Skip to content

Elements

Summary. Elements are "major systems and hardware that enable exploration", such as Orion, the Human Landing System and SLS, but also spacesuits, rovers, habitats and communications networks (ADD Rev C, p. 45). ADD Rev C has 15, each assigned to one sub-architecture and mapped to the Human Lunar Return and/or Foundational Exploration segments. Only "funded elements that the agency has formally committed to developing" are included (p. 45). This page is the overview from ADD Section 2.3 (pp. 45–46), plus what the 15 one-page element descriptions (pp. 47–68) show side by side, and Section 2.4 on utilization payloads and equipment (p. 69). Each element has its own page.

All page numbers below are ADD Rev C.

Key terms

The ADD's "Architecture Components Key Terms" (p. 21). The terms Segments and Sub-Architecture are defined in the same table; their definitions are on Architecture framework.

Term NASA's definition (p. 21)
Element "Any exploration system that enables a high-level functional allocation (e.g., crew transport, habitation, logistics delivery) that is primarily self-sufficient."
Exploration Asset "Any item that is in place and being used as part of the exploration architecture, including payloads."
Utilization Payloads and Equipment "Any item that is primarily in support of and attributed to utilization objectives. Utilization payloads include science/research payloads and technology demonstrations. Equipment includes other internal and external hardware, supporting tools, supplies, etc."

Utilization itself: "Utilization is the use of a platform, campaign, and/or mission to conduct science, research, test and evaluation, public outreach, education, and industrialization" (p. 21, footnote 8).

Appendix F repeats Element and Utilization Payloads and Equipment word for word, but defines Exploration Asset as "All items that are in place and being used as part of the exploration architecture", without "including payloads" (p. 297). It also defines "Integrated Element", "Large Asset" and "Small Asset" (more than or less than 6 t). See the Glossary.

Section 2 sums up the three kinds of component: "segments, broad phases of exploration; sub-architectures, tightly coupled systems, needs, and capabilities that function together to accomplish objectives; and elements and exploration assets, the systems and hardware that enable exploration and objective satisfaction, which include utilization payloads and equipment that realize science and technology demonstrations" (p. 21).

What makes something an element

  • Derived, not chosen. "NASA derives these elements through objective decomposition" (p. 45). "This Architecture Definition Document captures the formal allocation of use cases and functions to the defined element and maps the element to associated segments and sub-architectures" (p. 45). See Objective decomposition.
  • Funded and committed only. "The Architecture Definition Document only includes funded elements that the agency has formally committed to developing. It is a technical document that reflects the approved baseline for programs of record, contracts, partnerships, and funding. The agency avoids premature addition of element concepts to preserve opportunities for innovation, technology enhancements, and partnerships" (p. 45).
  • More to come. "NASA will add additional exploration assets in future revisions to close capability gaps" (p. 45).

  • How a new element gets in (Section 3.4, "Element Definition and Pre-Formulation", p. 82; new in Rev C per the revision table, p. 4). "When adding new exploration systems to fill architecture gaps, NASA follows a pre-formulation methodology that defines new elements and incorporates partnerships with industry and international space agencies." The steps, as the ADD gives them (p. 82):

    1. "the objective decomposition, where NASA maps exploration assets to needed capabilities and identifies capability gaps"
    2. "NASA and partner teams analyze these gaps, performing trade studies and developing preliminary concepts that might close them"
    3. teams "develop element concepts into potential programs or projects for implementation", reviewed by NASA leadership "at agency-defined decision gates". "Opportunities for input from industry and international partners exist throughout this process."
    4. "At element initiation reviews, NASA approves element concepts for further maturation and feasibility studies. After matured elements are approved at subsequent Mission Concept Reviews, NASA adds the elements into the next revision of the Architecture Definition Document."
    5. "Once the concept is sufficiently mature and includes a strategy for acquisition, NASA transitions the element from the Strategy and Architecture Office to the Moon to Mars Program Office for implementation."

