Spaceflight Control Research Articles

Software Package for Simulation and Control System Design for a Nonrigid Space Vehicle

New results in the field of automation of the space flight control system design are presented in this paper. The concept of a universal program for research of dynamic properties, calculation of comprehensive mathematical models, simulation of the flight motion and synthesis of smart control laws for different types of flexible aerospace constructions (launchers and missiles) is considered. Special attention is given to creation of mathematical models of different physical phenomena in aerospace vehicles. The basis of the program is a block that enables the analysis of dynamic characteristics, simulation, and the visual representation of information. The software package is supplied with a library of program modules. These modules are designed on the base of mathematical models of separate vehicle elements and different physical effects, such as flexibility, sloshing, sluggishness of engines, local angle of attack values, etc. Selection of different sets of mathematical models and program modules allows investigating different constructions for known and prospective vehicles. The interface of the program enables changing parameters of the vehicle in a wide range, simulate flight at any trajectory and output results of the analysis in a numerical or graphical form. For synthesis of control laws the smart control approach is used.

Internet-to-orbit gateway and virtual ground station: A tool for space research and scientific outreach

Students in higher education, and scientific and technological researchers want to communicate with the International Space Station (ISS), download live satellite images, and receive telemetry, housekeeping and science/engineering data from nano-satellites and larger spacecrafts. To meet this need the Ecuadorian Civilian Space Agency (EXA) has recently provided the civilian world with an internet-to-orbit gateway (Hermes-A/Minotaur) Space Flight Control Center (SFCC) available for public use. The gateway has a maximum range of tracking and detection of 22,000 km and sensitivity such that it can receive and discriminate the signals from a satellite transmitter with power∼0.1 W. The capability is enough to receive the faintest low-earth-orbit (LEO) satellites. This gateway virtually connects participating internet clients around the world to a remote satellite ground station (GS), providing a broad community for multinational cooperation. The goal of the GS is to lower financial and engineering barriers that hinder access to science and engineering data from orbit. The basic design of the virtual GS on a user side is based on free software suites. Using these and other software tools the GS is able to provide access to orbit for a multitude of users without each having to go through the costly setups. We present the design and implementation of the virtual GS in a higher education and scientific outreach settings. We also discuss the basic architecture of the single existing system and the benefits of a proposed distributed system. Details of the software tools and their applicability to synchronous round-the-world tracking, monitoring and processing performed by students and teams at Graz University of Technology, Austria, EXA-Ecuador, University of Michigan, USA and JAXA who have participated in various mission operations and have investigated real-time satellite data download and image acquisition and processing. Students and other remote users at these institutions undergo training with in orbit satellites in preparation for their own use with future university-class nano-satellites' post launch space operations. The exclusive ability of Hermes-A/Minotaur to act as a gateway between remote users (internet) and satellites (in orbit) makes the virtual GS at user-end more feasible for the long-term real-time nano/cubesats space operations. The only requirement is to have a mutual agreement between EXA and participating university/research organization and broadband internet connection at user-end. With successful and remote satellite tracking and downloading of real-time data from many operational satellites, the Hermes has been found a reliable potential GS for current and future university missions and a training platform for individuals pursuing space operations.

Adaptive Outlier-tolerant Exponential Smoothing Prediction Algorithms with Applications to Predict the Temperature in Spacecraft

The exponential smoothing prediction algorithm is widely used in spaceflight control and in process monitoring as well as in economical prediction. There are two key conundrums which are open: one is about the selective rule of the parameter in the exponential smoothing prediction, and the other is how to improve the bad influence of outliers on prediction. In this paper a new practical outlier-tolerant algorithm is built to select adaptively proper parameter, and the exponential smoothing prediction algorithm is modified to prevent any bad influence from outliers in sampling data. These two new algorithms are valid and effective to overcome the two open conundrums stated above. Simulation and practical results of sampling data from temperature sensors in a spacecraft show that this new adaptive outlier-tolerant exponential smoothing prediction algorithm has the power to eliminate bad infection of outliers on prediction of process state in future.

Laboratory tutorial practice with facility for attitude control simulation

The paper presents a combined approach to teaching of Spaceflight Dynamics, Theoretical Mechanics and Control Theory. In addition to a standard lecture course, this approach provides hands-on training at the laboratory, offering to the student a possibility to develop, design, assemble and test his/her own project of a nanosatellite attitude control system. We describe the software for mathematical modeling, the facilities for laboratory simulation of controlled system dynamics and student training based on these facilities.

