February 2024 workshop: white-paper briefing, Mars Challenges¶
Document: 10-2024-architecture-workshop-white-paper-mars-challenges.pdf, 10 slides, 3,651,062 bytes, from
https://www.nasa.gov/wp-content/uploads/2024/02/, fetched 2026-10-01T18:28:03Z (sources/manifest.csv). Title
slide: "M2M Architecture White Papers: Mars Challenges" (slide 1). No presenter or date. Footer: "2024 Moon to Mars
Architecture Workshops". Listed on the Architecture Workshops page
under "February 2024". Text:
sources/text/docs/2024-02-10-2024-architecture-workshop-white-paper-mars-challenges.txt; images in
sources/raw/slides/2024-02-10-2024-architecture-workshop-white-paper-mars-challenges/.
Rank and method. A briefing, not the architecture of record (SCHEMA, "Workshop slides"), older than Rev B and Rev C. It briefs three 2023 white papers the wiki doesn't hold: "Mars Mission Abort Considerations", "Round-Trip Mars Mission Mass Challenges" and "Mars Communications Disruption and Delay" (slide 10; the opening deck lists them, Overview and Updates, slide 11). All 10 slides were read in the text layer. The images of the text-poor slides 3 and 7 were viewed, and of slides 2, 5, 9 and 10 (tables, charts and the paper thumbnails); the title card (slide 1) wasn't. The text has no "Moon Base", "CUI" or "Pre-Decisional" (searched).
Summary. Why a crewed Mars mission is unlike anything flown: distance, gravity well, communications delay and blackout, landing mass, ascent, aborts and the rocket equation, each slide ending on a "new paradigm" banner. It adds to the wiki: two example 2039 trajectories with their legs (850 and 982 days); a table of Mars landers with a human-class lander concept whose figures differ from the 2024 EDL paper's (open question 91); ascent experience by body (Earth "100's", Moon "6", Mars "0" human launches); and gear ratios for each leg of a round trip.
Slides¶
| Slide | Title (as printed) | Content |
|---|---|---|
| 1 | "M2M Architecture White Papers: Mars Challenges" | Title card |
| 2 | "Mars Missions Are Different" | Distance and gravity (image) |
| 3 | "Example Mission Trajectory" | Two trajectories (image; QR code and https://go.nasa.gov/3UR60ON) |
| 4 | "Communication Challenges" | Delay and conjunction |
| 5 | "How to Get to the Surface?" | Landers (image) |
| 6 | "Getting Back Off the Surface" | Ascent |
| 7 | "Mission Abort Example" | Abort (image; https://go.nasa.gov/4bVbqy4) |
| 8 | "What Does Mission Abort Mean?" | Abort |
| 9 | "A Mass-ive Challenge" | Gear ratios (image) |
| 10 | "White Papers" | The three papers (image) |
Distance, gravity and time (slides 2–4)¶
Slide 2, "Mars Missions Are Different", read from the image. "Mars is much farther than the Moon":
| Closest approach to Earth | Farthest distance from Earth | Typical round-trip "odometer" reading | |
|---|---|---|---|
| Moon | 360,000 km | 405,000 km | 2,000,000 km |
| Mars | 54,600,000 km | 400,000,000 km | 2,000,000,000 km |
"Mars gravity well is 'deeper' than that of the Moon — Gravity wells help visualize gravitational pull — Mars's gravitational pull is stronger than that of the Moon, requiring more energy to escape." A gravity-well drawing marks the "average 'depth' of LDHEO" and of a "5-sol Orbit", the International Space Station, and "Lunar gravity is ~1/6 that of Earth", "Mars gravity is ~3/8 that of Earth" (the text layer garbles the fractions). "Typical Roundtrip Transit Time": ISS "Hours-Days", Moon "Days-Weeks", Mars "Years". Banner: "Mars mission is unlike anything we've ever done for human spaceflight". The 2025 "Why Moon and Mars?" paper makes the same comparison in other figures (Why Moon to Mars).
