Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187036
R. Aravind, S. Harsh, P. Bandyopadhyay
Retrograde High Earth Orbit (RHEO) Missions have been investigated for nuclear waste disposal, space debris observation and investigation of gravitomagnetic field. Satellite insertion into RGEO through conventional approach is very difficult owing to high-energy requirement and range safety constraints. Here, lunar gravity assist is explored to design a feasible space mission architecture for RGEO. To design a realistic RGEO mission, different launch and orbital trajectory options are explored. It is found out that it is preferable to target for RGEO from a Geosynchronous Transfer Orbit (GTO) rather than from a Retrograde Geo-equatorial Transfer Orbit (RGTO). Though Hohman transfer from GTO to RGEO results in a heavy payload loss, at the same time, it is also demonstrated that it is highly advantageous to reach RGEO from GTO through lunar swing-by. In an optimized mode of transfer, it is possible to change the Inclination of Earth Return Orbit to 180° (Boomerang Orbit) from a typical GTO inclination. The net velocity requirement for such transfer to RGEO from GTO through lunar swing-by is about 2.0 km/s, which is translated to about 90% of GSO payload.
{"title":"Mission to Retrograde Geo-equatorial Orbit (RGEO) using lunar swing-by","authors":"R. Aravind, S. Harsh, P. Bandyopadhyay","doi":"10.1109/AERO.2012.6187036","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187036","url":null,"abstract":"Retrograde High Earth Orbit (RHEO) Missions have been investigated for nuclear waste disposal, space debris observation and investigation of gravitomagnetic field. Satellite insertion into RGEO through conventional approach is very difficult owing to high-energy requirement and range safety constraints. Here, lunar gravity assist is explored to design a feasible space mission architecture for RGEO. To design a realistic RGEO mission, different launch and orbital trajectory options are explored. It is found out that it is preferable to target for RGEO from a Geosynchronous Transfer Orbit (GTO) rather than from a Retrograde Geo-equatorial Transfer Orbit (RGTO). Though Hohman transfer from GTO to RGEO results in a heavy payload loss, at the same time, it is also demonstrated that it is highly advantageous to reach RGEO from GTO through lunar swing-by. In an optimized mode of transfer, it is possible to change the Inclination of Earth Return Orbit to 180° (Boomerang Orbit) from a typical GTO inclination. The net velocity requirement for such transfer to RGEO from GTO through lunar swing-by is about 2.0 km/s, which is translated to about 90% of GSO payload.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"8 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88684681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187110
Leah Rosenbaum, Mohit Agrawal, Leah Birch, Yacoub H. Kureh, N. Lee, James Hant, Brian W. Wood
The performance of most satellite communication (SATCOM) systems is characterized by loading analyses that assess the percentage of users or total throughput a particular system can satisfy. These analyses usually assume a static allocation of resources in which users request communication resources 100% of the time and higher priority users often block lower priority users from getting service. However, the loading of more dynamic, circuit networks such as the public-switched telephone network (PSTN) is typically analyzed on a statistical basis where the probability of a blocked call is computed. These types of systems can potentially satisfy more users than those that use static resource allocation because they take advantage of statistical multiplexing. As SATCOM moves toward a more dynamic concept of operations (CONOPS) to take advantage of potential statistical multiplexing gains, it is crucial to develop analysis capabilities to evaluate performance. In this paper, a method is developed to calculate call-blocking, preemption, and resource utilization for dynamically-allocated SATCOM systems in which users have different priorities and bandwidth requirements. The first part of the study augments the classical M/M/m queuing model to account for users with different priorities and bandwidth requirements. In the second part of the study, the model is used to predict the performance for two competing traffic classes with different bandwidths or priorities and highlight important trends. Finally, the third part of the study directly compares the performance of static and dynamic resource allocation approaches. This work was performed by The Aerospace Corporation in collaboration with a team of students representing the Research in Industrial Projects for Students (RIPS) Program. Administered by the UCLA Institute for Pure & Applied Mathematics (IPAM), RIPS provides opportunities for high-achieving undergraduate students to work in teams on real-world research projects proposed by a sponsor from industry.
