Buzz
When we consider the possibility of human colonies in space, Mars is often the first place that comes to mind. Its allure has captivated humanity for centuries, and both NASA and various private companies are working toward colonizing it within the next few decades.
Yet, beyond Mars, there are numerous moons across the solar system that could be prime candidates for human settlement. Some of these moons show signs of liquid water, hinting that microbial life may already exist. Whether these moons could serve as launching points for further exploration or house thriving colonies, here are ten moons that might one day become homes for humans.
10. Europa
Not only is it likely that humans could establish a presence on Europa, but there is also a chance that life could already be flourishing there. Europa, one of Jupiter’s moons, is enveloped by a thick icy shell, but beneath this crust lies a vast ocean. It also has a rocky inner core, which may create an environment conducive to supporting life, whether it’s simple microorganisms or more complex organisms.
Investigating the ocean beneath Europa’s ice, particularly how it cycles oxygen and hydrogen, will provide valuable insight into the likelihood of life and human colonization. NASA intends to explore whether the water interacts with the moon’s rocky core, potentially generating heat and hydrogen, similar to the processes observed on Earth. Analyzing the icy crust for oxidants will reveal how much oxygen is produced and how it is transferred to the ocean.
By 2025, it is expected that NASA will have conducted much more detailed research on Europa to verify whether their theories are feasible. This closer examination could also uncover active volcanoes beneath the icy surface, which would boost the prospects of life on the moon. If such volcanoes exist, they could release water rich in vital minerals into the ocean.
Once NASA has a closer look at Europa, they will carry out various investigations to gain a deeper understanding of what lies beneath the thick ice shell. Magnetic sounding will provide data to estimate the ice’s thickness and the ocean’s depth. Additionally, they will study the salinity of the water. Radar technology will be employed to penetrate the ice layer, potentially uncovering any structures hidden beneath the surface.
9. Titan
Although it resides in the outer reaches of our solar system, Saturn’s moon Titan is considered one of the most promising candidates for human colonization in the future by many experts.
While humans would need to use breathing apparatuses, as the atmosphere is inhospitable to us, there would be no necessity for pressurized space suits. However, protective clothing would be essential due to the extremely cold temperatures, which average around –179 degrees Celsius (–290 degrees °F). The moon’s gravity would be slightly weaker than that of Earth's Moon, which would make walking feel awkward, but traveling through the air in simple, human-powered vehicles would be relatively easy.
Food production on Titan would need to be supported by artificial lighting, as Titan receives only between 1/300th and 1/1000th the amount of sunlight Earth does, depending on cloud coverage. Interestingly, Titan’s abundant clouds also offer protection from harsh environmental conditions. While Titan lacks water, it does have liquid methane, which has prompted some scientists to speculate that life there could be methane-based rather than water-based.
If humans were ever to visit Titan, there would be plenty to discover. Titan features numerous methane lakes and rivers, along with towering mountains. Moreover, its proximity to Saturn means the planet would be constantly visible (cloud cover permitting), filling about a third of the sky.
8. Miranda
Although Titania is the largest moon of Uranus, Miranda, the smallest of the planet’s five major moons, might be a more suitable location for a colony. Several of Miranda's fault cliffs are incredibly deep, in some cases nearly 12 times deeper than the Grand Canyon on Earth. These could provide ideal spots to establish a base that would offer some protection from the harsh environment, including charged, radioactive particles from Uranus’s magnetosphere. Additionally, Miranda lacks an atmosphere to shield against these particles.
Miranda is abundant in ice, making up about half of the moon’s total composition. Similar to Europa, there is a possibility that liquid water lies beneath this icy crust, although this can’t be confirmed until it is studied more closely. If liquid water is present, it would suggest significant geological activity beneath the surface since Miranda is too far from the Sun for heat to keep water in a liquid state. It is hypothesized that the tidal forces caused by Miranda's proximity to Uranus could be sufficient to drive this activity, though this theory remains unlikely.
Regardless of the presence of liquid water, if humans were to establish a colony on Miranda, the moon’s very low gravity would mean that any researchers falling from the cliffs into the deep canyons would experience a descent lasting minutes. The fall would be so gradual compared to Earth that it is unlikely to be fatal.
7. Enceladus
Some researchers believe that Enceladus, one of Saturn’s primary moons, not only offers potential for colonization and the opportunity to study Saturn’s rings, but it might also be the most likely place in our solar system to already harbor life.
Enceladus is coated in ice, but it has been observed releasing ice particles into space through geyser-like jets. The Cassini spacecraft collected samples, which revealed the presence of liquid water, nitrogen, and organic carbon—key elements that form the foundation of life. The next step for scientists is to determine if more complex life forms could be hidden beneath the icy surface. The early analysis of the plumes has made Enceladus a more intriguing target for further exploration.
It’s hypothesized that the ideal spot to establish a base on this icy moon would be near the source of the plumes—large fissures in the ice at the moon’s south pole. Known as Enceladus’s “tiger stripes,” these cracks release heat comparable to the energy output of 20 coal-fired power plants, which could be harnessed by future colonists as a heat source.
While there are many craters and ridges to explore and possibly use as bases, Enceladus has an extremely thin atmosphere and weak gravity, which would make movement on the surface quite challenging.
6. Charon
As NASA’s New Horizons probe journeyed towards Pluto, it also captured stunning images of Pluto’s largest moon, Charon. These images led to a debate among scientists about whether Charon might exhibit signs of geological activity, as the moon’s surface appeared much younger than previously expected.
