Gateway¶
Summary. In ADD Rev C, Gateway is "a lunar-orbiting outpost in NRHO" built from modules launched in stages by NASA and partner agencies, a Habitation Systems element in the Human Lunar Return and Foundational Exploration segments (ADD Rev C, p. 50). Rev C describes two configurations and seven components, from the Power and Propulsion Element to a UAE-provided airlock. Since Rev C, NASA "intends to pause Gateway in its current form" (Ignition release, March 2026), and its hardware is being repurposed: the PPE for the SR-1 Freedom Mars demonstration, and HALO power and avionics hardware for Moon Base surface demonstrations. NASA describes a "shift from an orbital-focused lunar strategy to one centered on surface operations" (see Changes since Rev C).
All page numbers are ADD Rev C unless noted.
NASA's description¶
"Gateway is a lunar-orbiting outpost in NRHO comprising incrementally launched and assembled modules provided by NASA and international partner space agencies. As the architecture progresses, Gateway evolves to enable more complex exploration operations and Mars-forward demonstrations.
During the Human Lunar Return segment, the Gateway Crew-Capable Configuration comprises the capabilities and components outlined in Section 2.3.4.1. This configuration offers the minimum core functions to support initial crewed missions to the lunar surface. It includes pressurized volumes, life support, propulsion, power, communications, avionics, docking ports, and opportunities for internal and external science and utilization. Deep Space Logistics services supply critical cargo deliveries to the station.
During the Foundational Exploration segment, the Gateway Expanded Capability Configuration adds the capabilities and components outlined in Section 2.3.4.2. This configuration grows crewed and uncrewed exploration and utilization opportunities on Gateway through external robotics, an airlock, refueling capabilities, and enhanced telecommunications systems." (p. 50)
At a glance¶
From the element one-pager (p. 50).
| ADD section | 2.3.4 (pp. 50–54) |
| Implementing program | Gateway Program; printed beneath: Moon to Mars Program Office |
| Functional mappings | Appendix B, B.3.4 |
| Segments | Human Lunar Return, Foundational Exploration |
| Sub-architecture | Habitation Systems; the Gateway Logistics Element is listed separately under Logistics Systems |
| Added in | Rev A: "Gateway expanded capability configuration" (elements index) |
| Header image | "Rendering of the full configuration of the Gateway space station. Gateway will be humanity's first space station around the Moon and will help the agency test technologies and operational paradigms for crewed Mars missions. (Credit: NASA)" |
The segment tables call this element "Gateway Crew-Capable Configuration" (pp. 26, 31); see the elements index.
Two configurations, seven components¶
"Gateway capabilities realized during the Human Lunar Return segment are referred to as the Gateway Crew-Capable Configuration" (p. 51). "Gateway capabilities realized during the Foundational Exploration segment are referred to as the Gateway Expanded Capability Configuration" (p. 53). Each component has a one-panel description with a "Partner Agencies" box, read from the text and checked against the PDF on pp. 51 and 54.
| Section | Component | Configuration | Partner agencies (as printed) |
|---|---|---|---|
| 2.3.4.1.1 (p. 51) | Power and Propulsion Element (PPE) | Crew-Capable | "Not Applicable" |
| 2.3.4.1.2 (p. 51) | Habitation and Logistics Outpost (HALO) | Crew-Capable | European Space Agency |
| 2.3.4.1.3 (p. 52) | Lunar I-Hab | Crew-Capable | European Space Agency; Japan Aerospace Exploration Agency |
| 2.3.4.1.4 (p. 52) | Gateway Logistics Element | Crew-Capable | "Not Applicable" |
| 2.3.4.2.1 (p. 53) | Gateway External Robotic System / Canadarm3 | Expanded Capability | Canadian Space Agency |
| 2.3.4.2.2 (p. 53) | Lunar View | Expanded Capability | European Space Agency |
| 2.3.4.2.3 (p. 54) | Crew and Science Airlock | Expanded Capability | Mohammed Bin Rashid Space Centre |
Power and Propulsion Element¶
"The Power and Propulsion Element (PPE) provides electrical power; attitude and translational control; and communication for Gateway.