{"title":"Calculating call blocking and utilization for communication satellites that use dynamic resource allocation","authors":"Leah Rosenbaum, Mohit Agrawal, Leah Birch, Yacoub H. Kureh, N. Lee, James Hant, Brian W. Wood","doi":"10.1109/AERO.2012.6187110","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187110","url":null,"abstract":"The performance of most satellite communication (SATCOM) systems is characterized by loading analyses that assess the percentage of users or total throughput a particular system can satisfy. These analyses usually assume a static allocation of resources in which users request communication resources 100% of the time and higher priority users often block lower priority users from getting service. However, the loading of more dynamic, circuit networks such as the public-switched telephone network (PSTN) is typically analyzed on a statistical basis where the probability of a blocked call is computed. These types of systems can potentially satisfy more users than those that use static resource allocation because they take advantage of statistical multiplexing. As SATCOM moves toward a more dynamic concept of operations (CONOPS) to take advantage of potential statistical multiplexing gains, it is crucial to develop analysis capabilities to evaluate performance. In this paper, a method is developed to calculate call-blocking, preemption, and resource utilization for dynamically-allocated SATCOM systems in which users have different priorities and bandwidth requirements. The first part of the study augments the classical M/M/m queuing model to account for users with different priorities and bandwidth requirements. In the second part of the study, the model is used to predict the performance for two competing traffic classes with different bandwidths or priorities and highlight important trends. Finally, the third part of the study directly compares the performance of static and dynamic resource allocation approaches. This work was performed by The Aerospace Corporation in collaboration with a team of students representing the Research in Industrial Projects for Students (RIPS) Program. Administered by the UCLA Institute for Pure & Applied Mathematics (IPAM), RIPS provides opportunities for high-achieving undergraduate students to work in teams on real-world research projects proposed by a sponsor from industry.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"38 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88726116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187162
M. E. Jungwirth, C. Wilcox, R. Romeo, D. Wick, E. Dereniak, R. Martin, M. Baker
Adaptive or active elements can alter their shape to remove aberrations or shift focal points. Carbon fiber reinforced polymer (CFRP) material improves upon current active mirror materials, such as Zerodur, in several ways: low stiffness-to-weight ratio, very low hysteresis, and greater dynamic range of correction. In this paper, we present recent developments in CFRP mirror actuation, i.e., changing the mirror's shape in an accurate and repeatable fashion. Actuation methods are studied both theoretically, using finite element analysis, and experimentally, using interferometric testing. We present results using two annular rings to push against the mirror's back, producing a wavefront with less than 20 waves of total error. Applications for this work include active telescope secondaries, phase diversity, and adaptive zoom systems.
{"title":"Actuation for carbon fiber reinforced polymer active optical mirrors","authors":"M. E. Jungwirth, C. Wilcox, R. Romeo, D. Wick, E. Dereniak, R. Martin, M. Baker","doi":"10.1109/AERO.2012.6187162","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187162","url":null,"abstract":"Adaptive or active elements can alter their shape to remove aberrations or shift focal points. Carbon fiber reinforced polymer (CFRP) material improves upon current active mirror materials, such as Zerodur, in several ways: low stiffness-to-weight ratio, very low hysteresis, and greater dynamic range of correction. In this paper, we present recent developments in CFRP mirror actuation, i.e., changing the mirror's shape in an accurate and repeatable fashion. Actuation methods are studied both theoretically, using finite element analysis, and experimentally, using interferometric testing. We present results using two annular rings to push against the mirror's back, producing a wavefront with less than 20 waves of total error. Applications for this work include active telescope secondaries, phase diversity, and adaptive zoom systems.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"48 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89346420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187327
W. M. Reid, C. Monaco
With the trend in spacecraft flight software systems toward the use of message-based architectures, flight software systems are being decomposed into several discrete applications each with a relatively narrow focus. These applications, however, share several common requirements for initialization, command processing, parameter management and telemetry generation. Even with a single common design, if each of these functions were left up to individual application developers, there would be multiple implementations. Each of these implementations would require testing and maintenance, which increases the overall development and maintenance costs and also increases the potential for bugs. In lieu of leaving these functions up to each individual developer of the applications the Radiation Belt Storm Probes (RBSP) Flight Software development team has isolated the commonality across all of the flight software applications and created an application framework. This framework separates the software functions that are common to all applications and the software functions that give a particular application its unique personality. An application deployment tool was also created that allows a developer to create a new application using this framework and insert it into a flight software system in a matter of minutes. The use of an application framework and deployment tool speeds up software development by enabling the creation of an executable application that can receive commands and generate basic telemetry in minutes. This approach, through the separation of the common application code and specific application code allows all applications to use the same overall design while enabling the batch maintenance of the common functionality. This paper discusses the design of the RBSP application framework, deployment tools, the flight software maintenance model, as well as the impact on the flight software development cycle.