Charon’s surface features cracks but remains surprisingly free from asteroid impacts and craters. The New Horizons team suggests this might indicate that Charon is geologically active. The cracks, resembling the lava tubes found on our own Moon, could make excellent locations for establishing a human research station or colony.
It is believed that Charon may possess an extremely thin atmosphere, which could further support the idea of geological activity if it turns out to be originating from within the moon itself.
5. Mimas
Referred to as the “Death Star” moon, Saturn’s frozen, rocky moon Mimas may harbor an ocean beneath its otherwise inhospitable exterior, potentially making it capable of supporting life. When scientists analyzed Cassini’s footage, they observed that Mimas seemed to rock back and forth in its orbit, suggesting possible activity beneath the surface.
While researchers were careful with their conclusions, acknowledging that there were no other signs of geological activity, they suggested that if an ocean were found, this moon would definitely be a candidate for colonization. The estimated ocean would likely be located about 24 to 29 kilometers (15–18 miles) below the surface.
If the rocking motion is not caused by liquid water beneath the surface, it is more likely due to an irregular core, potentially influenced by the immense gravitational forces from Saturn’s rings. With no additional surface signs of activity, the only way to confirm this would be to land on the moon, study the surface temperature, and measure its gravity field.
4. Triton
In August 1989, data and images transmitted by the Voyager 2 spacecraft revealed that the surface of Triton, Neptune's largest moon, is composed of rock and nitrogen ice. These findings also opened up the possibility that beneath the surface, activity might be occurring, suggesting the presence of liquid water.
Triton does have an atmosphere, but it is so thin that it would be almost imperceptible to anyone on its surface. Furthermore, stepping outside would require extremely robust protective gear. With an average temperature of –235 degrees Celsius (–391 °F), Triton holds the distinction of being the coldest known body in the universe.
Triton is certainly a moon of great interest for scientists, and with the right technological advancements, it could become a potential site for a permanent base. The moon has enough unique characteristics to warrant extensive study, including the following:
Certain regions of Triton’s surface reflect light in a manner that suggests they are made of smooth, hard substances such as metal. This effect is thought to be caused by dust, nitrogen gas, and possibly water being expelled from beneath the surface, dispersed by Triton’s ultra-thin atmosphere, and freezing on the surface to form smooth ice. It remains unclear how dangerous these emissions could be for the environment or human visitors.
It also appears that Triton did not form at the same time or from the same material as Neptune, which is unusual given its size. The moon is thought to have originated elsewhere in space before being captured by Neptune's gravitational pull. Notably, Triton orbits its host planet in the opposite direction of its rotation, making it the only moon in the solar system to do so.
3. The Moon
Without a doubt, the first celestial body that will likely be colonized is Earth's very own Moon, also known as Luna. Not only would it serve as an excellent “practice ground” for more ambitious missions to distant parts of space, but creating a base on the Moon would also act as a strategic launchpad for missions heading into deeper space.
In March 2016, a story gained traction across various media outlets suggesting that scientists believe a base could be established on the Moon within the next decade. Chris McKay, a NASA astrobiologist, is one of the strongest advocates for this plan. He points out that previous attempts to return to the Moon, following the Apollo 17 mission, failed due to prohibitive costs. However, McKay's team believes their approach will be far more affordable, partly thanks to innovations like self-driving cars and waste-recycling toilets, which were originally developed for Earth but can be highly effective in space as well.
While NASA's primary focus is landing humans on Mars, McKay contends that the agency cannot achieve that goal without first establishing a permanent base on the Moon. He argues that such a base would provide a crucial blueprint for future Mars missions. McKay is also optimistic that NASA will be motivated to act, given the growing interest from other space agencies and private companies, all of which have plans to establish their own lunar bases. He believes this will be the catalyst NASA needs to secure the necessary resources and, as he puts it, 'establish the rule of law' on the Moon.
2. Callisto
Jupiter's second-largest moon, Callisto, is nearly the same size as the planet Mercury. It is another candidate with the potential for colonization, thanks to its vast liquid ocean thought to exist beneath its icy crust.
Callisto’s surface is dominated by craters and vast icy plains. The moon also boasts a thin atmosphere composed of carbon dioxide, which is likely replenished by carbon dioxide that escapes from below the surface, as the atmosphere is too tenuous to stay intact otherwise. Early research hints that oxygen might also be present in the atmosphere, though further studies are needed to verify this.
Due to its safe distance from Jupiter, Callisto experiences relatively low levels of radiation. Combined with its lack of geological activity, this makes it an ideal candidate for human colonization. In fact, habitats could potentially be established on the surface rather than having to be built deep underground.
1. Ganymede
As the largest of Jupiter's moons, Ganymede has long been a subject of interest, especially with advancements in technology that hint at the presence of liquid water beneath its icy surface. Compared to other frozen moons, Ganymede’s outer layer is considered relatively thin, which could make it easier to penetrate.
Ganymede stands out as the only moon in our solar system with its own magnetic field, which produces auroras similar to Earth’s. These auroras remain relatively stable, leading scientists to suggest that an ocean lies beneath the moon’s icy exterior. Ganymede also boasts a thin layer of oxygen in its atmosphere, although it’s too sparse to support life as we know it. Despite this, the possibility of terraforming remains a topic of scientific interest.
In 2012, the European Space Agency was granted approval to launch a mission aimed at exploring Ganymede, along with two other moons of Jupiter—Callisto and Europa. The mission, set to begin in 2022, is expected to reach Ganymede a decade later. While all three moons hold great research potential, Ganymede is believed to offer the richest environment for study and possible settlement.
