Moon base, Mars settlement or orbital habitat

How do a Moon base, a Mars settlement, a rotating orbital habitat and a crewed Mars landing compare on travel time, gravity, radiation, current stage and main blocker?

The rows differ on distance from Earth, surface gravity and radiation. Each row is compared one dimension at a time, and the stage and blocker cells show where the sources stop.

Moon base, Mars settlement or orbital habitat. Each cell shows a value, how well it is evidenced, and its sources.
Option	Travel time from EarthOne-way time from Earth to the destination in days, or the crewed round-trip duration where a source states one. Null where no transit applies.	Surface gravityGravity at the destination surface as a fraction of Earth's surface gravity (g), or the artificial gravity produced in g.	Radiation environmentEstimated or measured radiation dose in sieverts (Sv) for a stated mission or setting, or a qualitative description of shielding.	Current stageThe horizon's current stage on the Vrulum scale, with the evidence behind it.	Biggest blockerThe largest unresolved technical or programme gap, as stated in the linked horizon and its sources.
Permanent Moon base	The Artemis II crewed lunar flyby lasted 9 days, 1 hour and 32 minutes in April 2026. It was a flyby, not a surface trip, and no one-way time to a surface site is given in the sources checked.Demonstrated[3]	One-sixth of Earth's surface gravity.Demonstrated[1]	The Moon has a very thin and weak atmosphere that does not protect the surface from solar radiation or meteoroid impacts. No dose figure is given in the sources checked.Demonstrated[1]	Engineering prototype on the Vrulum scale. NASA's Moon Base programme plans landers and rovers, with four landings targeted for late 2028. No integrated surface base or crewed surface stay is shown.Reported, unverified[9]	Surface power. No lunar power system is shown operating, and NASA plans to solicit a power and avionics demonstration with no date given.Reported, unverified[9]
Self-sustaining Mars settlement	NASA's reference mission uses 180 days outbound to Mars. No crewed round trip is shown in the sources checked.Proposed[4]	0.380 of Earth's surface gravity, or 3.73 m/s2.Demonstrated[2]	About 1 sievert estimated for a reference Mars mission, using RAD measurements. This is an estimate for a mission profile, not a dose measured in a crew.Reported, unverified[4]	Science unproven for the settlement as a whole. MOXIE made 122 grams of oxygen on Mars in 16 runs at demonstration scale, but no Mars system is shown supplying its own air, water, power and propellant.Reported, unverified[8]	Surface power. NASA names fission as the primary power source for crews, but gives no power figure, funding amount or mission date.Reported, unverified[7]
Rotating orbital habitat	No reliable public figure	No habitat built. A tether between two spacecraft in orbit in 1966 produced about 0.00015 g.Demonstrated[5]	No reliable public figure	Science demonstrated for the principle only. The 1966 tether test showed a small artificial gravity in orbit, and no rotating habitat has been built or flown.Demonstrated[5]	The gravity needed is not settled. NASA's concept study notes discomfort from rotation as low as 3 rpm, and near 1 g needs a kilometre-scale structure at 1 to 2 rpm.Reported, unverified[6]
Crewed Mars landing	NASA's reference mission uses 180 days outbound to Mars. No crewed round trip is shown in the sources checked.Proposed[4]	0.380 of Earth's surface gravity at the Martian surface, or 3.73 m/s2.Demonstrated[2]	About 1 sievert estimated for a reference Mars mission. Crewed missions have not yet tested shielding on a Mars trip.Reported, unverified[4]	Engineering prototype on the Vrulum scale. Crewed flight beyond low Earth orbit was shown on Artemis II in April 2026. The sources checked show no crewed Mars vehicle flown.Reported, unverified[3]	No reliable public figure

Moon base, Mars settlement or orbital habitat. Each cell shows a value, how well it is evidenced, and its sources.

Option

Travel time from EarthOne-way time from Earth to the destination in days, or the crewed round-trip duration where a source states one. Null where no transit applies.

Surface gravityGravity at the destination surface as a fraction of Earth's surface gravity (g), or the artificial gravity produced in g.

Radiation environmentEstimated or measured radiation dose in sieverts (Sv) for a stated mission or setting, or a qualitative description of shielding.

Current stageThe horizon's current stage on the Vrulum scale, with the evidence behind it.

Biggest blockerThe largest unresolved technical or programme gap, as stated in the linked horizon and its sources.

