Summary. Moving data and signals between every exploration asset, and telling each asset where it is and what time it is, against "a coordinated lunar time standard traceable to Earth's Coordinated Universal Time" (ADD Rev C, p. 41). Its one element is the Space Communications and Navigation Networks. NASA expects services to grow from the South Pole toward "GNSS-like" regional or global coverage. Four technology gaps list it, two of them named in the Moon Base Users Guide (near-term). The ACR25 C&PNT white paper adds the Foundational Exploration picture: surface elements as hubs, LunaNet's frequency plan, four user-demand characteristics, and a real-time navigation need of 25–50 m (below). The 2024 reference-frames paper explains the two lunar frames, Mean Earth and Principal Axis, and records a working group's endorsement of Mean Earth for initial surface operations (below). Decomposition letter: C.

NASA's description¶

"This sub-architecture enables transmission and reception of end-to-end data flows and exploitable signals across all exploration assets. It provides services to accurately and precisely determine current location and orientation; determine path to desired position; and acquire and maintain accurate and precise time from a coordinated lunar time standard traceable to Earth's Coordinated Universal Time.

C&PNT sub-architecture considerations include service regions, delivery mechanisms, and user burden, as well as how they evolve through the segments. Additionally, minimizing manual network management and maximizing interoperability of C&PNT services are key considerations in establishing an architecture that supports many different providers and users (e.g., government, commercial, scientific, international).

The C&PNT sub-architecture and concept of operations will mature in response to user needs. Services may improve (e.g., with high-throughput optical and radio frequency links, autonomous network management, higher accuracy, increased capacity and availability, additional cislunar and lunar surface infrastructure), and service regions may expand beyond the lunar South Pole. Positioning, navigation, and timing (PNT) services may grow to realize Global Navigation Satellite System (GNSS)–like capabilities, providing extended regional or global services. More accurate PNT information will empower precision navigation, tracking, surveying, geolocation services, and temporal and spatial science." (ADD Rev C, p. 41)

In the segments¶

From ADD Rev C:

Human Lunar Return missions "establish lunar orbital communication relays" (p. 24). Artemis I tested "communications and tracking systems (OP-2)" (p. 25).
Foundational Exploration. "The Communications & Positioning, Navigation, and Timing (C&PNT) sub-architecture (Section 2.2.2) provides additional exploration and utilization opportunities during uncrewed portions of the year" (p. 29). Section 2.2 has no numbered subsections in the contents (p. 5), so "2.2.2" doesn't resolve. Infrastructure objectives LI-2 and LI-3 drive expansion of "C&PNT and data systems and management" (p. 28).
Sustained Lunar Evolution. "communications capabilities must evolve via interoperability, scalability, and reconfigurability to allow concurrent science missions distributed across the lunar globe to send data via high-speed links. NASA and its partners can trade different approaches for satellite constellations, surface relay infrastructure, and technologies such as optical links to enable high-data-rate communications" (p. 34). The segment "will require additional investments in communications, navigation, ISRU, power, and transportation sub-architectures" (p. 35).
Humans to Mars. Infrastructure objectives for "communications (MI-2); and position, navigation, and timing (MI-3)" (p. 38).

Elements¶

Element	Segments	Source
Space Communications and Navigation Networks	Human Lunar Return, Foundational Exploration	ADD Rev C, pp. 26, 32

See the elements index. The element's four-page section (ADD pp. 64–67) holds most of the ADD's detail on this sub-architecture: the Near Space and Deep Space Networks, LunaNet and the interoperability standards, lunar reference systems and time, LCRNS service volumes by segment, the move from UHF and WiFi to 3GPP/5G on the surface, and a figure of Foundational Exploration links. All of it is on the element page. Its pointer to "Section 2.2.2 for the C&PNT sub-architecture" (p. 64) is the same dangling reference as on p. 29.

Technology gaps¶

Four gaps list this sub-architecture (derived from the tech gaps spreadsheet, Sub-Architectures column). MB = named in the Moon Base Users Guide (near-term).

