Moon vs Mars Exploration: The Big Space Debate of 2025

By Julia Seibert

Elon Musk’s North Star has always been Mars. So when the SpaceX CEO recently mentioned making the red planet a priority, it wasn’t exactly a surprise. But SpaceX also plays a key role in another deep space exploration mission: the US’s Artemis program, established by Musk’s best buddy President Trump in 2017 with the mission of returning Americans to the moon. 

Now, Musk has called the moon a distraction and criticized Artemis’s stodgy architecture. So what are the main differences between exploring the Moon and Mars – and what do Musk’s musings mean for Artemis?

The History of Moon and Mars Exploration

Human deep space exploration began with a bang in the 1960s. Fueled by the desire to demonstrate technological superiority, the US and the Soviet Union invested heavily in their space programs to beat each other to landing a man on the moon: the ultimate display of dominance. But when the US clinched the win in 1969, the point was made and there was no political need for a sustained presence on the moon. So while proposals for crewed missions to Mars were floating around as early as the 1950s, any missions for human deep space exploration were canned before concrete plans could materialize. That’s not to say no exploration took place, though; over the next few decades, the US, USSR, Russia, and China – plus a few other countries – deployed a flurry of scientific probes to the Moon and Mars.

While a few renewed efforts to send people reared their heads over the years, it wasn’t until the 2020s that things began to kick off again. The US announced Artemis in 2017, which aims to establish a continued US presence on the moon and eventually move on to Mars; after years of delays and cost overruns, the first (uncrewed) mission took off in 2022. In 2021, China and Russia announced a joint lunar base known as the International Lunar Research Station (ILRS); two years later, China announced its goal to land people on the moon by 2030. 

Meanwhile, a small army of commercial space companies had set up shop in the US. Among them is SpaceX, which in 2023 began launching Starship: the first rocket designed for Martian colonization. The company is pursuing a relentless testing campaign and aims to send the first uncrewed missions to Mars in 2026. NASA also contracted it to land the next Americans on the moon in 2027.  

Read also: The Pros and Cons of Space Colonization: Should We Expand?

The Moon vs Mars: Key Differences in Exploration

Distance

What goes for Earthly real estate also rings true in space: location, location, location. The Moon is clearly the frontrunner here; at a distance of 384,400 kilometers, travel time for human ships is only around three days. Since it’s so close (cosmically speaking), launch windows – dictated by Earth and the moon’s alignments – are much more frequent than for further destinations. The short distance also makes mission logistics less complicated, and it’s easier to abort a mission if something goes sideways. 

Mars isn’t quite as peachy in this respect. On average, it’s 225 million kilometers away from Earth. That’s a lot of fuel and travel time, so missions to Mars usually wait for the perfect planetary alignment to make the trip as quick as possible; this launch window only opens every two years. Travel time varies according to the mission and the spacecraft’s capabilities, but one-way trips usually take around nine months (though Musk has suggested 80- to 150-day journeys). 

Atmosphere

Neither the Moon nor Mars features a particularly attractive atmosphere, but Mars wins this round simply because the Moon, for all intents and purposes, is a vacuum. While it’s got a few gases floating around, their importance to any mission is pretty much negligible. Mars does have an atmosphere, albeit a feeble one; it consists of 95% carbon dioxide and has an atmospheric pressure over 100 times weaker than Earth’s. 

In either case, you’d quickly croak without a spacesuit. Even with one on, you’d need to figure out how to shield yourself from deadly radiation hailing from the sun and deep space. The moon and Mars both lack the protection of a global magnetic shield; in Mars’s case, losing its magnetic field billions of years ago allowed solar wind to strip away its atmosphere.

Gravity

Again, neither candidate is truly impressive here; still, Mars has about a third of Earth’s gravitational pull, while the Moon has about a sixth. That can pose serious health concerns for astronauts, making Mars the slightly better option. But low gravity can also be a plus; since so little energy is needed to take off from the Moon, it could become a useful jumping-off point for missions headed deeper into space.

Resources

Both the Moon and Mars have some things going for it when it comes to resources. Both have water, which can be used for sustenance and rocket fuel; on the moon, it’s mostly in icy craters at the poles, while Mars has its ice caps and underground lakes. Mars’s ice and CO2 can be used to make methane, the fuel used by Starship (alongside oxygen). The Moon and Mars also have a good view of the sun, though Martian dust storms make solar panels tricky to maintain; still, Mars has wind that could be used for power generation. While their compositions are different, the moon and Mars both feature a set of raw materials that could be used to build dwellings and other things needed for survival. 

