A simplified explicit guidance scheme for orbital injection.
Onboard computer equations for rocket vehicle guidance to elliptical orbit, discussing iteration absence from computations and digital simulation results
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Onboard computer equations for rocket vehicle guidance to elliptical orbit, discussing iteration absence from computations and digital simulation results
Adaptive terminal guidance scheme for circular orbit rendezvous to provide near optimal trajectory
Optical communication equipment design and integration - propulsion subsystem - guidance, navigation, and environmental control
Discrete change in ballistic coefficient for trajectory control in Mars entry guidance
Saturn 5 suboptimal continuous guidance design, eliminating discontinuous control encountered in SA-502 flight
Information which will aid in the choice by the U.S. Government and industry of system concepts, design criteria, operating procedures for STOL aircraft and STOL ports, STOL landing guidance systems, air traffic control systems, and airborne avionics and flight control systems. Ames has developed a terminal-area STOL operating systems experiments program which is a part of the joint DOT/NASA effort is discussed. The Ames operating systems experiments program, its objectives, the program approach, the program schedule, typical experiments, the research facilities to be used, and the program status are described.
A system study to determine the application of short takeoff aircraft for a high speed, short haul air transportation service was conducted. The study focused on developing information which will aid in choosing system concepts, design criteria, operating procedures, landing guidance systems, air traffic control systems, and airborne avionics and flight control systems. A terminal area STOL operating system experiments program was developed. The objectives, program approach, program schedule, typical experiments, research facilities to be used, and program status are discussed.
An overview is given of current electronics R and D activities, potential future thrusts, and related NASA payoffs. Major increases in NASA mission return and significant concurrent reductions in mission cost appear possible through a focused, long range electronics technology program. The overview covers: guidance assessments, navigation and control, and sensing and data acquisition processing, storage, and transfer.
General-purpose rigid-body six-degrees-of-freedom program is used to solve wide variety of atmospheric flight mechanics and orbital transfer problems. Written for analysis of powered or unpowered vehicles operation near rotating oblate planet, typical applications include: guidance and flight-control system simulation and analysis, loads and dispersion-type analysis.
The Orbital Transfer Vehicle (OTV) is to be employed for the delivery of a paylod to a high earth orbit, such as a geosynchronous orbit. Subsequently, the OTV is to return to a low earth parking orbit. The present investigation is concerned with an aeroassisted OTV (AOTV) which achieves the required reduction in velocity on its return to the parking orbit through aerodynamic braking. An adaptive guidance logic is employed to control and AOTV as it passes through the earth's upper atmosphere. Attention is given to details regarding the adaptive guidance logic, and a performance evaluation. It is found that the performance of the adaptive guidance logic is satisfactory for the considered conditions.
Three atmospheric guidance concepts proposed for an aeroassist flight experiment are presented. The flight experiment will simulate a return from geosynchronous orbit by an aeroassisted orbital transfer vehicle and is proposed to be flown on board the Space Shuttle in 1992. The three guidance concepts include an analytic predictor/corrector, a numeric predictor/corrector, and an energy controller. The algorithms for the three guidance methods are developed and performance results are presented for the nominal case and for several cases dispersed from the nominal conditions.
6D POST is general-purpose, six-degree-of-freedom computer program for optimization of simulated trajectories of rigid bodies. Direct extension of three-degree-of-freedom POST program. 6D POST program models trajectory of powered or unpowered vehicle operating at or near rotating planet. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Written in FORTRAN 77 and FORTRAN V.
A joint NASA Dryden Flight Research Facility and Johnson Space Center program was conducted to determine the feasibility of the autonomous recovery of a spacecraft using a ram-air parafoil system for the final stages of entry from space that included a precision landing. The feasibility of this system was studied using a flight model of a spacecraft in the generic shape of a flattened biconic which weighed approximately 150 lb and was flown under a commercially available, ram-air parachute. Key elements of the vehicle included the Global Positioning System guidance for navigation, flight control computer, ultrasonic sensing for terminal altitude, electronic compass, and onboard data recording. A flight test program was used to develop and refine the vehicle. This vehicle completed an autonomous flight from an altitude of 10,000 ft and a lateral offset of 1.7 miles which resulted in a precision flare and landing into the wind at a predetermined location. At times, the autonomous flight was conducted in the presence of winds approximately equal to vehicle airspeed. Several techniques for computing the winds postflight were evaluated. Future program objectives are also presented.