Slide 3, "Example Mission Trajectory", read from the image:
| Example 850-day trajectory | Example 982-day trajectory | |
|---|---|---|
| Opportunity | 2039 | 2039 |
| Total distance traveled | 1,772,051,938 km; 11.84 AU | 2,148,373,298 km; 14.36 AU |
| Longest roundtrip comm delay | 43.51 minutes | 41.19 minutes |
| Outbound segment | 279 days | 337 days |
| Mars stay | 51 days | 348 days |
| Inbound segment | 519 days | 295 days |
NASA's workshops page captions the matching animation "850-day and 980-day"; the slide says 982 (Architecture Workshops page).
Slide 4, "Communication Challenges": "Example 850-day Roundtrip Mission"; "~35-40 Minutes Roundtrip Delay when Crew is at Mars"; "Solar Conjunction Causing Communications Disruption". Banner: "Need a new paradigm on HOW we communicate with crew". Slide 3's longest delays (41–44 minutes) are higher than slide 4's "when Crew is at Mars"; the deck doesn't say where on the trajectory the longest delay falls.
Landing and ascent (slides 5–6)¶
Slide 5, "How to Get to the Surface?", read from the image:
| Viking 1&2 | Pathfinder | Spirit & Opportunity | Phoenix | Curiosity | InSight | Perseverance | Human Class Lander Concept | |
|---|---|---|---|---|---|---|---|---|
| Diameter (m) | 3.505 | 2.65 | 2.65 | 2.65 | 4.5 | 2.65 | 4.5 | 16-19 |
| Entry mass (kg) | 930 | 585 | 840 | 602 | 3,151 | 606 | 3,369 | 47,000-65,000 |
| Landed mass (kg) | 603 | 360 | 539 | 364 | 899 | 375 | 1,026 | 36,000-40,000 |
Under it: "Steady Progression of 'in family' Entry, Descent, Landing", a scroll "Upcoming ACR24 White Paper", a picture "Alternate Mid-L/D Concept", and the banner "New paradigm needed for Human Class Landers". The upcoming paper is the 2024 EDL paper the wiki holds (source page).
Against that paper's Figure 5 (the wiki's comparison): the banner is the same, but seven heritage cells differ. Phoenix entry mass 602 kg here, 0.573 t there; Curiosity 3,151 kg and 3.153 t; InSight 606 kg and 0.608 t; Perseverance entry 3,369 kg and 3.368 t, landed 1,026 kg and 1.050 t; Curiosity and Perseverance diameter 4.5 m and 4.52 m. The human-class lander differs most: diameter 16–19 m here, "16+" there; entry 47,000–65,000 kg here, "49 - 65" t there; landed 36,000–40,000 kg here, "26 - 36" t there. The paper is the newer (December 2024) and is kept as the reference on Transportation Systems; the difference is open question 91.
Slide 6, "Getting Back Off the Surface":
| Human launches | Conditions | |
|---|---|---|
| Earth | "100's" | "Significant in-person ground support"; "Generous delay/abort capability" |
| Moon | "6" | "Vehicle is delivered with crew prepared for ascent"; "Real-time ground support via coms" |
| Mars | "0" | "Little to no margin for delays"; "Little to no real-time ground support"; "Vehicle likely arrives unprepared for launch" |
"Humans have ascended from only two celestial bodies to date, usually with significant support."
Aborts and mass (slides 7–9)¶
Slide 7, "Mission Abort Example" (image): "Example: Hybrid Mars Abort on Mission Day 30 During 850-Days Roundtrip Mission", a frame at "DAY 361" with "Odometer (km): 934,818 million", "Odometer (AU): 8.28 AU", "Roundtrip Communication Delay: 0.00 minutes".
Slide 8, "What Does Mission Abort Mean?": "Mars mission aborts will be very different from past or current experience — For LEO or Lunar operations, abort can return crew to Earth within hours or days — For Mars missions, Earth return will be months or years after abort initiation — Abort may only shorten mission duration by a few weeks." "Even if initiated soon after departure, abort will require hundreds of days to return to Earth"; "Later aborts only reduce total mission duration by a few weeks or months". Banner: "New paradigm needed for risk buy-down and contingency planning".