    Partner-built elements wait for a formal agreement: "For concepts developed with international space agencies, NASA adds element partnership information to the document after the U.S. and partner nation formally establish an appropriate international agreement." Section 3.4 repeats p. 45's "funded and committed" rule in slightly different words: the ADD "only includes elements that the agency has formally adopted into the architecture" (p. 82). For more, the ADD points to "the Moon to Mars Architecture website" (p. 82, footnote 24: www.nasa.gov/architecture, not among the wiki's sources). See also Architecture definition process. A 2024 white paper, older than Section 3.4, draws the same process as a figure with partner and industry lanes, and adds an "Acquisition Strategy Meeting" to decide "whether to make, buy, or partner", which Rev C doesn't name. See RT-1 and the figure.

  • Not only elements. "In addition to exploration elements, crew members (i.e., astronauts), payloads, and utilization equipment satisfy many use cases and functions" (p. 45). Payloads and equipment are below; their function mappings are in Appendix B.4 (p. 166). B.4 maps "Equipment" only, one function in Human Lunar Return and eight in Foundational Exploration, all sample collection and stowage. "Science/research payloads and technology demonstrations are forward work" (Lunar function allocation).

  • Where the mappings are. Function mappings for the Human Lunar Return and Foundational Exploration elements are in Appendix B.3. "Functional mapping for the Sustained Lunar Evolution and Humans to Mars segments is forward work" (p. 45).

The 15 elements

Names and section numbers follow the Section 2.3 headings and the contents (pp. 5, 7), which agree. Sub-architecture and segments are from the segment tables (pp. 26, 31–32) and the Section 2.3 table (pp. 45–46), all checked against the PDF; on pp. 45–46 these two columns are icons only. The mapping column gives the Appendix B.3 section, per the contents (pp. 6–7). The functions column counts the functions in each B.3 table, HLR / FE (pp. 148–165). Each element page lists them under "Functions (ADD Appendix B.3)", and Lunar function allocation compares them with the lunar spreadsheet.

Section Element Sub-architecture Segments Mapping B.3 functions, HLR / FE Added in
2.3.1 (p. 47) Commercial Lunar Payload Services Transportation Systems HLR, FE B.3.1 3 / 5
2.3.2 (p. 48) Exploration EVA System Mobility Systems HLR, FE B.3.2 5 / 9
2.3.3 (p. 49) Exploration Ground Systems Infrastructure Support HLR, FE B.3.3 7 / 7
2.3.4 (p. 50) Gateway Habitation Systems HLR, FE B.3.4 16 / 23 Rev A: "Gateway expanded capability configuration"
2.3.4.1.4 (p. 52) Gateway Logistics Element (part of Gateway) Logistics Systems HLR, FE within B.3.4 7 / 7
2.3.5 (p. 55) Human Landing System Transportation Systems HLR, FE B.3.5 21 / 28
2.3.6 (p. 56) Human-Class Delivery Lander Transportation Systems FE B.3.6 — / 5 Rev A
2.3.7 (p. 57) Initial Surface Habitat Habitation Systems FE B.3.7 — / 23 Rev B
2.3.8 (p. 58) Lunar Nuclear Fission System Power Systems FE B.3.8 — / 3 Rev C
2.3.9 (p. 59) Lunar Surface Cargo Lander Transportation Systems FE B.3.9 — / 4 Rev B
2.3.10 (p. 60) Lunar Terrain Vehicle Mobility Systems FE B.3.10 — / 18 Rev A
2.3.11 (p. 61) Lunar Utility Rover Mobility Systems FE B.3.11 — / 6 Rev C
2.3.12 (p. 62) Orion Spacecraft Transportation Systems HLR, FE B.3.12 13 / 14
2.3.13 (p. 63) Pressurized Rover Mobility Systems FE B.3.13 — / 21 Rev A
2.3.14 (p. 64) Space Communications and Navigation Networks C&PNT Systems HLR, FE B.3.14 NSN and DSN 5 / 10; LCRNS 5 / 5
2.3.15 (p. 68) Space Launch System Transportation Systems HLR, FE B.3.15 6 / 6

The B.3 segments match the segment column: elements mapped to Foundational Exploration only have no Human Lunar Return table.

