vector, deceleration advisory, locations of the hold line and of the selected exit, and alphanumeric information about the progress of the aircraft. Deceleration guidance is provided to the hold short line or to a pilot selected exit prior to this line. Logic is provided to switch the display automatically to the next available exit. The report includes descriptions of the algorithms utilized in the displays, and a report on the techniques of HUD alignment, and results.
Hyer, Paul V.↗
Evaluation of Model-Based Training for Vertical Guidance Logic
This paper will summarize the results of a study which introduces a structured, model based approach to learning how the automated vertical guidance system works on a modern commercial air transport. The study proposes a framework to provide accurate and complete information in an attempt to eliminate confusion about 'what the system is doing'. This study will examine a structured methodology for organizing the ideas on which the system was designed, communicating this information through the training material, and displaying it in the airplane. Previous research on model-based, computer aided instructional technology has shown reductions in the amount of time to a specified level of competence. The lessons learned from the development of these technologies are well suited for use with the design methodology which was used to develop the vertical guidance logic for a large commercial air transport. The design methodology presents the model from which to derive the training material, and the content of information to be displayed to the operator. The study consists of a 2 X 2 factorial experiment which will compare a new method of training vertical guidance logic and a new type of display. The format of the material used to derive both the training and the display will be provided by the Operational Procedure Methodology. The training condition will compare current training material to the new structured format. The display condition will involve a change of the content of the information displayed into pieces that agree with the concepts with which the system was designed.
Feary, Michael↗
Capturing and tracking performance of the horizontal guidance and control systems of the terminal configured vehicle
A twin-jet commercial transport equipped with digital navigation, guidance, and control systems and advanced electronic display system was used for airborne operational research. The results of flight tests which evaluated a second-order horizontal-path guidance control law and the autopilot and airplane response are presented. This evaluation was accomplished through analysis of recorded flight data and through pilot opinion of the airplane maneuvers during automatic path-capture scenarios and path tracking. Four different path captures were flown at a ground speed of approximately 160 knots and repeated at approximately 300 knots. Path tracking tracking error was measured in terms of cross track error along two paths: one pat at cruise speeds and one at airport-terminal-area speeds. The path tracking accuracy and the smoothness of the airplane maneuvers were judged satisfactory for high speeds; however, at lower speeds the control law design should be improved so that tracking will be more accurate for operations in the airport terminal area.
Knox, C. E.↗
Data driven drift correction for complex optical systems
To exploit the thousand-fold increase in spectral brightness of modern light sources, increasingly intricate experiments are being conducted that demand extremely precise beam trajectory. Maintaining the optimal trajectory over several hours of an experiment with the needed precision necessitates active drift control. Here, we outline time varying Bayesian optimization (TVBO) as a data driven approach for robust drift correction, and illustrate its application for a split and delay optical system composed of six crystals and twelve input dimensions. Using numerical simulations, we exhibit the application of TVBO for linear drift, non-smooth temporal drift as well as constrained TVBO for multi-objective control settings, representing real-life operating conditions. This approach can be easily adapted to other X-ray beam conditioning and guidance systems, including multi-crystal monochromators and grazing-incidence mirrors, to maintain sub-micrometer and nanoradian beam stability over the course of an experiment spanning several hours.
Bayesian optimization↗
Handling Qualities of a Capsule Spacecraft During Atmospheric Entry
A piloted simulation was conducted to study handling qualities for capsule spacecraft entering the Earth s atmosphere. Eight evaluation pilots, including six pilot astronauts, provided Cooper-Harper ratings, workload ratings, and qualitative comments. The simulation began after descending through the atmospheric entry interface point and continued until the drogue parachutes deployed. There were two categories of piloting tasks, both of which required bank angle control. In one task category, the pilot followed a closed-loop bank angle command computed by the backup guidance system to manage g-loads during entry. In the other task category, the pilot used intuitive rules to determine the desired bank angle independently, based on an open-loop schedule of vertical speed, Mach, and total energy specified at several range-to-target gates along the entry trajectory. Pilots were able to accurately track the bank angle guidance commands and steered the capsule toward the recovery site with essentially the same range error as the benchmark autopilot trajectory albeit with substantially higher propellant usage, and the handling qualities for this task were satisfactory. Another key result was that the complex piloting task of atmospheric entry could be performed satisfactorily, even in the presence of large dispersions, by controlling bank angle to follow a simple open-loop schedule.
Bilimoria, Karl D.↗