{"title":"Flight software application framework simplifies development for RBSP spacecraft","authors":"W. M. Reid, C. Monaco","doi":"10.1109/AERO.2012.6187327","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187327","url":null,"abstract":"With the trend in spacecraft flight software systems toward the use of message-based architectures, flight software systems are being decomposed into several discrete applications each with a relatively narrow focus. These applications, however, share several common requirements for initialization, command processing, parameter management and telemetry generation. Even with a single common design, if each of these functions were left up to individual application developers, there would be multiple implementations. Each of these implementations would require testing and maintenance, which increases the overall development and maintenance costs and also increases the potential for bugs. In lieu of leaving these functions up to each individual developer of the applications the Radiation Belt Storm Probes (RBSP) Flight Software development team has isolated the commonality across all of the flight software applications and created an application framework. This framework separates the software functions that are common to all applications and the software functions that give a particular application its unique personality. An application deployment tool was also created that allows a developer to create a new application using this framework and insert it into a flight software system in a matter of minutes. The use of an application framework and deployment tool speeds up software development by enabling the creation of an executable application that can receive commands and generate basic telemetry in minutes. This approach, through the separation of the common application code and specific application code allows all applications to use the same overall design while enabling the batch maintenance of the common functionality. This paper discusses the design of the RBSP application framework, deployment tools, the flight software maintenance model, as well as the impact on the flight software development cycle.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"1 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89241956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187407
K. A. Kipp, S. Ringler, E. L. Chapman, C. Freaner
This study explores instrument schedule delays and their impacts on mission development schedule and cost growth for recent NASA missions. This study examines 86 instruments across 32 NASA missions. First, the relationship between instrument schedule growth and mission development cost growth is examined. It is found that instrument development delays have a prominent role in contributing to mission development schedule and cost growth. Second, instrument developments are analyzed in order to explore specific trends related to schedule growth and to determine potential contributing factors. Instrument schedule growth is examined as a function of mass, power, instrument type, and spacecraft destination. The results are then used to establish schedule rules-of-thumb that can be used for planning purposes by project and program managers in charge of future NASA development efforts.
{"title":"Impact of instrument schedule growth on mission cost and schedule growth for recent NASA missions","authors":"K. A. Kipp, S. Ringler, E. L. Chapman, C. Freaner","doi":"10.1109/AERO.2012.6187407","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187407","url":null,"abstract":"This study explores instrument schedule delays and their impacts on mission development schedule and cost growth for recent NASA missions. This study examines 86 instruments across 32 NASA missions. First, the relationship between instrument schedule growth and mission development cost growth is examined. It is found that instrument development delays have a prominent role in contributing to mission development schedule and cost growth. Second, instrument developments are analyzed in order to explore specific trends related to schedule growth and to determine potential contributing factors. Instrument schedule growth is examined as a function of mass, power, instrument type, and spacecraft destination. The results are then used to establish schedule rules-of-thumb that can be used for planning purposes by project and program managers in charge of future NASA development efforts.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"17 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90716723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187420
K. Cook
In today's fast paced and ultra-competitive environment, businesses in the aerospace and defense industry may be tempted to cut corners in order to gain a leg up on their competition. Corporate compliance programs help ensure that companies are complying with federal laws and regulations and employees are complying with corporate policies and procedures. Companies in the aerospace and defense industry have a legal obligation to create and maintain a compliance program, as required by certain laws and regulations. In addition to legal obligations, companies also have a moral obligation to promote organizational integrity, which can best be done through the operation of an effective compliance program. This paper outlines the laws and regulations that require companies in the aerospace and defense industry to implement compliance programs, companies' moral obligations for doing so, and some best practices for implementing them.