"Added in" is from the revision history (pp. 3–4) and the Executive Summary (p. 9), as summarized on the ADD source page. A blank means the history doesn't name the element, not that it was in the initial release. The 2023 executive overview confirms the Rev A rows: it lists the HDL, LTV, Pressurized Rover and three Gateway components as added in 2023 (below).

The one-pagers agree with this table. Each element's one-page description (pp. 47–68) shows its segments and sub-architecture as labeled icons. For all 15 they match the segment tables. Checked in the PDF on pp. 47, 63 and 68; the text layer carries the labels for the rest.

Who implements each element

Each one-pager has an "Implementing Program" box: a program name in bold, with a second line in italics beneath it (pp. 47–68; layout checked in the PDF on pp. 47, 63, 68). The ADD doesn't label the second line, so the table gives it as printed.

Implementing program Printed beneath Elements
Human Landing System Program Moon to Mars Program Office Human Landing System, Human-Class Delivery Lander, Initial Surface Habitat, Lunar Surface Cargo Lander
EVA and Human Surface Mobility Program Moon to Mars Program Office Exploration EVA System, Lunar Terrain Vehicle, Lunar Utility Rover, Pressurized Rover
Exploration Ground Systems Moon to Mars Program Office Exploration Ground Systems
Gateway Program Moon to Mars Program Office Gateway
Orion Program Moon to Mars Program Office Orion Spacecraft
Space Launch System Program Moon to Mars Program Office Space Launch System
CLPS Program Science Mission Directorate Commercial Lunar Payload Services
Space Communications and Navigation Program Space Operations Mission Directorate Space Communications and Navigation Networks
Fission Surface Power NASA's Glenn Research Center Lunar Nuclear Fission System

Read off the table: two programs carry eight of the 15 elements. The habitat and both cargo landers sit with the Human Landing System Program; the suit and all three rovers sit with EVA and Human Surface Mobility.

Partners named on the one-pagers. JAXA provides the Pressurized Rover "in collaboration with the Japanese automotive industry" (p. 63). ESA provides Orion's European Service Module (p. 62). Gateway's components name ESA, JAXA, the Canadian Space Agency and the UAE's Mohammed Bin Rashid Space Centre (Gateway).

Elements by sub-architecture

Read off the table above. Elements fall in only 7 of the 12 sub-architectures:

Sub-architecture Elements
Transportation Systems 6: CLPS, Human Landing System, Human-Class Delivery Lander, Lunar Surface Cargo Lander, Orion, SLS
Mobility Systems 4: Exploration EVA System, Lunar Terrain Vehicle, Lunar Utility Rover, Pressurized Rover
Habitation Systems 2: Gateway, Initial Surface Habitat
Logistics Systems 1: Gateway Logistics Element
Infrastructure Support 1: Exploration Ground Systems
Power Systems 1: Lunar Nuclear Fission System
C&PNT Systems 1: Space Communications and Navigation Networks
Autonomous Systems and Robotics, Data Systems and Management, Human Systems, ISRU Systems, Utilization Systems none

Each element has one sub-architecture in these tables. Their functions range wider (Appendix B.3, pp. 148–165; the wiki's reading of the function IDs' letters):

  • Only their own letter: three elements, Exploration Ground Systems (all G), the Lunar Nuclear Fission System (all P) and the Lunar Surface Cargo Lander (all T).
  • Several letters: every other element.
    • Gateway, a Habitation Systems element, has functions under ten of the twelve letters, all but G and I (Expanded Capability Configuration).
    • The Initial Surface Habitat and the Pressurized Rover each have nine: H, X, L, P, M, C, D, A, U.
    • The Lunar Utility Rover, a Mobility Systems element, has three FN-A (Autonomous Systems and Robotics) functions beside three FN-M ones (Lunar Utility Rover).
  • Four of the five sub-architectures with no element (above) still have functions mapped to elements. Data (D), Autonomous Systems and Robotics (A), Human Systems (X) and Utilization (U) functions are spread across the crewed elements and rovers. ISRU (I) is the exception: no I function is mapped to any element, and B.5 lists all 15 as unallocated (Lunar function allocation).

