Mobility Systems (M)¶

Summary. Everything that moves crew or cargo "on and around a destination", from spacesuits to unpressurized and pressurized rovers, crewed or robotic (ADD Rev C, p. 43). In Human Lunar Return, mobility means spacesuits; later segments add rovers and the ability to haul systems of up to 15 tons kilometers across mountainous terrain. Four Rev C elements belong here: the Exploration EVA System, the Lunar Terrain Vehicle, the Lunar Utility Rover and the Pressurized Rover. Eleven technology gaps list it, seven named in the Moon Base Users Guide (near-term). A 2024 white paper sized the cargo problem: 500 to 15,000 kg moved up to 5,000 m, against 800 kg for the LTV (below). Decomposition letter: M.

NASA's description¶

"This sub-architecture comprises capabilities that convey crew and/or cargo on and around a destination, including EVA systems. It spans robotic and crewed systems with both pressurized and unpressurized capabilities that extend exploration and utilization ranges.

For the Human Lunar Return segment, spacesuits provide local lunar surface mobility. As the sub-architecture progresses to later segments, NASA adds mobility systems that provide unpressurized and pressurized local surface mobility for crewed and uncrewed periods. These systems provide faster and farther traverses as well as significantly increased carrying capacity. Autonomous and/or tele-operations enable key activities during uncrewed periods such as logistics resupply, outfitting, laying and connecting cables, and additional science and utilization opportunities.

Additional capabilities provided by this sub-architecture may include the aggregation of infrastructure, including for larger elements like habitation and power systems. Associated mobility elements would transport these systems (up to 15 tons) from landing sites to points of use, which can be kilometers away in mountainous terrain." (ADD Rev C, p. 43)

The "up to 15 tons" here and tech gap #0808's ">6 metric tons" for relocating large assets are different scopes, not a contradiction (#0808).

In the segments¶

From ADD Rev C:

Foundational Exploration surface missions "will feature increased durations, expanded mobility, and regional exploration of the lunar South Pole" (p. 27); infrastructure objective LI-6 drives "mobility" (p. 28). Two reference missions are about mobility (p. 29):
- Unpressurized Mobility: "an unpressurized mobility platform to extend EVA range and scientific exploration", including PSR sample collection and deploying power systems around the South Pole.
- Pressurized Mobility: longer stays, IVA research, excursions and "crew relocation and exploration in a shirt-sleeve environment", which must "mitigate increasingly complex challenges of the lunar environment, such as dust, plasma interactions, radiation, etc." The "Robotic Uncrewed Operations" mission includes "uncrewed relocation of mobility elements to landing sites around the lunar South Pole" (p. 29).
Sustained Lunar Evolution. Science "might first expand through additional mobility and range" (p. 34); "mobility" is among the areas for expanded demand signals (p. 36).

Elements¶

Element	Segments	Source
Exploration EVA System ("Exploration EVA Systems" in the tables)	Human Lunar Return, Foundational Exploration	ADD Rev C, pp. 26, 31
Lunar Terrain Vehicle	Foundational Exploration	p. 31
Lunar Utility Rover (new in Rev C)	Foundational Exploration	p. 31
Pressurized Rover	Foundational Exploration	p. 32

See the elements index. All four share one implementing program, the EVA and Human Surface Mobility Program (pp. 48, 60, 61, 63). Two appear on the Moon Base Phases page: lunar terrain vehicles in Phase One and the JAXA pressurized rover in Phase Two. Matching them to these elements is the wiki's reading, explained on each element page.

