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PAPERBACK list:$21.00 Web:$18.90 add to cart Rights & Permissions Free PDF Access Free Resources Sign in to download PDF book and chapters PDF EXECUTIVE SUMMARY Display this book on your site! Related Titles Space Studies Board Annual Report 2005 Principal-Investigator-Led Missions in the Space Sciences Other Related Titles Review of the Space Communications Program of NASA's Space Operations Mission Directorate (2006) Aeronautics and Space Engineering Board (ASEB) Web Search Builder Use this book's key terms to search within this book, across our collection, or across the Web. Skim This Chapter Skim this chapter and use this chapter's key terms to search within this book. Reference Finder Paste in your own text to find books that relate to your topic. Page 38   E-mail  Facebook  Digg  Stumble  Twitter More The following HTML text is provided to enhance online readability. Many aspects of typography translate only awkwardly to HTML. Please use the page image as the authoritative form to ensure accuracy. 5 Data Standards Management INTRODUCTION There is agreement among the world’s space agencies that the use of standardized techniques for handling space data is beneficial to all. Although data formats are generally standardized, the standards activity for space data is more complex, involving designing or adopting systems and procedures that can utilize these standardized data formats. In this context, the term “data standards” encompasses standards for the end-to-end transmission, handling, and storage of all data associated with space operations: scientific data originating on spacecraft, uplink and downlink data needed to conduct associated operations, tracking data, and even voice communications with astronauts. As with other uses of standards, the objective is to reduce costs and enable interoperability by adopting compatible systems and procedures. The role of standards in space operations mirrors the history of standards in general, although accelerated by the extremely rapid development of the associated communications and computing technologies. Technology typically develops in many places simultaneously, with people doing similar things differently simply because there is little coordination. Space operations present a classic example of independently developed approaches to data handling. Experts were needed to build and operate each of various different data-handling systems performing essentially the same fundamental tasks. Most of the effort is spent on inventing (designing and developing), whereas the costs of producing and owning (maintaining) the products are relatively minor. Standardization minimizes reinventing. Assuming agreement in principle that standardization is desirable, how can it be done right? The first step is to understand what it makes sense to standardize. Standardization generally focuses on interfaces: compatible form, fit, and function where components join. Standard components avoid the expense of reengineering and redesigning at the component level, of reinventing for each application. Yet these components can be combined in ways that make them unique and appropriate for a variety of purposes. To be effective, standards must be developed by users, rather than imposed from outside. Users must be motivated to look for commonalities, not differences. What are some of the motivations to standardize? Generally, as technology develops and markets grow, pressures for standardization increase, primarily for economic reasons. Standards permit mass production, thereby reducing both production and ownership costs, and they facilitate expansion of markets, permitting products developed for one market to be sold elsewhere. There are also motivations beyond economic incentives for standardizing, such as safety. Countervailing factors that can inhibit standardization might also reflect economic interests, expressed, for example, in internecine battles to gain competitive advantages, or to maintain or expand contract bases. Often, simple inertia is also an impediment to standardization. An international body, the Consultative Committee for Space Data Systems, commonly referred to as the CCSDS, is the primary organization that develops space-associated standards that facilitate and enable more cost-effective missions through the shared use of common components, procedures, and infrastructure (Box 5.1). SOMD’s data standards program element is essentially synonymous with NASA’s participation in the CCSDS. NASA is a founding member of the CCSDS, which is supported by more than 30 space agencies (and their associated industrial bases) distributed across the world space community. Acting as a technical arm of the International Organization for Standardization (ISO), CCSDS generates the world body of standards in the field of space data and information transfer systems. The CCSDS is the undisputed world leader in space data standardization, and to date well over 300 space missions are able to interoperate using these standard capabilities. Within the United States, virtually all Page 38 Front Matter (R1-R12) Executive Summary (1-6) 1 Introduction (7-12) Assessment of Operational Networks, 2 Space Network Program Element Assessment (13-22) 3 NASA Integrated Services Network (23-28) Assessment of Other Program Elements, 4 Spectrum Management (29-37) 5 Data Standards Management (38-44) 6 Search and Rescue (45-50) 7 Communications and Navigation Architecture (51-55) 8 Technology (56-61) 9 Operations Integration Program Element (62-68) General Issues, 10 Overarching Issues and Recommendations (69-74) Appendix A: Statement of Task (75-78) Appendix B: Committee Member Biographies (79-83) Appendix C: Acronyms (84-86)

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate 5 Data Standards Management INTRODUCTION There is agreement among the world’s space agencies that the use of standardized techniques for handling space data is beneficial to all. Although data formats are generally standardized, the standards activity for space data is more complex, involving designing or adopting systems and procedures that can utilize these standardized data formats. In this context, the term “data standards” encompasses standards for the end-to-end transmission, handling, and storage of all data associated with space operations: scientific data originating on spacecraft, uplink and downlink data needed to conduct associated operations, tracking data, and even voice communications with astronauts. As with other uses of standards, the objective is to reduce costs and enable interoperability by adopting compatible systems and procedures. The role of standards in space operations mirrors the history of standards in general, although accelerated by the extremely rapid development of the associated communications and computing technologies. Technology typically develops in many places simultaneously, with people doing similar things differently simply because there is little coordination. Space operations present a classic example of independently developed approaches to data handling. Experts were needed to build and operate each of various different data-handling systems performing essentially the same fundamental tasks. Most of the effort is spent on inventing (designing and developing), whereas the costs of producing and owning (maintaining) the products are relatively minor. Standardization minimizes reinventing. Assuming agreement in principle that standardization is desirable, how can it be done right? The first step is to understand what it makes sense to standardize. Standardization generally focuses on interfaces: compatible form, fit, and function where components join. Standard components avoid the expense of reengineering and redesigning at the component level, of reinventing for each application. Yet these components can be combined in ways that make them unique and appropriate for a variety of purposes. To be effective, standards must be developed by users, rather than imposed from outside. Users must be motivated to look for commonalities, not differences. What are some of the motivations to standardize? Generally, as technology develops and markets grow, pressures for standardization increase, primarily for economic reasons. Standards permit mass production, thereby reducing both production and ownership costs, and they facilitate expansion of markets, permitting products developed for one market to be sold elsewhere. There are also motivations beyond economic incentives for standardizing, such as safety. Countervailing factors that can inhibit standardization might also reflect economic interests, expressed, for example, in internecine battles to gain competitive advantages, or to maintain or expand contract bases. Often, simple inertia is also an impediment to standardization. An international body, the Consultative Committee for Space Data Systems, commonly referred to as the CCSDS, is the primary organization that develops space-associated standards that facilitate and enable more cost-effective missions through the shared use of common components, procedures, and infrastructure (Box 5.1). SOMD’s data standards program element is essentially synonymous with NASA’s participation in the CCSDS. NASA is a founding member of the CCSDS, which is supported by more than 30 space agencies (and their associated industrial bases) distributed across the world space community. Acting as a technical arm of the International Organization for Standardization (ISO), CCSDS generates the world body of standards in the field of space data and information transfer systems. The CCSDS is the undisputed world leader in space data standardization, and to date well over 300 space missions are able to interoperate using these standard capabilities. Within the United States, virtually all