The PPE maintains attitude using reaction wheels and a chemical propulsion system. When uncrewed, it performs translation maneuvers and orbital maintenance using a solar electric propulsion system. This propulsion system also serves as a technology demonstration for potential solar electric propulsion for Mars missions.
The PPE has power storage and systems necessary to convert and distribute power to the rest of Gateway. It includes internal avionics systems and is one part of the integrated command and control architecture for Gateway. PPE also performs other functions, such as hosting external payloads and science investigations." (p. 51)
Habitation and Logistics Outpost (HALO)¶
"The Habitation and Logistics Outpost (HALO) is one of two habitation modules where astronauts will live, exercise, eat meals, rest, conduct research, and prepare for lunar surface missions.
This pressurized living quarters provides docking ports for visiting spacecraft like the Orion spacecraft, lunar landers, and logistics resupply spacecraft. HALO also serves as the backbone for Gateway command, control, and power distribution.
Additionally, HALO performs other core functions, including hosting internal and external science investigations, communicating with Earth, visiting vehicles, and assets on the lunar surface, and providing stowage for consumables and payloads. The European Space Agency is leading development of the HALO Lunar Communication System." (p. 51)
Lunar I-Hab¶
"The Lunar I-Hab is Gateway's second habitable element, a pressurized module that will provide multiple docking ports for visiting vehicles and other modules, as well as crew quarters, galley, and stowage.
In addition, I-Hab provides services for internal and external payloads and provides attachment points to allow end-to-end translation of external robotics. The European Space Agency is leading development of the Lunar I-Hab. The Japan Aerospace Exploration Agency is making significant contributions to this Gateway component, providing the environmental control support system, thermal cooling pumps, and batteries." (p. 52)
Gateway Logistics Element¶
"Gateway Logistics Element transports cargo, payloads, and consumables to Gateway. These logistics flights supply the space station with critical deliveries necessary to maximize the length of crew stays. NASA anticipates at least one logistics services delivery for each Gateway mission of 30 days.
The logistics module will provide consumable resupply, outfitting equipment, and cargo delivery including utilization and spares. Each module is also capable of providing additional stowage volume while attached to Gateway, and trash disposal upon departure.
The associated Gateway Logistics Services contract and technical capabilities are extensible to deliver unique payload configurations and supply cargo deliveries to other destinations beyond Gateway. Additional capabilities may be added in future segments." (p. 52)
The element tables list it as its own row under Logistics Systems, the only element in that sub-architecture. Its Appendix B mapping number differs by table: B.3.4.1.1 (p. 26), B.3.4.2.1 (p. 31), B.3.4 (p. 45) (elements index). Appendix B has both of the first two: B.3.4.1.1 is its Human Lunar Return table (p. 151) and B.3.4.2.1 its Foundational Exploration table (p. 153). So each segment table gives the number for its own segment (below).
Gateway External Robotic System / Canadarm3¶
"The Gateway External Robotic System includes a robotic arm, the Canadarm3, provided by the Canadian Space Agency.
The system uses cutting-edge software and robotics to help maintain, repair, and inspect Gateway. It captures visiting vehicles, assists astronauts during spacewalks, and enables external utilization on Gateway in NRHO. The system will self-deploy and translate to multiple locations on the Gateway using low-profile grapple fixtures." (p. 53)
Lunar View¶
"The Lunar View module — previously known as European System Providing Refueling Infrastructure and Telecommunication (ESPRIT) Refueling Module (ERM) — provided by the European Space Agency, is a habitable module that transports cargo to Gateway, provides storage space once docked, will provide refueling capabilities to the PPE through HALO, and offers views of space and the Moon through its windows." (p. 53)
Crew and Science Airlock¶
"The Crew and Science Airlock, provided by the United Arab Emirates Mohammad Bin Rashid Space Centre, allows for the transfer of crew and utilization payloads to and from Gateway's habitable modules and the vacuum of space and provides EVA capability for the Gateway crew. These transfers empower maintenance and expanded science on the lunar orbiting space station. In addition, the airlock provides services for internal and external payloads." (p. 54)
The text spells "Mohammad"; the partner label beneath the flag spells "Mohammed" (p. 54, checked against the PDF). The Exploration EVA System one-pager says that "With the addition of airlock at Gateway", the suits also support EVAs "in cislunar orbit" (p. 48).
