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RF and Optical Communications: A Comparison of High Data Rate Returns From Deep Space in the 2020 TimeframeAs NASA proceeds with plans for increased science data return and higher data transfer capacity for science missions, both RF and optical communications are viable candidates for significantly higher-rate communications from deep space to Earth. With the inherent advantages, smaller apertures and larger bandwidths, of optical communications, it is reasonable to expect that at some point in time and combination of increasing distance and data rate, the rapidly emerging optical capabilities would become more advantageous than the more mature and evolving RF techniques. This paper presents a comparison of the burden to a spacecraft by both RF and optical communications systems for data rates of 10, 100, and 1000 Mbps and large distances. Advanced technology for RF and optical communication systems have been considered for projecting capabilities in the 2020 timeframe. For the comparisons drawn, the optical and RF ground terminals were selected to be similar in cost. The RF system selected is composed of forty-five 12-meter antennas, whereas the selected optical system is equivalent to a 10-meter optical telescope. Potential differences in availability are disregarded since the focus of this study is on spacecraft mass and power burden for high-rate mission data, under the assumption that essential communications will be provided by low-rate, high availability RF. For both the RF and optical systems, the required EIRP, for a given data rate and a given distance, was achieved by a design that realized the lowest possible communications subsystem mass (power + aperture) consistent with achieving the lowest technology risk. A key conclusion of this paper is that optical communications has great potential for high data rates and distances of 2.67 AU and beyond, but requires R&D and flight demonstrations to prove out technologies.
Document ID
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Williams, W. Dan
(NASA Glenn Research Center Cleveland, OH, United States)
Collins, Michael
(ASRC Management Services Reston, VA, United States)
Boroson, Don M.
(Massachusetts Inst. of Tech. Lexington, MA, United States)
Lesh, James
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Biswas, Abihijit
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Orr, Richard
(Satel, LLC Rockville, MD, United States)
Schuchman, Leonard
(Satel, LLC Rockville, MD, United States)
Sands, O. Scott
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 23, 2013
Publication Date
March 1, 2007
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking
Report/Patent Number
Meeting Information
Meeting: 12th Ka and Broadband Communications Conference
Location: Naples
Country: Italy
Start Date: September 27, 2006
End Date: September 29, 2006
Sponsors: Communications and Power Industries, Inc., Finmeccanica, MARS, Alcatel Alenia Space, Space Engineering, Galileo Industries, Telespazio S.p.A., European Space Agency
Funding Number(s)
WBS: WBS 439432.
Distribution Limits
Public Use Permitted.
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