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Architecture technology gaps: all 57

The current architecture lists 57 architecture-driven technology gaps, ESDMD #0101 to ESDMD #1202, each with a priority bin (1–6) and a unique overall rating (1–57) (Tech gaps spreadsheet, Dec 2025). The Moon Base Users Guide names 19 of them among its challenges for "near-term Moon Base development", which Phase 1 missions help close "to enable essential phase two and phase three capabilities" (Users Guide, pp. 11–13; see Technology and knowledge challenges). Rating 1 is the highest priority. The rating is "the gap's location in the prioritized list of gaps", and bins are "distinct groupings" of gaps of similar priority, so bin 1 is the highest bin (ADD Rev C, pp. 78, 199–200). How NASA arrives at the order is below.

What a technology gap is

ADD Rev C Section 3.2 (pp. 77–79) sets out the definition, and the spreadsheet holds the gaps themselves. Page numbers in this section and the next three are ADD Rev C.

  • Definition. NASA identifies "gaps between available functional capabilities and desired future capabilities". "While many of these capability gaps may be closed with engineering or operational solutions, a subset of these capability gaps will require technology investment". Architecture-driven technology gaps "are defined as areas where technology development is required to close the gap between the current state of the art and the Moon to Mars Architecture's anticipated performance or capability targets" (p. 77).
  • A narrow definition. "It is important to note that this is a narrow definition: a technology gap is not simply an area of the architecture that requires further work or the initiation of an element. If NASA can initiate a project or program to meet an architectural need using existing technology, then that area is not a technology gap. Architecture-driven technology gaps require entirely new technologies or significant performance advancement in existing technologies to establish a capability needed to achieve the Moon to Mars Objectives" (p. 77).
  • Where they come from. "NASA identifies technology gaps by assessing architecture documentation, including use cases and functions decomposed from NASA's exploration objectives, architecture definition tasks, and historical data. Engineers compare the state of the art for a technology with the notional architecture performance targets" (p. 77). See Objective decomposition and Key definition tasks.
  • What each gap records. "Each architecture-driven technology gap includes a gap title, gap description, architecture impact and benefits, target performance metrics, and current state-of-the art metrics" (p. 77). These are the spreadsheet's columns, and the sections of each gap page. Appendix D defines all 13 fields (below).
  • Solution-agnostic. The gaps are "designed to be solution-agnostic, focusing on a documented capability need, not a specific technology solution to achieve the capability" (p. 77).
  • Not a list of everything. In a boxed note: "The prioritized list of gaps is not encompassing of all research and development necessary to prepare for future exploration and does not attempt to capture all outstanding risk. The demand signal is focused only on those capabilities most enabling for the Moon to Mars Architecture, which matures and evolves" (p. 79).
  • More detail is in "the associated white paper published in 2024" (p. 77, footnote 23: the ACR24 technology-gaps white paper). Its "narrow definition" paragraph is word for word the ADD's; what it adds is below.

What each gap's table holds (ADD Appendix D)

ADD Rev C's Appendix D holds "a set of gap detail summary tables for each of the architecture-driven technology gaps". They "describe the gap, identify the target capability or performance expected based upon the current architecture documentation, and track how the gap traces to the architecture and objective decomposition" (p. 199). Section D.1 defines each field (p. 199, checked against the PDF):

Field NASA's definition (p. 199) Gap-page section
Gap Title "Summary of the needed capability in the Moon to Mars Architecture" title
Gap ID No. "A four-digit unique identifier; the first two digits are determined by the gap's most relevant sub-architecture" title; see By ID group
Overall Prioritization Rating "The gap's location in the prioritized list of gaps, indicating architecture preference of gap closure based upon the weighting and combination of the four priority metrics" Priority
Priority Bin "Distinct groupings of architecture preference of gap closure based upon prioritized list to show relative priority" Priority
Gap Description "Description of the gap between the current state of the art and the Moon to Mars Architecture's needed capabilities/performance targets" Description
Architecture-Driven Child Gaps "List of the titles of the child gaps related to this technology gap, which are also architecture-driven; the * symbol denotes a child gap with multiple parents" Child gaps
Architecture Impacts and Benefits "High-level summary of positive benefits to the Moon to Mars Architecture if the gap is closed or negative impacts to the Moon to Mars Architecture if the gap is not closed" Description ("Impacts and benefits")
Architecture Traceability: Definition Tasks "List of architecture definition tasks with strong relevance to the gap; to be considered relevant, the definition task outcome affects the degree of need for the gap directly" Traceability
Architecture Traceability: Use Cases & Functions "List of the use cases and functions from which the needed Moon to Mars Architecture capability was derived" Traceability
Metrics: Current State of the Art "Description of the current state-of-the-art capabilities" Current state of the art
Metrics: Performance Target "Description of the Moon to Mars Architecture's needed capabilities/performance targets" Performance target
Segments "The Moon to Mars Architecture segment(s) for which the capability is needed. A gap's urgency score is partly based on the first segment for which the capability is needed." Segments and sub-architectures
Sub-Architectures "List of the Moon to Mars sub-architecture(s) with strong relevance to the gap's content and scope" Segments and sub-architectures

These are the 13 columns of the tech gaps spreadsheet, under the same names.