Technology gaps¶

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

Gap	Rating	MB
#0801 Lunar Dust-Tolerant Systems and Dust Mitigation	1	MB
#0301 Systems to Survive Extended Lunar Shadow	3	MB
#0806 Payload Offloading, Handling, and Manipulation	7	MB
#0805 Autonomous Surface Mobility and Navigation	8
#1001 High-performance Actuators, Sensors, and Interfaces	14	MB
#0807 Docking and Berthing between Surface Elements	15	MB
#0804 Robotic and Mobility Systems in Extreme Cold	19	MB
#0808 Relocation of Large Assets	25
#0803 EVA and IVA Suits for Mars Missions	31
#0802 Mars Dust-Tolerant Systems and Dust Mitigation	35
#0605 Lunar Regolith Excavation, Manipulation, and Transportation	53	MB

Lunar mobility drivers and needs (ACR24 white paper, 2024)¶

The 2024 white paper "Lunar Mobility Drivers and Needs" sizes the job of moving cargo on the surface. It predates Revisions B and C, so it is context, not the current architecture. Page numbers in this section are the paper's PDF pages; its printed numbers skip 2 (source page).

The problem. "One of the largest drivers of mobility needs on the lunar surface is moving cargo from its landing site to its point of use" (p. 1). Cargo often has to be offloaded "before the crew arrives at each landing location (point of origin) and then again at local lunar exploration and habitation sites (point of use)", which "will likely be located away from each landing location" (p. 1). In 2024, "The current defined mobility elements — the Lunar Terrain Vehicle (LTV) and Pressurized Rover (PR) — are primarily for crew transportation, with limited cargo mobility functions", and CLPS missions "provide only small-scale mobility" (p. 1).

How far (p. 1). Three reasons to move cargo away from a lander:

"Separation from lander shadowing (tens of meters)"
"Lander blast ejecta constraints (>1,000 m) due either to separation between the lander and existing infrastructure or lander ascent"
"Support for aggregation of elements in ideal habitation zones from available regional landing areas (up to 5,000 m)"

Habitation and "seasonal hibernation points" go high, on ridges, to cut darkness, so "Traverses from landing zones to habitation zones could encounter slopes of up to 20 degrees" (p. 3). The example map (Figure 1, p. 2) shows traverses of 1.2 to 5.0 km between landing sites, a habitation module, ISRU mining and processing, and power augmentation, with the note "Not meant as an accurate depiction of a planned lunar site".

How much (p. 3). For Foundational Exploration, NASA expected "four crew members operating on the lunar surface for approximately 30 days", plus demonstrations, infrastructure and elements delivered over time:

"Smaller deployed demonstrations are estimated in the 500-to-2,000 kg range"
"logistics elements needed on a recurring basis can total 2,000 to 6,000 kg per crewed surface mission"
habitation systems "could deploy in the 12,000-to-15,000 kg range"

Against that, "the LTV, for example — developed as a crew transportation element — is limited to 800 kg of uncrewed cargo mass"; Apollo's Lunar Roving Vehicle carried 490 kg. "In total, current demand and mobility capacity are mismatched on the order of 1,000 to 15,000 kg per asset for ranges of 50 to 5,000 m" (p. 3). Figure 2 sets the cargo items against the LTV's 800 kg and the LRV's 490 kg (p. 3, PDF). The paper's distance and mass ranges vary from page to page, and its introduction gives a different capacity, "approximately 1,500 kg" (p. 1); see the source page.

What makes it hard (p. 4):

Autonomy. Relocation ranges from one-off moves of large elements to "multiple trips per year for logistics containers or smaller scientific cargo", so "mobility assets will require sufficient autonomy and/or tele-robotic operation capability to operate throughout the year".
Scale. "Wheel and soil interactions for large mobility systems do not scale linearly with transported mass or the size of the mobility system. Transportation becomes exponentially more difficult at the upper end of the mass range." "Slopes of more than 10 degrees are common at the lunar South Pole (analogous to unimproved mountain passes)."
Energy, terrain and dust. Energy demand depends on payload, speed and "the ability for the system to survive lunar night conditions". "Studies should consider regolith mitigation strategies to prevent wheel wear."
"This combination of factors creates a significant technological gap between existing systems and mobility demands for future exploration" (bold in the paper).