A mechanical simulator of the Hubble Space Telescope (HST) Aft Shroud was built to perform verification testing of the Servicing Mission Scientific Instruments (SI's) and to provide a facility for astronaut training. All assembly, integration, and test activities occurred under the guidance of a contamination control plan, and all work was reviewed by a contamination engineer prior to implementation. An integrated approach was followed in which materials selection, manufacturing, assembly, subsystem integration, and end product use were considered and controlled to ensure that the use of the High Fidelity Mechanical Simulator (HFMS) as a verification tool would not contaminate mission critical hardware. Surfaces were cleaned throughout manufacturing, assembly, and integration, and reverification was performed following major activities. Direct surface sampling was the preferred method of verification, but access and material constraints led to the use of indirect methods as well. Although surface geometries and coatings often made contamination verification difficult, final contamination sampling and monitoring demonstrated the ability to maintain a class M5.5 environment with surface levels less than 400B inside the HFMS.
A joint NASA Dryden Flight Research Facility and Johnson Space Center program was conducted to determine the feasibility of the autonomous recovery of a spacecraft using a ram-air parafoil system for the final stages of entry from space that included a precision landing. The feasibility of this system was studied using a flight model of a spacecraft in the generic shape of a flattened biconic that weighed approximately 150 lb and was flown under a commercially available, ram-air parachute. Key elements of the vehicle included the Global Positioning System guidance for navigation, flight control computer, ultrasonic sensing for terminal altitude, electronic compass, and onboard data recording. A flight test program was used to develop and refine the vehicle. This vehicle completed an autonomous flight from an altitude of 10,000 ft and a lateral offset of 1.7 miles that resulted in a precision flare and landing into the wind at a predetermined location. At times, the autonomous flight was conducted in the presence of winds approximately equal to vehicle airspeed. Several novel techniques for computing the winds postflight were evaluated. Future program objectives are also presented.
An in-situ propellant production system (ISPP) is designed to make rocket fuel from chemicals in the Martian atmosphere in order to reduce the amount of materials that would need to be brought from Earth to support Mars missions. We have developed a description of a hypothetical ISPP system that we would like to make available to researchers who are interested in the problem of automatically diagnosing failures in complex NASA systems. This problem description will help researchers to investigate problems of interest to NASA. We would like to make the following material publicly available: (1) a 'common sense' model of an ISPP system; (2) low- and medium-fidelity simulations of the ISPP system written in Microsoft Excel and HCC; and (3) previously published data and diagrams concerning ISPP components. We do not believe there are any export considerations on these materials for the following reasons: (1) These models are not useful for guidance and real time control of vehicles, encrpytion, or any other software purpose categorized under the Export Control Classification Numbers; and (2) The models are very high level and would not by themselves enable real-time control of a real hardware system. The models are at the level of common sense. They capture, for example, that if a heater is turned on an increase in temperature should result(see the attached excerpt). We do not believe there is any commercial value to this material, given the low commercial demand for propellant plants on mars. We have spoken to acting Code IC Division Chief Dan Clancy, and he concurs with our desire to make these materials publicly available via a technical report.
This slide presentation proposes using the unprecedented capability of the planned Ares V launch vehicle, to place a 8 meter monolithic space telescope at the Earth-Sun L2 point. This new capability enables a new design pardigm -- simplicity. The six to eight meter class telescope with a massive high Technical Readiness Level ground observatory class monolithic primary mirror has been determined feasible. The proposed design, structural analysis, spacecraft design and shroud integration, thermal analysis, propulsion system, guidance navigation and pointing control assumptions about the avionics, and power systems, operational lifetime, and the idea of in-space servicing are reviewed.
Marshall Aerospace Vehicle Representation in C (MAVERIC) is a computer program for generic, low-to-high-fidelity simulation of the flight(s) of one or more launch vehicle(s) or spacecraft. MAVERIC is designed to accommodate multi-staged vehicles, powered serially or in parallel, with multiple engines, tanks, and cargo elements. Engines can be of jet or conventional rocket types, using either liquid or solid propellants. MAVERIC includes generic subsystem software models for propulsion systems, mass properties, reaction control systems, aerodynamic properties, guidance systems, and navigation systems. Simulations can be started at points other than liftoff. Also included are guidance-system software models that accommodate the ascent, orbit, coasting, deorbiting, entry, terminal-area-energy-management, approach, and landing phases of flight. Options to use different wind profiles and atmospheres are included. A Monte Carlo capability is provided for modeling dispersions associated with atmospheric effects (including winds), propulsion, navigation, aerodynamics, and mass properties. Failures of engines and other subsystems can be modeled. The program is written in the C programming language, which makes it possible for the program to have high degrees of modularity, reusability, and maintainability, thereby also facilitating modification for modeling new vehicles.