Titles for the use-case and function IDs. The gap pages print the IDs in "Use Cases & Functions" as the sheet does, without titles. The ADD's titles are in Appendix B.2: lunar IDs on pp. 110–127, Mars IDs on pp. 127–147. They are on Lunar use cases, Lunar functions, Mars use cases and Mars functions, each with a column listing the gaps that cite the ID. The counts are the wiki's:

  • 61 of the 163 lunar use cases are cited by a gap, and 59 of the 148 Mars use cases.
  • 41 of the 208 lunar functions are named by one, and 40 of the 263 Mars functions. Both counts include only functions a gap names, not those behind "All FN".
  • "All FN" entries can't be expanded from B.2. The two decomposition spreadsheets pair functions with use cases, so the entries are expanded below, for the Moon and for Mars.

  • Three Mars pairings the decomposition doesn't make: #0202's UC-A-403 M – FN-A-402 M, and #0401–#0404's UC-X-101 M – FN-X-101 M and UC-X-102 M – FN-X-102 M. And #0308 lists three use cases with no function that the decomposition gives functions to (open question 60).

  • Two lists, two orders. D.2 lists the gaps "in priority order", with ID, title, "Priority Rating" and "Priority Bin" (pp. 200–202). D.3, the catalog, holds one full table per gap, and "The technology gaps appear in numerical order, not priority order" (p. 203). The catalog runs from #0101 on p. 204 to #1202 on p. 260, one page per gap. Page 261 is the divider for Appendix E (PDF checked).

  • How the tables look (from the PDF; the text layer loses it). In all 57 tables, each performance target carries an icon labeled "Moon", "Mars" or "Moon/Mars", and each definition task a Moon or Mars icon. The spreadsheet writes these as text ("Moon:", "Mars:", "Moon/Mars:"). Segments and sub-architectures are shown as labeled icons, with the C&PNT sub-architecture labeled "C&PNT" (e.g. pp. 206, 208).
  • A pointer to TechPort. A boxed note above the D.2 list reads: "Note: For additional current state-of-the-art details, refer to the NASA TechPort at the link below: https://techport.nasa.gov/" (p. 200, PDF checked). This wiki quotes the note and uses no TechPort data.

  • Checked against the spreadsheet. D.2's 57 IDs, titles, ratings and bins all match the spreadsheet (pp. 200–202, PDF checked). All 57 catalog tables (pp. 204–260) match their spreadsheet rows field for field (text layer, every page checked in the PDF), with two exceptions:

    • One print difference: "FN-C-107M" under #0102 (p. 205), where the sheet has "FN-C-107 M".
    • One content difference: under #1107 the ADD pairs UC-U-501 M with FN-U-501 M (p. 258), where the sheet has FN-U-502 M. Both documents are from December 2025, and the wiki doesn't pick one (open question 37).

    The ADD also confirms the sheet's open items: the same four "High-performance processors" child gaps, all unstarred (pp. 209, 240, 248, 250), and #0902's solar and fuel-cell child gaps beside a ticked MD-07 (p. 245).

How NASA prioritizes the gaps

"To inform technology investment strategies and investments both internally and externally to NASA, the architecture-driven technology gaps follow a priority order. Four priority metrics — gap attributes that capture an aspect of architecture preference and can be evaluated for every gap — drive this order: criticality, urgency, breadth, and depth" (p. 77).

Metric What it measures (p. 78) How it was scored (p. 78)
Criticality "the degree to which closing the technology gap would enable or enhance the Moon to Mars Architecture" "based upon architecture trade studies and alignment with the use case and function decomposition"
Urgency "how soon investment in a technology gap is needed to ensure the capability is available for future missions" "by comparing gap closure timelines with the estimated technology development timelines to capture long-lead developments". Appendix D adds: "A gap's urgency score is partly based on the first segment for which the capability is needed" (p. 199).
Breadth "the prevalence of a technology gap's applicability across sub-architectures" "Technology gaps were mapped to sub-architectures, and gaps that address cross-cutting capabilities scored higher relative to single-application gaps"
Depth "the degree to which closing the gap is dependent on future architecture definition tasks" "based upon mapping to definition tasks, along with an assessment of how much those definition task outcomes affect the need for the gap's closure". A task is listed against a gap only if "the definition task outcome affects the degree of need for the gap directly" (p. 199).

The figure on p. 78 (read from the PDF; the text layer drops it), "Overview of Gap Prioritization Process", shows "Architecture-Driven Gaps" scored on the four metrics. The scores pass through a step labeled "Analytical Hierarchy Process" ("Weighting, Scoring Aggregation, and Normalization") to a "Prioritized Gaps List". Beneath it, the caption "Architecture-Driven Technology Gap Prioritization and Weighting Formula" sits under a sum: the criticality, urgency, breadth and depth scores, each multiplied by its own percentage weight (printed only as symbols, W with a subscript and "%"), give the "Gap Overall Prioritization Rating".

What the ADD says about the weights and bins (p. 78):

  • Weights. "The relative weightings were determined through comparison of each metric's importance to the Moon to Mars Architecture. Architecture teams weighted the metrics in the following descending order: criticality, urgency, breadth, and depth." The weight values are not printed in Section 3.2. No gap's metric scores appear in the spreadsheet, in the D.2 list (p. 200, whose columns are ID, Gap Title, "Priority Rating" and "Priority Bin", checked against the PDF) or in the gap tables (e.g. p. 204).
  • No cost. "Note that implementation-specific metrics, such as cost, are not considered in the gap prioritization process because they are not tied to an architectural demand signal for the capability."
  • Bins. "Technology gaps' overall prioritization rating fall into distinct groupings of preference, referred to as priority bins … Note that all gaps, even those in the lowest priority bin, are highly architecture driven."