Collected from the "Moon Base relevance" section of each element page. The kinds of link are kept apart: the source names the element; the wiki matches by name or wording; and the wiki joins by shared function ID (an element's ADD functions that the Users Guide lists as Phase 1 functional gaps). Every element is checked by function ID against ADD Appendix B.3. The last column of the table below counts the element's B.3 functions that are Phase 1 functional gaps (the wiki's join; each element page lists them).

Element What the Moon Base sources say Kind of link Phase 1 functional gaps among its B.3 functions
CLPS Most Phase One missions fly through CLPS; Phase 2 and 3 goals raise CLPS payload capability to "5MT" and "8MT" Source names it 2 of 5 (FN-T-201 L, FN-M-401 L)
Initial Surface Habitat Example of an early element "designed … for self-sufficiency" (Users Guide, p. 6); no phase Source names it 9 of 23, the most of any element
Gateway HALO hardware reused for Moon Base surface demonstrations, no phase; PPE goes to SR-1 Freedom (Mars) Source names it 2 of 23 (FN-C-101 L, FN-C-105 L)
Pressurized Rover JAXA pressurized rover, Phase Two The wiki's match (same name, provider, wording) 5 of 21
Lunar Terrain Vehicle "Lunar Terrain Vehicles", Phase One, delivery 2028 The wiki's match (same name, ADD wording repeated) 6 of 18
Lunar Nuclear Fission System Lunar Reactor-1, 2030, under "Fission Surface Power"; no phase The wiki's match (same project name) 3 of 3 (FN-P-101 L, FN-P-301 L, FN-P-401 L)
Lunar Utility Rover No phase Not established by the sources 4 of 6 (FN-A-104 L, FN-A-105 L, FN-A-302 L, FN-M-501 L)
SCaN Networks Altus-1 relay on IM-3 (Phase One), under a "Near Space Network Services contract" Source names the NSN; the contract match is the wiki's 5 (FN-C-101 L, FN-C-105 L, FN-C-201 L, FN-A-201 L, FN-A-401 L)
Human Landing System Phase Three: "As cargo‑capable human landing systems (HLS) come online, NASA will deliver heavier infrastructure" (Ignition release); "Human Landing System" labeled on Ignition deck 2's Phase 1 render (slide 10) Source names it (Ignition release); slide 10's label is the wiki's match by name 4 (FN-T-201 L, FN-M-401 L; FN-H-101 L and FN-L-301 L in HLR only)
Lunar Surface Cargo Lander — Not established by the sources so far 1 of 4 (FN-T-202 L)
Exploration EVA System, Exploration Ground Systems, Human-Class Delivery Lander, Orion, SLS — Not established by the sources so far none

The guide doesn't say which half of its definition of a functional gap ("unallocated" or "need additional performance") applies to an allocated function (open question 65).

No source maps segments to Moon Base phases. An FE-only element appearing in Phase One (the LTV) or Phase Two (the Pressurized Rover) is not such a mapping (Segments). The wiki's matches are listed in open question 11.

Utilization payloads and equipment (Section 2.4)

Section 2.4 (p. 69, checked against the PDF) is a sibling of the elements, not one of them. Page 70 is the divider "03. Architecture Evolution" (checked in the PDF; its text layer carries only the running header and page number), and Section 3 starts on p. 71. The term's definition is above.

"One of the Moon to Mars Architecture's key services is the transportation, delivery, deployment, and operation of utilization payloads and equipment to cislunar space and the lunar surface, plus the return of samples and other cargo to Earth. Utilization payloads and equipment encompass any item that primarily addresses utilization objectives. Payloads include science and research payloads and technology demonstrations. Equipment includes tools, supplies, and other supporting materials." (p. 69)

