Rosas Moon Base: a Starship as a lunar habitat

Elon Musk, head and shoulders, smiling slightly, in a dark jacket against a pale grey wall.

“This will be so awesome 🤩”
Elon Musk on X, 9 February 2026, quoting a post about the ISU team's Starship lunar base

The next step forward in space exploration is returning humans to the Moon and establishing a permanent human presence.

Sending humans to the Moon means facing an environment that is hard on both human performance and human health.

Current state-of-the-art technologies, like the Artemis program and the SpaceX Starship Human Landing System (HLS), are the inspiration for the Rosas mission, and keep it feasible.

"The Moon is the first milestone on the road to the stars"
Arthur C. Clarke

Landing site chosen for the Rosas Moon Base. Shackelton Crater 3d model from LROC, NASA; rendered in blender.

The pains of building a lunar base

1973: The Saturn V and the explored Saturn Workshop, best known as Skylab:

A Saturn V upper stage and Skylab side by side against black, with a spacewalking astronaut between them. — The Saturn V upper stage on the left, and Skylab on the right; with astronaut for scale. Modeled in Sketchup, rendered in Blender.

1992: STS-Lab Space station Concept (Ware and Culbertson, 1992):

The Space Shuttle orbiter on its external tank with both solid rocket boosters firing, and an astronaut floating nearby. — The Space Shuttle; modeled in Sketchup, rendered in Blender.

Line drawing of a station built around a Shuttle external tank, with labels for Orbiter-II, the long laboratory, SPEDO, the pressurized transfer tunnel and a visiting orbiter. — The Enterprise Shuttle Space Station; NASA

Today: SpaceX Lunar Starship

The upcoming, largest, piece of infrastructure in history that can land on the Moon.

Three rockets side by side against black: the orange SLS, a landed lunar Starship on its legs and a much taller Starship on its booster. — From left to right: Space Launch System Block II; Lunar Starship (landed); Lunar starship mounted on top of Superheavy

Concept generation for the base design

Before proceeding with the engineering design, a series of concept proposals were explored.

With this rapid sketching of the baseline mission it was possible to arrive at a stronger concept faster.

Sketch headed 'How to get started with a lunar base?' showing a lunar Starship on landing legs beside a finned Earth Starship marked payload, crew and tanker. — The two main Starship variants; Left: HLS Starship; Right: Orbital/Cargo Starship

Sketch adding a lunar crew Starship to a payload Starship to make a lunar payload Starship, in white line on black. — Study of a potential third variant: Lunar cargo Starship.

Two sketches of a payload Starship with its nose door swung open and a hooked crane lowering a cargo module to the surface. — Lunar Cargo Starship deploying a Moon base module.

Horizontal hypothesis base concept

In order to maximize the utility of the volume, the selected orientation was a difficult one: by tipping the whole vehicle on the side, hazards to the crew could be diminished and the base could be further expanded.

However, how do you tip a 50-metre-high Starship?

Sketch of a lunar Starship held by long guy lines, upright and then tipping to one side, with a question mark. — Concept of harness system + cantilever to tip Starship sideways in the surface of the Moon..

Sketch of horizontal Starships joined in a cross around a central node, drawn twice, with a ring structure, a crane and a rover between them. — Quick concept sketch of an expanded Moon Base built from repurposed HLS Starships.

The baseline Concept proposal

In order to assure all of the requirements for habitability, the design needed to include flooring, wall mounts, stairways, entrance hatches and airlocks.

Surrounding the base, a 3 m thick regolith layer would be deposited.

Cutaway of a Starship lying under a regolith mound, labelled with 3 m of regolith shielding, stairways, three floors assembled on Earth, fuel tanks turned into habitable volume, the transformed airlock and a node for future expansion. — Starship-derived Moon Base interior volume study.

The transfer mission

But how do you get a starship to the Moon? And, most importantly, how do you create a construction site on the Moon?

For that we need to consider a concept of operations derived from the state-of-the-art knowledge of how SpaceX Starships travel to the Moon.

Two mission Starships were needed (besides the fuelling tankers), across two mission phases:

Phase 1 - Workshop vehicle launch

SS Rosas transfer mission will launch the workshop vehicle, which lands on the Moon without a crew.

Phase 2 - Crew vehicle launch

SS 501 transfer mission will launch the return starship with the crew that will continue the mission inside the habitat workshop (SS Rosas) already on the site.

Diagram of the Rosas phase 1 transfer: cislunar insertion, four refuels and landing

Diagram of the Rosas phase 2 transfer: the crew vehicle, with eight refuels for the return

The MOROCAS: Modular robotic construction autonomous system

A modular, remotely operated, team of robots capable of performing construction tasks.

This system was designed in order to reduce the amount of EVA time necessary.

Seven labelled MOROCAS variants on six-wheel chassis (drill, crew transport, hinge, scissor lift, de-tanker and two regolith movers), with a bare chassis, an astronaut and a 2.26 m scale bar. — Modeling Study of MOROCAS variants.

The construction timeline

1. Horizontalization: After landing both starships, the base Starship (the future Rosas Base) is horizontalized with the help of the MOROCAS system.