Gap	Rating	MB
#0103 Surface-to-Surface Communications	5	MB
#0101 PNT for Lunar Surface Extreme Environments	20	MB
#0104 Earth-Independent Surface PNT	48
#0102 Deep Space Communications	51

0102 and #0104 are Mars-only. No tech gap covers lunar surface-to-Earth bandwidth; the Users¶

Guide handles that as a Phase 1 functional gap, below.

The 2025 Architecture Update¶

The companion 2025 Architecture Update treats C&PNT as one of three lunar "services … akin to the utilities that serve communities on Earth", with power and logistics (p. 9):

"Lunar explorers need to communicate with Earth, establish their position on the Moon, navigate to locations of interest, and maintain common time with other explorers and assets. These services fall into the broad umbrella of C&PNT (communications and positioning, navigation, and timing) and are provided by a mix of government, international, and commercial providers. As exploration expands, these services may need to cover more parts of the Moon, provide increased throughput, or offer more precise accuracy, depending on exploration needs. Growing networks will provide an increasing range of capabilities." (Update, p. 9)

For more, it points to the "Communications and Navigation Needs for Foundational Exploration" white paper, read below. "Examining the communications and navigation needs of crewed Mars missions" is one of its three focus areas for 2026 (p. 18). Communications was the first Moon to Mars architecture standard adopted, in 2024 (p. 15; see RT-7).

Foundational Exploration needs (ACR25 white paper)¶

The ACR25 white paper "Communications and Navigation Needs for the Foundational Exploration Segment" describes how this sub-architecture must grow from Human Lunar Return through Foundational Exploration. Page numbers in this section are the paper's. Its definition of the sub-architecture: "assets, elements, and service providers that enable data transmission and reception, determination of location and orientation, and precise time synchronization. C&PNT sub-architecture users comprise exploration assets utilizing shared C&PNT resources at Earth, in orbit, or on the surface of planetary bodies" (p. 1).

Users and challenges (p. 1). Users "will increasingly rely on shared C&PNT sub-architecture infrastructure, capabilities, and services": "landing assets, mobility assets, habitats, long-term telerobotic science investigations, in-situ resource utilization payloads, Mars-forward technology demonstrations, and more". The challenges:

electronics that "operate across widely varying temperatures and in an extreme radiation environment"
enough power to reach Earth, and antennas that can track Earth stations and lunar relays
"the effects of lunar regolith on signal propagation"
"Polar lighting conditions present a navigation challenge for both crewed and robotic missions, with long shadows and sharp contrast between dark and light regions"
interoperability, and "extensibility and scalability … into the Sustained Lunar Evolution segment"

NASA's response: "advance new technologies, establish interoperability standards, and grow its understanding of the lunar environment", while building infrastructure that "minimizes user burden (e.g., by reducing power needed to access C&PNT services, enabling higher throughput, or offering more accurate position and timing data)" (pp. 1–2).

How the network grows (p. 2):

Early: "During Human Lunar Return and for the early Foundational Exploration segment", services link users "direct with Earth or through lunar relays". "Surface exploration elements (e.g., landing systems, rovers, habitats) will serve as C&PNT hubs for other lunar users (e.g., astronauts performing EVAs, surface science payloads)", aggregating their data. "Certain hubs (e.g., Lunar Terrain Vehicle, Pressurized Rover) will have dual roles as network users and hubs."
Mid and late Foundational Exploration: "increased reliance on lunar relay links and data aggregation on the surface. For example, NASA could add surface relays to aggregate and relay data, much like a terrestrial cell tower or wireless hub."
The whole: "a lunar network comprising a variety of lunar surface and orbital assets operated by NASA, commercial partners, and international space agencies. It can scale up to support new exploration assets as they come online (or scale down as assets reach the ends of their operational mission.)"

The paper's p. 3 diagram is the ADD's p. 67 figure of Foundational Exploration links (the wiki's match, by its labels); it is described on SCaN Networks.

