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Emergency communications for NASA's deep space missions

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dc.contributor.author Shambayati, Shervin
dc.contributor.author Lee, Charles H.
dc.contributor.author Morabito, David D.
dc.contributor.author Cesarone, Robert J.
dc.contributor.author Abraham, Douglas S.
dc.date.accessioned 2014-09-24T23:38:33Z
dc.date.available 2014-09-24T23:38:33Z
dc.date.issued 2011-03-05
dc.identifier.citation 2011 IEEE Aerospace Conference, Big Sky, Montana, March 5-12, 2011 en_US
dc.identifier.clearanceno 10-5149
dc.identifier.uri http://hdl.handle.net/2014/44776
dc.description.abstract The ability to communicate with spacecraft during emergencies is a vital service that NASA’s Deep Space Network (DSN) provides to all deep space missions. Emergency communications is characterized by low data rates(typically ∼10 bps) with the spacecraft using either a low-gain antenna (LGA, including omnidirectional antennas) or, in some cases, a medium-gain antenna (MGA). Because of the use of LGAs/MGAs for emergency communications, the transmitted power requirements both on the spacecraft and on the ground are substantially greater than those required for normal operations on the high-gain antenna (HGA) despite the lower data rates. In this paper, we look at current and future emergency communications capabilities available to NASA’s deep-space missions and discuss their limitations in the context of emergency mode operations requirements. These discussions include the use of the DSN 70-m diameter antennas, the use of the 34-m diameter antennas either alone or arrayed both for the uplink (Earth-to-spacecraft) and the downlink (spacecraft-to-Earth), upgrades to the ground transmitters, and spacecraft power requirements both with unity gain (0 dB) LGAs and with antennas with directivity (>0 dB gain, either LGA or MGA, depending on the gain). Also discussed are the requirements for forward-error-correcting codes for both the uplink and the downlink. In additional, we introduce a methodology for proper selection of a directional LGA/MGA for emergency communications. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2011 en_US
dc.title Emergency communications for NASA's deep space missions en_US
dc.type Preprint en_US


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