Exploration Ground Systems (EGS)

Summary. The ground infrastructure at Kennedy Space Center that processes, launches and recovers the Space Launch System and Orion. It is the only element in the Infrastructure Support sub-architecture, in the Human Lunar Return and Foundational Exploration segments (ADD Rev C, p. 49). Its step into Foundational Exploration is Mobile Launcher 2, for SLS Block 1B.

All page numbers are ADD Rev C unless noted.

NASA's description

"NASA's Exploration Ground Systems (EGS) program develops and operates systems and facilities that process, launch, and recover vehicles. EGS provides critical ground infrastructure for processing, launch, and landing of the Space Launch System and Orion spacecraft.

EGS utilizes the Vehicle Assembly Building at Kennedy Space Center for integration, testing, and vertical stacking of the Space Launch System on the Mobile Launcher platform. EGS moves the stacked vehicle on the mobile launcher to Launch Pad 39B via the crawler-transporter. Vehicle testing, final propellant servicing, launch countdown, and launch occur at the pad.

As EGS progresses through the Human Lunar Return segment to Foundational Exploration, it offers additional capabilities, such as the transition to the Mobile Launcher 2, which enables Space Launch System Block 1B missions. As human exploration expands deeper into the solar system, NASA applies capabilities and lessons learned by EGS in earlier segments to the challenges of increasingly ambitious missions and destinations." (p. 49)

At a glance

From the element one-pager (p. 49).

ADD section	2.3.3 (p. 49)
Implementing program	Exploration Ground Systems; printed beneath: Moon to Mars Program Office
Functional mappings	Appendix B, B.3.3
Segments	Human Lunar Return, Foundational Exploration
Sub-architecture	Infrastructure Support
Header image	"Exploration Ground Systems teams transport the Artemis II Space Launch System core stage to the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. (Credit: NASA)"

Functions (ADD Appendix B.3)

B.3.3 maps the same seven functions in Human Lunar Return (B.3.3.1) and Foundational Exploration (B.3.3.2) (p. 150). 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	HLR	FE
FN-G-101 L	Provide ground services on Earth	✓	✓
FN-G-102 L	Stack and integrate system(s) on Earth	✓	✓
FN-G-103 L	Manage consumables and propellant	✓	✓
FN-G-104 L	Enable vehicle launch(es)	✓	✓
FN-G-105 L	Enable multiple launch attempts for vehicle(s)	✓	✓
FN-G-201 L	Recover crew after Earth landing	✓	✓
FN-G-202 L	Recover cargo after Earth landing	✓	✓

FN-G-102 L, FN-G-104 L and FN-G-105 L are also mapped to the Space Launch System (p. 165).

Against the lunar spreadsheet. The sheet's HLR column is the same. In FE+ it adds two functions:

• FN-G-106 L, "Provide ground services on Earth to support large nuclear assets"
• FN-G-107 L, "Enable vehicle launch(es) to support large nuclear assets"

No ADD table for Foundational Exploration names either one. Neither is mapped in B.3 or listed as unallocated in B.5. Both are in the ADD's list of lunar functions (p. 120) (Lunar function allocation; open question 64). The ADD doesn't say what the "large nuclear assets" are.

Gaps that mention it

None. No technology or data gap names EGS, the Vehicle Assembly Building or the mobile launchers (search of both spreadsheets).

Changes since Rev C

• Mobile launcher configuration. NASA's plan announced in February 2026 "standardizes the SLS upper stage and mobile launcher configuration" (Going back to the Moon, p. 1). The fact sheet doesn't say which configuration is the standard. Rev C ties Mobile Launcher 2 to SLS Block 1B in Foundational Exploration (p. 49). No source newer than Rev C mentions Mobile Launcher 2; Ignition deck 1 names only Mobile Launcher 1 (below). So whether Rev C's tie still holds is open (open question 25).
• Briefed at Ignition, March 2026. With the Centaur V replacing the Exploration Upper Stage, "Changes to Mobile Launcher 1 to relocate umbilicals is also under assessment", and "SLS, EGS, Orion, and ULA are actively working the implementation of this new stage" (slide 15). One Artemis III goal is to "Demonstrate increasing mission cadence with prompt turnaround of pad and ground systems" (slide 12) (Ignition deck 1). The deck doesn't mention Mobile Launcher 2.

Moon Base relevance

Not established by the sources so far. The Users Guide, the Moon Base web pages and releases, and the Moon Base Program's Ignition deck (deck 2) don't name EGS (searched). The 2026 workshop decks name it only in their thumbnails of ADD Rev C pages (January 2026 deck, slide 6; February 2026 deck, slides 6 and 22). Two other 2026 sources name it, neither in connection with the Moon Base: Ignition deck 1, on the new SLS upper stage (slide 15, above), and NASA's undated Artemis page, which describes EGS as the program that "develops and operates the systems and facilities needed to process, launch, and recover rockets and spacecraft for NASA's Artemis missions" (Artemis page, "The Infrastructure").

Related pages

Elements · Infrastructure Support · Space Launch System · Orion Spacecraft

Sources

ADD Rev C, pp. 49, 120, 150, 165 · Going back to the Moon, p. 1 · Ignition deck 1, slides 12, 15 · Lunar objective decomposition, allocation sheets · Users Guide, pp. 8–10 · Ignition deck 2 · Artemis page, "The Infrastructure" · January 2026 workshop deck, slide 6 · February 2026 workshop deck, slides 6, 22