Interoperability and standards¶

"Establishing a cohesive C&PNT sub-architecture depends on defining interface standards for all elements and assets" (p. 2). The types needed: "provider-side service interfaces, user-side interfaces, spectrum allocations, and networking protocols, as well as time and reference systems" (p. 2).

LunaNet, "an internationally coordinated framework for an interoperable lunar network of networks". "The initial LunaNet Interoperability Specification includes a frequency plan for the lunar vicinity and surface" (p. 2). Its allocations:

Link Bands (p. 2)

Connections with Earth Ka- and X-band

Lunar relays to surface assets Ka- and S-band

Lunar surface wireless networking C- and S-band
The International Communication System Interoperability Standard "enables collaborative operations among international partner systems" (p. 2).
On the surface, "NASA plans to use Third Generation Partnership Project (3GPP) cellular and 802.11 Wi-Fi standards to best meet users' growing needs" (p. 2). Compare the completed definition task LD-103, which adopted "Space-to-Space Communications Systems, WiFi 6, and 3GPP (5G)" (ADD Rev C, p. 75); the paper doesn't cite it.
Spectrum: NASA works with "the Space Frequency Coordination Group, the Interagency Operations Advisory Group, and others" (p. 2).
Who negotiates. "C&PNT standards are agreed to internationally but are often implemented by individual nations … NASA's Space Communications and Navigation program … represents the agency when negotiating many of these standards." And "Individual Programs have latitude to broker C&PNT services for their vehicles to meet the requirements for human space flight" (p. 2).

User demand: four characteristics¶

"User demand describes which services users will need from the C&PNT sub-architecture" (p. 2). Table One's four characteristics (p. 3), with what the text adds (p. 4):

Characteristic	Definition (p. 3)	What the paper adds (p. 4)
Connectivity	"The need to create links between host and destination and sustain the associated communications protocol such that data is successfully exchanged over the established links."	Expressed "as the number and types of links": direct-with-Earth from the surface and from orbit, surface-to-surface, surface-to-cislunar. One spacesuit-to-lander link "could facilitate, for example, five unique data streams and/or service types" (voice, suit telemetry, several video streams, instrument data).
Coverage	"The need to provide an acceptable quality of service connectivity over a given region or volume, where users reside."	Includes transit, cislunar space and "the lunar far side". "Earth visibility can be intermittent in the polar region due to orbital geometry and rugged topography." Asset separation is driven by "lunar blast ejecta from landing vehicles, long shadows that could impair solar array systems", and grouping of elements. Relay service grows "to include a greater portion of the lunar South Pole region and increasing orbital altitudes".
Capacity	"The need for sufficient data throughput across multiple simultaneous links, throughout operational mission phases."	Expressed as "instantaneous throughput rate". A lander "might require a large data throughput"; "A rover with fewer payloads and telemetry sensors might only need half that data throughput". "Since many high-rate data needs are associated with video feeds required by crew or crewed elements, priority throughput approaches that of total throughput." Habitation elements "have larger needs"; "large-scale in-situ resource utilization demonstrations would greatly increase the C&PNT needs of the utilization systems sub-architecture".
PNT Accuracy	"The need for a time synchronization and navigation system to enable users to establish their selenographic position to a specified degree of accuracy."	"Accuracy requirements will evolve as NASA gains operational experience" and "may become more stringent", e.g. for aggregated systems or "logistics deliveries near hazardous terrain". See the next paragraph.

Navigation accuracy, as presented at the 2025 Architecture Concept Review. "To satisfy the Artemis mission needs and support early utilization activities (e.g., science, technology demonstrations), the C&PNT sub-architecture needs to offer a real-time absolute accuracy of 25-50 meters. While NASA needs 25-50-meter accuracy early in the Foundational Exploration segment, NASA has procured systems to realize 10-meter or better accuracy, which offers margin for future missions" (p. 4). For comparison, gap #0101's target is real-time localization "to within 10m, 3 sigma" (tech gaps spreadsheet, ESDMD #0101). The paper gives no sigma level and doesn't name the procured systems.