Mars’ atmosphere, though thin, is a significant asset and makes the planet the better option for independent human presence; an experiment for transforming Martian atmospheric gases into oxygen is already at work aboard NASA’s Perseverance Mars rover. Lugging all the equipment and resources needed to kickstart a colony to Mars is a bit of a pain, but the red planet is not just richer in useful raw materials, but they’re also generally easier to access than on the moon. 

Meanwhile, the Moon’s closer distance to Earth means that colonies can be resupplied much easier than on Mars. The lunar surface is rich in Helium-3, an isotope that could prove useful as a fuel for fusion energy; however, it’s unclear just how hot an asset it’ll become. The moon is also home to a slew of rare-Earth metals – but again, it’s uncertain whether they’ll be worth the effort of mining the moon. 

Why Does Elon Musk Want To Go To Mars and Skip The Moon?

Elon Musk’s Vision for Mars

Musk founded SpaceX because of what he perceives as an existential threat: if something wipes out life on Earth, that extinguishes the only known life in the universe. ‘Making humanity multiplanetary,’ as SpaceX calls its mission, ensures that life survives if Earth goes bust. Since Mars is the most Earth-like body in the solar system, Musk has made reaching it SpaceX’s number one priority. Along the way, SpaceX conquered the Earthly launch industry and became a favorite of NASA’s, who plans on using Starship to land on the Moon. Musk prefers Mars since it’s more suitable for independent colonies, but it wasn’t until recently that he expressed his distaste for NASA’s plans.

What Does This Mean for NASA?

SpaceX is heading to Mars with or without NASA; in theory, their plans need not interfere with each other. But SpaceX’s Mars project – with Starship at the helm – is advancing at a pace no governmental agency could afford, neither in budget nor public image. Sitting that out would be one hell of a missed opportunity for NASA. And now that Musk is Trump’s right-hand man – and former SpaceX astronaut Jared Isaacman has been nominated as NASA administrator – it’s likely that NASA sharpens its focus on Mars. 

Until recently, this would’ve been unthinkable. Artemis and the SLS rocket at its core depend on politically influential contractors like Boeing, who greatly profited off the Space Shuttle program; US Congress directed NASA to carry over their cost-plus contracts to SLS, resulting is an astronomically expensive and delayed program whose primary mission is providing jobs. Now, there’s a considerable chance SLS is binned and Artemis gets a shakeup under the new administration. 

The Arguments for Moon Exploration

• Closer in distance, shorter travel time
• Sustaining resources available:
  • Water ice
  • Sunlight for solar power
  • Regolith (soil) can be processed for shielding, solar panels, and more
• Could be mined for Helium-3 and REMs

Key lunar exploration efforts:

• NASA (US): Artemis
• CNSA (China): Chang’e, ILRS
• Roscosmos (Russia): ILRS (partner), Luna-Glob
• ISRO (India): Chandrayaan

 The Arguments for Mars Exploration

• More Earth-like atmosphere and gravity
• Sustaining resources available:
  • Water ice and underground lakes
  • Sunlight, wind for power
  • CO2 and water converted to oxygen and rocket fuel
  • More abundant resources for colony sustenance that are easier to access

Key Martian exploration efforts:

• SpaceX (US)
• NASA (US): Artemis (later phases; details unclear)
• CNSA (China): Tianwen (a suite of robotic deep-space probes; crewed mission details unclear)

Read also: The Benefits of Space Exploration and Its Importance

The Future of Space Exploration: Moon, Mars, or Both?

Neither the moon nor Mars are pleasant places to find oneself, but both their characteristics cater to different cosmic goals. The more Earthlike Mars is the better option for permanent, fully independent colonies, while the Moon is more practical for mining and trying one’s hand at space tech. 

It’s therefore likely that both will have a part to play in the future of crewed space exploration. For governmental agencies, the Moon is the logical first step before sending astronauts further out. Geopolitics is another important factor; the US or China wouldn’t want to put all its energy towards a risky Mars mission and leave the Moon to its rival. That’s why NASA is unlikely to dump its lunar program altogether even if it takes Mars more seriously. 

But to SpaceX, which is working under the urgency of its Mars mission – the sooner the planet is colonized, the sooner that existential threat is eliminated – the Moon might really be a distraction. Mars is a massive goal for which SpaceX will need all the help it can get, hence Musk’s lobbying for the US to shift its focus. But one day, SpaceX might get the last laugh; its Starlink T&Cs state its intention to recognize Mars as a ‘free planet’ that no Earthly government will have authority over. For now, though, the question remains whether any of these endeavors are possible in the first place; be it the Moon and Mars, both have some devilish obstacles to overcome. Space is hard – pick your poison.