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Orbiter Interface Unit and Early Communication SystemThis report describes the Orbiter Interface Unit (OIU) and the Early Communication System (ECOMM), which are systems of electronic hardware and software that serve as the primary communication links for the International Space Station (ISS). When a space shuttle is at or near the ISS during assembly and resupply missions, the OIU sends groundor crew-initiated commands from the space shuttle to the ISS and relays telemetry from the ISS to the space shuttle s payload data systems. The shuttle then forwards the telemetry to the ground. In the absence of a space shuttle, the ECOMM handles communications between the ISS and Johnson Space Center via the Tracking and Data Relay Satellite System (TDRSS). Innovative features described in the report include (1) a "smart data-buffering algorithm that helps to preserve synchronization (and thereby minimize loss) of telemetric data between the OIU and the space-shuttle payload data interleaver; (2) an ECOMM antenna-autotracking algorithm that selects whichever of two phased-array antennas gives the best TDRSS signal and electronically steers that antenna to track the TDRSS source; and (3) an ECOMM radiation-latchup controller, which detects an abrupt increase in current indicative of radiation-induced latchup and temporarily turns off power to clear the latchup, restoring power after the charge dissipates.
Document ID
20110016844
Acquisition Source
Johnson Space Center
Document Type
Other - NASA Tech Brief
Authors
Cobbs, Ronald M.
(NASA Johnson Space Center Houston, TX, United States)
Cooke, Michael P.
(NASA Johnson Space Center Houston, TX, United States)
Cox, Gary L.
(NASA Johnson Space Center Houston, TX, United States)
Ellenberger, Richard
(NASA Johnson Space Center Houston, TX, United States)
Fink, Patrick W.
(NASA Johnson Space Center Houston, TX, United States)
Haynes, Dena S.
(NASA Johnson Space Center Houston, TX, United States)
Hyams, Buddy
(NASA Johnson Space Center Houston, TX, United States)
Ling, Robert Y.
(NASA Johnson Space Center Houston, TX, United States)
Neighbors, Helen M.
(NASA Johnson Space Center Houston, TX, United States)
Phan, Chau T.
(NASA Johnson Space Center Houston, TX, United States)
Prendergast, Kelly M.
(NASA Johnson Space Center Houston, TX, United States)
Siekierski, James D.
(NASA Johnson Space Center Houston, TX, United States)
Wade, Randall S.
(NASA Johnson Space Center Houston, TX, United States)
Weisskopf, George A.
(NASA Johnson Space Center Houston, TX, United States)
Yim, Hester J.
(NASA Johnson Space Center Houston, TX, United States)
Adkins, Antha A.
(NASA Johnson Space Center Houston, TX, United States)
Carl, James R..
(NASA Johnson Space Center Houston, TX, United States)
Loh, Y. C.
(NASA Johnson Space Center Houston, TX, United States)
Roberts, Charles
(NASA Johnson Space Center Houston, TX, United States)
Steele, Douglas J.
(NASA Johnson Space Center Houston, TX, United States)
DeSilva, Buveneka Kanishka
(NASA Johnson Space Center Houston, TX, United States)
Killenb, Harold B.
(NASA Johnson Space Center Houston, TX, United States)
Williams, Robert M.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 25, 2013
Publication Date
June 1, 2004
Publication Information
Publication: NASA Tech Briefs, June 2004
Subject Category
Man/System Technology And Life Support
Report/Patent Number
MSC-23385
Distribution Limits
Public
Copyright
Public Use Permitted.
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