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate NASA space missions—and a growing number operated by NOAA, the DOD, and U.S. industry—implement a significant complement of CCSDS standards. Specific missions are listed in Table 5.1. CCSDS products are properly termed and treated as recommendations that space mission programs are free to accept or reject as they determine best for their individual programs. In this regard, neither the data standards management program element nor the broader SOMD program exercises any control over adoption of the standards. Establishment and approval of any “waivers” are totally outside the purview of SOMD. Thus, the degree to which spaceflight missions adopt recommended standards is a meaningful metric of the usefulness of SOMD’s data standards management element, and the committee has accordingly attempted to determine the degree of adoption. Table 5.1 lists 78 new space missions that have adopted CCSDS standards recommendations in whole or in part.1 In addition, other organizations frequently see compatibility with NASA space communications standards as a valuable means of enabling support or cross-support with NASA assets. Although the evidence to date is not compelling that NASA’s mission directorates have a clear understanding of the benefits of adopting standards, there are indications that the directorates are coming to recognize the value to their programs of adopting standards. One such observation focused on utilization by JPL and GSFC as discussed in Box 5.2. ASSESSMENT Formulation of the Program Plan The standards management program element’s goals and objectives are clearly defined. As explicitly stated in the charter of the CCSDS: “The major space agencies of the world recognize that there are benefits in using standard techniques for handling space data and that, by cooperatively developing these techniques, future data system interoperability will be enhanced.”2 The Strategic Plan of the Consultative Committee for Space Data Systems identifies and defines the goals and objectives of the international forum in which this NASA program element plays a leadership role. As stated in the plan’s vision: “The NASA Communications & Data Standards Program provides the forum to advocate, coordinate, and recommend NASA, interagency, and international data communications standards required to carry out NASA missions, including NASA participation in international missions.”3 By its basic nature, the scope of this program element extends beyond NASA. As noted above, standards development must be a broad-based effort, both to ensure full recognition of the needs of the broader user community and to obtain buy-in by those users. In this regard, NASA accomplishes associated objectives through participating in—and in this case, providing significant leadership to—the CCSDS.4 All CCSDS member organizations are fully involved in the planning and review process. The standards management program element’s deliverables are also articulated in the CCSDS’s strategic plan.5 The expected services continue to be delivered by this program element’s activities. The planning is well supported and documented in the strategic plan, and appropriate customer agreements are in place. The deliverables, which are coordinated and agreed to by the customers as indicated by their participation in the collaborative development, provide sufficient near-term standards and metrics according to which the standards management program element can be regularly assessed. There appears to be little value in developing off-ramps to enable reallocation of funding, given the continuing delivery of the agreed-to standards. The international scope of the activity would make an independent review of the CCSDS program complex, likely not adding significant value, given that the members continually review their individual participation in the activity. There is no evidence that NASA has previously had independent or external reviews of its participation in the CCSDS. The program element’s objectives, developing standards in coordination with and subscribed to by space activities around the world, are appropriate. Adequate personnel and resources are available, as evidenced by the continuing development and adoption of common standards. Connections to the Broader Community The data standards management program element focuses on national and international collaboration aimed at achieving consensus on space data standards, and thus it necessarily has forged extensive