Why Moon and Mars? Building an Evolutionary Architecture (ACR25 white paper)¶
Document: Why Moon and Mars? Building an Evolutionary Architecture, a nine-page white paper
headed "2025 Moon to Mars Architecture" and footed "2025 Moon to Mars Architecture Concept
Review". No date is printed. The download path (/2025/12/) dates it to December 2025, and the
file name ends in -v2. Files: text sources/text/docs/2025-12-acr25-wp-why-moon-and-mars-v2.txt;
raw sources/raw/docs/2025-12-acr25-wp-why-moon-and-mars-v2.pdf (fetched 2026-10-01T07:22:47Z
from https://www.nasa.gov/wp-content/uploads/2025/12/acr25-wp-why-moon-and-mars-v2.pdf, per
sources/manifest.csv). Page numbers: the printed page numbers (1–9) match the PDF pages and
the text file's [page N] markers. Pages 1–8 were checked against the PDF; p. 9 is references
only.
Summary. NASA's case for reaching Mars by way of the Moon. The paper compares low Earth orbit, the Moon and Mars on three challenges (distance, gravity and hazards), and sets out four "programmatic considerations": American leadership, engineering and design, operations, and human systems. Its argument is Apollo's "crawl-walk-run approach": lunar missions build the technology and operating experience that Mars needs, where support is distant and aborts may take months or be impossible. ADD Rev C Section 1.3.1 is a shorter version, and points to this paper for "Additional detail" (ADD Rev C, p. 15).
The content is on Why Moon to Mars.
Contents¶
| Page | Section | Wiki home |
|---|---|---|
| 1 | Introduction: three pillars; Apollo's "crawl-walk-run approach" | Why Moon to Mars |
| 2 | Mercury, Gemini, Apollo graphic; Exploration Challenges: Distance, Gravity (start) | Why Moon to Mars |
| 3 | "Exploration Challenges by Destination" graphic; Gravity (end) | same |
| 4 | Hazards; Programmatic Considerations: American Leadership; Engineering and Design (start) | Why Moon to Mars |
| 5 | Engineering and Design (end); Operations; Human Systems (start) | same |
| 6 | Human Systems (end): Operational Experience; Conclusion | same |
| 7 | "Programmatic Considerations" diagram (no text in the text layer) | same |
| 8 | Key Takeaways; references 1–6 | this page |
| 9 | References 7–38 | this page |
What the PDF shows that the text layer loses¶
- p. 2, a three-panel graphic headed by "Crawl", "Walk" and "Run" icons: Project Mercury (1961–1963, "Six Crewed Flights"), Project Gemini (1964–1966, "10 Crewed Flights") and the Apollo Program (1967–1972, "Nine Crewed Flights"), each with a sentence and three objectives. Tabulated on Why Moon to Mars.
- p. 3, "Exploration Challenges by Destination": bars for Earth orbit, the Moon and Mars on distance from Earth, one-way journey and light-time delay, and a gravity panel. Tabulated on Why Moon to Mars.
- p. 7, "Programmatic Considerations": a tree of the four considerations and their sub-headings, with the five health hazards under Human Systems. It is the only content on the page. Reproduced on Why Moon to Mars.
- p. 4's two columns are interleaved in the text layer: the Artemis Accords sentence breaks across "Space Leadership" and "Partnerships". The PDF reads in normal column order.
Compared with ADD Rev C Section 1.3.1¶
The ADD's section (pp. 14–15) and the paper share their framing and some sentences. This comparison is the wiki's:
- Same wording. The ADD's "Engineering and Design" facet is word for word the paper's Engineering and Design paragraph (p. 4). The ADD's "Operations" facet matches the paper's Operations paragraph except "decades of human spaceflight experience" (ADD) against "decades of flight experience" (p. 5).
- Renamed. The ADD's facet "National Posture" is the paper's "American Leadership". Its paragraph changes "will reinforce the United States' global leadership" (ADD p. 14) to "will require and enable the United States' global leadership" (p. 4). The paper's takeaways call the same consideration "national posture" (p. 8), which is also the name of one of NASA's three "pillars of exploration" (p. 1).
- The human system. The ADD's facet is one sentence on deconditioning, gravity, isolation and radiation (p. 14). The paper gives it two sub-sections (pp. 5–6).
- New in the paper: the three-way comparison of distance, gravity and hazards (pp. 2–4), the sub-headings under each consideration (pp. 4–7), and its figures for logistics, maintenance time, abort times and mission length.
Key takeaways (p. 8)¶
- "Human space exploration becomes increasingly challenging as missions ascend beyond low Earth orbit to the Moon and Mars. These challenges grow due to many factors, including distance, gravity, and hazards at each destination."
- "Learning from the success of the Apollo Program, NASA must take an iterative, programmatic approach that leverages lunar exploration to realize the first crewed missions to the Red Planet. These considerations include national posture, engineering design, mission operations, and human systems."
- "Sustaining an exploration campaign from the Moon to Mars will foster continued American leadership in space, maximize the benefits of space exploration, and ensure humanity is ready for the next giant leap."
References that are other architecture white papers¶
The paper cites 38 references, most of them NASA web pages. Those that are Moon to Mars Architecture white papers, as printed (pp. 8–9):
| Ref. | Title, as printed | Among the wiki's sources? |
|---|---|---|
| 13 | Mars Transportation, 2022 | no |
| 14 | Mars Communications Disruption and Delay, 2023 | no |
| 16 | Round-trip Mars Mission Mass Challenges, 2023 | no |
| 20 | Surface EVA Architectural Drivers, 2023 | no |
| 21 | Human Health and Performance, 2023 | no |
| 22, 36 | Mars Mission Abort Considerations, 2023 | no |
| 27 | Architecture-Driven Technology Gaps, 2024 | yes, source page |
| 28 | Mars Surface Power Technology Decision, 2024 | yes, source page |
| 31 | Lunar Surface Cargo, 2024 | yes, source page. Cited for "annual logistics needs of 5,000 to 6,000 kgs" (p. 5), a figure that paper's text doesn't contain (open question 45) |
| 33 | Mars Crew Complement Considerations, 2024 | yes, source page |
| 34 | Why Artemis Will Focus on the Lunar South Pole Region, 2022 | no |
"No" means no file in sources/manifest.csv has a matching name; the check is the wiki's.
Oddities¶
- Apollo's crewed flights. The p. 2 graphic gives Apollo "Nine Crewed Flights". The text on the same page says "nine Apollo missions on and around the Moon (plus two Earth orbit missions)". The wiki quotes both.
- Mars light-time delay. "Between 4 and 24 minutes" one way (p. 2; "4-24 Minutes" in the p. 3 graphic). The 2025 Architecture Update, from the same month, says "up to 22 minutes" (Update, p. 13; open question 31).
- Reference 36 is cited for "The five main hazards of human spaceflight" (p. 5), but it is "Mars Mission Abort Considerations", the same paper as reference 22. Reference 18 is "Five Hazards of Human Spaceflight" (p. 9).
- A paragraph printed twice. "Understanding the effects of spaceflight on human physiology … operational paradigms" appears twice in a row (pp. 5–6, PDF checked).
- As printed: "NASA must must" (p. 4); "The light-time communications delay due is essentially negligible" (p. 2); "operate under in one-sixth and one-third" (p. 3); "new design solutions, health countermeasures, operational paradigms" (p. 5); a stray "\" after reference mark 22 (p. 4); "kgs" (p. 5).
Related pages¶
Why Moon to Mars · Mars-forward · Humans to Mars · ADD Rev C · 2025 Architecture Update · "Architecture Definition" white paper