Four-step diagram of the Starship going from upright to horizontal: cable anchors placed by MOROCAS, a hinge system, a MOROCAS scissor lift, and the lift folding and driving out from under the hull. — The starship tipping sequence using Hinges, anchors, cables, and a scissor lift.

2. Volume connection: after the Starship is horizontalized, the construction crew moves in and starts preparing the fuel tank transformation.

Three section drawings of the horizontal Starship: the payload volume with construction equipment, passages cut through the LOX and methane tanks, then airlocks and insulation installed. — Sequence of adapting the tanks into interconnected habitable volumes.

3. Interior installation: Happening after the whole structure is stable and pressurized. The crew brings a series of modular tiles to assemble the interior divisions of Rosas Base.

Section drawing of the horizontal Starship with three floors and stairs installed, life support and infrastructure below, and a docking port at the nose for expansion. — Projection of starship-derived Moon Base's interiors.

4. Regolith coverage: The lunar environment is a dangerous place. Micrometeoroids and radiation can be deadly to the whole crew and mission. This way a layer of regolith is deposited by the MOROCAS over several weeks to months.

The base under a sculpted regolith mound with an open entrance court, a solar tower, a round module on a yellow frame at one end, and rovers and astronauts around it. — Fully covered Starship-derived Moon Base.

Five stages along an arrow, from the bare horizontal Starship in a shallow pit to a full regolith mound with a round module at one end. — Sequence of regolith layer deposition through a MOROCAS fleet.

A window to our Home

Three steps on the side of the hull: a hatch outline, the hatch swinging open, and a box-shaped cupola extending out on a bellows. — Deployment of the OSCAR cupola from the interior of the base.

On the side of the Starship, one of the airlocks is transformed into a cupola-style expandable volume. This enables a space for the astronauts to look at the exterior of the base, and, most importantly, to gaze at our Earth.

The OSCAR cupola is retractable. This way, the interior of the base can stay under the protecting regolith, while the viewing area can stay outside for short-duration observations of the Lunar vista, and of Earth.

Line drawing of the cupola extended from the hull on a bellows, with a triangulated window frame, side shields open and an arrow showing its direction. — Fully deployed OSCAR cupola with the radiation shields open. The base was designed so that the cupola is constantly pointing Earthward.

Photorealistic gallery

An astronaut stepping out of a bellows airlock on the side of the hull onto a ramp where a pressurized rover is parked, with a second astronaut on the regolith. — Model of Rosas Base main entrance, designed on top of the HLS main airlock and compatible with both MOROCAS and astronauts..

Two astronauts and a six-wheel MOROCAS drill rover around a large boulder, casting long shadows. — Astronauts and MOROCAS driller variant approaching a nearby Moon boulder.

Aerial view of the Starship hull lying uncovered on the regolith, with its airlock ramp, a round module on a frame at the nose, and astronauts and equipment nearby. — Overview of the first stage of the mission. Before covering the structure with regolith.

A white pressurized MOROCAS rover with lit windows driving across dark lunar hills. — A lone MOROCAS pressurized crew transport venturing in the lunar landscape.

Astronauts and a MOROCAS drill rover around a large boulder in front of the horizontal Starship hull. — Rosas Base as a vantage point for Geology and science at the lunar surface. Astronauts and MOROCAS inspecting nearby Moon boulder.

From inside the airlock, an astronaut walking out toward the back of a pressurized rover on the ramp. — View from the main airlock of Rosas Base.

A spherical tank on a six-wheel MOROCAS rover at the open aft end of the Starship hull, with an astronaut, a crew rover and a crescent Earth in the sky. — De-tanking in progress.

Two MOROCAS rovers fitted with large treaded drums beside a group of boulders on the regolith. — MOROCAS Plower variants moving larger rocks away from the base.

Video

The team

All ISU SSP21 participants from Team Lunar who took part in the project: 21 people from 13 countries.

Participants

Chairs

Rob PostemaEuropean Space Agency

Matthew SorgenfreiCruise LLC

Antonio Martelo GómezGerman Aerospace Center

Teaching associate

Xiaochen ZhangUniversity of Western Ontario

A special thank you

Mission patch with a red rose on the lunar surface beside a standing Starship, Earth in the sky, national flags around the rim and the words Rosas Mission. — Mission logo for the Rosas Base Assembly. Designed in honor of Oscar Federico Rosas Castillo, SSP21 Strasbourg's participant liaison, which tragically passed away during the program.

In loving memory of Oscar Federico Rosas Castillo – an adventurous, spirited soul who brought us together and made our world a better place. We are better for having known you. May your light shine bright upon us until we see you on the other side of the stars. Ad Astra.

Acknowledgements

ISU and Team Project Solutions for Construction of a Lunar Base wish to express their sincere appreciation to Lockheed Martin Corporation for its sponsorship of this project.

We would also like to thank the chairs and teaching assistants for their amazing support during this team project. They have been the key factor in supporting this team during the process and therefore the success of this lunar team report.

Lastly, we would like to thank the International Space University and SSP21 staff for making this year’s program happen, during the COVID-19 period and supporting the team in the best way possible.