and effective connections with the broader community, which contributes to the development of standards and shares ownership in the process and products. CCSDS standards find their way into the space-related communications and Internet Protocol marketplace. In calendar year 2005, the CCSDS surveyed the dollar value of the U.S. space communications protocol marketplace and concluded that the value exceeded $24 billion per annum.6 If accurate, this would represent a very impressive return on investment, given the very modest NASA investments (see “Resources and Funding”). Participation by the Department of Defense, the U.S. commercial space industry, and others in developing space data standards is evidence that NASA’s data standards work is appropriately recognized and is effective. This program element leverages other work done in the U.S. government and industry, as well as by international associates. NASA appears to use out-of-house resources effectively to supplement its civil service team in providing leadership for the development of standards, with the latter managing and coordinating the program element and the former per-

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate BOX 5.1 Consultative Committee for Space Data Systems The Consultative Committee for Space Data Systems (CCSDS) was formed in 1982 by the major space agencies of the world to provide a forum for discussion of common problems in the development and operation of space data systems.1 It is currently composed of 10 member agencies, 22 observer agencies, and more than 100 industrial associates. Since its establishment, it has been actively developing recommendations for data- and information-systems standards to reduce the cost to the various agencies of performing common data functions by eliminating project-unique design and development, and to promote interoperability and cross-support2 among cooperating space agencies to reduce operations costs by sharing facilities and other common resources. In 1991, the CCSDS entered into a cooperative arrangement with the International Organization for Standardization (ISO). Under this arrangement, CCSDS recommendations are advanced to Subcommittee 13 within Technical Committee 20 (Aircraft and Space Vehicles), where they then advance via the normal ISO procedures of review and voting to become full international standards. A telling indicator of the broad understanding and appreciation of this effort is the degree of participation in developing the standards, and the degree to which they are subsequently adopted and used in space programs. Although the growing acceptance of its recommendations is testimony to the quality of the CCSDS’s work, much remains to be done. Not only must NASA continue to maintain the current recommendations, but it also must address new areas for standardization and incorporate new technologies. The challenges of capitalizing early on advancing technology while dealing with increasing budgetary pressures continue to confront the agency. Within the CCSDS structure, a member agency is a governmental or quasi-governmental organization that fully participates in all CCSDS activities and provides a commensurate level of support. Unlike other participating entities, each member agency has CCSDS voting rights and thus the power to decide on CCSDS business. Member agencies name to the CCSDS Management Council individual representatives who exercise member agency voting rights to determine the overall direction of the organization. The CCSDS has over 100 active associate members. These associates are typically U.S. aerospace corporations that are consumers of CCSDS publications and products. Objectives and goals are defined for six areas: systems engineering, mission operations and information management, cross-support services, spacecraft onboard interface services, space link services, and space internetworking services. Within each of these areas, specialized working groups are chartered to develop recommended standards. Recommended practices and experimental standards have also been added as additional categories to the specification hierarchy.    