The published number is a rank, not the weighted score. Appendix D defines the "Overall Prioritization Rating" as "The gap's location in the prioritized list of gaps, indicating architecture preference of gap closure based upon the weighting and combination of the four priority metrics", and the "Priority Bin" as "Distinct groupings of architecture preference of gap closure based upon prioritized list to show relative priority" (p. 199). Its list "captures the architecture-driven technology gaps in priority order", starting with #0801 at rating 1 (p. 200). So the 1–57 in the spreadsheet is each gap's place in the order, 1 first. One naming wrinkle: the p. 78 figure gives the weighted sum the same name, "Gap Overall Prioritization Rating", and D.2's text lists "rating, overall prioritization rating" as if two fields, while its table has one column, "Priority Rating" (p. 200). The wiki follows D.1's definition for the published number (open question 21). D.2's full list matches the spreadsheet's ratings and bins for all 57 gaps (above).

What the order is for (p. 78): "First, the prioritized list of gaps can be used to inform technology investment strategies that align with the Moon to Mars Architecture needs. This data is expected to inform and help NASA technology development organizations, ESDMD programs, industry, interagency groups, international partners, and academia plan investments. Second, this demand signal provides focus for the architecture teams to engage with technology developers on technology options based upon their potential benefits, schedule drivers, and risk reduction relative to the gaps."

Why no gap lists Human Lunar Return

"The Human Lunar Return Segment contains technology development and investment by the current programs, so the technology gaps captured in this document do not trace to Human Lunar Return. Instead, the gaps map to the other three segments: Foundational Exploration, Sustained Lunar Evolution, and Humans to Mars" (p. 79). Data gaps are different: 17 of the 25 list Human Lunar Return (data gaps index).

How the list changes

  • "The current list of gaps and gap priorities represents a snapshot in time and will be updated annually as part of the strategic analysis cycle as the Moon to Mars Architecture matures and technology advances. As later segments are better defined, existing technology gaps may be re-prioritized and new architecture-driven technology gaps may be identified" (p. 79). See Architecture definition process.
  • Technology gaps and data gaps can swap. "Data gaps are a counterpart of technology gaps that communicate the need for information, rather than technology development. Technology gaps may transition to data gaps and vice versa as the architecture's needs evolve and technology development advances. NASA re-evaluates this relationship annually as part of the strategic analysis cycle" (p. 79).
  • The list "will evolve as gaps close and NASA identifies new gaps" (p. 77).

What changed in Rev C. The companion 2025 Architecture Update says: "The agency refines this list each year, adding new technology gaps as they arise, closing gaps as their needs are fulfilled, and updating the priority order to reflect the current state of the architecture. Revision C of the Architecture Definition Document adds two new technology gaps and removes one former gap, which has been replaced by multiple new architecture-driven data gaps" (2025 Architecture Update, p. 14):

The Update doesn't say how the priority order changed. The 2024 white paper gives Rev B's count, 56, and its five highest gaps (below). Rev B's whole ranked list was briefed at the February 2025 workshops, and is set against Rev C below.

The 2024 white paper and the first list

The ACR24 white paper "Architecture-Driven Technology Gaps" came out with Revision B in December 2024: "This year, for the first time, NASA has published a prioritized list of these architecture-driven technology gaps in Revision B of its Architecture Definition Document" (p. 1). Page numbers in this section are the paper's.

  • The first list had 56 gaps. "The initial list included 56 total gaps, but the gaps will change each year" (p. 4). With the Update's two added and one removed, 56 + 2 − 1 = 57, Rev C's count. The arithmetic is the wiki's.
  • Its five highest-priority gaps (Table 1, p. 4) are, by title, Rev C's ratings 1, 2, 3, 5 and 6: #0801, #0201, #0301, #0103 and #1104. Rev C's rating 4, #1107 Cryogenic Fluid Transfer, is not among them. The table isn't numbered; its rows follow Rev B's ranks 1 to 5 as briefed in February 2025 (below; source page).
  • Technology pull and push. "Much of NASA's architecture work involves identifying unallocated functions and filling them with new or existing exploration assets or elements … However, there are instances where filling a gap in the architecture requires new technology. In these instances, architecture-driven technology gaps provide architecture technology pull." Its definitions: "Technology Pull: innovation to meet documented mission needs. Technology Push: innovation to meet anticipated mission needs" (p. 1).
  • Gaps and STMD's shortfalls. "A shortfall is a technology area requiring further development to meet future exploration, science, and other mission needs. The term 'gap' … implies both ends of the problem – the current state of the art and the technology performance target needed – are known. In the case of shortfalls, we may only know where we are today." "ESDMD provided STMD with its architecture-driven technology gaps during development of these shortfalls. As such, the Civil Space Shortfalls document includes all the architecture-driven technology gaps, plus ESDMD's ranking of shortfalls for applicability to future human exploration missions" (p. 2). Its Venn figure puts the gaps in the overlap of "STMD Shortfalls" and "ESDMD Gaps", under "100% of technology gaps are included in Shortfalls" (p. 2, PDF). Neither ADD Rev C nor the Update mentions shortfalls or push and pull (search of both). The wiki holds only part of a shortfall list: STMD briefed its 2024 ranking at the February 2025 workshops ("Documented 187 shortfalls within 20 capability areas"; "1,231 responses"; "Survive and operate through the lunar night ranked #1"), and the top 30 are transcribed on the FE gaps deck's page (slides 9–11). Many of their titles are close to gap titles; no source pairs them, and the wiki hasn't (open question 87).
  • Where gaps come from. Its Figure 2 runs from "Objectives & Goals" through "Characteristics & Needs", functions and use cases to "Technology Gaps" and "Decisions", all "Identified, Prioritized, and Documented in Architecture Definition Document Appendixes". Technology development organizations close them: "NASA … relies on technology development organizations to close them" (p. 3, figure caption). See Objective decomposition.
  • What changed in the method by Rev C. Little. The narrow definition is word for word the same. Two metric definitions were reworded: breadth now measures "a technology gap's applicability", and depth's dependence is on "future architecture definition tasks" where 2024 said "future architecture decisions" (p. 3; ADD p. 78). Rev C adds the weight order and the note on cost. The 2024 prioritization figure's boxes and formula match the p. 78 figure as described above (the wiki's comparison, at the 2024 PDF's resolution).