{"title":"Corporate compliance programs — Who needs them?","authors":"K. Cook","doi":"10.1109/AERO.2012.6187420","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187420","url":null,"abstract":"In today's fast paced and ultra-competitive environment, businesses in the aerospace and defense industry may be tempted to cut corners in order to gain a leg up on their competition. Corporate compliance programs help ensure that companies are complying with federal laws and regulations and employees are complying with corporate policies and procedures. Companies in the aerospace and defense industry have a legal obligation to create and maintain a compliance program, as required by certain laws and regulations. In addition to legal obligations, companies also have a moral obligation to promote organizational integrity, which can best be done through the operation of an effective compliance program. This paper outlines the laws and regulations that require companies in the aerospace and defense industry to implement compliance programs, companies' moral obligations for doing so, and some best practices for implementing them.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"1 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90750233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6186997
E. García-Llama, M. Ivanov, R. Winski, M. Grover, J. Shidner, R. Prakash
In 2011, the Mars Science Laboratory (MSL) was launched in a mission to deliver the largest and most capable rover to date to the surface of Mars. A follow on MSL-derived mission, referred to as Mars 2018, is being proposed to launch in 2018. Mars 2018 is investigating performance enhancements of the Entry, Descent and Landing (EDL) system over that of its predecessor MSL mission of 2011. This paper will discuss the main elements of the proposed Mars 2018 EDL preliminary design that are being considered to increase performance on the entry phase of the mission. In particular, these elements are discussed with the goals of increasing the parachute deploy altitude to allow for more time margin during the subsequent descent and landing phases, increasing the entry mass, and reducing the delivery ellipse size at parachute deploy, through modifications in the entry reference trajectory design, vehicle's lift to drag ratio, parachute deploy trigger logic design, and the effect of additional navigation hardware.
{"title":"Mars Science Laboratory entry guidance improvements study for the Mars 2018 mission","authors":"E. García-Llama, M. Ivanov, R. Winski, M. Grover, J. Shidner, R. Prakash","doi":"10.1109/AERO.2012.6186997","DOIUrl":"https://doi.org/10.1109/AERO.2012.6186997","url":null,"abstract":"In 2011, the Mars Science Laboratory (MSL) was launched in a mission to deliver the largest and most capable rover to date to the surface of Mars. A follow on MSL-derived mission, referred to as Mars 2018, is being proposed to launch in 2018. Mars 2018 is investigating performance enhancements of the Entry, Descent and Landing (EDL) system over that of its predecessor MSL mission of 2011. This paper will discuss the main elements of the proposed Mars 2018 EDL preliminary design that are being considered to increase performance on the entry phase of the mission. In particular, these elements are discussed with the goals of increasing the parachute deploy altitude to allow for more time margin during the subsequent descent and landing phases, increasing the entry mass, and reducing the delivery ellipse size at parachute deploy, through modifications in the entry reference trajectory design, vehicle's lift to drag ratio, parachute deploy trigger logic design, and the effect of additional navigation hardware.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"46 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91239454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187219
A. Donnellan, J. Parker, R. Granat, E. D. De Jong, S. Suzuki, M. Pierce, G. Fox, J. Rundle, D. McLeod, R. Al-Ghanmi, L. G. Ludwig
The QuakeSim Project improves understanding of earthquake processes by integrating model applications and various heterogeneous data sources within a web services environment. The project focuses on the earthquake cycle and related crustal deformation. Spaceborne GPS and Interferometric Synthetic Aperture data provide information on near-term crustal deformation, while paleoseismic geologic data provide longer-term information on earthquake fault processes. These data sources are integrated into QuakeSim's QuakeTables database and are accessible by users or various model applications. An increasing amount of UAVSAR data is being added to the QuakeTables database through a map browsable interface. Model applications can retrieve data from QuakeTables or remotely served GPS velocity data services or users can manually input parameters into the models. Pattern analysis of GPS and seismicity data has proved useful for mid-term forecasting of earthquakes and for detecting subtle changes in crustal deformation. The GPS time series analysis has also proved useful for detecting changes in processing of the data. Development of the QuakeSim computational infrastructure has benefitted greatly from having the user in the development loop. Improved visualization tools enable more efficient data exploration and understanding. Tools must provide flexibility to science users for exploring data in new ways, but also must facilitate standard, intuitive, and routine uses for end users such as emergency responders.