1Consultative Committee for Space Data Systems (CCSDS), About CCSDS, available at http://www.CCSDS.org.    2Cross-support is the cross-utilization of operational resources among agencies. forming the detailed work. This balance seems quite appropriate to the endeavor, as evidenced by the demonstrated and continuing success in delivering coordinated standards. The benefits and costs of increasing interoperability with military space systems, commercial space systems, and the systems of foreign space agencies seem properly considered, as evidenced by the direct involvement in ongoing standards development activities. The basic motivation for developing space data standards is to increase reliability and efficiencies with military, commercial, and foreign space operators, with the attendant benefits and cost savings achievable by enabling interoperability. Methodology The primary component of standards development is working groups that meet on a periodic and rotating basis.7 Virtual collaboration is used effectively to minimize the need for the physical presence of working group members. The Collaborative Work Environment, a secure area in the CCSDS website, enables all working groups and area directors to have “net meetings” or to submit products, papers, or draft positions asynchronously for commentary and the formulation of draft positions. Often the give-and-take of the technical people as well as voting by the Engineering Steering Group and the Management Council occurs in this e-forum. The committee judged the standards management program element planning to be quite well crafted, as evidenced by the program element’s long history of demonstrated successes. Since its formation in 1982 the CCSDS has grown to 10 member agencies and 22 observer agencies. As noted, the CCSDS has a currently active suite of 78 standards, 29 of which have become ISO standards. Table 5.1 lists more than 70 new missions slated for launch in 2006 through 2008 that have adopted CCSDS standards in whole or in part. Such accomplishments would not have been possible without effective planning and execution, particularly when the limited authority of the CCSDS is taken into consideration. Resources and Funding NASA’s funding and level of effort for the total CCSDS program are as follows:8 SOMD (Space Operations), $5 million annually and SMD, $1.5 million annually. Neither ESMD (Exploration) nor PAE (Chief Engineer) contribute

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate TABLE 5.1 Missions That Implement Consultative Committee for Space Data Systems Standards Mission Description Launch Date Related Organizations NPP National Polar Orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project 2006 (Dec.) NASA/GSFC AIM Aeronomy of Ice in the Mesosphere 2006 (Sept.) NASA/GSFC SBIRS-High Space Base Infrared System 2006 DOD New Horizon Pluto-Kuiper belt mission 2006 NASA/APL Dawn Meteorite Explorer 2006 JPL, UCLA THEMIS 5 Time History of Events and Macroscale Interactions during Substorms 2006 NASA/SSL THEMIS 4 Time History of Events and Macroscale Interactions during Substorms 2006 NASA/SSL THEMIS 3 Time History of Events and Macroscale Interactions during Substorms 2006 NASA/SSL THEMIS 2 Time History of Events and Macroscale Interactions during Substorms 2006 NASA/SSL THEMIS 1 Time History of Events and Macroscale Interactions during Substorms 2006 NASA/SSL Solar-B   2006 ISAS GLAST Gamma-ray Large Area Space Telescope 2006 NASA COROT Convection Rotation a Transits planetaires (Convection Rotation and Planetary Transits) 2006 CNES INMARSAT 4F 3 International Maritime Satellite 4F3 2006 INMARSAT GOCE Gravity Field and Steady State Ocean Circulation Explorer 2006 ESA ATV-3 Automated Transfer Vehicle 3 2006 ESA CRM Coral Reef Mission 2006 PCRF, MIT/CSR RascomStar-Qaf 1 Telecommunications 2006 (June) RascomStar-QAF ARABSAT4B   2006 ARABSAT ARABSAT4A   2006 ARABSAT SKYNET 5B   2006 British Ministry of Defence SKYNET 5A   2006 British Ministry of Defence HOTBIRD 8 Telecommunications 2006 Eutelsat Anik F3 Telecommunications 2006 Telesat Canada/ESA Galaxy 17 Telecommunications 2006 PanAmSat/ESA COSMO-Skymed3 Mediterranean Basin Observation 2006 ASI COSMO-Skymed2 Mediterranean Basin Observation 2006 ASI Rømer After the Danish astronomer Ole Rømer 2006 DSRI Formosat3/ROCSAT-3/COSMIC 6 Republic of China Satellite-3/Constellation Observing System 2006 (Mar.) NSPO Formosat3/ROCSAT-3/COSMIC 5 Republic of China 2006 (Mar.) NSPO Formosat3/ROCSAT-3/COSMIC 4 Republic of China 2006 (Mar.) NSPO Formosat3/ROCSAT-3/COSMIC 3 Republic of China 2006 (Mar.) NSPO Formosat3/ROCSAT-3/COSMIC 2 Republic of China 2006 (Mar.) NSPO Formosat3/ROCSAT-3/COSMIC 1 Republic of China 2006 (Mar.) NSPO ST5 3 Space Technology 5 2006 (Mar.) NASA ST5 2 Space Technology 5 2006 (Mar.) NASA Cassiope ePOP probe meteorological satellite 2007 CSA SBSS Space-Based Space Surveillance 2007 NASA/GSFC ADM-Aelous Atmospheric Dynamic Mission 2007 (Oct.) ESA OCO Orbiting Carbon Observatory 2007 (Oct.) NASA/GSFC GOSAT Global Climate Observation System 2007 JAXA COF Columbus Orbital Facility 2007 DLR Aeolus-S Sim 2007 ESA Aeolus-X 2007 ESA

