Space Communications and Navigation Program
The Space Communications and Navigation (SCaN) program places the three prime NASA space communications networks, Space Network (SN), Near Earth Network (NEN) (previously known as the Ground Network or GN), and the Deep Space Network (DSN), under one Management and Systems Engineering umbrella. It was established in 2006.
History
Before NASA's administrator Michael Griffin created SCaN to direct an integrated networks program, different organizations at NASA Headquarters have managed the Agency’s space communications capabilities and functions under separate Programs using a variety of administrative approaches. [1]
The SCaN Office was established by direction of Griffin in a Memorandum entitled “Establishment of a Space Communications and Navigation Office,” dated July 19, 2006.[2] SCaN operates as a central organization within the Space Operations Mission Directorate (SOMD):
The Office’s responsibilities encompass the management of existing space networks including the Tracking and Data Relay Satellite system, the Deep Space Network, the Ground Network, the NASA Integrated Services Network; implementing any improvements and upgrades to those systems and networks; and developing any future NASA communications and navigation architectures.
The Ground Network (GN) has since been renamed the Near Earth Network.
Services
SCaN is viewed as a service provider supporting interfaces and performing a standard set of functions, including:[3]
- Forward data transfer (uplink to spacecraft)
- Return data transfer (downlink from spacecraft to ground)
- Dissimilar voice communications
- Emergency communications
- Post-landing communications
- Radiometric measurement
- Time correlation
- Service monitoring
- Ephemeris exchange
- Operational coordination
- Service scheduling.
Forward and return services may be MA (Multiple Access) or SA (Single Access).
Communications schemes
Communications with spaceborne platforms is performed by RF, with a selection of spectra, modulation, and encoding methods, enumerated below.
Spectra
The Space Network communicates with spacecraft using S-band, Ka-band, and Ku-band[4] with planned laser/optical communications.
Modulation
SN uses Phase Shift Keying and Phase Modulation of the carrier frequency.[4]
Encoding
The Space Network supports the following encoding schemes:[4]
The Reed-Solomon method is used as the initial error-correcting block code prior to the selected secondary encoding scheme.
Applicability to Constellation
The Constellation missions will be different from previous NASA campaigns, in that the number of simultaneously interacting space and ground systems will be larger, and systems will need to coordinate with each other both to achieve their science objectives and to accomplish the 'routine' mechanics of mission operations. The interaction between combinations of these systems is deemed important, and the SCaN program must provide and maintain the data links. The small set of Constellation RF links is based on Space Network (SN) standards that are currently used in human spaceflight.[5]
See also
- Space Network
- Deep Space Network
- Near Earth Network
- Indian Deep Space Network
- Tracking and Data Relay Satellite
- Eastern Range
References
- ^ NASA. Space Communications and Navigation (SCaN) Program Plan. National Aeronautics and Space Administration.
{{cite book}}: Cite has empty unknown parameter:|coauthors=(help) - ^ NASA (January 30, 2009). SCaN Systems Engineering Management Plan (SEMP). NASA Space Communication and Navigation Program Office. SCaN-SEMP.
{{cite book}}: Cite has empty unknown parameter:|coauthors=(help)CS1 maint: year (link) - ^ NASA (June 28, 2008). Constellation Design Reference Missions And Operational Concepts (ConOps), Annex 1: Constellation Communications and Tracking Concept of Operations (Baseline ed.). National Aeronautics and Space Administration. CxP 70007, ConOps.
{{cite book}}: Cite has empty unknown parameter:|coauthors=(help)CS1 maint: year (link) - ^ a b c NASA, Exploration and Space Communications Projects Division (August 2007). Space Network User's Guide (SNUG), 2.3, Elements of the SN (Rev 9 ed.). National Aeronautics and Space Administration. 450-SNUG.
{{cite book}}: Unknown parameter|coauthors=ignored (|author=suggested) (help)CS1 maint: year (link) Cite error: The named reference "SNUG" was defined multiple times with different content (see the help page). - ^ NASA (September 8, 2008). CxP 70022-2 Rev. B, Constellation Program Command, Control, Communication, and Information (C3I) Interoperability Standards Book, Volume 2: Spectrum And Channel Plan (Rev. B ed.). National Aeronautics and Space Administration. CxP 70022-2.
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