{"title":"QuakeSim: Integrated modeling and analysis of geologic and remotely sensed data","authors":"A. Donnellan, J. Parker, R. Granat, E. D. De Jong, S. Suzuki, M. Pierce, G. Fox, J. Rundle, D. McLeod, R. Al-Ghanmi, L. G. Ludwig","doi":"10.1109/AERO.2012.6187219","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187219","url":null,"abstract":"The QuakeSim Project improves understanding of earthquake processes by integrating model applications and various heterogeneous data sources within a web services environment. The project focuses on the earthquake cycle and related crustal deformation. Spaceborne GPS and Interferometric Synthetic Aperture data provide information on near-term crustal deformation, while paleoseismic geologic data provide longer-term information on earthquake fault processes. These data sources are integrated into QuakeSim's QuakeTables database and are accessible by users or various model applications. An increasing amount of UAVSAR data is being added to the QuakeTables database through a map browsable interface. Model applications can retrieve data from QuakeTables or remotely served GPS velocity data services or users can manually input parameters into the models. Pattern analysis of GPS and seismicity data has proved useful for mid-term forecasting of earthquakes and for detecting subtle changes in crustal deformation. The GPS time series analysis has also proved useful for detecting changes in processing of the data. Development of the QuakeSim computational infrastructure has benefitted greatly from having the user in the development loop. Improved visualization tools enable more efficient data exploration and understanding. Tools must provide flexibility to science users for exploring data in new ways, but also must facilitate standard, intuitive, and routine uses for end users such as emergency responders.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"1 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89853049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187127
P. E. Finch, D. Sullivan, W. Ivancic
NASA is utilizing Global Hawk aircraft in high-altitude, long duration Earth science missions. Communications with the science payload is via Ku-Band satellites in geostationary orbits. All payload communications use standard Internet Protocols and routing, and much of the data to be transferred is comprised of very large files. The science community is interested in fully utilizing these communication links to retrieve data as quickly and reliably as possible. A test bed was developed at NASA Ames to evaluate modern transport protocols as well as Protocol Enhancing Proxies (PEPs) to determine what tools best fit the needs of the science community. This paper describes the test bed used, the protocols, the PEPs that were evaluated, the particular tests performed and the results and conclusions.
{"title":"An evaluation of Protocol Enhancing Proxies and modern file transport protocols for geostationary satellite communication","authors":"P. E. Finch, D. Sullivan, W. Ivancic","doi":"10.1109/AERO.2012.6187127","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187127","url":null,"abstract":"NASA is utilizing Global Hawk aircraft in high-altitude, long duration Earth science missions. Communications with the science payload is via Ku-Band satellites in geostationary orbits. All payload communications use standard Internet Protocols and routing, and much of the data to be transferred is comprised of very large files. The science community is interested in fully utilizing these communication links to retrieve data as quickly and reliably as possible. A test bed was developed at NASA Ames to evaluate modern transport protocols as well as Protocol Enhancing Proxies (PEPs) to determine what tools best fit the needs of the science community. This paper describes the test bed used, the protocols, the PEPs that were evaluated, the particular tests performed and the results and conclusions.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"73 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76551994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187124
O. Kegege, M. Fuentes, N. Meyer, A. Sil
There is a need to understand NASA's Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data.
{"title":"Three-dimensional analysis of Deep Space Network antenna coverage","authors":"O. Kegege, M. Fuentes, N. Meyer, A. Sil","doi":"10.1109/AERO.2012.6187124","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187124","url":null,"abstract":"There is a need to understand NASA's Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"31 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76753559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：