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate Mission Description Launch Date Related Organizations Orbview 5 Commercial Imaging Satellite 2007 GSFC Star-One C-2   2007 ESA Planck Satellite for the imaging of the anisotropies of the cosmic background radiation 2007 ESA Herschel Space Observatory Formerly Far Infrared and Submillimetre Telescope (FIRST)—ESA Horizon 2000 cornerstone 4 (CS4) 2007 ESA SDO Solar Dynamic Observatory 2007 NASA/GSFC Kepler Satellite for the search of Earth-size and smaller planets 2007 NASA Ames SMOS Soil Moisture and Ocean Salinity 2007 ESA/CNES/SNP Megha-Tropiques Convective systems, water cycle, and energy budget in the tropical atmosphere 2007 CNES/ISRO Solar Probe   2007 NASA/JPL Mars Premier Orbiter   2007 CNES ACCESS Advance Cosmic Ray Composition Experiment for the Space Station 2007 NASA/GSFC ATV-4 Automated Transfer Vehicle 4 2007 ESA HTV-01 H-II Transfer Vehicle 2007 JAXA HTV-DM H-II Transfer Vehicle Demonstration Flight Model 2007 JAXA Phoenix Study Mars Polar Region 2007 NASA COSMO-SkyMed4 Constellation of Small Satellites for Mediterranean Basin Observation 2007 ASI THEOS Thai Earth Observation System 2007 GISTDA Orbview-5 Commercial remote sensing satellite 2007 ORBIMAGE Astra-1M Telecommunication Satellite 2008 ESA LRO Lunar Reconnaissance Orbiter 2008 NASA GSFC ZX 9 (Chinasat) Telecommunications Satellite 2008   Spirale 2 Early Detection System 2008 CNES Spirale 1 Early Detection System 2008 CNES Eddington L2 Astroseismology Mission 2008 (June) ESA Chandrayaan-1 Lunar Mission 2008 ISRO Skynet 5C   2008 British Ministry of Defence GLORY The GLORY satellite is an Earth science mission that uses the refurbished bus of the cancelled VCL satellite 2008 NASA/GSFC MSG-3 Meteosat Second Generetion-3 2008 ESA ATV-5 Automated Transfer Vehicle 5 2008 ESA SST Space Solar Telescope 2008 CNSA HTV-03 H-II Transfer Vehicle 2008 JAXA HTV-02 H-II Transfer Vehicle 2008 JAXA Picard 2008 CNES Pleiades HR 1 Pleiades High Resolution 1 2008 CNES, ASI SOURCE: John D. Kelley, NASA, “NASA Communications and Data Standards Program,” briefing to the NRC Committee to Review NASA’s Space Communications Program, Washington, D.C., January 26-27, 2006, pp. 13-14, 16-18. any funding. (Recall the point above that the total value of CCSDS standards was said to exceed $24 billion per annum.) The corresponding figures for CCSDS activity outside NASA are not readily available. A way of estimating the level of effort is to consider that the CCSDS has 130 active associate members, typically U.S. aerospace corporations that are consumers of CCSDS publications and products. These companies adopt or adapt the CCSDS line of products to their own applications. The USAF and other agencies are also consumers of CCSDS products, which usually come to them via the associate members. There is an indirect economic relationship between corporate/U.S. government consumers and the private-sector producers and vendors of private-sector communication applications with CCSDS standards integrated into them. CCSDS member agencies of other countries contribute to CCSDS in the form of full-time-equivalent (FTE) personnel. Typically the European Space Agency (ESA) matches NASA’s contribution, and the Japanese Aerospace Exploration Agency plus a number of other agencies such as INPE (Brazil) contribute roughly one-fourth of the total contributed by NASA plus ESA. The CCSDS Operating Plan for Standards Development,9 which is subordinate to the CCSDS strategic plan, is updated yearly and defines near-term products in detail. Sys-

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate BOX 5.2 Examples of CCSDS Usage by NASA Centers Jet Propulsion Laboratory As described by NASA, JPL tends to strictly enforce compliance with use of CCSDS standards mainly because much of the CCSDS’s work addresses the challenges of deep-space links such as poor quality of service and other problems associated with sending radio frequency (RF) waves across the solar system. All JPL missions since Mars Observer have complied at the link layer and below, meaning that they are using standard TC and TM at the link layer, or Advanced Orbiting Systems (AOS) for high-data-rate missions, for direct to Earth (DTE) or direct from Earth (DFE) links. The Command Operation Procedure (COP-1) with the Frame Acceptance and Reporting Method (FARM) is typically used for uplink reliability. Because two-way recall times are very long in deep-space applications, downlink data are typically sent in “unreliable” modes, although various nonstandard retransmission schemes are in use for critical frame or packet data. The rover and lander missions are configured similarly for their DTE/DFE links, but they also use Proximity-1 in reliable mode for their orbiter-to-landed element links. The bulk of data being transferred from the very successful MER Rovers has come down over Proximity-1 relays to Odyssey and other orbiters. Odyssey and the other orbiters that support relaying also implement Proximity-1 for these local links. Some of the hardware implementations of Proximity-1 have known problems (CE-505 radio), but there are well-understood work-arounds for these. The missions using this radio tend to be compliant with the Proximity-1 standard at the undifferentiated byte stream (rather than packet stream) level. The more recent radio implementation— Electra—does not have this problem; it is a software defined radio that can be reconfigured as needed to support a fully compliant Proximity-1 link protocol. NASA expects that future missions using Electra will be fully compliant at the packet transfer level to better support relay operations. Below the link layer, other CCSDS and Space Frequency Coordination Group (SFCG) standards are used for coding, modulation, and appropriate selection of frequencies. A variety of different frequencies and coding approaches are used, depending on the operating environment and characteristics of the mission links. Reed-Solomon, Convolutional, and now Turbo codes are used. High-data-rate missions are expected to use Deep Space LDPC codes as these are stabilized in the future. Above the link layer a variety of different approaches are used for file delivery. Some missions have fully embraced the CCSDS File Delivery Protocol (CFDP) and used it successfully for uplink and downlink file transfers. Where missions are flying on-board file systems this is easier to accomplish, but even some missions that do not fly file systems have found it useful to adopt CFDP protocol elements and use the standard CFDP ground implementation. This provides lower-risk and lower-cost ground system implementation. One mission, Deep Impact, used JPL-developed CFDP software for both its flight and ground implementations. Other missions, like Messenger, used CFDP on-board in a fully automated approach, with no human in the loop. Most of the Mars rover missions have adopted a file management and retransmission method that was first used on Mars Pathfinder. This has been driven by a desire to be able to more closely manage downlink prioritization, on-board data handling, and uplink bandwidth. It also provides support for handling compressed data in a way that recognizes the need to handle compression block boundaries to support error containment. Discussions are in progress to identify ways to accommodate all of these needs within the CFDP specification, or in some simple extensions to the specification that NASA will propose to CCSDS. Many of the higher-level CCSDS protocols either are not appropriate for use in deep space or are not yet mature enough to be adopted. These include Space Link Extension (SLE) Service Management, and Spacecraft On-board Interface Services (SOIS). The command/uplink SLE data transfer protocols (SLE-FCLTU) are effectively in use by all missions that use the Deep Space Network (DSN) since they are part of the command subsystem. The SLE downlink protocols (SLE-RAF, SLE-RCF) are being used widely by the DSN to provide cross-support to external missions. CCSDS standards for exchange of navigation data (orbits) are just coming into use. Other navigation data exchange standards (tracking, attitude) are expected to be adopted as they become finalized. Future JPL missions are expected to adopt the existing space link protocols and to also adopt more fully the use of CFDP. As support is provided for more networked sets of missions NASA expects to see use of the standard relay operations in CFDP, and eventually to see use of the newly developed Delay Tolerant Networking (DTN) protocols. These protocols, and the SCPS, Internet tuned for space, protocols are more likely to see first use in the lunar environment in support of Constellation. Goddard Space Flight Center Nearly every Goddard mission in the past 10 years has used the CCSDS telecommand protocols (including COP-1) for commanding and the TM/AOS protocols for telemetry. (TM was used for telemetry until AOS replaced it.) The rare exceptions to the general rule are typically very small missions, for example, a balloon experiment out of Wallops. Goddard missions that use CCSDS telecommand and telemetry protocols include FAST, SWAS, WIRE, SAMPEX, HESSI, TRACE, SWIFT, GLAST, XTE, TRMM, MAP, IMAGE, EO-1, ST5, SDO, and LRO. (Some of these missions are still in development.) The GPM mission started on a non-CCSDS track but returned to CCSDS when the designers discovered that spacecraft vendors had considerable knowledge, experience, and a reliable track record with CCSDS protocols—qualities not evident with the alternative that was being considered. Although CFDP is not universally used, it is gaining acceptance, with planned use by JWST, LRO, GPM, and (possibly) MMS. Reasons given for not using CFDP include “it didn’t exist when we designed our mission” and “it doesn’t have Goddard flight heritage.” SOURCE: John D. Kelley, NASA SOMD, March 1, 2006.