The 2024 executive overview retells the paper in a two-page feature (2024 overview, PDF p. 13). It prints the same five titles in the same order as "Example Technology Gaps (2024)", with the same caption: "The initial list included 56 total gaps". It describes the same four weighted metrics, and says "All of the architecture-driven technology gaps appear in that list of shortfalls". One line says what the public list is for: "Public documentation of the technology gaps allows NASA to communicate desired capabilities to industry and international partners. Each gap represents fruitful areas for research, development, and innovation that can help NASA and its partners invest technology development resources wisely." Its example table is #0101 in its 2024 form, with a target of "TBD meters" (#0101).

The C&PNT white paper names three gaps by titles that match neither list. The 2024 paper's one surface-communications title is #0103's current one (open question 35).

Rev B's list against Rev C (February 2025 briefing)

The technology-gaps briefing at both February 2025 workshops, older than Rev C, printed Revision B's whole prioritized list: "NASA Technology Gaps Priority Bin Results (in ADD Rev B, Appendix C)", 56 gaps with a ranking and a bin each, ranks 37 and 53 tied (technology gaps briefing, slide 5; the same slide in the partners' copy). The list as printed, with its titles, is on the briefing's source page. Rev B's ranking is the field Rev C calls the "Priority Rating"; the slide says "Priority Ranking".

The comparison below is the wiki's. Rev C's ratings and bins are the spreadsheet's (the table at the top of this page). Rev C's bins: 1 (ratings 1–6), 2 (7–15), 3 (16–30), 4 (31–36), 5 (37–48), 6 (49–57). Rev B's: 1 (ranks 1–5), 2 (6–15), 3 (16–27), 4 (28–33), 5 (34–46), 6 (47–56).

  • Three gaps moved up a bin, none down. #1107 Cryogenic Fluid Transfer, 11 to 4 (bin 2 to 1); #1101 Lunar Precision Landing and Hazard Avoidance, 29 to 27 (bin 4 to 3); #1106 Cryogenic Fluid Storage, 43 to 32 (bin 5 to 4).
  • The top of the list reordered. Rev B: #0801, #0301, #0103, #1104, #0201. Rev C: #0801, #0201, #0301, #1107, #0103, #1104.
  • Moved up: the three above, and #0201 5 to 2, #0806 9 to 7 and #0701 26 to 23. No other gap rises.
  • The same number in both: #0801 (1), #1105 (12), #0901 (13), #1001 (14), #0807 (15), #0303 (16), #0307 (17), #1003 (18), #0804 (19), #0101 (20), #0702 (21), #0302 (22) and #0902 (45).
  • Moved down: every other gap, by one to five places, as the six above rise past them, #0504 and #0505 come in at 29 and 30, and #0602 leaves. The largest slips are #0404 (37 to 42), #0403 (37 to 41) and #0405 (42 to 46).
  • Ties broken. Rev B's three at 37 (#0401, #0403, #0404) are Rev C's 40, 41 and 42, in the same order; its two at 53 (#0601, #0603) are 54 and 55.
  • Out and in. #0602 (Rev B rank 48, bin 6) is gone, replaced by data gaps (above). #0505 (29) and #0504 (30) are new, both in bin 3.
  • Bin sizes changed: Rev B 5, 10, 12, 6, 13, 10; Rev C 6, 9, 15, 6, 12, 9.

No source read says why any gap moved. Rev B's titles differ from the sheet's for eight gaps (#0101, #0304,

0305, #0307, #0501, #0701, #0803, #0804), listed on the

briefing's source page. The same briefing prints #0301's Rev B table, with a target of "150 (TBR) hours" where Rev C has 350 (#0301).

The Mars Campaign Office's priority areas (February 2025)

A briefing at the February 2025 industry and academia workshop, older than Rev C, shows one NASA office using the gaps (Paths to Partnership deck, slides 20–21). The Mars Campaign Office's "New Start Process" begins each November–February when "SAO holds Architecture Concept Review and releases annual Architecture Definition Document revision", followed by a "Call for New Start Task Submissions"; from August to October, "DLs coordinate with Portfolio Leads to provide technical progress updates to SAO CIT for ESDMD architecture gap updates". Its "MCO Priority Development Areas" end with a box: "Other ADD technology gaps will be considered". The slide prints no gap IDs. The wiki matches the areas to gaps by title; the matches are the wiki's:

MCO area (as printed) Gap, matched by title (the wiki's)
"Lunar dust-tolerant systems and dust mitigation" (cleaning tools; connectors and sealing surfaces "for cryo, power, pneumatics, and fluids"; dust-tolerant fabrics and electrodynamic dust shields) #0801 Lunar Dust-Tolerant Systems and Dust Mitigation (same words)
"Power management and distribution between surface elements (with STMD)" #0903 Power Management and Distribution
"Cryo fluid storage (with STMD)" #1106 Cryogenic Fluid Storage
"Food systems improvements" #0305 Food and Nutrition
"Fire Safety" (safer materials, partial-g detection and suppression, emergency breathing mask) #0302 Fire Safety Upgrades
"Smaller exercise equipment"; "Better vibration isolation systems for exercise equipment" #0401 Crew Exercise Countermeasures
"Wearable sensorimotor countermeasures devices" #0402 Sensorimotor Countermeasures
"Medical" (wearable diagnostics, "Autonomous clinical decision support (doc in a box)", sterilization) #0405 Exploration Medical Capabilities
"Communications, position, navigation, and timing work with LunaNet and SCaN coordination"; "Lunar surface clock" #0101 PNT for Lunar Surface Extreme Environments
"ISRU manufacturing"; "Surface science tools development"; "Bearing materials, seals, and lubricants for extreme environments"; "Fiber optic sensors"; "Autonomous photogrammetry"; "Nano sensors" not matched: no gap title is close enough

Rev C doesn't describe the office's cycle or its use of the gaps.

Summary by bin

Bin Ratings Gaps Moon only Mars only Both Named in the Moon Base Users Guide (near-term)
1 1–6 6 2 1 3 4
2 7–15 9 1 2 6 4
3 16–30 15 6 0 9 7
4 31–36 6 0 2 4 0
5 37–48 12 0 4 8 0
6 49–57 9 4 2 3 4
All 57 13 11 33 19

Two things stand out. None of the gaps in bins 4 and 5 is named in the Moon Base Users Guide. And four of the 19 Moon Base gaps, the lunar ISRU gaps #0601, #0603, #0604 and #0605, sit in bin 6, the lowest, rated 53–56. The ADD notes that "all gaps, even those in the lowest priority bin, are highly architecture driven" (p. 78), and its ratings predate the Moon Base (Dec 2025).

How to read the table

  • Destination is derived here, not a spreadsheet field. It comes from the labels in each gap's performance target: "Moon" if the target has only a "Moon:" part, "Mars" if only "Mars:", and "Both" if it has a "Moon/Mars:" part or separate "Moon:" and "Mars:" parts. All 57 of the ADD's gap tables print the same labels as icons beside each target (e.g. ADD Rev C, p. 208); the "Both" grouping is the wiki's.
  • Segments: FE = Foundational Exploration, SLE = Sustained Lunar Evolution, H2M = Humans to Mars, as in the ADD's acronym list (pp. 292–293). The spreadsheet spells the segment names out.
  • Sub-architectures are shortened: Autonomy = Autonomous Systems & Robotics; Comms/PNT = Communications and Positioning, Navigation, and Timing Systems; Data = Data Systems and Management; Habitation, Human, Infrastructure (Support), ISRU (In-Situ Resource Utilization Systems), Logistics, Mobility, Power, Transportation and Utilization (all "… Systems").
  • MB marks the 19 gaps named in the Moon Base Users Guide (near-term): the guide's challenges for "near-term Moon Base development", whose work starts with Phase 1 missions "to enable essential phase two and phase three capabilities" (p. 11). It doesn't mean Phase 1 needs. A blank does not mean a gap is irrelevant to the Moon Base, only that the Users Guide does not name it.