Three notional charts (p. 5) show links, cumulative throughput (Mbps) and maximum throughput by sub-architecture across early, mid and late Foundational Exploration, each split into total and "priority" (crew-critical) demand. Their labels are on the source page; the wiki reads no values off them. They are segment charts, not Moon Base phase charts, so they are not compared with the Users Guide's Phase 1 target below.

Technologies and gaps¶

Gaps. "Some of these are already captured in the architecture-driven technology gaps … (e.g., Position, Navigation, and Timing (PNT) for In-Orbit and Surface Applications, High Rate Comm Across the Lunar Surface, and High-Rate Deep Space Comm), Others will arise as the architecture evolves" (p. 6). These are not titles in the Dec 2025 spreadsheet. By subject they look like #0101, #0103 and #0102; the match is the wiki's. They aren't the 2024 white paper's titles either: its one surface-communications title is "High-bandwidth, High-reliability Surface-to-Surface Communications", the same as #0103's today (ACR24 technology-gaps white paper, p. 4).
In development: "optical communications, which can offer higher data rates using infrared lasers; delay/disruption tolerant networking, which can offer internet-like protocols for space applications; autonomous network management, which can use artificial intelligence and machine learning to realize self-operating systems; deploying real time in situ radionavigation and timing services to the Moon" (p. 6). The takeaways add "lunar-equivalent GPS" (p. 7).
Mars. "NASA will use lunar missions as opportunities to test technologies and operational paradigms that can enable the first human mission to Mars." A 2023 white paper, "Mars Communications Disruption and Delay", "captures many of the C&PNT challenges NASA will face at Mars, many of which can be simulated or addressed at the Moon" (p. 6; not among the wiki's sources). The paper doesn't discuss the open Mars task MD-12, "Maximum Allowable Crewed Communications Disruption" (Key definition tasks).

Lunar reference frames (ACR24 white paper, 2024)¶

The 2024 white paper "Lunar Reference Frames" is the one ADD Rev C points to "for more information about lunar reference frame considerations" (ADD Rev C, p. 66, footnote 21). It is 2024 context. Page numbers in this section are the paper's.

Why it matters. "Accurate and precise lunar navigation data improves safety, enhances planning, and enables crewed and robotic missions to achieve agency goals" (p. 1). The paper grounds the work in the lunar infrastructure objective "Develop a lunar position, navigation and timing architecture capable of scaling to support long term science, exploration, and industrial needs" (LI-03 L, word for word in the lunar decomposition). It also cites the 2022 National Cislunar Science and Technology Strategy, which "calls for NASA to lead the development of standards around 'a Lunar reference frame tied to the celestial and terrestrial reference frames'" (p. 1).

Terms. It quotes the International Astronomical Union. A reference system is the "theoretical concept of a system of coordinates, including time and standards necessary to specify the bases used to define the position and motion of objects in time and space". A reference frame is the "practical realization of a reference system". "Simply put, reference frames help mission planners understand where things are in space relative to one another" (p. 1).

Two frames in use (p. 2). Both are body-fixed, with the Moon's center of mass as origin.

Frame	How it is defined	Who uses it
Mean Earth	"the mean direction of Earth defines zero longitude (the x axis) and the mean direction of the Moon's rotation determines latitude (the z axis)". "used since the 18th century".	"The lunar surface science community", for spatial data, terrain and elevation models, and surface features. Updates "remain consistent with previous frames" (Apollo sample locations, for example).
Principal Axis	"adopts the principal axes and rotation of the Moon (i.e., the coordinate frame orientation is determined by the Moon's shape and mass distribution and rotates with the Moon)". Its rotation axes don't coincide with Mean Earth's.	"Mission operators … for flight dynamics and navigation for cislunar spacecraft because lunar gravity is commonly computed in this frame"; studies of gravity, topography, geodesy and the interior.