Features (p. 4). "A stated capability for mass relocation means little if the interfaces between the mobility element and the cargo are incompatible." Mobility systems may need to offload landers, level elements "to support surface docking of multiple elements", and support "mated power or other types of connectors". Several robots working together "would be additional motivation for standardization among robotic interfaces".

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

The Lunar Utility Rover. Rev C added an uncrewed cargo rover for "thousands of kg" (Lunar Utility Rover; ADD p. 61). The Update ties it to a 2024 paper it calls "Lunar Logistics and Mobility" (Update, p. 5), a title that isn't this paper's (open question 30). NASA's August 2024 solicitation for industry studies, NextSTEP-2 Appendix R, cites this paper by its own title, one of three papers stating "the envisioned logistics and mobility capabilities" behind "two gaps in its lunar architecture", one of them "uncrewed surface mobility systems for lunar surface assets" (Appendix R page, "Solicitation Overview"; Lunar Utility Rover).
The description above. Rev C's "up to 15 tons" moved to points of use "kilometers away in mountainous terrain" (ADD p. 43) matches the paper's upper figures, 15,000 kg and 5,000 m.
Gaps. The paper's themes are the subjects of #0805 (autonomous mobility), #0806 (offloading), #0808 (assets over 6 t), #0807 (surface docking) and #0801 (dust). The pairing is the wiki's; the gaps don't cite the paper.

In the February 2024 workshop briefing¶

Older than Rev B and Rev C, the February 2024 workshops briefed the 2023 paper "Surface EVA Architectural Drivers" (not held) (surface EVA briefing). Experience so far (slide 2): "Extensive micro-gravity experience across heritage programs, Shuttle, and the International Space Station (260+ EVAs on the space station alone)", against "Six total Apollo partial-gravity lunar surface missions (14 EVAs totaling ~159 hours)"; "Environmental differences are a critical driver to extension of EVA expertise for Artemis and beyond".

Ten "Key Considerations", one picture each with no further text (slides 3–5): "Dust (Regolith) Mitigation"; "Partial Gravity"; "Atmospheric Pressure"; "Habitation and Pressurized Volumes"; "Commodities and Logistics"; "Ingress and Egress"; "Communications, Lighting, and Navigation"; "Enabling Suited Crew Decision Making"; "Site Planning"; "Contingencies and Operations". Summary (slide 6): surface EVAs "have significant number of environmental and mission drivers different from microgravity", which "will influence several facets of the lunar surface architecture".

What changed by Rev C (the wiki's comparison): the subject is still open there, as the Surface Operations tasks "Exploration EVA Schema" and "Surface EVA Capability Strategy" (Key definition tasks); dust is #0801, rated first. The slides cite no gap.

Moon Base Phase 1¶

The Users Guide's "Mobility systems" group: "Systems to move crew and cargo around the lunar surface and between Moon Base components" (Users Guide, p. 9). Four functional gaps (p. 10): two FN-M functions for unpressurized mobility in sunlit areas and in PSRs, plus FN-A-103 L (robotic reconnaissance) and FN-U-103 L (resource identification). Two other FN-M functions, for unloading and repositioning cargo, sit in the guide's Autonomous systems and robotics group. Capability targets: "small utility rovers and hoppers" and "large crewed and uncrewed rovers with speeds of 10 km/hr". Full list: Phase 1 functional gaps.

Sub-architectures · Autonomous Systems and Robotics · Logistics Systems · Elements · Foundational Exploration · Gaps index · Lunar Mobility Drivers and Needs · Lunar Surface Cargo

Sources¶

ADD Rev C, pp. 26–29, 31–32, 34, 36, 40, 43, 61 · Tech gaps spreadsheet · Users Guide, pp. 8–10 · Lunar Mobility Drivers and Needs, PDF pp. 1–4 (checked against the PDF) · 2025 Architecture Update, p. 5 · NextSTEP-2 Appendix R page