All 57 by rating

Rating Bin Gap Destination Segments Sub-architectures MB
1 1 #0801 Lunar Dust-Tolerant Systems and Dust Mitigation Moon FE, SLE Mobility, Habitation, Logistics, Power MB
2 1 #0201 Extreme Environment Avionics Both FE, SLE, H2M Data MB
3 1 #0301 Systems to Survive Extended Lunar Shadow Moon FE, SLE Habitation, Mobility, Autonomy MB
4 1 #1107 Cryogenic Fluid Transfer Both FE, SLE, H2M Transportation, Infrastructure
5 1 #0103 Surface-to-Surface Communications Both FE, SLE, H2M Comms/PNT MB
6 1 #1104 Mars Transportation Propulsion Mars H2M Transportation
7 2 #0806 Payload Offloading, Handling, and Manipulation Both FE, SLE, H2M Mobility, Autonomy, Logistics MB
8 2 #0805 Autonomous Surface Mobility and Navigation Both FE, SLE, H2M Mobility, Autonomy
9 2 #0305 Food and Nutrition Both FE, SLE, H2M Habitation
10 2 #1103 Mars Entry, Descent, and Landing Mars H2M Transportation
11 2 #0304 Habitat Environmental Monitors Both SLE, H2M Habitation
12 2 #1105 Mars Ascent Propulsion Mars H2M Transportation
13 2 #0901 Scalable Lunar Surface Power Generation Moon FE, SLE Power MB
14 2 #1001 High-performance Actuators, Sensors, and Interfaces Both SLE, H2M Autonomy, Mobility MB
15 2 #0807 Docking and Berthing between Surface Elements Both FE, SLE, H2M Mobility, Logistics, Habitation MB
16 3 #0303 Dormancy Recovery for Habitat Water Both FE, SLE, H2M Habitation
17 3 #0307 Radiation Monitoring and Forecasting Both FE, SLE, H2M Habitation, Human
18 3 #1003 Fault/Anomaly Diagnosis, Decision Support, and Response Both FE, SLE, H2M Autonomy, Data
19 3 #0804 Robotic and Mobility Systems in Extreme Cold Moon FE, SLE Mobility, Autonomy MB
20 3 #0101 PNT for Lunar Surface Extreme Environments Moon FE, SLE Comms/PNT MB
21 3 #0702 Waste Management Both FE, SLE, H2M Logistics
22 3 #0302 Fire Safety Upgrades Both FE, SLE, H2M Habitation
23 3 #0701 Packing, Transport, and Use of Conditioned Supplies Both FE, SLE, H2M Logistics MB
24 3 #0903 Power Management and Distribution Both FE, SLE, H2M Power MB
25 3 #0808 Relocation of Large Assets Moon FE, SLE Mobility, Autonomy
26 3 #0202 High-Performance Onboard Computing Both FE, SLE, H2M Data
27 3 #1101 Lunar Precision Landing and Hazard Avoidance Moon FE, SLE Transportation MB
28 3 #1005 Safe Human-Robot Interaction and Teaming Both FE, SLE, H2M Autonomy, Human
29 3 #0505 In-Situ Additive/Subtractive Construction Moon FE, SLE Infrastructure, ISRU MB
30 3 #0504 Autonomous Lunar Surface Structure Assembly and Construction Moon FE, SLE Infrastructure, Autonomy MB
31 4 #0803 EVA and IVA Suits for Mars Missions Mars H2M Mobility, Human
32 4 #1106 Cryogenic Fluid Storage Both FE, SLE, H2M Transportation, Infrastructure
33 4 #1004 Trustworthy Autonomy for Planning and Decision-making Both SLE, H2M Autonomy, Data, Human
34 4 #1002 Autonomous Monitoring Both FE, SLE, H2M Autonomy, Data
35 4 #0802 Mars Dust-Tolerant Systems and Dust Mitigation Mars H2M Mobility, Habitation, Logistics, Power
36 4 #0501 Robotic Inspection, Maintenance, and Repair Both FE, SLE, H2M Infrastructure, Autonomy
37 5 #1102 Mars Precision Landing and Hazard Avoidance Mars H2M Transportation
38 5 #1201 In-Situ Sample Storage and Processing Both FE, SLE, H2M Utilization
39 5 #0402 Sensorimotor Countermeasures Both SLE, H2M Human
40 5 #0401 Crew Exercise Countermeasures Both SLE, H2M Human
41 5 #0403 Physiological Countermeasures Both SLE, H2M Human
42 5 #0404 Behavioral Countermeasures Both SLE, H2M Human
43 5 #0406 Spacesuit Physiology Both SLE, H2M Human
44 5 #1202 Planetary Protection Technologies Mars H2M Utilization
45 5 #0902 Scalable Mars Surface Power Generation Mars H2M Power
46 5 #0405 Exploration Medical Capabilities Both SLE, H2M Human
47 5 #0308 Radiation Countermeasures Both SLE, H2M Habitation, Human
48 5 #0104 Earth-Independent Surface PNT Mars H2M Comms/PNT
49 6 #0306 Advanced Structures and Materials for Habitats Both SLE, H2M Habitation
50 6 #0503 Transfer of Earth-Storable Propellants Both SLE, H2M Infrastructure
51 6 #0102 Deep Space Communications Mars H2M Comms/PNT
52 6 #0606 Mars ISRU Mars H2M ISRU
53 6 #0605 Lunar Regolith Excavation, Manipulation, and Transportation Moon SLE ISRU, Autonomy, Mobility MB
54 6 #0601 Oxygen Extraction from Lunar Regolith Moon FE, SLE ISRU MB
55 6 #0603 Water Recovery from Lunar Regolith/Ice Moon FE, SLE ISRU MB
56 6 #0604 Metal Extraction from Lunar Regolith Moon FE, SLE ISRU MB
57 6 #0502 In-situ Manufacturing of Spares, Repairs, and New Parts Both SLE, H2M Infrastructure, ISRU, Logistics

By ID group

The first two digits of the ID group related gaps. ADD Appendix D says what sets them: "A four-digit unique identifier; the first two digits are determined by the gap's most relevant sub-architecture" (ADD Rev C, p. 199). The ADD doesn't print which number stands for which sub-architecture. The pairs below are the wiki's reading: in all 57 spreadsheet rows, the sub-architecture named here is listed first in the gap's Sub-Architectures field, and every gap in the group lists it. Ratings in brackets.

The lunar decomposition spreadsheet's key also numbers the sub-architectures 1 to 12, but in a different order: 1 Transportation, 2 Infrastructure Support, … 10 Autonomous Systems & Robotics, 11 ISRU, 12 Utilization (source page). Four of its numbers match the gap-ID groups above (3 Habitation, 4 Human Systems, 10 Autonomous Systems and Robotics, 12 Utilization); the other eight don't. So the key neither confirms nor contradicts the reading above: it numbers the same twelve in another order.

"All FN", expanded from the lunar decomposition

Eleven gaps trace to a lunar use case with "All FN" instead of a function. The "FE+ Functions to Use Cases" sheet of the lunar decomposition spreadsheet lists the functions under each of those use cases. This table is built from that sheet. It is not the gap's own list: the gap tables say only "All FN". Function titles are on Lunar functions; which asset performs each function is on Lunar function allocation.

