Space Launch System (SLS)¶
Summary. The super-heavy-lift rocket that is "the only launch vehicle that can send Orion, astronauts, and payloads directly to the Moon on a single launch" (ADD Rev C, p. 68). It is a Transportation Systems element in the Human Lunar Return and Foundational Exploration segments. Rev C lists five variants, from Block 1 (Artemis I–III) to Block 2 Cargo. NASA's February 2026 plan "standardizes the SLS upper stage and mobile launcher configuration". No source names the standard mobile launcher; ESDMD's Ignition deck captions a "Standardized Block 1 configuration" and replaces the Exploration Upper Stage with the Centaur V (below).
All page numbers are ADD Rev C unless noted.
NASA's description¶
"The Space Launch System (SLS) is a super-heavy-lift launch vehicle that provides the foundation for human exploration beyond low Earth orbit. SLS is the only launch vehicle that can send Orion, astronauts, and payloads directly to the Moon on a single launch. It transports humans and payloads efficiently, effectively, and — most importantly — safely, enabling complex missions in cislunar space and beyond.
The SLS's evolvable design makes it possible to conduct more types of missions. This includes human missions to Mars; assembly of large structures; and robotic, scientific, and exploration missions to destinations like the Moon, Mars, Saturn, and Jupiter.
The first SLS crew transportation system, called Block 1, uses an Interim Cryogenic Propulsion Stage to send the Orion spacecraft on to the Moon. Block 1 was used for Artemis I and is planned for Artemis II and III. The Block 1B variant uses an Exploration Upper Stage to enable more advanced missions, such as carrying the Orion spacecraft along with a co-manifested large cargo payload in a single launch.
Block 1 and Block 1B Crew are the only SLS variants for the Human Lunar Return Segment. Future segments include the Block 1B Cargo, Block 2 Crew, and Block 2 Cargo variants, which add key capabilities." (p. 68)
At a glance¶
From the element one-pager (p. 68), checked against the PDF.
| ADD section | 2.3.15 (p. 68; numbered 2.3.14 in the Section 2.3 table, p. 46) |
| Implementing program | Space Launch System Program; printed beneath: Moon to Mars Program Office |
| Functional mappings | Appendix B, B.3.14 as printed on p. 68. The contents (p. 7), the segment tables (pp. 26, 32) and the Appendix B heading itself ("B.3.15 Space Launch System", p. 165) give B.3.15; B.3.14 is the SCaN networks' number (p. 64). See elements index. |
| Segments | Human Lunar Return, Foundational Exploration |
| Sub-architecture | Transportation Systems |
| Header image | "NASA's Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test, Wednesday, Nov. 16, 2022, from Launch Complex 39B at NASA's Kennedy Space Center in Florida. (Credit: NASA)" |
Variants¶
| Variant | Upper stage (as named) | Segment (p. 68) |
|---|---|---|
| Block 1 | Interim Cryogenic Propulsion Stage | Human Lunar Return; "used for Artemis I and is planned for Artemis II and III" |
| Block 1B Crew | Exploration Upper Stage | Human Lunar Return |
| Block 1B Cargo | Exploration Upper Stage | "Future segments" |
| Block 2 Crew | not stated | "Future segments" |
| Block 2 Cargo | not stated | "Future segments" |
The ADD names the Exploration Upper Stage for "The Block 1B variant" without splitting Crew and Cargo; the wiki applies it to both. Mobile Launcher 2 "enables Space Launch System Block 1B missions" (Exploration Ground Systems, p. 49).
Functions (ADD Appendix B.3)¶
B.3.15 maps the same six functions in Human Lunar Return (B.3.15.1) and Foundational Exploration (B.3.15.2) (p. 165). Titles are the ADD's. None is on the Users Guide's list of Phase 1 functional gaps (Users Guide, pp. 8–10; Phase 1 functional gaps; the wiki's check).
| ID | Function |
|---|---|
| FN-T-101 L | Transport crew from Earth to cislunar space |
| FN-T-112 L | Enable abort(s) to safety |
| FN-T-216 L | Deliver free flying asset(s) from Earth to cislunar space |
| FN-G-102 L | Stack and integrate system(s) on Earth |
| FN-G-104 L | Enable vehicle launch(es) |
| FN-G-105 L | Enable multiple launch attempts for vehicle(s) |
SLS shares FN-T-101 L and FN-T-112 L with Orion and the three G functions with Exploration Ground Systems. It is the only element mapped to FN-T-216 L. B.3 doesn't distinguish the variants. The lunar spreadsheet's SLS column has the same six in both segments.