Permanent Moon base

The Artemis II crewed lunar flyby lasted 9 days, 1 hour and 32 minutes in April 2026. It was a flyby, not a surface trip, and no one-way time to a surface site is given in the sources checked.Demonstrated[3]

One-sixth of Earth's surface gravity.Demonstrated[1]

The Moon has a very thin and weak atmosphere that does not protect the surface from solar radiation or meteoroid impacts. No dose figure is given in the sources checked.Demonstrated[1]

Engineering prototype on the Vrulum scale. NASA's Moon Base programme plans landers and rovers, with four landings targeted for late 2028. No integrated surface base or crewed surface stay is shown.Reported, unverified[9]

Surface power. No lunar power system is shown operating, and NASA plans to solicit a power and avionics demonstration with no date given.Reported, unverified[9]

Self-sustaining Mars settlement

NASA's reference mission uses 180 days outbound to Mars. No crewed round trip is shown in the sources checked.Proposed[4]

0.380 of Earth's surface gravity, or 3.73 m/s2.Demonstrated[2]

About 1 sievert estimated for a reference Mars mission, using RAD measurements. This is an estimate for a mission profile, not a dose measured in a crew.Reported, unverified[4]

Science unproven for the settlement as a whole. MOXIE made 122 grams of oxygen on Mars in 16 runs at demonstration scale, but no Mars system is shown supplying its own air, water, power and propellant.Reported, unverified[8]

Surface power. NASA names fission as the primary power source for crews, but gives no power figure, funding amount or mission date.Reported, unverified[7]

Rotating orbital habitat

No reliable public figure

No habitat built. A tether between two spacecraft in orbit in 1966 produced about 0.00015 g.Demonstrated[5]

No reliable public figure

Science demonstrated for the principle only. The 1966 tether test showed a small artificial gravity in orbit, and no rotating habitat has been built or flown.Demonstrated[5]

The gravity needed is not settled. NASA's concept study notes discomfort from rotation as low as 3 rpm, and near 1 g needs a kilometre-scale structure at 1 to 2 rpm.Reported, unverified[6]

Crewed Mars landing

NASA's reference mission uses 180 days outbound to Mars. No crewed round trip is shown in the sources checked.Proposed[4]

0.380 of Earth's surface gravity at the Martian surface, or 3.73 m/s2.Demonstrated[2]

About 1 sievert estimated for a reference Mars mission. Crewed missions have not yet tested shielding on a Mars trip.Reported, unverified[4]

Engineering prototype on the Vrulum scale. Crewed flight beyond low Earth orbit was shown on Artemis II in April 2026. The sources checked show no crewed Mars vehicle flown.Reported, unverified[3]

No reliable public figure

What the table shows

The Moon is one-sixth of Earth's surface gravity and Mars is 0.380 of Earth's, while the 1966 orbital tether test gave about 0.00015 g and no rotating habitat has been built.
The only radiation figure in the sources checked is an estimate of about 1 sievert for a reference Mars mission, and the sources checked give no dose figure for the Moon.
Surface power is the blocker named for both the Moon base and the Mars settlement, the gravity threshold is the blocker for the rotating habitat, and the crewed Mars landing row has no blocker cell.
The stage cells run from science demonstrated for the rotating habitat principle, to engineering prototype for the Moon base and crewed Mars landing, to science unproven for the Mars settlement.

Read with care

Lab, simulant and analogue results are not directly comparable with conditions on the Moon or Mars, and MOXIE ran at small scale.
Transit times and launch dates come from NASA reference profiles and programme plans, not from flown missions to the destination.
Radiation values are estimates for a mission profile, not crew dose measurements, so they should not be compared with dose limits directly.
The rotating habitat row describes a concept. Its gravity cell refers to a 1966 tether test far smaller than any habitat floor, so it does not show floor-level gravity.

Sources

government report
Moon Facts
NASA, 12 Feb 2026. Accessed 21 Oct 2026.
dataset
Mars Fact Sheet
NASA National Space Science Data Center, 19 May 2025. Accessed 21 Oct 2026.
government report
Artemis II: NASA's First Crewed Lunar Flyby in 50 Years
NASA, 6 Oct 2026. Accessed 21 Oct 2026.
government report
Radiation Exposure Comparisons with Mars Trip Calculation
NASA Science, 9 Dec 2013. Accessed 21 Oct 2026.
government report
Sept. 14, 1966 – Gemini XI Artificial Gravity Experiment
NASA, 14 Sept 2016. Accessed 21 Oct 2026.
government report
Kilometer-Scale Space Structures from a Single Launch
Zac Manchester. NASA, 19 Feb 2022. Accessed 21 Oct 2026.
government report
NASA Outlines Latest Moon to Mars Plans in 2024 Architecture Update
NASA, 13 Dec 2024. Accessed 21 Oct 2026.
government report
NASA's Oxygen-Generating Experiment MOXIE Completes Mars Mission
NASA/JPL, 6 Sept 2023. Accessed 21 Oct 2026.
government report
NASA Awards More Moon Base Science, Previews New Opportunities
NASA, 30 Jun 2026. Accessed 21 Oct 2026.