Buzz
What child hasn't stared at the night sky, wondering, even for a moment, what life might be like on another planet? For as long as humanity has existed, the vastness of the universe has been something we could only dream of. Never has humanity stepped foot on a world beyond Earth.
That might soon change within the next 20 years. The excitement surrounding Mars is reaching new heights, and the first person to walk on the red planet will likely be remembered alongside the greats like Neil and Buzz. But as all eyes turn to Mars, we're overlooking the other unexplored possibilities within our own solar system.
10. Floating Cities on Venus
Our neighboring planet Venus is a true challenge. Its surface averages a scorching 500 degrees Celsius (900 °F), and the ground pressure is about 92 times that of Earth. Its thick cloud cover is laced with sulfuric acid clouds, but that's less of a concern because the heat would likely be fatal before the acid could burn through your skin. Yet, NASA engineers Chris Jones and Dale Arney believe this hellish environment might offer one of the best opportunities for colonizing another world.
They suggest constructing a floating colony of airships around 50 kilometers (30 miles) above the surface. Just like Earth, the atmosphere on Venus becomes thinner as you go higher. At this altitude, the pressure would resemble Earth's, and temperatures would stay around 75 degrees Celsius (167 °F). For perspective, the highest recorded temperature on Earth is 56.7 degrees Celsius (134 °F). While it still wouldn't be pleasant outside, the temperature-controlled airships would be easier to manage. According to Chris Jones, Venus's upper atmosphere is “probably the most Earth-like environment that exists.”
It's an intriguing idea for colonization enthusiasts, but how could it actually work? The first airships would be helium-filled zeppelins, featuring a gondola suspended beneath an inflated balloon. While not an entirely groundbreaking concept, these balloons would be equipped with solar panels to harness the intense sunlight that bathes Venus. The balloons would be launched in capsules into Venus's upper atmosphere, where they would self-inflate and, hopefully, float before the dense lower atmosphere pulls them back down and results in disaster for those aboard.
9. Paraterraforming Ceres
Nestled in the asteroid belt between Mars and Jupiter, Ceres is a dwarf planet with a diameter of roughly 950 kilometers (590 mi), making its surface area slightly larger than that of Argentina. It's an enormous, icy rock positioned in the vast emptiness of space, with gravity only about 2.8 percent of Earth's strength.
So why would anyone want to visit? While Mars hasn’t yielded any particularly valuable minerals, Ceres lies within one of the richest mineral deposits in the solar system. It could serve as a base for extracting precious metals like platinum and palladium, which are key to construction. Even more exciting, there's a strong possibility that this small rock holds more fresh water than Earth. Colonists could potentially extract this water and convert it into breathable oxygen and hydrogen fuel for rockets.
However, making this a reality would require a process known as paraterraforming. Given Ceres' minuscule atmosphere, astronauts would need to construct a transparent dome on the surface. As the colony expands, they could add more interconnected domes, increasing the habitable area until it covers the entire surface, resembling the many facets of a massive space insect's eye. Is this feasible? Probably not in the immediate future, especially on such a large scale. Still, researchers have managed to build self-sustaining dome habitats on Earth, so it’s really a matter of scaling up technology and hoping that nothing goes wrong in the unforgiving vacuum of space.
8. Concrete Dwellings on the Moon
Since the last Apollo lunar mission in 1972, no one has returned to the Moon. It's cold, dusty, and completely inhospitable—a true lunar wasteland. But that doesn’t mean it's not worth revisiting. A recent NASA study revealed that the cost of establishing a permanent colony on the Moon would be far lower than initially thought—only $10 billion, instead of the original $100 billion estimate. Given NASA's budget, it's a project they could feasibly start right now.
The reasons for setting up a Moon base are even more convincing. A base on the Moon would make both financial and practical sense. It would be more affordable to launch long-distance missions (like those to Mars) from the Moon, and a significant portion of the hydrogen and oxygen required for rocket fuel could be extracted from water at the lunar poles. If we avoid running into any space Nazis, the Moon could very well be our golden opportunity.
