Moon Base Phase 1 functional gaps¶
The Users Guide lists 31 architecture functions that "NASA and its partners must close to enable the first phase of Moon Base development". It groups them under seven sub-architectures and gives each group an "architectural value" and "capability targets" (Users Guide, pp. 8–10). It is the only source that states what Phase 1 must deliver by function ID; the Ignition material and the other Moon Base pages list what Phase 1 brings, without function or gap IDs (Needs, by phase). Every entry below was checked against the PDF, because the text extraction interleaves the columns.
Definition. "Functional gaps are architecture functions that are either currently unallocated to any existing elements, or functions that need additional performance to be fully satisfied." "A full list of unallocated functions can be found in an appendix of the Architecture Definition Document", and the list "will evolve over time to reflect the needs of the base and the closure of gaps through instantiation of base systems and capabilities" (p. 9). That appendix, by its title, is ADD Appendix B.5. It holds 11 of the 31 (below).
ID format. The Users Guide does not explain the parts of the IDs. ADD Rev C gives each of its 12 sub-architectures a one-letter "Decomposition Abbreviation" used in the objective decomposition (A, C, H, L, M, P, T, U, X and others; ADD Rev C, p. 40), and the second part of each ID here is one of those letters. Reading it as the function's sub-architecture is the wiki's reading of p. 40. The trailing L marks the ADD's lunar list: all 31 IDs are in ADD Appendix B.2.2, "List of Lunar Functions" (Use cases and functions; open question 8). The IDs are normalized here (see the source page).
Checked against the ADD. Each of the 31 entries was compared with the ADD's own list of lunar functions (ADD Rev C, pp. 117–127, PDF checked). The tables below keep the guide's wording.
- 19 match word for word.
- Eight differ only in typography or are cut short.
- Three differ in wording:
- FN-A-201 L: the ADD adds "and/or cislunar space" after "from Earth"
- FN-H-102 L and FN-X-103 L: the ADD has "mid-duration(s)" where the guide has "moderate"
- One carries another function's title. FN-P-102 L (below; open question 40).
The full comparison is on Lunar functions.
The groups are ADD sub-architectures. The guide says it groups the gaps "by associated sub-architecture" (p. 9), and its seven group names are short forms of seven of the ADD's 12 (the summary table links each to its page). Six functions sit in a group whose letter differs from their own: FN-M-401 L and FN-M-501 L under robotics, FN-X-103 L and FN-L-301 L under habitation, FN-A-103 L and FN-U-103 L under mobility (Sub-architectures).
Summary table¶
| Group | ADD sub-architecture | Functions | Capability targets (abridged) |
|---|---|---|---|
| Autonomous systems and robotics | Autonomous Systems and Robotics (A) | 7 | unload and manipulate 10 kg cargo; site preparation; remote cable mating |
| Communications and PNT | C&PNT Systems (C) | 4 | second relay constellation plus ground stations for >500 Mbps; orbital navigation and timing assets |
| Habitation systems | Habitation Systems (H) | 5 | extended habitation, medical, Earth-independent ops, waste management |
| Logistics systems | Logistics Systems (L) | 4 | transfer pressurized goods, water, gases |
| Mobility systems | Mobility Systems (M) | 4 | small utility rovers and hoppers; large rovers at 10 km/h |
| Power systems | Power Systems (P) | 5 | 5 kW generation and storage through 120+ h darkness; RTG survive-the-night |
| Transportation systems (cargo) | Transportation Systems (T) | 2 | landers delivering 2 t to the South Pole region |
The ADD's other five sub-architectures (Data Systems and Management, Human Systems, Infrastructure Support, ISRU, Utilization) have no group here (Sub-architectures).
Autonomous systems and robotics¶
"Software and hardware to assist crews and develop and maintain the Moon Base during uncrewed periods" (p. 8).