Examples of utilization payloads (p. 69) Examples of utilization equipment (p. 69)
"Secondary payloads aboard transportation systems (e.g., SLS CubeSats)" "Tools and containers used to collect scientific samples (e.g., geological, biological)"
"Externally mounted sensors on transportation and habitation systems" "Freezers for conditioning samples"
"Science experiments and technology demonstrations deployed on the lunar surface by crew or robotic landers"
"Internally operated experiments in crew volumes"
"Portable devices used to make scientific observations (e.g., cameras)"
"Scientific samples and data"
  • Who develops them. "Several NASA organizations develop utilization payloads for the Moon to Mars Architecture, including the Space Technology Mission Directorate and the Science Mission Directorate." Science Mission Directorate payloads "are small but sophisticated measurement systems required for addressing the pure and applied science objectives". Space Technology Mission Directorate payloads "demonstrate and mature cutting-edge technologies to build new capability and capacity that support future exploration and address a wide range of Moon to Mars Objectives" (p. 69).
  • Not yet mapped to objectives. "Information about planned utilization payloads can be found at the websites for those NASA mission directorates. NASA will formalize how science payloads map to Moon to Mars science objectives and point to reference locations as part of the next revision of the Architecture Definition Document" (p. 69).
  • Dual use. "Some payloads (e.g., cameras, medical equipment) are dual use, supporting both utilization and operations, depending on the context" (p. 69).
  • Functions. "The functions fulfilled by payloads and equipment are captured in Appendix B.4" (p. 69). B.4 maps equipment only; see "Not only elements" above and Lunar function allocation.

The Utilization Systems sub-architecture has no element; its needs are met by payloads and equipment like these.

Where the ADD's element tables disagree

ADD Rev C lists the elements three times in pp. 21–46, and the lists don't match. Checked against the PDF. The wiki follows the Section 2.3 headings and the contents (open question 21).

  • The Section 2.3 table (pp. 45–46) leaves out the Lunar Nuclear Fission System. It has 14 elements plus the Gateway Logistics Element. From the cargo lander on, its section and mapping numbers run one lower than the contents: Lunar Surface Cargo Lander 2.3.8 / B.3.8, Lunar Terrain Vehicle 2.3.9, and so on to Space Launch System 2.3.14 / B.3.14 (all on p. 46). The contents (p. 5) and the headings put the fission system at 2.3.8 and SLS at 2.3.15. The Foundational Exploration table (pp. 31–32) agrees with the contents.
  • The SLS one-pager prints the wrong mapping number. Its "Functional Mappings" box reads "Appendix B, B.3.14" (p. 68, checked against the PDF), the SCaN networks' number (p. 64). The contents (p. 7), the segment tables and the Appendix B heading "B.3.15 Space Launch System" (p. 165) all give B.3.15. Every other one-pager matches the contents.
  • The fission system's name. "Lunar Nuclear Power System" in the Foundational Exploration table (p. 31), mapping "B.3.8.1"; "Lunar Nuclear Fission System" in the contents (pp. 5, 7), the heading (p. 58) and the Executive Summary ("lunar nuclear fission system element", p. 9). The 2025 Architecture Update repeats the split: "Lunar Nuclear Power System" in its contents, "Lunar Nuclear Fission System" on its element page (2025 Architecture Update, pp. 2, 7).
  • Gateway's name. "Gateway Crew-Capable Configuration" in both segment tables (pp. 26, 31); "Gateway" in the Section 2.3 table, the contents and the heading. The one-pager uses "Gateway Crew-Capable Configuration" for the Human Lunar Return form and "Gateway Expanded Capability Configuration" for the Foundational Exploration form (p. 50).
  • EVA. "Exploration EVA Systems" in all three tables and in the Appendix B contents (p. 7); "Exploration EVA System" in the Section 2.3 contents entry (p. 5) and heading (p. 48).
  • Mapping numbers differ by table. Gateway Logistics Element: B.3.4.1.1 (HLR table, p. 26), B.3.4.2.1 (FE table, p. 31), B.3.4 (Section 2.3 table, p. 45). Human Landing System: B.3.5.1 (HLR table), B.3.5 (FE and Section 2.3 tables, and its one-pager, p. 55). Appendix B has all of these sub-sections. B.3.4.1.1 and B.3.4.2.1 are the Gateway Logistics Element's HLR and FE tables (pp. 151, 153). B.3.5.1 and B.3.5.2 are the HLS's (pp. 154–155). B.3.8.1, the number the FE table gives the fission system, is its FE table (p. 158). So the segment tables give the sub-section for their own segment, and the other tables the section.

In the executive overviews (2023 and 2024)

The 2023 and 2024 executive overviews are older than Rev C. They tell how the element list grew and how new elements were meant to get in. Page numbers in this section are their PDF pages.