What gets truly fascinating, however, is how we might construct such a colony. Ideas range from inflatable pods nestled inside lava tubes to space stations orbiting the Moon, but the wildest—yet most straightforward—plan might involve concrete homes. In 1992, Dr. Tung Dju Lin, a materials scientist, analyzed a small sample of Moon rock he borrowed from NASA. He discovered that the Moon’s surface already contained everything necessary to create concrete. Specifically, it has an abundance of a mineral called ilmenite, which contains both iron and titanium oxides. By grinding Moon rock into powder and running steam through it for hours, Lin created a concrete slab stronger than anything produced on Earth. So, while living in futuristic Moon pods sounds exciting, we might end up with something as simple as a concrete bungalow.
7. Kuiper Belt Cities
Freeman Dyson is often regarded as either a genius or an eccentric, depending on your perspective. His qualifications are beyond question, having earned prestigious honors like the Lorentz Medal, the Max Planck Medal, and the Enrico Fermi Award. However, his ideas frequently stretch the boundaries of conventional scientific thinking.
One of Freeman Dyson’s most well-known proposals is the Dyson sphere, a gigantic structure intended to surround a star and capture its energy for interstellar travel. But Dyson also had grand ambitions for other regions of the solar system, particularly the Kuiper Belt, a zone rich in comets beyond Neptune’s orbit.
Within this region, comets tend to cluster together in dense groups that could potentially be connected to form a city. As Dyson envisioned, “A Kuiper Belt metropolis would likely be a flat, disk-shaped assembly of cometary objects, joined by long tethers and rotating slowly around a central point to keep the tethers taut.”
Even if these comets weren't physically tethered, they would frequently pass close to each other, often within a million miles, allowing colonists to easily travel from one comet to another. To provide light and warmth in the chilly Kuiper Belt, Dyson proposed a vast array of mirrors 100 kilometers (60 miles) wide, capable of generating 1,000 megawatts of solar energy.
6. Bolo Habitats
Back in 1975, NASA explored the practicality of various "free-space" habitats—colonies that would not be anchored to any celestial body. One of the concepts they examined was incredibly simple yet feasible at the time: the bolo habitat.
Imagine a string with a ball at each end, and you have the fundamental concept. Each "ball" would be a 22-meter (72-foot) sphere, capable of accommodating 10 people. The string between the spheres would measure 2 kilometers (1.2 miles), and the whole structure would rotate once every minute, providing a gravity-like force for its inhabitants. Cover each sphere in 5 meters (16 feet) of Moon soil for radiation protection, and you’ve got yourself a no-frills space home.
Bolo habitats were conceived as self-sufficient homesteads, designed to offer everything a family could need. There would be space for agriculture, solar panels to generate power, and a manufacturing pod suspended in the middle of the tether—a weightless environment perfect for creating more bolos. Much like pioneers expanding their homesteads in the Old West, settlers in bolo habitats could establish entire cities of counterbalanced, free-floating homes.
5. Subsurface Ocean Pods On Europa
Europa has recently gained attention as the most likely location in the solar system to host extraterrestrial life. NASA is so committed to the possibility that they are preparing an unmanned mission to orbit Jupiter and conduct 45 flybys of the moon, searching for telltale signs of life in the salty ocean believed to lie beneath its icy surface. The mission is planned for launch sometime in the 2020s.
While the idea of discovering microbial aliens around geothermal vents deep below Europa’s frozen exterior is thrilling, one private company isn’t willing to wait for robotic explorers. They want humans to take the journey—and they want to make it happen within the next 50 years. Like Mars One, Objective Europa offers a one-way ticket, but the goal is not just sacrifice, but discovery. However, the mission will face enormous challenges to ensure that their astronauts survive long enough to make meaningful discoveries.
Europa’s surface temperatures drop to a frigid –170 degrees Celsius (–270 °F). The moon lacks any significant atmosphere (in fact, it has barely any at all), and the nearby radiation from Jupiter bombards it with a deadly dose of 540 rem daily. To tackle these extreme conditions, Objective Europa plans to keep their crew sheltered underground. After setting up a temporary surface station, they would drill through the icy crust to reach the comparatively warmer ocean below. There, or within the ice tunnel itself, they would establish a subterranean base, protected by permanent air bubbles. Here’s a technical schematic of how it might work.
4. Free-Floating O’Neill Cylinders
An O’Neill cylinder is a gigantic structure, 32 kilometers (20 mi) in length and 8 kilometers (5 mi) in diameter, designed to rotate in order to generate artificial gravity. Built in pairs that rotate in opposite directions, each cylinder could theoretically accommodate up to 10 million people.
