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Appendix H: TA05 Communication and Navigation
Pages 167-181

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From page 167...
... The roadmap focuses on several key issues for the future of communications: development of radio frequency (RF) technology while initiating a parallel path to develop optical communications capability, application of Earth's internetworking technology and processes to reduce operational costs through simplified 1 The draft space technology roadmaps are available at http://www.nasa.gov/offices/oct/strategic_integration/technology_roadmap.html.
From page 168...
... Reconfigurable Large Apertures Rename: 5.6.7. Reconfigurable Large Apertures Using Nanosat Constellations NOTE: Technologies 5.4.1, Timekeeping, and 5.4.2, Time Distribution, have been merged and renamed: 5.4.1 Timekeeping and Time Distribution because the technologies are very similar and it would be most effective to develop them together.
From page 169...
... 2. Communications Constraint Mitigation: Minimize communication data rate and range constraints that impact planning and execution of future NASA space missions.
From page 170...
... = High Priority, QFD score override; M = Medium Priority; L = Low Priority. CHALLENGES VERSUS TECHNOLOGIES Figure H.3 shows the relationship between the individual level 3 TA10 technologies and the top technical challenges.
From page 171...
... Technology 5.4.3, Onboard Autonomous Navigation and Maneuvering Systems Onboard autonomous navigation and maneuvering (OANM) techniques are critical for improving the capabilities and reducing the support requirements for many future space missions.
From page 172...
... FIGURE H.3 Level of support that the technologies provide to the top technical challenges for TA05 Communication and Navigation. to NASA's needs is high because it will impact deep space exploration with crew, robotic science missions, planetary landers and rovers.
From page 173...
... Advances in timekeeping and distribution of several orders of magnitude were judged to provide major benefits, since increased precision of timekeeping and transfer leads to increased precision of relative and absolute position and velocity which in turn provides better starting solutions to enable autonomous rendezvous, docking, landing, and formation flying remote from Earth. In addition, precision timekeeping enables new tests of fundamental physics, time and frequency metrology, geodesy, gravimetry, and ultra-high-resolution VLBI science applications.
From page 174...
... Advancements in radio systems integration focus on one of the highest priority technical challenges within TA05: Minimize communications constraints on data rate and range that impact planning and execution of future NASA space missions. Like all technologies in TA05, these advancements benefit multiple types of missions in deep space as well as near-Earth orbit.
From page 175...
... ; tracking or searching for multiple targets simultaneously; and nulling-out discrete or extended sources of interference while receiving faint signals from sources with only small separations in look angle and measuring their spectra, Doppler shifts, and angular structure. With this technology, NASA could improve the data rates and efficiency of communication with deep space missions, including enabling high-rate communica tion with multiple missions simultaneously.
From page 176...
... The remaining three medium-priority technologies and six low-priority technologies were judged to have only minor benefits to NASA missions within the next 20 to 30 years. These technologies included 5.2.2 Power Efficient Technologies, 5.2.4 Flight and Ground Systems, 5.2.1 Spectrum Efficient Technologies, 5.5.6 RF/Optical Hybrids, 5.2.3 RF Propagation, 5.2.5 Earth Launch and Reentry Communication, 5.5.5 Hybrid Optical Communication and Navigation Sensors, 5.5.4 Science from the Communication System, and 5.3.3 Information Assurance.
From page 177...
... . NASA mentioned that the integration of optical communications and disruption-tolerant networking (DTN)
From page 178...
... Because NASA deep space missions operate in a much higher radiation environment than missions in LEO and GEO, there may be hardware-based challenges to implementing space networking solutions. Ekici indicated that there are likely to be hardware/processing issues that will have to be addressed, and recommended that this work occur in parallel with the networking and protocol development.
From page 179...
... provided a briefing with comments on specific sections of the roadmap that impact accuracy and performance of deep space navigation. Wood assessed the roadmap as conservative in estimates of deep space navigation accuracy for single antenna applications (e.g., line-of-sight Doppler and ranging)
From page 180...
... provided inputs on the roadmap's treatment of navigation for lunar and interplan etary applications. In this area, Cangahuala identified top technical challenges as: (1)
From page 181...
... For navigation components (e.g., fiber-optic gyros, atomic clocks) , there are potential industrial base/market size issues that may drive NASA toward a particular solution.


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