- Architectural value: "Maximizes exploration value, reducing burden on crew or performing functions that the crew cannot, including: Unloading and repositioning of surface items. Remote surveys, reconnaissance, and identification of resources or other sites of interest."
- Capability targets:
- "Demonstration of capabilities to unload and manipulate cargo (10kg) on the surface."
- "Demonstration of lunar site preparation capabilities."
- "Demonstration of remote mating/demating of cables."
| ID | Function |
|---|---|
| FN-A-104 L | Perform robotic manipulation of payloads, logistics, and/or equipment on the lunar surface. |
| FN-A-105 L | Interface robotic system(s) with logistics carriers on the lunar surface. |
| FN-A-201 L | Control robotic system(s) in sunlit areas and non-PSRs on the lunar surface from Earth. |
| FN-A-302 L | Provide safeguards for automated asset(s) operating near crew. |
| FN-A-401 L | Command and control asset(s) from Earth on the lunar surface during uncrewed periods. |
| FN-M-401 L | Unload a limited amount of cargo (100s of kg) on the lunar surface. |
| FN-M-501 L | Reposition a limited amount of cargo (100s of kg) in the south pole region on the lunar surface. |
The capability target says 10 kg of cargo, while FN-M-401 L and FN-M-501 L say "100s of kg".
Communications and PNT¶
"Systems to transmit data, commands, and timing information between Moon Base components and between the Moon Base and Earth" (p. 8).
- Architectural value:
- "Communications between astronauts, surface assets, and Earth."
- "Wayfinding for crewed and uncrewed excursions."
- "Location documentation of surface samples and resources."
- Capability targets:
- "Deployment of a second orbital relay constellation with surface imaging capabilities and lunar surface ground stations to enable > 500Mbps capability."
- "Deployment of orbital navigation and timing assets."
| ID | Function |
|---|---|
| FN-C-101 L | Provide communications and data exchange between the lunar surface and Earth. |
| FN-C-103 L | Provide communications and data exchange between assets on the lunar surface. |
| FN-C-105 L | Provide high bandwidth, high-availability communications and data exchange between the lunar surface and Earth. |
| FN-C-201 L | Provide position, navigation, and timing services at the south pole region on the lunar surface. |
The target refers to a "second" relay constellation. The Users Guide does not say what the first one is. The Phase 1 missions include Intuitive Machines' Altus-1 relay, "the first satellite in a planned lunar relay network" (Moon Base Phases, "Intuitive Machines' IM-3"). No source links the two.
Habitation systems¶
"Habitable volumes and supporting systems ensuring the health and performance of astronauts in controlled environments of the Moon Base" (p. 8). The architectural value, capability targets and functions below are on p. 9.
- Architectural value: habitation lets crews stay longer on the surface, allowing "Expanded exploration and science. More excursions. Additional EVA time."
- Capability targets:
- "Demonstrate extended crew habitation capabilities, including hygiene, exercise, and nutrition."
- "Demonstrate extended duration medical capabilities."
- "Demonstrate Earth-independent operations."
- "Demonstrate management of waste streams on the lunar surface."
| ID | Function |
|---|---|
| FN-H-101 L | Enable a pressurized, habitable environment on the lunar surface for short durations (days to weeks). |
| FN-H-102 L | Enable a pressurized, habitable environment on the lunar surface for moderate duration (month+) use. |
| FN-X-103 L | Provide crew countermeasure system(s) to support the crew for moderate durations (month+) on the lunar surface. |
| FN-L-301 L | Manage waste from habitable assets(s) on the lunar surface. |
| FN-H-201 L | Operate habitation systems(s) in uncrewed mode between crewed missions on the lunar surface. |
Logistics systems¶
"Systems and capabilities related to the packaging, handling, transportation, staging, storage, tracking, and transfer of items and cargo for the Moon Base" (p. 9).
- Architectural value:
- "Resupply of crew consumables (food, clothing, etc.)"
- "Resupply of key resources (water, gases)."