Commercial launch isn't mapped. B.3 opens: "while commercial launch vehicles will play a vital role in the architecture, they are not mapped here, as they are subject to future implementations and procurements" (p. 148).
Gaps that mention it¶
None by name (search of both spreadsheets).
Changes since Rev C¶
- Artemis II has flown. The Users Guide shows photos taken by Orion and its crew "on April 6, 2026, during the Artemis II mission" as the crew "flew around the Moon" (Users Guide, pp. 11, 15). The photos don't show the rocket.
- Upper stage and mobile launcher standardized. The plan announced in February 2026 "standardizes the SLS upper stage and mobile launcher configuration" and lists "Vehicle standardization to enable serial production and faster launch pad turnaround" (Going back to the Moon, pp. 1–2). It doesn't say which upper stage or launcher. NASA's undated Artemis page says "Beginning with Artemis IV, NASA is standardizing the configuration of the SLS" (Artemis page, "Artemis IV"), and the Administrator's note of 22 May 2026 directs NASA to "Standardize the SLS architecture to the greatest extent possible" (workforce note); neither names a configuration. No source newer than Rev C mentions Block 1B or Mobile Launcher 2 (searched), so whether Rev C's Block 1 / Block 1B split and the Mobile Launcher 2 transition still hold is open (open question 25).
- Artemis III changes role. It is now a "Human landing system & EVA suit test mission in Earth orbit — 2027" (fact sheet, p. 2). Rev C plans Block 1 for Artemis III. The fact sheet doesn't say which SLS configuration flies it.
- Briefed at Ignition, March 2026: the Centaur V replaces the EUS. ESDMD's Ignition deck says "NASA is replacing the Exploration Upper Stage (EUS) with the Centaur V – a proven capability that enables mission repeatability"; "The first Centaur V mission may be Artemis IV or Artemis V"; "A new Stage Adapter will be required"; "SLS, EGS, Orion, and ULA are actively working the implementation of this new stage" (slide 15). Its Artemis poster is captioned "Standardized Block 1 configuration" (slide 2). Artemis III flies "Block 1, TBD: ICPS OR spacer" (slide 12); the 2028 landing, "Block 1 Crewed (ICPS or Centaur V)" (slide 18) (Ignition deck 1). Rev C's Block 1B is built around the EUS; the deck doesn't mention Block 1B, so whether a Block 1B remains is not stated (open question 25).
- Artemis III flies a spacer (May 2026). Deck 1's "TBD: ICPS OR spacer" is settled: "Instead of using the interim cryogenic propulsion stage as the upper stage of the rocket, NASA will use a spacer without propulsion capabilities as a representation of the overall upper stage dimensions", keeping "the same overall dimensions and interface connection points" between the Orion stage adapter and the launch vehicle stage adapter; it is being built at Marshall. Orion's service module then circularizes the orbit "in low Earth orbit" (Artemis III plans, May 2026). This is about Artemis III only; the article doesn't mention the Centaur V or later flights.
Moon Base relevance¶
Not established by the sources so far. The Users Guide, the Moon Base web pages and the Moon Base Program's Ignition deck (deck 2) don't name SLS (searched). The 2026 workshop decks name it only in the text of their images of ADD pages (January 2026 deck, slide 6; February 2026 deck, slides 6, 21 and 22). The other 2026 sources that name it (the Ignition release and fact sheet, Ignition deck 1, the Artemis III article, NASA's Artemis page and the Administrator's note of 22 May) speak of it for Artemis, mostly the standardized configuration, not for the Moon Base (Ignition release).
Related pages¶
Elements · Transportation Systems · Orion Spacecraft · Exploration Ground Systems · Human Lunar Return
Sources¶
ADD Rev C, pp. 7, 26, 32, 46, 49, 64, 68, 148, 150, 160–161, 165 · Lunar objective decomposition, allocation sheets · Going back to the Moon, pp. 1–2 · Users Guide, pp. 8–11, 15 · Ignition deck 1, slides 2, 12, 15, 18 · Artemis III plans, May 2026 · Artemis page, "Artemis IV" · Administrator's workforce note, 22 May 2026 · Ignition deck 2 · Ignition release · January 2026 workshop deck, slide 6 · February 2026 workshop deck, slides 6, 21, 22