2023: six elements. "In the first edition of the Architecture Definition Document, NASA established nine elements for the Human Lunar Return segment. In 2023, NASA added six new elements to the segment" (2023 overview, PDF p. 10). It doesn't list the first nine.

2023 card, as printed Partner named The card's line Rev C home
Gateway Extravehicular Robotic System Canadian Space Agency "The next-generation Canadarm3 will install science experiments on the outside of Gateway, assist astronauts in spacewalks, and perform external surveys." Gateway External Robotic System / Canadarm3
Gateway ESPIRIT Refueling Module European Space Agency "This habitable module will contain refueling tanks, cargo space, and large windows to allow astronauts aboard Gateway to view outside the station." Lunar View
Gateway Airlock Module none "The airlock is the access point between Gateway's pressurized cabin and the vacuum of space. It will enable astronauts aboard Gateway to conduct spacewalks and can also be used as an additional docking port." Crew and Science Airlock
Human-class Delivery Lander none "This lander will transport cargo for human lunar missions. Crew members will arrive aboard the Human Landing System, and additional cargo will arrive aboard the Human-class Delivery Lander." Human-Class Delivery Lander
Pressurized Rover none "This rover will allow astronauts to live and work at a variety of locations on the lunar surface. It will carry scientific equipment and function as a mobile laboratory and can be remotely repositioned between missions." Pressurized Rover
Lunar Terrain Vehicle none "This unpressurized vehicle will transport crew and equipment across the lunar surface. It can also be operated remotely." Lunar Terrain Vehicle

These are Rev A's additions. Its revision note names them as "Gateway expanded capability configuration, Human-class Delivery Lander, Lunar Terrain Vehicle, and Pressurized Rover", the three Gateway components counted as one (ADD Rev C, p. 3).

2023: element initiation. "In 2023, NASA's Exploration Systems Development Mission Directorate introduced a new integration milestone for formulating Moon to Mars architecture elements: element initiation. During element initiation, the directorate reviews whether a potential concept provides a solution to needs or gaps identified in the Moon to Mars Architecture. The element initiation process will ensure that NASA invests in the most effective technologies and capabilities to meet the Moon to Mars objectives, and that those technologies and capabilities demonstrate sufficient maturity and contribute to the needs of the architecture." "NASA initiated two new elements through the element initiation process in 2023: a lunar surface habitation element, which may provide an initial home for astronauts on the Moon, and a lunar surface cargo lander element, which may deliver supplies and equipment to the Moon" (2023 overview, PDF p. 10). Both entered the ADD a year later: Rev B "adds two new exploration elements" (2024 overview, PDF p. 3), the Initial Surface Habitat and the Lunar Surface Cargo Lander (ADD Rev C, p. 3). That is the order Section 3.4 now prescribes: initiation, then a Mission Concept Review, then "the next revision" (above; the pairing is the wiki's).

2024: the lunar coffee maker (2024 overview, PDF p. 11). The partner pre-formulation feature walks "a totally fictional Moon to Mars Objective, one that requires NASA to make coffee beverages for astronauts on the Moon" through the process:

  • "First, the agency would decompose that objective through its characteristics and needs into the use cases and functions that would fulfill them. Upon finding gaps for a lunar coffee maker element, NASA would begin the pre-formulation process, which includes a series of key reviews."
  • "Initial studies consider a host of options that trade against one another for considerations like cost, technical maturity, and objective satisfaction", here "a drip coffee maker, an espresso machine, and a French press".
  • "This analysis feeds into the first major review: element initiation. During element initiation, NASA assesses whether a preliminary capability meets the architecture's needs."
  • "Next, NASA begins to produce a preliminary concept for the element that will be assessed at mission concept review … After a successful mission concept review, the concept is added in as an element in the Architecture Definition Document."
  • "At an acquisition strategy meeting, where the element moves ahead for implementation, NASA decides whether the new element should be built by NASA, an industry partner, or an international partner."

The figure, with its partner points, is transcribed on the source page. It follows the same sequence as the 2024 partnerships paper's chart, with fewer steps, as the wiki reads both (International Partnerships, Figure 2).