- "Supply of system spares."
- Capability target: "Demonstration of capabilities to transfer pressurized goods, water, and gases on the lunar surface."
| ID | Function |
|---|---|
| FN-L-101 L | Provide mating between pressurized assets on the lunar surface. |
| FN-L-201 L | Transfer pressurized cargo into habitable assets on the lunar surface. |
| FN-L-203 L | Transfer water to habitable assets on the lunar surface. |
| FN-L-205 L | Transfer gases to habitable assets on the lunar surface. |
Mobility systems¶
"Systems to move crew and cargo around the lunar surface and between Moon Base components" (p. 9). The architectural value and capability targets are on p. 9; the four functions are on p. 10.
- Architectural value: "Expand the area of crewed and uncrewed exploration on the surface, allowing for extended excursions from landing sites."
- Capability targets:
- "Deployment of small utility rovers and hoppers to conduct science, reconnaissance, and resource discovery."
- "Deployment of large crewed and uncrewed rovers with speeds of 10 km/hr."
| ID | Function |
|---|---|
| FN-M-302 L | Enable local unpressurized surface mobility in sunlit areas and non-PSRs in the south pole region on the lunar surface. |
| FN-M-304 L | Enable local unpressurized surface mobility in PSRs at the south pole region of the lunar surface. |
| FN-A-103 L | Provide a robotic system capable of conducting reconnaissance. |
| FN-U-103 L | Conduct resource identification utilization payload and/or equipment operations on the lunar surface. |
Power systems¶
"Systems to generate, store, condition, and distribute electricity for the Moon Base, supporting infrastructure, and utilization systems" (p. 10).
- Architectural value: power is "a critical shared resource" for:
- "Recharging mobility assets."
- "Crew habitation on the surface."
- "Science payloads in shadowed regions."
- "In-situ resource utilization (ISRU) processing."
- Capability targets:
- "Demonstrate 5 kW power generation and storage, as well as survival through 120+ hours of darkness."
- "Demonstrate survive the night capability using radioisotope thermal generators."
| ID | Function |
|---|---|
| FN-P-101 L | Generate power in the south pole region on the lunar surface. |
| FN-P-102 L | Store energy in the south pole region on the lunar surface. |
| FN-P-301 L | Distribute power in the south pole region on the lunar [surface]. |
| FN-P-401 L | Provide power for deployed surface utilization payloads/equipment. |
| FN-P-402 L | Provide power for deployed external surface utilization payload(s) and/or equipment for mid- (month+) to long-durations (year+). |
FN-P-102 L: the ID and the title don't match in the ADD. The guide prints "FN-P 102 L" with "Store energy in the south pole region on the lunar surface." (p. 10, PDF checked). In ADD Rev C's list of lunar functions:
- FN-P-102 L is "Generate power at multiple distributed locations outside of the south pole region on the lunar surface".
- The guide's title belongs to FN-P-202 L (ADD Rev C, p. 121, PDF checked).
The wiki keeps the guide's entry as printed. It doesn't decide which function the guide means, and doesn't use the capability target to guess (open question 40).
Transportation systems (cargo)¶
"Systems that convey cargo between Earth and the Moon (e.g., launch vehicles, transportation systems, cargo landers)" (p. 10).
- Architectural value:
- "Delivery of surface assets and infrastructure."
- "Delivery of logistics items and carriers to the surface."
- "Delivery of science and utilization payload."
- Capability target: "Deployment of landers with two metric ton cargo delivery capability to the lunar South Pole region."
| ID | Function |
|---|---|
| FN-T-201 L | Transport a limited amount of cargo (100s of kg) from Earth to South Pole region sites on the lunar surface. |
| FN-T-202 L | Transport a moderate amount of cargo (1000s of kg) from Earth to South Pole region sites on the lunar surface. |
The 2 t lander target sits below the CLPS payload goals of 5 MT in Phase 2 and 8 MT in Phase 3 (Users Guide, p. 4; see Phases).