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Review of the Space Communications Program of Nasas Space Operations Mission Directorate tem-level assessments are conducted routinely as an integral aspect of developing the operating plan. The CCSDS strategic plan is updated as necessitated by changing events, and at least every 3 years. The strategic plan redefines goals, the organization’s current objectives, and domains for standardization as appropriate. Development of the operating and strategic plans evidences planning that is thoroughly considered, projecting future activities that are both reasonable and justifiable. Managers executing plans for the data standards program have both an understanding of the objectives and processes for space data handling, and an acceptable ability for risk10 management, as demonstrated by their continuing success in delivering standards in a timely manner and within available resources. Overall Capabilities The quality of the work of NASA’s data standards management program element is clearly comparable with that of other world-class efforts, as demonstrated by the fact that the products—data standards—have been adopted as ISO standards as appropriate. As noted above, there are currently 78 active publications (standards), of which 29 have become ISO standards. Also, as witnessed by their adoption and use, the standards meet the requirements of both internal and external customers. The qualifications of the NASA/contractor staff are clearly sufficient to achieve the goals of the data standards management program element, as demonstrated by its continuing success in playing a leading role in CCSDS activities. In addition, the capabilities, quantity, and state of readiness of the equipment and facilities used to achieve program element goals appear to be quite satisfactory, again given the continuing delivery and acceptance of the program element’s data standards. Personnel, equipment, and facilities appear to be used efficiently, with support contractors effectively complementing government personnel. There are no laboratories or other facilities dedicated specifically to standards development. Although testbeds are utilized to advance standards development, existing mission testbeds are normally used as appropriate to develop prototype standards.11 As NASA has noted,12 the majority of the resources applied to standards development are people with unique expertise, and thus overlap in personnel resources is usually minimal. Assimilation of the common threads that contribute to standards development usually occurs via agency-wide and international working groups; therefore standards development work tends not to be tied to geographic locations, such as specific NASA centers. Finding: It appears that the expected services are being successfully provided by NASA’s space data standards management program element, as evidenced by the continuing development of standards that are being adopted by space activities around the world. The relatively modest funding allocated seems stable, and no funding threats are foreseen. NOTES    1. Kelley, John D., “NASA Communications and Data Standards,” briefing to the NRC Committee to Review NASA’s Space Communications Program, Washington, D.C., January 26-27, 2006.    2. Consultative Committee for Space Data Systems (CCSDS), About CCSDS, available at http://www.CCSDS.org.    3. CCSDS Secretariat, Strategic Plan of the Consultative Committee for Space Data Systems, CCSDS A01.1-Y-2, Draft 4, Version 3, March 8, 2005.    4. CCSDS, available at http://www.ccsds.org.    5. CCSDS Secretariat, Strategic Plan of the Consultative Committee for Space Data Systems, CCSDS A01.1-Y-2, Draft 4, Version 3, March 8, 2005.    6. Kelley, John D., NASA SOMD, personal communication, March 1, 2006.    7. Kelley, John D., NASA SOMD, personal communication, April 24, 2006.    8. Kelley, John D., NASA SOMD, personal communication, March 1, 2006.    9. CCSDS, CCSDS Operating Plan for Standards Development, CCSDS Record A01.2-Y-4 Yellow Book, July 2005.    10. Both the technical risks associated with capitalizing on technologies that are leading edge, yet sufficiently mature to be viable, and the risks from working within limited resources.    11. Kelley, John D., NASA SOMD, personal communication, April 26, 2006.    12. Kelley, John D., NASA SOMD, personal communication, April 24, 2006.

Representative terms from entire chapter:

goddard spectrum