Gap Use case Functions under it (FE+ sheet)
#0202 UC-D-201 L FN-D-103 L, FN-D-104 L, FN-D-203 L, FN-D-204 L
#0406 UC-M-101 L FN-M-101 L, FN-M-102 L, FN-M-202 L, FN-M-203 L
#0406 UC-M-102 L FN-M-104 L, FN-M-301 L
#0601 UC-I-102 L FN-T-202 L, FN-P-401 L, FN-M-101 L, FN-M-402 L, FN-M-503 L, FN-C-101 L, FN-I-102 L, FN-I-105 L, FN-I-107 L, FN-I-201 L, FN-I-203 L, FN-U-103 L
#0603 UC-I-103 L FN-T-202 L, FN-P-401 L, FN-M-101 L, FN-M-402 L, FN-M-503 L, FN-C-101 L, FN-I-101 L, FN-I-103 L, FN-I-106 L, FN-I-108 L, FN-U-103 L
#0604 UC-I-106 L FN-T-202 L, FN-P-401 L, FN-M-101 L, FN-M-402 L, FN-M-503 L, FN-C-101 L, FN-I-201 L, FN-I-202 L, FN-I-204 L, FN-U-103 L
#0605 UC-I-202 L FN-T-202 L, FN-P-401 L, FN-M-402 L, FN-M-503 L, FN-C-101 L, FN-I-201 L, FN-I-204 L, FN-I-205 L
#0806 UC-A-103 L FN-A-104 L, FN-A-105 L, FN-A-201 L
#0901 UC-P-101 L FN-P-101 L, FN-P-202 L
#0901 UC-P-102 L FN-P-102 L, FN-P-201 L
#0903 UC-P-301 L FN-P-301 L, FN-P-305 L
#0903 UC-P-302 L FN-P-302 L, FN-P-305 L
#1101 UC-T-401 L FN-T-401 L, FN-T-403 L
#1101 UC-T-402 L FN-T-402 L, FN-T-403 L
#1201 UC-T-303 L FN-T-207 L, FN-T-209 L, FN-T-211 L, FN-T-301 L, FN-T-304 L, FN-T-307 L, FN-M-506 L, FN-U-402 L, FN-U-405 L, FN-U-408 L, FN-U-411 L, FN-U-414 L
#1201 UC-T-304 L FN-T-208 L, FN-T-210 L, FN-T-212 L, FN-T-301 L, FN-T-304 L, FN-T-307 L, FN-M-507 L, FN-U-402 L, FN-U-405 L, FN-U-408 L, FN-U-411 L, FN-U-414 L
#1201 UC-T-305 L FN-T-207 L, FN-T-209 L, FN-T-211 L, FN-T-302 L, FN-T-305 L, FN-T-308 L, FN-M-508 L, FN-U-403 L, FN-U-406 L, FN-U-409 L, FN-U-412 L, FN-U-415 L
#1201 UC-T-306 L FN-T-208 L, FN-T-210 L, FN-T-212 L, FN-T-302 L, FN-T-305 L, FN-T-308 L, FN-M-509 L, FN-U-403 L, FN-U-406 L, FN-U-409 L, FN-U-412 L, FN-U-415 L
#1201 UC-T-307 L FN-T-208 L, FN-T-210 L, FN-T-212 L, FN-T-303 L, FN-T-306 L, FN-T-309 L, FN-M-510 L, FN-U-404 L, FN-U-407 L, FN-U-410 L, FN-U-413 L, FN-U-416 L

Things to note (the wiki's reading of the table):

  • The ISRU use cases include support functions. Their lists start with cargo delivery, payload power, EVA, unloading and repositioning, and communications, before the ISRU functions themselves. This fits B.1's "support functions" note (Use cases and functions).
  • Power. The South Pole use case, UC-P-101 L, pairs FN-P-101 L (generate, South Pole) with FN-P-202 L (store energy, South Pole). The distributed-sites use case pairs FN-P-102 L with FN-P-201 L. So #0901's functions include both IDs in open question 40. That doesn't say which one the Users Guide meant.
  • Gaps that also name a function under the same use case use one from the list: #0801 (FN-M-101 L) and #0807 (FN-M-203 L) under UC-M-101 L, and #1106 (FN-I-105 L) and #1107 (FN-I-107 L) under UC-I-102 L.

"All FN", expanded from the Mars decomposition

Sixteen gaps trace to a Mars use case with "All FN", 33 entries in all. The "Functions to Use Cases" sheet of the Mars decomposition spreadsheet lists the functions under each use case. This table is built from that sheet. It is not the gap's own list: the gap tables say only "All FN". Function titles are on Mars functions. No source says which element performs a Mars function.