In the executive overviews (2023 and 2024)¶
Both are older than Rev C; page numbers are their PDF pages.
- The Expanded Capability components arrived in 2023. The 2023 overview lists three Gateway components among the six elements "added" that year: "Gateway Extravehicular Robotic System" (Canadian Space Agency), "Gateway ESPIRIT Refueling Module" (European Space Agency) and "Gateway Airlock Module", with no partner named (PDF p. 10). Rev A's note calls them "Gateway expanded capability configuration" (ADD p. 3). The overview adds them to Human Lunar Return; Rev C puts the Expanded Capability Configuration in Foundational Exploration (p. 53; open question 33).
- All seven, with partners, in 2024. The 2024 overview's spread labels them "Power and Propulsion Element", "External Robotics System" (CSA), "Logistics Element", "Crew and Science Airlock" (MBRSC), "Lunar View Refueling Module" (ESA), "HALO Habitation and Logistics Outpost" (ESA) and "I-Hab International Habitat" (ESA, JAXA), under the tagline "Our Home in Lunar Orbit" (PDF p. 25). The badges agree with Rev C's partner boxes (above; the wiki's comparison). The 2023 card named no partner for the airlock; in 2024 it carries the MBRSC badge. The refueling module has its new name, Lunar View, with "Refueling Module" still attached.
In the February 2024 workshop briefing¶
The opening briefing of the February 2024 workshops, a month after Rev A, shows the 2023 "New Elements" as seven hexagons, not six: the 2023 overview's three Gateway components ("Gateway ESPIRIT Refueling Module (ERM)" with an ESA dot, "Gateway Extra-Vehicular Robotic System (GERS)" with a CSA dot, "Gateway Airlock Module" with none), and a dashed seventh, "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's reading: the dashed hexagon reuses the airlock's rendering, and by the 2024 overview the airlock carries the MBRSC badge under the name "Crew and Science Airlock" (above), so the two hexagons are one module, named for its partner once the arrangement was signed. The slide doesn't say so. It is the only source that dates the partner's arrival in the ADD, and it follows the 2024 partnerships paper's rule that NASA documents an element as partner-provided only in the revision after the agreement (RT-1; the pairing is the wiki's; open question 90).
The Program Office deck at the same workshops puts Gateway on Artemis IV and V with the same modules as its February 2025 deck below (Program Office updates, February 2024), and shows the "PPE 12-kilowatt Solar Electric Propulsion Test" and the HALO "After completion of final welds in Turin, Italy" (slide 17).
What changed by Rev C (the wiki's comparison): Rev C names the MBRSC as the airlock's provider (p. 54), as the slide promised for Rev B; it assigns no Gateway component to a mission.
In the February 2025 workshop briefing¶
The Moon to Mars Program Office's February 2025 workshop deck, ten months before Rev C, puts Gateway on two missions as then planned (Program Office updates, slides 10 and 12):
- Artemis IV, "First Lunar Space Station Assembly Mission" (slide 3): "Crewed mission to Gateway"; "Crew transfer from Orion to human landing system (HLS) via Gateway"; "Precursor Deep Space Logistics flight to Gateway". New elements: "Gateway modules: Power and Propulsion Element and Habitation and Logistics Outpost (pre-staged in orbit); International Habitat (launched on SLS Block 1B alongside the crew aboard Orion); Deep Space Logistics" (slide 10).
- Artemis V, "Gateway Expansion" (slide 3): "Gateway modules: ESPRIT Refueling Module (European System Providing Refueling Infrastructure and Telecommunications), Canadarm3 robotic arm" (slide 12).
- Captions. "ESA Lunar View Refueling Module will supply cargo, storage, and fuel for Gateway" (slide 13); "Artist's concept of Gateway, including Canadarm3 and United Arab Emirates Gateway Airlock" (slide 14), with no mission given for the airlock (slide 14).
Against Rev C (the wiki's comparison). The Artemis IV modules are Rev C's four Crew-Capable components, two under other names: "International Habitat" is the Lunar I-Hab (the 2024 overview's "I-Hab International Habitat", above), and "Deep Space Logistics" the Gateway Logistics Element, whose deliveries Rev C calls "Deep Space Logistics services" (p. 50). The deck names the refueling module both ways on consecutive slides; Rev C says Lunar View was "previously known as" the ESPRIT Refueling Module (p. 53). Rev C assigns no component to a mission. Since then, Gateway has been paused "in its current form" (below).
