Space Communications and Navigation Program: Difference between revisions

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{{Short description|Office within NASA}}

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. It was previously known as the Space Communications & Data Systems (SCDS) Program.

{{Third-party|date=August 2023}}

[[File:NASA's Space Communications Testbed.jpg|thumb|right|Technicians at NASA [[Glenn Research Center]] at work on the Space Communications and Navigation Testbed, formerly known as the Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) project<ref>[https://web.archive.org/web/20120526151316/http://spaceflightsystems.grc.nasa.gov/SOPO/SCO/SCaNTestbed/ SCaN Testbed homepage at NASA Glenn Research Center]</ref>]]

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. It was previously known as the '''Space Communications & Data Systems''' ('''SCDS''') Program.

==History==

Before NASA's administrator [[Michael D. Griffin]] created SCaN to direct an integrated networks program, different organizations at NASA Headquarters have managed the Agency’sAgency's space communications capabilities and functions under separate Programs using a variety of administrative approaches.<ref name="ProgramPlan">{{cite book| title = Space Communications and Navigation (SCaN) Program Plan| edition = | last = NASA| first = | coauthors = | year = | publisher = National Aeronautics and Space Administration| id = | pages =}}</ref>

The SCaN Office was established by direction of Griffin in a Memorandum entitled “Establishment"Establishment of a Space Communications and Navigation Office,”" dated July 19, 2006.<ref name="SEMP">{{cite book| title = SCaN Systems Engineering Management Plan (SEMP)| edition = | last = NASA| first = | coauthors = | yeardate = January 30, 2009| publisher = NASA Space Communication and Navigation Program Office| id = SCaN-SEMP| pages =}}</ref> SCaN operates as a central organization within the ''Space Operations Mission Directorate.'' (SOMD):

{{cquote2quote|The Office’sOffice'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:<ref name="ConOps">{{cite book| title = Constellation Design Reference Missions And Operational Concepts (ConOps), Annex 1: Constellation Communications and Tracking Concept of Operations| edition = Baseline| last = NASA| first = | coauthors = | yeardate = June 28, 2008| publisher = National Aeronautics and Space Administration| id = CxP 70007, ConOps| pages =}}</ref>

* Forward data transfer ([[uplink]] to spacecraft)

* Return data transfer ([[downlink]] from spacecraft to ground)

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* [[Ephemeris]] exchange

* Operational coordination

* Service scheduling.

Forward and return services may be MA ([[Channel access method|Multiple Access]]) or SA ([[Channel access method|Single Access]]).

==Communications schemes==

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===Spectra===

The Space Network communicates with spacecraft using [[S-band]], [[Ku-band]],<ref name="SNUGSNUG1">{{cite book| title =Space Network User's Guide (SNUG), 2.3, Elements of the SN | edition = Rev 9| last = NASA| first = Exploration and Space Communications Projects Division | coauthors author2= Goddard Space Flight Center | yeardate = August 2007 | publisher = National Aeronautics and Space Administration| id =450-SNUG | pages = }}</ref>, and [[Ka-band]] with planned laser/optical communications.

The Deep Space Network communicates with spacecraft using S-band, [[X-band]], and [[KKa-band]], and Ka-band.

===Modulation===

SN uses [[Phasephase-shift Shift Keyingkeying]] and [[Phasephase Modulationmodulation]] of the [[carrier frequencysignal]].<ref name="SNUGSNUG2">{{cite book| title =Space Network User's Guide (SNUG), 6.2 SSA Forward Services, and 6.2.3 Phase Modulation (PM) Signal Parameters| edition = Rev 9| last = NASA| first = Exploration and Space Communications Projects Division | coauthors author2= Goddard Space Flight Center | yeardate = August 2007 | publisher = National Aeronautics and Space Administration| id =450-SNUG | pages = }}</ref>

===Encoding===

The Space Network (used for near-Earth communications) supports the following encoding schemes:<ref name="SNUGSNUG3">{{cite book| title =Space Network User's Guide (SNUGx)| edition = Rev 9| last = NASA| first = Exploration and Space Communications Projects Division | coauthors author2= Goddard Space Flight Center | yeardate = August 2007 | publisher = National Aeronautics and Space Administration| id =450-SNUG | pages = }}</ref>

* [[BPSK]]

* [[QPSK]]/[[SQPSK]]

* [[8PSK]]

* Rate 1/2 [[Convolutional code|convolutional coding]]

* [[Phase-shift keying|SQPN]]

* [[Pseudorandom noise|PNPRN coding]] - used to reduce power spectral density for low bit rate signals, and for time transfer.

The [[Reed-SolomonReed–Solomon error correction|Reed–Solomon]] method is used as the initial [[error-correcting code|error-correcting]] [[block code]] prior to the selected secondary encoding scheme.

==Applicability to [[Project Constellation|Constellation]]==

The [[Project Constellation|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.<ref name="70022-2">{{cite book| title =CxP 70022-2 Rev. B, Constellation Program Command, Control, Communication, and Information (C3I) Interoperability Standards Book, Volume 2: Spectrum And Channel Plan| edition = Rev. B| last = NASA| first = | coauthors = | year = September 8, 2008 | publisher = National Aeronautics and Space Administration| id =CxP 70022-2 | pages = }}</ref>

==See also==

* [[Space Network]]

* [[Deep Space Network]]

* [[Near Earth Network]]

* [[Indian Deep Space Network]]

* [[Tracking and Data Relay Satellite]]

* [[Eastern Range]]

* [[NASCOM]]

==References==

{{Reflist}}

==External links==

* [http://www.nasa.gov/directorates/heo/scan/index.html#.U15I0SfbyWY NASA.gov]

{{NASA centers}}

{{NASA navbox|state=collapsed}}

{{Use American English|date=January 2014}}

[[Category:Deep Space Network]]

[[Category:Deep Spacespace Networknetworks]]

[[Category:NASA radio communications and spacecraft tracking facilities]]