RT-8: Leverage Low-Earth Orbit¶

Summary. "Leverage infrastructure in low-Earth orbit to support Moon to Mars activities" (ADD Rev C, p. 83). ADD Rev C points to more than two decades of International Space Station experience and to the planned move to commercial LEO destinations. After that move, ESDMD will look to those destinations for human research, food growth, and technology demonstrations and certifications. LEO "cannot simulate certain spaceflight hazards with total fidelity", but NASA will use it "to inform human system risks for Mars missions". One of the nine recurring tenets.

All page numbers below are ADD Rev C, Section 3.5.8 (pp. 100–101). The heading spells it "low Earth orbit" (p. 100).

The assessment¶

"The Moon to Mars Architecture builds upon past and current human and robotic spaceflight experience to inform future system design and operational needs" (p. 101).
The ISS. "Enabled by a robust international partnership of five space agencies from 15 countries, the International Space Station has served as a space laboratory of unprecedented scale and sophistication and has hosted a continuous human presence in LEO for more than two decades. During this time, more than 270 astronauts from 21 countries have lived and worked there, conducting over 3,700 scientific experiments" (p. 101).
"NASA will continue to operate and utilize the space station to support exploration goals through 2030 and is preparing for a successful transition of these capabilities to other destinations in LEO" (p. 101).
Commercial LEO. "NASA's Commercial Low Earth Orbit Development Program (CLDP) is supporting the development of commercially owned and operated LEO destinations from which NASA, along with other customers, can purchase services … Transition of LEO operations to the private sector will yield efficiencies in the long term, enabling NASA to shift resources toward other objectives" (p. 101).
What ESDMD would use them for. After the transition, "ESDMD will coordinate with CLDP to leverage available commercial LEO destination utilization facilities and services that may accommodate Moon to Mars Objectives. Research and development opportunities could include" (p. 101):
- "Studies of human behavioral and physiological exposure to in-space environments, habitability, and operations"
- "Development of in-space growth of alternative nutritional sources for human consumption"
- "Space-related technology demonstrations, tests, and certifications"

Future considerations¶

"Some potential opportunities to leverage LEO infrastructure remain unexplored, and additional studies and refinement are needed to evaluate all available options. While LEO cannot simulate certain spaceflight hazards with total fidelity, NASA will use LEO destinations to inform human system risks for Mars missions" (p. 101).
"NASA will continue to take full advantage of the International Space Station before its planned decommission after 2030, after which the agency will enable the development of and transition to other LEO assets" (p. 101).
"NASA should also create and demonstrate decision support system capabilities in the content of future architectural assumptions" (p. 101; "content" as printed).

RT-2 makes the same point from the industry side: "As commercial LEO destinations come online, NASA should investigate opportunities to use those platforms" (p. 88; RT-2).

In the February 2025 workshop briefing¶

Ten months before Rev C, SOMD's part of the "Foundational Exploration" panel at both February 2025 workshops was "Connections to LEO Microgravity Strategy" (FE gaps deck, slides 12–14). "NASA's Low Earth Orbit Microgravity Strategy document outlines what NASA intends to achieve by continuing human activities in low Earth orbit after the retirement of the International Space Station" (slide 13). The strategy itself is not among the wiki's sources. Its three "LEO Exploration Goals", as printed (slide 14):

"Exploration Technology": "Leverage the unique environment of low Earth orbit to advance technologies that enable future human exploration on and around the Moon and Mars."
"Human Health and Performance Research in Exploration Analog Environments": "Advance understanding of how to sustain human health and performance using relevant exploration analog environments in low Earth orbit to reduce risks and inform Moon, Mars, and deep space missions."
"Using Low Earth Orbit Operations to Prepare for Deep Space Exploration": "Validate crewed mission operations in low Earth orbit as part of a timely and effective methodology to test the agency's evolutionary approach to living and working in environments relevant to Moon and Mars exploration."

The first two cover the same ground as two of Rev C's three research areas above (technology demonstrations; human exposure studies), and the third adds operations, which Rev C's list doesn't name. The slides don't cite the tenet; the comparison is the wiki's.

In the February 2024 workshop briefing¶

A year earlier, older than Rev B and Rev C, the February 2024 workshops briefed the 2023 paper "Exploration Lessons Learned from the Space Station" (not held) as "Exploration Lessons From The International Space Station" (ISS lessons briefing). The slides don't name the tenet; the pairing is the wiki's.