Key considerations (p. 2):

Accuracy and safety. "Equivalent coordinates on the lunar surface for Mean Earth and Principal Axis frames can differ by as much as 875 meters", a risk "during mission-critical activities (e.g., lunar landings)". Both frames "are accurate to about the meter level, which is about 10% of the navigation accuracy budget for Artemis missions". The paper doesn't give the budget.
Collaboration and consensus. "No single reference frame is ideal for all stakeholders." Artemis assets "will, by necessity of mission and vehicle design optimization, use different reference frames", which may also vary by commercial or international provider. NASA "should establish standards, roles, and responsibilities to ensure proper configuration management of reference frame definitions and transformations", and share them with partners.
Backwards compatibility. Transformations to earlier frames must be documented, to preserve "heritage data and systems".
Architectural flexibility. "Receivers of navigation signals should be designed to perform transformations to the reference frame best suited to their mission", as GNSS receivers do between GPS and Galileo. Spectrum limits mean "lunar navigation will likely secure relatively low bandwidth", which "will limit satellite systems to broadcasting in a single reference frame (and data to support transformations by users)".
Artemis continuity. "For the Artemis campaign, NASA is utilizing a Mean Earth frame for site selection and surface analyses. Transitioning to Principal Axis would disrupt progress."

What the 2024 working group recommended (p. 3). "In 2024, NASA established a working group to begin developing an agency approach to lunar reference frames":

"that NASA develop a flexible lunar exploration architecture that supports the use of more than one frame"
"that NASA work with the international community to establish standards for the exchange of surface location data"
it "endorsed the Mean Earth lunar reference frame as the standard for initial surface operations, including planning and user location data exchange"
it "did not endorse a corresponding orbital standard, understanding the need for mission-driven flexibility"

NASA "plans to use the Architecture Concept Review as a forum to adopt reference frame updates" and will set up configuration management and dissemination processes (p. 3).

What Rev C says. The ADD states the need without naming a frame: "NASA must define, adopt, and implement lunar reference systems (including reference frames) in the early stages of architecture development", and "U.S. policy on these topics is available and international coordination is underway" (ADD Rev C, pp. 65–66; quoted in full on SCaN Networks). Rev C never names Mean Earth or Principal Axis (search of its text), so the sources read don't say whether the working group's endorsement was adopted. The paper deals with frames, not with the lunar time standard in NASA's description above or FN-C-205 L, "Provide a coordinated lunar time scale" (Lunar functions).

Moon Base Phase 1¶

The Users Guide's "Communications and PNT" group: "Systems to transmit data, commands, and timing information between Moon Base components and between the Moon Base and Earth" (Users Guide, p. 8). Four functional gaps, all FN-C: surface-to-Earth, surface-to-surface, high-bandwidth surface-to-Earth (FN-C-105 L) and South Pole PNT (FN-C-201 L). The capability targets are "a second orbital relay constellation with surface imaging capabilities and lunar surface ground stations to enable > 500Mbps capability" and "orbital navigation and timing assets". Full list: Phase 1 functional gaps.

Sub-architectures · Data Systems and Management · Segments · Foundational Exploration · Elements · Gaps index · C&PNT white paper · Lunar Reference Frames white paper · RT-7 Interoperability · Lunar Terrain Vehicle · Pressurized Rover

Sources¶

ADD Rev C, pp. 5, 24–26, 28–29, 32, 34–35, 38, 40–41, 65–66, 75 · 2025 Architecture Update, pp. 9, 15, 18 · C&PNT white paper, pp. 1–7 (checked against the PDF) · Lunar Reference Frames white paper, pp. 1–3 (checked against the PDF) · ACR24 technology-gaps white paper, p. 4 · Tech gaps spreadsheet · Users Guide, p. 8

Link	Bands (p. 2)
Connections with Earth	Ka- and X-band
Lunar relays to surface assets	Ka- and S-band
Lunar surface wireless networking	C- and S-band

Communications and Positioning, Navigation, and Timing (C&PNT) Systems (C)¶