2024: where elements come from. "Some elements predate the architecture development effort (e.g., the Space Launch System rocket and Orion spacecraft) and were mapped to the use cases and functions they already fulfill when this effort began. Other elements have arisen from capability gaps that were not fulfilled by existing elements. As the Moon to Mars Architecture progresses through the segments, NASA will instantiate more elements to increase the number of Moon to Mars Objectives that missions may accomplish" (2024 overview, PDF p. 24). Its two-page spread of element tiles, with providers and partner badges, is transcribed on the source page.

What changed by Rev C (the wiki's comparison):

  • The 2023 six are Foundational Exploration elements now. The overview adds them to Human Lunar Return. Rev C maps the HDL, LTV and Pressurized Rover to Foundational Exploration only, and calls the three Gateway components the "Gateway Expanded Capability Configuration", the Foundational Exploration form of Gateway (pp. 26, 31–32, 53). The wiki follows Rev C (open question 33).
  • The first nine aren't known. Rev C's Human Lunar Return table has eight elements plus the Gateway Logistics Element (p. 26). The overview doesn't name its nine, so the wiki doesn't equate the two.
  • Element initiation is one review among several. Section 3.4 keeps "element initiation reviews" and the Mission Concept Review, and the hand-off to the Moon to Mars Program Office. It doesn't name an acquisition strategy meeting (p. 82).
  • Two elements since. Rev C added the Lunar Utility Rover and the Lunar Nuclear Fission System (p. 4).

In the February 2024 workshop briefings

Two decks from the February 2024 workshops, a month after Rev A and older than Rev C, add to the overviews:

  • Seven hexagons for the 2023 elements. The opening briefing's "New Elements" slide shows the 2023 overview's six plus a seventh hexagon, dashed, the airlock again as "Crew and Science Airlock Module" with a United Arab Emirates dot: "The United Arab Emirates Implementing Arrangement was signed shortly after ACR23. The collaboration will be included in ADD Rev-B during ACR24" (Overview and Updates, slide 10; the wiki reads it as Gateway's airlock under its partner, not a seventh element, Gateway; open question 90).
  • What element initiation is for. "Overt integration point and commitment to formulate element based on identified architecture gap", with "ESDMD Associate Administrator approval at Directorate Program Management Council (DPMC)". It "Affirms strategic alignment and coordination of architecture need, priority, and budget/programmatic intent", and includes "Initial architecture use case & functions and a preliminary concept", any "Potential international partner contribution", and a pre-project team for the Mission Concept Review. It is "Applied to large elements/systems that need to integrate across programs and projects" and "Not intended for small payloads, utilization, or similar contributions or partnerships" (element initiation breakout, slide 4).
  • Who leads when. "SAO leads architecture and strategy until acquisition strategy"; "M2MPO leads implementation and mission execution" (slide 7). The deck's two pre-formulation charts, one for partners and one for industry, are compared with the 2024 paper's single chart on its source page.

What changed by Rev C (the wiki's comparison): Section 3.4 keeps element initiation and the Mission Concept Review before an element enters the ADD, but names no approving council and says nothing of small payloads (p. 82; above); utilization payloads and equipment have their own section (above).

Changes since Rev C

Each element page has a "Changes since Rev C" section. The main ones:

The ADD "reflects changes to the program of record after formal approval of and adoption by the U.S. government" (p. 9), and a new element is added to "the next revision" only after approval at a Mission Concept Review (p. 82; above). No source says which other Moon Base assets, if any, will become ADD elements.

Segments · Sub-architectures · Architecture framework · Objective decomposition · Moon Base missions and assets · ADD Rev C source page

Sources

ADD Rev C, pp. 3–5, 7, 9, 21, 26, 31–32, 45–69, 82, 160, 165, 296–298, 301 · Users Guide, pp. 2, 4, 6, 8–10 · 2025 Architecture Update, pp. 2, 5, 7 · Moon Base Phases · Lunar Surface Technology · Moon Base update, Aug 2026 · 2023 executive overview, PDF p. 10 · 2024 executive overview, PDF pp. 3, 11, 24–25. Element pages cite further sources.