Six lesson areas (slide 3): "Fly-Off Plans"; "Environmental Control and Life Support Systems"; "Navigation"; "Food Storage Systems"; "Extravehicular Activities"; "Human Research". Only life support and navigation get slides of their own.
Life support (slides 4–5): "Up to 98% Mars-class water recycling has been achieved"; a "Next generation 4-bed CO2 scrubber"; "Advanced Oxygen Generation Assembly will launch in 2024"; "CO2 reduction assembly to be added in 2025, completing the air string".
Navigation (slide 6): Orion's optical navigation system, OpNav, "installed in the ISS cupola" as a demonstration; SEXTANT, using the NICER payload, "uses pulsar's radiation flashes to determine position in space, similar to GPS".
The station as a platform (slides 2, 9): "Enable Deep Space Exploration" ("Validate Exploration Technologies and Reduce Human Health Risks") among its six goals, and "a platform for technology demonstrations in space, including those needed for future Moon and Mars missions".

What changed by Rev C (the wiki's comparison): Rev C's assessment, as quoted above, names none of these systems; whether the 2024 and 2025 life-support additions flew is in no source the wiki holds.

Changes since Rev C¶

NASA's Ignition fact sheet on low Earth orbit (24 March 2026) adds an option to the plan for the move from the station to commercial destinations. Its "phases" and its "Updated Architecture" are the LEO plan's, not the Moon to Mars Architecture's. It doesn't mention the Moon, Mars or the architecture, so setting it against this tenet is the wiki's pairing (LEO fact sheet).

An added strategy. "Alongside existing plans for transitioning the International Space Station to commercial destinations, NASA is introducing an additional low Earth orbit (LEO) strategy", which "preserves the existing pathway" (p. 1).
Why. "NASA cannot afford the originally envisioned path of developing two commercial stations and today cannot even afford one", and "There is still no independently verifiable evidence that a commercial station funded partially by NASA would be economically viable" (p. 1).
NASA's preferred path. The "Incremental Transition Approach (NASA's Preferred Path, Insufficient Funding)": commercial modules "that attach to the International Space Station first", tested and validated with the station's infrastructure; then "the International Space Station will be decommissioned, the new stations will detach into free flight, and NASA will be one of many customers purchasing commercial services" (p. 2). The other option is "Status‑Quo Commercial Replacement (Insufficient Funding)" (p. 2).
The LEO plan's four phases (pp. 2–3): a "NASA Core Module" attached to the station, "supplying propulsion, refueling, power, cooling, docking ports, and basic life support"; two "Commercial Modules"; "Separation and Growth", "supporting continuous crew presence"; and "Market‑Driven Expansion", with NASA "one customer among many".
For industry (pp. 3–4): "Two private astronaut missions per year", "Sale of a commander seat for eligible flyers", "Potential joint commercial–NASA crew missions", module competitions and prize awards; an RFI from 25 March.

The Ignition release of the same day summarizes the same plan: "a government‑owned Core Module that attaches to the space station, followed by commercial modules that are validated using International Space Station capabilities and later detach into free flight". It says "The orbital laboratory cannot operate indefinitely."

Briefed at Ignition, March 2026 (the LEO Program's deck; also no Moon or Mars content). The deck calls the core-module plan an "Alternate approach" and "Alternate option" rather than the preferred path, says NASA is "open to continue with original commercial plan or to pivot", and asks for RFI feedback "for both options" (slides 8, 10, 17, 18). Its procurement chart runs to 2035 with its own three phases (core module, a "Market Driven" power and cooling module, commercial expansion), and states "Available budget is $250 million per year through end of ISS", without an end date (slide 17). It calls a replacement station "a national imperative to maintain an orbital laboratory and proving ground in Low Earth Orbit", without saying a proving ground for what (slide 2) (Ignition deck 3; the difference from the fact sheet is noted in open question 81).

The event's closing recap states the core-module plan without the alternative (the wiki's comparison with deck 3): "We are staying in LEO. Expansion of the International Space Station with a core module and commercial modules" (Ignition deck 6, slide 14).

What the fact sheet doesn't say: it gives no date for the station's retirement (Rev C: "planned decommission after 2030", p. 101), and nothing on what ESDMD would use LEO for (Rev C's three research areas, above). That is silence, not a change. Its station figures ("more than 4,000 research investigations", "visitors from 26 countries", p. 1) count other things than Rev C's "over 3,700 scientific experiments" and "270 astronauts from 21 countries" (p. 101), so the wiki doesn't compare them.

Technology gaps on the same subjects. The ADD doesn't link them; the pairing is the wiki's: #0305 Food and Nutrition (in-space food growth); #0402 Sensorimotor, #0403 Physiological and #0404 Behavioral Countermeasures (human exposure studies).

Recurring tenets · Why Moon to Mars (the LEO experience gap) · RT-3 Crew Return · Human Systems

Sources¶

ADD Rev C, pp. 83, 88, 100–101 · LEO fact sheet, Mar 2026, pp. 1–4 · Ignition release, Mar 2026 · Ignition deck 3, Mar 2026, slides 2, 8, 10, 17, 18 · Ignition deck 6, Mar 2026, slide 14 · FE gaps deck, Feb 2025, slides 12–14