Functions (ADD Appendix B.3)¶
B.3.4 maps functions to each configuration, and to the Gateway Logistics Element separately (pp. 151–153):
- B.3.4.1: "Human Lunar Return (Gateway Crew-Capable Configuration)", 16 functions
- B.3.4.1.1: the Gateway Logistics Element in Human Lunar Return, 7 functions
- B.3.4.2: "Foundational Exploration (Gateway Expanded Capability Configuration)", 23 functions
- B.3.4.2.1: the Gateway Logistics Element in Foundational Exploration, the same 7
Titles are the ADD's. The last column is the wiki's join with the Users Guide's Phase 1 list (Phase 1 functional gaps).
Gateway (HLR = Crew-Capable, FE = Expanded Capability):
| ID | Function | HLR | FE | Moon Base Phase 1 functional gap? |
|---|---|---|---|---|
| FN-T-106 L | Rendezvous, proximity operations, mating and unmating of assets in cislunar space | ✓ | ✓ | |
| FN-H-103 L | Enable a pressurized, habitable environment in cislunar space | ✓ | ✓ | |
| FN-H-202 L | Operate habitation system(s) in uncrewed mode between crewed missions in cislunar space | ✓ | ✓ | |
| FN-X-102 L | Provide hardware for crew medical care in cislunar space | ✓ | ✓ | |
| FN-L-202 L | Transfer pressurized cargo into habitable assets in cislunar space | ✓ | ✓ | |
| FN-L-302 L | Manage waste from habitable asset(s) in cislunar space | ✓ | ✓ | |
| FN-P-303 L | Distribute power to utilization payloads and/or equipment in cislunar space | ✓ | ✓ | |
| FN-M-301 L | Ingress/egress from habitable asset(s) to cislunar vacuum | ✓ | ||
| FN-C-101 L | Provide communications and data exchange between the lunar surface and Earth | ✓ | ✓ | yes, communications and PNT group |
| FN-C-102 L | Provide communications and data exchange between Earth and cislunar space | ✓ | ✓ | |
| FN-C-105 L | Provide high bandwidth, high availability communications and data exchange between the lunar surface and Earth | ✓ | ✓ | yes, communications and PNT group |
| FN-C-106 L | Provide high bandwidth, high availability communications and data exchange between cislunar space and the Earth | ✓ | ✓ | |
| FN-C-108 L | Provide high bandwidth, high availability communications and data exchange between cislunar space and the lunar surface | ✓ | ✓ | |
| FN-D-102 L | Collect, store, and locally distribute data in cislunar space | ✓ | ✓ | |
| FN-D-106 L | Provide data capabilities, including protection for communication, and interface to support crew medical care in cislunar space | ✓ | ✓ | |
| FN-D-202 L | Process data locally in cislunar space | ✓ | ||
| FN-A-106 L | Enable repositioning of externally mounted utilization payloads in cislunar space | ✓ | ||
| FN-A-203 L | Control robotic system(s) in cislunar space from Earth and/or cislunar space | ✓ | ||
| FN-A-204 L | Control robotic system(s) in cislunar space by in-situ crew | ✓ | ||
| FN-A-404 L | Transition assets between crewed and uncrewed mode in cislunar space | ✓ | ||
| FN-U-202 L | Provide extravehicular utilization accommodation, interfaces, and resources, operable during crewed and uncrewed increments, in cislunar space | ✓ | ✓ | |
| FN-U-205 L | Provide intravehicular activity facilities, utilization accommodation, and resources, operable during crewed and uncrewed increments, in cislunar space | ✓ | ✓ | |
| FN-U-508 L | Transfer propellant/fluids between assets in space | ✓ |
Gateway Logistics Element (the same seven in both segments):
| ID | Function |
|---|---|
| FN-T-106 L | Rendezvous, proximity operations, mating and unmating of assets in cislunar space |
| FN-T-213 L | Transport cargo from Earth to cislunar space |
| FN-T-214 L | Provide delivery of live, actively growing biological specimens to cislunar space, including late load of cargo prior to launch |
| FN-L-202 L | Transfer pressurized cargo into habitable assets in cislunar space |
| FN-L-204 L | Transfer water to habitable assets in cislunar space |
| FN-L-206 L | Transfer gases to habitable assets in cislunar space |
| FN-L-302 L | Manage waste from habitable asset(s) in cislunar space |
Against the lunar spreadsheet.