Gap Use case Functions under it (Mars sheet)
#0201 UC-C-107 M FN-D-101 M
#0201 UC-D-201 M FN-D-104 M, FN-D-202 M
#0302 UC-H-101 M FN-H-101 M, FN-H-118 M
#0302 UC-X-101 M FN-H-123 M, FN-H-125 M, FN-X-109 M, FN-X-111 M, FN-L-301 M
#0302 UC-X-102 M FN-H-124 M, FN-H-126 M, FN-X-110 M, FN-X-112 M, FN-L-302 M
#0302 UC-X-103 M FN-H-111 M, FN-H-112 M, FN-H-113 M, FN-H-127 M
#0302 UC-X-104 M FN-H-114 M, FN-H-115 M, FN-H-128 M, FN-H-129 M
#0501 UC-G-401 M FN-G-404 M, FN-G-405 M, FN-G-411 M, FN-G-412 M, FN-G-413 M, FN-L-203 M
#0501 UC-G-402 M FN-G-402 M, FN-G-403 M, FN-G-406 M, FN-G-408 M, FN-G-409 M, FN-G-410 M, FN-L-203 M
#0501 UC-A-107 M FN-A-111 M, FN-A-112 M, FN-A-125 M, FN-A-126 M
#0502 UC-I-201 M FN-I-101 M, FN-I-201 M, FN-I-202 M, FN-I-203 M
#0503 UC-U-501 M FN-U-501 M, FN-U-502 M, FN-U-503 M, FN-U-504 M
#0606 UC-I-101 M FN-C-101 M, FN-C-102 M, FN-U-201 M
#0606 UC-I-102 M FN-I-101 M, FN-I-102 M, FN-I-103 M, FN-I-104 M, FN-I-105 M, FN-I-107 M
#0606 UC-I-201 M FN-I-101 M, FN-I-201 M, FN-I-202 M, FN-I-203 M
#0803 UC-M-101 M FN-U-107 M, FN-U-301 M, FN-U-701 M
#0805 UC-A-101 M FN-A-127 M, FN-U-105 M, FN-U-304 M
#0806 UC-A-105 M FN-A-107 M, FN-A-108 M, FN-A-109 M, FN-A-128 M, FN-A-129 M, FN-A-130 M
#0902 UC-P-101 M FN-P-101 M, FN-P-201 M
#0902 UC-P-102 M FN-P-102 M, FN-P-202 M
#1001 UC-A-101 M FN-A-127 M, FN-U-105 M, FN-U-304 M
#1001 UC-A-102 M FN-A-101 M, FN-A-102 M, FN-A-103 M
#1001 UC-A-103 M FN-A-104 M
#1001 UC-A-104 M FN-L-203 M, FN-A-106 M, FN-A-121 M, FN-A-122 M, FN-A-123 M
#1002 UC-A-404 M FN-G-407 M, FN-A-402 M
#1103 UC-T-102 M FN-T-401 M, FN-H-102 M, FN-C-204 M
#1103 UC-T-207 M FN-T-202 M, FN-T-404 M, FN-C-204 M
#1104 UC-T-105 M FN-T-104 M, FN-C-202 M
#1104 UC-T-108 M FN-T-104 M, FN-T-210 M, FN-T-211 M, FN-T-212 M, FN-T-213 M, FN-C-306 M
#1104 UC-T-203 M FN-T-213 M, FN-C-202 M
#1105 UC-T-208 M FN-T-215 M, FN-T-216 M, FN-C-205 M
#1201 UC-T-302 M FN-T-213 M, FN-T-215 M, FN-T-302 M, FN-T-305 M, FN-T-306 M, FN-T-403 M, FN-M-503 M, FN-U-403 M, FN-U-404 M, FN-U-405 M, FN-U-406 M, FN-U-407 M
#1201 UC-T-303 M FN-T-213 M, FN-T-215 M, FN-T-307 M, FN-T-308 M, FN-T-309 M, FN-T-403 M, FN-M-504 M, FN-U-408 M, FN-U-409 M, FN-U-410 M, FN-U-411 M, FN-U-412 M

Things to note (the wiki's reading of the table):

  • #0803, the Mars suit gap, gets no EVA function. UC-M-101 M's three functions are utilization ones; the Mars list has no EVA functions at all (Mars functions).
  • The Mars power pairs run in step: FN-P-101 M with FN-P-201 M, FN-P-102 M with FN-P-202 M, unlike the lunar pairs above.
  • Gaps that also name a function under the same use case use one from the list: #1106 (FN-T-211 M, FN-T-212 M) and #1107 (FN-T-210 M) under UC-T-108 M; #1106 (FN-I-104 M) and #1107 (FN-I-105 M) under UC-I-102 M; #1106 (FN-U-504 M) and #1107 (FN-U-502 M) under UC-U-501 M; #0501 (FN-A-106 M) under UC-A-104 M; #0201 (FN-G-407 M), #0202 and #1004 (FN-A-402 M) under UC-A-404 M; #0406 (FN-H-124 M) under UC-X-102 M. The exception is #0401 to #0404: they name FN-X-101 M and FN-X-102 M under UC-X-101 M and UC-X-102 M, and neither is on those use cases' lists (open question 60).
  • #0302 Fire Safety covers emergency functions across four X use cases and one H use case: safe havens, emergency egress, medical response and survival equipment.

Tech gaps spreadsheet · Technology and knowledge challenges · Phase 1 functional gaps · Mars-forward · data gaps index · Key definition tasks · Segments · Use cases and functions · Lunar function allocation · Lunar objectives · Mars use cases · Mars functions · ACR24 technology-gaps white paper

Sources

Tech gaps spreadsheet, all rows · Users Guide, pp. 12–13 · ADD Rev C, pp. 77–79 (Section 3.2), 199 (D.1 field definitions), 200–202 (D.2 list, TechPort note, #0602 note), 203 (D.3), 204–260 (catalog tables #0101 to #1202), 261 (Appendix E divider), 110–127 (Appendix B.2 lunar lists), 127–147 (Mars lists) · 2025 Architecture Update, p. 14 · Lunar objective decomposition spreadsheet, "FE+ Functions to Use Cases" and key sheet · Mars objective decomposition spreadsheet, "Functions to Use Cases" · ACR24 technology-gaps white paper, pp. 1–4 (checked against the PDF) · 2024 executive overview, PDF p. 13