Conjugation-mediated plasmid exchange between bacteria grown under space flight conditions

Mobile genetic elements (MGE) such as phages, plasmids and transposons play a crucial role in bacterial adaptation and evolution. These MGE mobilize and reorganize genes within a given genome or between bacterial cells. The impact of space flight conditions on these processes is largely unknown. The Mobilisatsia/Plasmida experiment was set up to investigate the impact of space flight conditions on plasmid-mediated conjugation. The experiment was done aboard the International Space Station during the Soyuz Mission 8S (April 19(th) until April 30(th) 2004). An experiment was performed with the Gram-positive Bacillus thuringiensis AND931 (carrying the conjugative plasmid pXO16), B. thuringiensis 4Q7 (with mobilizable plasmid pC194) and B. thuringiensis GBJ002 (final recipient). A second experiment was carried out with the Gram-negative Escherichia coli CM140 (carrying the conjugative plasmid RP4), E. coli CM1962 (with the mobilizable plasmid pMOL222) and Cupriavidus metallidurans AE815 (final recipient). It was observed by selective platings that plasmid exchange between the Gram-positive bacterial strains occurred in the space flight experiment. It is speculated that the latter plasmid exchange occurs more efficient than in the ground control experiment. No significant differences could be observed between space flight and ground control for the Gram-negative bacteria. The data indicate that plasmid exchange between microorganisms is occurring under space flight conditions. Since microorganisms are endogenous to any spacecraft and their presence considered as a possible jeopardy for manned space exploration, more experiments are needed to evaluate the occurrence and implications of microbial adaptation and evolution via MGE.

Extraterrestrial hemorrhage control: Terrestrial developments in technique, technology, and philosophy with applicability to traumatic hemorrhage control in long-duration spaceflight

Abstract : It is likely humans will venture beyond the relative safety of low earth orbit (LEO) during the next century, in space-faring journeys termed exploration class missions (ECMs). These missions will include manned missions to the Moon and, ultimately, Mars. Such a mission to Mars could entail a period of years in which space travelers would be unable to quickly return to Earth in the event of a serious surgical condition. These medical care challenges are greater than the engineering ones. Space medicine will always be limited by logistical factors such as limitations in weight, volume, power, and crew training. It will be driven by a focus on conditions that are most likely to occur, or would have the most impact on the crewmembers and mission. A human surgical event has not yet occurred in space, though injury has been ranked at the highest level of concern regarding the probable incidence versus impact and is considered a critical problem for which no reliable countermeasures exist in the National Aeronautics and Space Administration (NASA) Bioastronautics Critical Path Roadmap for long-duration, human space exploration.

The effect of space flight on the production of actinomycin D by Streptomyces plicatus.

The effect of space flight on production of the antibiotic actinomycin D by Streptomyces plicatus WC56452 was examined onboard the US Space Shuttle mission STS-80. Paired space flight and ground control samples were similarly prepared using identical hardware, media, and inoculum. The cultures were grown in defined and complex media under dark, anaerobic, thermally controlled (20 degrees C) conditions with samples fixed after 7 and 12 days in orbit, and viable residuals maintained through landing at 17 days, 15 h. Postflight analyses indicated that space flight had reduced the colony-forming unit (CFU) per milliliter count of S. plicatus and increased the specific productivity (pg CFU(-1)) of actinomycin D. The antibiotic compound itself was not affected, but its production time course was altered in space. Viable flight samples also maintained their sporulation ability when plated on agar medium postflight, while the residual ground controls did not sporulate.

Human unilateral lower limb suspension as a model for spaceflight effects on skeletal muscle

To the Editor: Widrick et al. ([18][1]) have published data from a 12-day unilateral lower limb suspension (ULLS) study conducted in 1994 using the methods originally published by Berg et al. in 1991 ([3][2]). Analyses included the morphology and contractile behavior of skinned skeletal muscle

Evaluation of Attitude and Orbit Estimation Using Actual Earth Magnetic Field Data

Asingle,augmentedextendedKalmane lter (EKF),whichsimultaneouslyandautonomouslyestimatesspacecraft attitude and orbit, hasbeen developed and successfully tested with real magnetometer and gyro data only. Because theEarthmagnetice eld isa functionoftimeand position,andbecausetimeisknownquiteprecisely,thedifferences between the computed and measured magnetic e eld components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both orbit and attitude errors. Thus, conceivably these differences could be used to estimate both orbit and attitude; an observability study validated this assumption. The results of testing the EKF with actual magnetometer and gyro data, from four satellites supported by the NASA Goddard Space Flight Center Guidance, Navigation, and Control Center, are presented and evaluated. They cone rm the assumption that a single EKF can estimate both attitude and orbit when using gyros and magnetometers only.

Automatic Control in Space Flight: Peaceful Uses of Automation in Outer Space . Proceedings of the First IFAC (International Federation of Automatic Control) Symposium on Automatic Control in the Peaceful Uses of Space, held in Norway in 1965. Edited by John A. Aseltine. Plenum, New York, 1966. 601 pp., illus. $22.50.

Automatic Control in Space Flight: <i>Peaceful Uses of Automation in Outer Space</i> . Proceedings of the First IFAC (International Federation of Automatic Control) Symposium on Automatic Control in the Peaceful Uses of Space, held in Norway in 1965. Edited by John A. Aseltine. Plenum, New York, 1966. 601 pp., illus. $22.50.

Automatic Control in Space Flight

Automatic Control in Space Flight

Digital Command - A Network for Manned Spaceflight

Error-free radio command control of manned and unmanned spacecraft used in the manned spacecraft program is mandatory for mission success. This paper outlines the history, philosophies, and methods used in the development of the Digital Command Network implemented for this purpose. This network is designed to the concepts of error detection, versatility, and reliability. This paper will explain the basic concepts of design, the configuration of ground command sites involved, and the overall network which evolved to satisfy the command requirements of manned spaceflight control.