- FE matches. The sheet's "Gateway Expanded Capability" column has the same 23, and its "Gateway Logistics Element" column the same 7 in both segments.
- HLR doesn't quite. The sheet's HLR "Gateway" column has 14. It lacks FN-D-102 L and FN-P-303 L, and neither is among the sheet's 58 HLR functions (Lunar function allocation; open question 43).
B.3 maps functions to the two configurations, not to the components. The wiki doesn't assign the seven FE-only functions to the Expanded Capability components.
Gaps that mention it¶
- #1104 Mars Transportation Propulsion: "SEP for Gateway is at TRL 6" (tech gaps spreadsheet, ESDMD #1104). In the ADD, Gateway's solar electric propulsion is on the PPE, and "serves as a technology demonstration for potential solar electric propulsion for Mars missions" (p. 51).
Changes since Rev C¶
Newer sources change the picture.
- Paused "in its current form." The Ignition release (24 March 2026): "the agency intends to pause Gateway in its current form and shift focus to infrastructure that enables sustained surface operations. Despite challenges with some existing hardware, the agency will repurpose applicable equipment and leverage international partner commitments to support these objectives" (Ignition release, "Going back to the Moon"). It doesn't say what happens to the partners' components. NASA's undated Artemis page still calls Gateway "central to the NASA-led Artemis missions"; the wiki follows the dated release (Artemis page, "Deep Space Exploration"; open question 79).
- The PPE is repurposed for Mars. The Moon Base Users Guide describes "Space Reactor 1 (SR-1) Freedom, a nuclear electric propulsion demo repurposing the Power and Propulsion Element originally planned for the Gateway space station" (Users Guide, p. 2). Rev C presents the PPE's propulsion as a solar electric demonstration for Mars (p. 51). See Mars-forward. The Ignition nuclear power fact sheet (24 March 2026) says the same: "SR-1 would repurpose a nearly built, NASA-developed spacecraft bus — the Power and Propulsion Element", with a launch to Mars in December 2028 (nuclear power fact sheet, pp. 1–2).
- The Ignition fact sheet's wording differs slightly from the release's: "NASA intends to pause Gateway in its current form and shift focus to surface infrastructure that enables sustained operations. Applicable equipment will be repurposed, and international partner commitments leveraged to meet objectives" (Ignition fact sheet, p. 1). ESDMD's Ignition deck on Artemis doesn't mention Gateway (Ignition deck 1).
- Briefed at Ignition, March 2026: why, and what is reused. The Moon Base Program's deck opens with a "Gateway Pivot": "The current Gateway architecture, while relevant to long term exploration goals, is not required to accomplish the primary objectives of landing humans on the Moon and establishing a Moon Base", so "NASA is using Gateway elements to enable building the Moon Base", which "will also include orbital elements to support surface ops". Its reasons: "HLS providers do not require Gateway to accomplish their missions. Docking with orbiting platform came with performance penalties"; "PPE+HALO launch will likely be further delayed due to on-going HALO corrosion mitigation. Not expected to reach initial operational status until 2030+"; other modules face "corrosion mitigation (same issues as with HALO), overweight, complex assembly sequence" (slide 2). Under "Gateway Evolution": "Repurposing options include using PPE for other high-priority missions, existing communications HW on the Moon Base, HALO subsystems/components/structures on future Moon Base modules"; "The NASA Gateway team will pivot to support Moon Base development efforts or other high priority initiatives"; NASA is "working with our international partners to … repurpose our partnerships towards building Moon Base" (slide 3) (Ignition deck 2, slides 2–3). Slides 2–3 name no partner component.