Slide 9, "A Mass-ive Challenge", read from the image: a round trip in five stops, "Stop 1: LDHEO", "Stop 2: Mars Orbit", "Stop 3: Mars surface", "Stop 4: Mars Orbit", "Stop 5: LDHEO", each with stacks of payload and propellant units, and gear ratios ("GR = Gear Ratio (Multiplying Factor)") on the legs. As the wiki reads the drawing: 1.9 on the outbound arc, 1.4 down to the surface, 4.0 back up to orbit, 3.5 on the return arc. "The tyranny of the Rocket Equation": "Every kg added has multiplicative impact on the total mass required"; "But mass is not EVERYTHING"; "Sometimes mass penalty can offset other challenge and be a net positive trade". Banner: "Potential new paradigm for launch mass / cost, but need to manage complexity".
The three papers (slide 10)¶
The slide shows the first page of each paper, with a QR code. Its text layer carries the text of those first pages, so the following comes from the papers' thumbnails, not from the papers themselves (none is held):
- "Mars Mission Abort Considerations" evaluated "three propulsion concepts for a crewed Mars mission" on "an example trajectory with a roundtrip duration of 850 days with a short stay in Mars vicinity": a hybrid abort (nuclear electric plus chemical), a NEP-only abort, and a ballistic abort with "a high-thrust propulsion system (e.g., a nuclear thermal propulsion [NTP] or all-chemical propulsion system)", all assuming no "abort-specific contingency propellant". "For transportation architectures that refuel in Mars vicinity, mission abort during outbound transit may not even be possible." For descent and ascent at Mars, "Even a successful abort to the surface may leave crew stranded".
- "Round-Trip Mars Mission Mass Challenges" "explains how gravity wells, combined with the distance and desired transit duration between them, serve as a mass, and potentially cost, multiplier"; it cites the 2022 "Mars Transportation" white paper.
- "Mars Communications Disruption and Delay": conjunction "Approximately every 26 months"; blackouts "can last weeks", "generally occur while the crew is at Mars for long-stay missions, and during transit for higher energy, short-stay missions"; "the one-way communications delay for a crewed Mars mission can be upward of 21–23 minutes"; relays "could potentially provide some relief from communications blackouts but would not eliminate delays".
Each page's footer reads "2023 Moon to Mars Architecture Concept Review". The ACR25 C&PNT paper points to the communications paper for Mars (C&PNT white paper), and its subject is open task MD-12, "Maximum Allowable Crewed Communications Disruption" (Key definition tasks; the pairing is the wiki's).
What changed by Rev C¶
These comparisons are the wiki's.
- The human-class lander's landed mass is 36–40 t on this slide and 26–36 t in the December 2024 EDL paper (open question 91). Rev C's #1103 targets "25–75+ t" (#1103).
- Communications disruption became a priority definition task in 2024 (MD-12), still open in Rev C.
- Propulsion remains open: Rev C's #1104 lists NTP, NEP, chemical and SEP options (#1104), the families slide 10's abort paper compares.
Oddities¶
As printed, images checked:
- Slide 7's odometer, "934,818 million" km beside "8.28 AU". By the deck's own ratio (slide 3: 1,772,051,938 km = 11.84 AU), 8.28 AU is about 1,239 million km and 934.818 million km about 6.25 AU (the wiki's arithmetic); one of the two figures is off.
- The 850-day abort frame shows a "Roundtrip Communication Delay" of "0.00 minutes" on day 361.
- "850-Days Roundtrip Mission" (slide 7).
- The title card says "M2M Architecture White Papers"; the opening deck lists no paper called "Mars Challenges".
Related pages¶
Transportation Systems · Humans to Mars · Why Moon to Mars · Key definition tasks · 2024 EDL white paper · Mars EDL briefing, February 2025 · Mars decisions briefing, February 2024