813 research outputs found
Minimum time control of the rocket attitude reorientation associated with orbit dynamics
In this paper, we investigate the minimal time problem for the guidance of a
rocket, whose motion is described by its attitude kinematics and dynamics but
also by its orbit dynamics. Our approach is based on a refined geometric study
of the extremals coming from the application of the Pontryagin maximum
principle. Our analysis reveals the existence of singular arcs of higher-order
in the optimal synthesis, causing the occurrence of a chattering phenomenon,
i.e., of an infinite number of switchings when trying to connect bang arcs with
a singular arc.
We establish a general result for bi-input control-affine systems, providing
sufficient conditions under which the chattering phenomenon occurs. We show how
this result can be applied to the problem of the guidance of the rocket. Based
on this preliminary theoretical analysis, we implement efficient direct and
indirect numerical methods, combined with numerical continuation, in order to
compute numerically the optimal solutions of the problem.Comment: 33 pages, 14 figure
Engineers handbook - Low-G propellant behavior
Engineers handbook applicable in prediction of low gravity behavior of liquids in rocket propellant tank
Dynamics Explorer launch
Simultaneously launched from the WSMC, two satellites are to be placed into polar, copolar orbit in order to acquire data on the coupling phenomena between Earth's lower thermosphere and the magnetosphere, as part of the Solar-Terrestrial Program. The mission sequence, instruments, and science data processing system are described as well as the characteristics of the Delta 3913 launch vehicle, and payload separation staging
Comparative studies of conceptual design and qualification procedures for a Mars probe/lander. Volume V - Subsystem and technical analyses. Book 5 - Attitude control and propulsion Final report
Mars probe attitude control and propulsion syste
Environmental protection requirements for scout/shuttle auxiliary stages
The requirements for enabling the Scout upper stages to endure the expected temperature, mechanical shock, acoustical and mechanical vibration environments during a specified shuttle mission were determined. The study consisted of: determining a shuttle mission trajectory for a 545 kilogram (1200 pound) Scout payload; compilation of shuttle environmental conditions; determining of Scout upper stages environments in shuttle missions; compilation of Scout upper stages environmental qualification criteria and comparison to shuttle mission expected environments; and recommendations for enabling Scout upper stages to endure the exptected shuttle mission environments
Orion Guidance and Control Ascent Abort Algorithm Design and Performance Results
During the ascent flight phase of NASA s Constellation Program, the Ares launch vehicle propels the Orion crew vehicle to an agreed to insertion target. If a failure occurs at any point in time during ascent then a system must be in place to abort the mission and return the crew to a safe landing with a high probability of success. To achieve continuous abort coverage one of two sets of effectors is used. Either the Launch Abort System (LAS), consisting of the Attitude Control Motor (ACM) and the Abort Motor (AM), or the Service Module (SM), consisting of SM Orion Main Engine (OME), Auxiliary (Aux) Jets, and Reaction Control System (RCS) jets, is used. The LAS effectors are used for aborts from liftoff through the first 30 seconds of second stage flight. The SM effectors are used from that point through Main Engine Cutoff (MECO). There are two distinct sets of Guidance and Control (G&C) algorithms that are designed to maximize the performance of these abort effectors. This paper will outline the necessary inputs to the G&C subsystem, the preliminary design of the G&C algorithms, the ability of the algorithms to predict what abort modes are achievable, and the resulting success of the abort system. Abort success will be measured against the Preliminary Design Review (PDR) abort performance metrics and overall performance will be reported. Finally, potential improvements to the G&C design will be discussed
Technology requirements to be addressed by the NASA Lewis Research Center Cryogenic Fluid Management Facility program
The NASA Lewis Research Center is responsible for the planning and execution of a scientific program which will provide advance in space cryogenic fluid management technology. A number of future space missions were identified that require or could benefit from this technology. These fluid management technology needs were prioritized and a shuttle attached reuseable test bed, the cryogenic fluid management facility (CFMF), is being designed to provide the experimental data necessary for the technology development effort
NASA Lewis Research Center low-gravity fluid management technology program
A history of the Lewis Research Center in space fluid management technology program is presented. Current programs which include numerical modeling of fluid systems, heat exchanger/radiator concept studies, and the design of the Cryogenic Fluid Management Facility are discussed. Recent analytical and experimental activities performed to support the Shuttle/Centaur development activity are highlighted
Mars Geoscience Orbiter and Lunar Geoscience Orbiter
The feasibility of using the AE/DE Earth orbiting spacecraft design for the LGO and/or MGO missions was determined. Configurations were developed and subsystems analysis was carried out to optimize the suitability of the spacecraft to the missions. The primary conclusion is that the basic AE/DE spacecraft can readily be applied to the LGO mission with relatively minor, low risk modifications. The MGO mission poses a somewhat more complex problem, primarily due to the overall maneuvering hydrazine budget and power requirements of the sensors and their desired duty cycle. These considerations dictate a modification (scaling up) of the structure to support mission requirements
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