- Briefed at Ignition, March 2026: under logistics and habitation. In the same deck's map of how the Moon Base is built, slide 42 ("Every Asset, Every Kilogram, and All Lunar Exploration Resources Focused On Building the Moon Base") joins "GATEWAY" to two of its six capability areas, "LOGISTICS" and "HABITATION" (beside "MPH"), and not to transportation, whose programs are "LSP / DSL", "CLPS" and "HDL" (Ignition deck 2, slides 41–42). The deck's habitation and logistics slides (60–62) don't mention Gateway, so it doesn't say which Gateway hardware or team serves those areas. Rev C also places Gateway under Habitation Systems, with the Gateway Logistics Element listed separately under Logistics Systems (At a glance); setting the two side by side is the wiki's comparison.
- HALO hardware is repurposed for the surface. Northrop Grumman's three Moon Base demonstration payloads "build on power and avionics hardware developed for the Gateway program's HALO (Habitation And Logistics Outpost) module, now being repurposed following NASA's shift from an orbital-focused lunar strategy to one centered on surface operations" (Moon Base update, Aug 2026, "Northrop Grumman").
- No Gateway visit in the updated Artemis plan. The March 2026 fact sheet's "Original Plan" had "Artemis IV: Gateway visit & lunar landing — TBD" and the same for Artemis V. Its "Updated Plan —announced Feb 2026" mentions no Gateway visit on any mission (Going back to the Moon, pp. 1–2). That is an omission, not a stated cancellation.
- Gateway's surface-relevant work moves to the Moon Base Program, and the PPE's funding to SR-1. The Administrator's Directive 6 (22 May 2026) consolidates "the current Gateway surface relevant scope", with CLPS, cargo landers, habitation and other lunar programs, into the Moon Base Program. Directive 7 realigns "the Power and Propulsion Element of Gateway (WFTCA-funded), Gateway funding allocated for the Launch Services Program" to SR-1 Freedom's program manager (workforce note). The Moon Base Program Manager adds, as reported: the PPE's "electric propulsion thrusters" matched with "a nuclear reactor"; the Northrop Grumman HALO deal, "three types of systems to show how we can survive the night"; talks with all Gateway partners on reuse, for example Canada's arm technology for "a robing arm on the moon on a rover" (podcast, August 2026).
Rev C itself builds Gateway into the Human Lunar Return segment ("initial Gateway deployment (OP-6)", p. 25) and into three of the nine lunar reference missions (pp. 25, 30). See Human Lunar Return and open question 22.
Moon Base relevance¶
Gateway itself is not named for any Moon Base phase. Gateway hardware is, in two places:
- HALO hardware on the surface. The Northrop Grumman demonstrations built on HALO hardware will "test survive-the-night systems capable of enduring the Moon's extreme conditions, including multi-day shadow periods", and "shared surface power infrastructure designed to support critical payloads or other Moon Base assets, along with essential avionics and power capabilities" (Moon Base update, Aug 2026, "Northrop Grumman"). No phase is stated (Missions and assets).
- The PPE goes to SR-1 Freedom, a Mars demonstration announced with the Moon Base, not a Moon Base asset (Users Guide, p. 2).
Shared function IDs (the wiki's join). Two of Gateway's ADD functions, FN-C-101 L and FN-C-105 L (lunar surface–Earth communications), are on the Users Guide's list of Phase 1 functional gaps (above). The ADD maps both to Gateway, to the Initial Surface Habitat and to the SCaN networks, and doesn't list them as unallocated. The guide names no element against them (open question 65).
Related pages¶
Elements · Habitation Systems · Logistics Systems · Human Lunar Return · Foundational Exploration · Orion Spacecraft · Human Landing System · Exploration EVA System · Moon Base missions and assets · Mars-forward
Sources¶
ADD Rev C, pp. 25–26, 30–31, 45, 48, 50–54, 151–153 · Users Guide, pp. 2, 8 · Lunar objective decomposition, allocation sheets · Moon Base update, Aug 2026 · Going back to the Moon, pp. 1–2 · Ignition release · Artemis page · Tech gaps spreadsheet, ESDMD #1104 · 2023 executive overview, PDF p. 10 · 2024 executive overview, PDF p. 25 · Ignition fact sheet, p. 1 · Nuclear power fact sheet, pp. 1–2 · Ignition deck 2, slides 2–3, 41–42 · Program Office updates, February 2025, slides 3, 10, 12–14