Moon Base relevance¶
All of these functions are Phase 1 needs, by the Users Guide's own heading (pp. 8–10). For the technologies and data behind them, see Technology and knowledge challenges.
Ten of the 31 functions are also named by a technology gap's traceability field. The list is on Lunar functions, from the tech-gap spreadsheet.
Against the ADD's own allocation¶
The join by function ID is the wiki's. ADD Rev C maps lunar functions to elements in Appendix B.3 and lists the ones no element performs in B.5, "Unallocated Functions by Use Case" (ADD Rev C, pp. 148–184). Against the 31:
-
11 are in B.5, listed as unallocated for Foundational Exploration. Seven have no Foundational Exploration element in B.3:
- FN-H-102 L (month-plus habitation)
- FN-X-103 L (month-plus countermeasures)
- FN-L-301 L (surface waste; HLS has it in Human Lunar Return only)
- FN-L-203 L and FN-L-205 L (water and gas transfer)
- FN-U-103 L (resource identification)
- FN-P-102 L
Four are also mapped to an element in B.3:
- FN-P-101 L and FN-P-301 L: the fission system, as in the spreadsheet
- FN-A-105 L: the Lunar Utility Rover
- FN-A-103 L: the Pressurized Rover
The ADD lists both of the last two as unallocated and maps them to elements; the spreadsheet only allocates them (open question 64).
-
20 are mapped to at least one element in B.3 and are not in B.5. The spreadsheet allocates each of them to the same elements. For three (FN-C-101 L, FN-C-103 L, FN-C-105 L) it adds its generic "Communication/PNT Asset", which isn't an ADD element.
The function-by-function table, with the use cases B.5 files each function under, is on Lunar function allocation. The element pages list each element's functions and mark the Phase 1 ones; for example, four of the Lunar Utility Rover's six functions are on this list, and all three of the Lunar Nuclear Fission System's.
The guide's appendix and its definition. The guide says "A full list of unallocated functions can be found in an appendix of the Architecture Definition Document" (p. 9). On p. 3 it calls these "appendixes for needed functions not currently allocated to exploration elements". By its title, that is B.5, the ADD's only list of unallocated functions (the wiki's match). The 11 in B.5 fit the first half of the guide's definition, "currently unallocated". The 20 allocated ones would fit the second, "need additional performance". The guide doesn't sort its 31 that way, though, and no source says what more performance any of the 20 needs. Two of the 11, FN-A-103 L and FN-A-105 L, are also allocated in the ADD (open question 65).
An older NASA slide doesn't sort them that way either. At the February 2025 workshops, before the Moon Base, ESDMD's architecture office gave four of these functions as examples of two kinds of gap: FN-P-101 L and FN-P-202 L as an "Example Capability Gap from ADD" (unfilled functions), and FN-H-102 L and FN-X-103 L as an "Example Performance Gap" ("only partially addressed capability") (FE gaps deck, slide 2). All four are in B.5 (FN-P-202 L is the title the guide prints under "FN-P-102 L"). FN-H-102 L and FN-X-103 L were also "Unallocated" in NASA's 2024 table, the allocation in force when the slide was shown: 75 of the 2025 table's 76 Unallocated functions were Unallocated in 2024 too, and the exception is FN-M-402 L (Lunar function allocation). So being on the unallocated list didn't stop NASA calling two of them performance gaps (the wiki's reading of the counts and the wiki's comparison).
Related pages¶
Phases · Technology and knowledge challenges · Missions and assets · Surface technology · Moon Base hub · Sub-architectures · Lunar functions · Use cases and functions
Sources¶
Users Guide, pp. 3, 8–10 · ADD Rev C, pp. 40, 117–127, 148–184 · 2025 Architecture Update, pp. 5, 7 · Lunar objective decomposition, allocation sheets