The concept of O’Neill cylinders has been around since 1974, when physicist Gerard K. O’Neill first presented the idea in an article for Physics Today. Back then, it was firmly rooted in science fiction. Having just visited the Moon, it seemed far-fetched to think we could soon construct a massive cosmic habitat for millions. Yet, O’Neill’s vision ignited something in the scientific community, and the idea has remained relevant ever since.
Although O’Neill cylinders are still beyond our current technological capabilities, science is catching up to what was once fictional. The British Interplanetary Society, which predicted the feasibility of lunar missions decades before Apollo, believes we could actually build an O’Neill cylinder today. The main challenge now is securing the necessary funding. The raw materials for construction would be sourced from the Moon, and the development of more affordable spacecraft like Reaction Engines’s Skylon could make such a project possible.
3. Bioengineered Trees
Imagine a gigantic tree sprouting from a comet. Its roots intertwine with the cracks and crevices inside the comet, while its vast canopy shelters the surrounding area. Inside, its hollow trunk serves as a thriving home for human colonists.
Step back into the brilliant mind of Freeman Dyson.
In a 1997 essay for The Atlantic titled “Warm-Blooded Plants and Freeze-Dried Fish,” Dyson proposed the idea of bioengineered “greenhouse trees” to create sustainable habitats for humans in space. The essay reads like a vision from a dreamer who imagined rocket ships and space exploration as a child, then grew up without letting go of that imagination. Dyson describes the steps needed to colonize a comet, starting with something as simple as planting a seed.
Dyson suggested that once the seed touched the surface of a comet, it would grow into a massive, warm-blooded tree, genetically modified to survive the freezing temperatures by utilizing only the weak sunlight from afar. The tree would eventually create a warm, enclosed environment filled with oxygen produced by its photosynthesis. By the time humans arrived, the greenhouse tree would already serve as their new home.
2. Bubbleworlds
Before Gerard O’Neill introduced his idea of rotating cylinders, NASA scientist Dandridge Cole had already imagined a similar concept he called a “bubbleworld.” While O’Neill’s cylinders would be built from raw materials sourced from the Moon, Cole’s vision involved something much more metallic in nature.
To begin, we would need to locate an asteroid predominantly composed of metal, ideally one made of more malleable alloys like nickel-iron. This isn’t a difficult task as there are thousands of them scattered throughout space. The next phase involves drilling a tunnel through the asteroid’s core and filling it with water. Then, using focused solar energy, we’d seal the tunnel’s ends. After that, by adjusting the focus of the solar heat, we’d gradually soften the asteroid’s metal exterior, while simultaneously boiling the water inside, creating steam that would expand and inflate the asteroid’s softened shell, hollowing out the interior.
Once the asteroid cooled down, mirrors would direct sunlight into the hollow interior. To simulate gravity, the asteroid would be made to spin, and people could live on the inside surface.
1. Bigelow Aerospace’s Balloon Stations
As the most expensive object ever created and the largest artificial satellite orbiting Earth, the International Space Station (ISS) stands as a monumental achievement in human history. Built through the cooperation of over two dozen nations and at a cost of more than $160 billion, the ISS has hosted groundbreaking research in fields like microgravity, cosmic radiation, biotechnology, and dark energy, just to name a few.
When Robert Bigelow, a real estate mogul from Las Vegas, observed the ISS, his thought was clear: “I can do better.” With a personal investment of $500 million, Bigelow launched Bigelow Aerospace to develop commercial space stations at a fraction of the cost. Unlike the ISS, which was constructed piece-by-piece in space over a two-year period, Bigelow’s B330 uses a more straightforward design: a massive balloon packed inside the nose cone of a rocket. Once the rocket reaches space, the balloon inflates into a fully operational space station capable of housing six crew members.
It’s a bold concept, but is it outlandish? Perhaps not; Bigelow has already launched two inflatable space station modules, Genesis I and Genesis II, and he has plans to send the larger Space Complex Bravo into orbit by 2016. And Robert Bigelow’s ambitions don’t end in Earth’s vicinity. His future vision for his inflatable space venture includes lunar bases, deep-space stations, and Martian outposts.
