Mercury is the closest planet to the Sun and the smallest of the four inner terrestrial planets. With its lack of an atmosphere, scorching heat on the day side, freezing cold on the night side, and a rotation period that lasts 59 Earth days, surely this sun-baked cratered rock doesn't have much to offer when compared to Mars or even Venus, right?
As it turns out, Mercury is the second-densest planet in the Solar System after the Earth, meaning it's very metal rich and a prime candidate for future mining operations; conversely, given its proximity to the Sun, Terraforming Mercury is usually out of the question because of its hostile conditions all of which gives space pioneers a legitimate excuse to exploit the planet for its raw resources alone. For this reason, science fiction writers have often used Mercury as a hub for mining and industrialization to meet the needs of humanity's expansion across the system.
Note: Mercury was formerly believed to be tidally-locked to the Sun, with a day side in permanent light and a night side in eternal darkness. This has now been disproved, but a lot of older stories using the Industrialized Mercury trope refer to it; see below for examples.
Expect to see a lot of mining outposts, factories, and power plants that take full advantage of solar energy on the surface, and mining may be controlled from a Mercurial Base to avoid the extreme heat. Operations will usually be run by a local Mega-Corp that often forms its own government separate from Earth's, which may be autocratic by nature depending on how corrupt the leaders are. Additionally, Mercury may be used as a base of operations for constructing and maintaining a Dyson Sphere around the Sun.
If taken to the logical extreme, the planet may be entirely disassembled to its very core for its resources, which may result in Mercury becoming an empty shell of its former self or ceasing to exist. The ethics of such environmental destruction are rarely questioned due to Mercury being too extreme of a place to set up permanent colonies, and as such, is often given lower priority for preservation than the other terrestrial planets. (Its just a big rock.) If preservation is considered, it's usually for the opportunity to seize solar energy production rather than out of any need to keep the planet as it is, let alone terraform it.
While primarily talking about Mercury itself, this trope can also extend to include Mercury-like exoplanets of similar properties (fictional or otherwise), since most star systems generally follow the same rule of having the densest, metal-rich planets form and orbit close to their stars (Hot Jupiters notwithstanding).
Sub-trope of Colonized Solar System. See also Venus Is Wet and Once-Green Mars for classic sci-fi portrayals of Venus and Mars respectively, and Pluto Is Expendable for when Pluto gets the short end of the stick for being demoted to dwarf planet status. Compare Asteroid Miners. Subtrope of Industrial World.
- In Mercury Heat, Mercury is a mining colony populated mainly by people like protagonist Luiza who can't find work anywhere else, in a future where people are routinely locked out of gainful employment because of genetic and neurological profiling.
- In Transmetropolitan, Mercury is said to be covered by solar panels on its surface to gather large amounts of solar energy needed to power the advanced technology on Earth.
- 400 graden in de schaduw (400 degrees in the shade) by Dutch author Tais Teng is set in the year 2375, when humanity has colonized Mercury to mine it. They use mobile cities that move along with the planet's rotation so that they stay in the relatively safe twilight just before sunrise.
- Isaac Asimov:
- "The Dying Night": Stanley Kaunas is one of several scientists living on Mercury, which was colonized in order to build an observatory at the northern rotational pole. From there, half is always in darkness and the other half, with the telescope, is pointing at the sun, where they can analyze sunspots and solar flares in the minutest detail.
- Lucky Starr and the Big Sun of Mercury: Lucky visits a scientific outpost on Mercury, which has mining operations to make the outpost more self-sufficient. The primary project occurring is Project Light, where hyperspace is used to manipulate sunlight, but the project itself is facing setbacks.
- "Runaround": Mercury is the site of an abandoned mining facility. The problems with Mercury mining had caused humanity to retreat for years, so United States Robots & Mechanical Men Corporation has sent Gregory Powell and Mike Donovan with a new robot model to test the feasibility of restarting operations on sunside.
- Stranger in Paradise: Scientists want to send a probe to test the environment of Mercury. These are the initial stages of what would eventually be a colony, but first the scientists have to prove that robots can handle the logistical problems.
- The Killing Star: By 2076, Mercury has been covered in a planet-spanning array of solar panels and particle accelerators, all constructed by self-replicating robots, that provide humanity with the antimatter necessary for space travel. It's one of the first targets of the R-Bombings that destroy most of human civilization across the Solar System.
- Karl Schroeder's Lockstep, taking place 14,000 years in the future, mentions that Mercury has been completely stripped of its resources to build a Dyson Sphere around the Sun. As such, the planet no longer exists in the Solar System.
- The Medusa Chronicles by Stephen Baxter and Alastair Reynolds showcases several of these scenarios. The humans have a solar farm on the planet, and then the machines kick them off and pick the planet apart to turn it into a fleet of satellites that almost encapsulate the sun.
- Red Dwarf: Better Than Life mentions Mercury having solar power stations, which provide the entire solar system with cheap, clean energy.
- In Arthur C. Clarke's novel Rendezvous with Rama, Mercury is inhabited by a community of temperamental miners, Hermians, who plot to destroy the titular alien spacecraft out of paranoia. Colonising such a hostile environment has made them over-cautious by nature.
- Mutant Chronicles' Mercury is the home planet of Mishima, the solar system's second-largest Mega-Corp, so heavy industrialization is a given; its vast terraformed subterranean habitats are surprisingly pleasant to live in too... as long as you don't mind living in a society that takes its cues from both Tokugawa Era and Imperial Japan.
- Starfinder's analogue of Mercury, Aballon, is mostly inhospitable to organic life. However, its rich metal deposits and population of hardworking Mechanical Lifeforms have made it the the Pact Worlds' primary industrial hub.
- In Transhuman Space, Mercury is the Solar System's capital of antimatter production (used for catalyzing fusion drives).
- In Destiny, the Vex has taken control of Mercury, hollowed it out, and transformed it into a giant supercomputer that houses the Infinite Forest. Prior to their invasion, the planet had already been terraformed by the Traveler.
- Mass Effect: It is mentioned that Mercury is being used by the Alliance as a hub for solar energy production, housing a series of solar panels at both the north and south poles due to the planet's low axial tilt. In addition, you can also scour its surface for valuable minerals for crafting.
- Mercury in Warframe is under control of the Grineer who mine the planet and nearby asteroids for their resources. It's also the site of Doctor Tengus' research on an ancient bioweapon known as the Infestation, which predictably got out of control and is now a constant threat to any life in the Solar System.
- Kurzgesagt: Discussed in a video about the Dyson Sphere. They note that Mercury's proximity to the Sun, its rich abundance of metals and its low surface gravity makes it an ideal place to build and launch a series of satellites into orbit around the Sun to gather solar energy called a Dyson Swarm. It can also be used to speed up the infrastructure around Mercury, creating a feedback loop to help with the construction effort.
- Orion's Arm: In the Solar System's early history — that is, for a couple thousand years after the present day — Mercury was a major hub for mining and industrial activity. Mining flourished thanks to Mercury's high concentration of metals, including ones like osmium and platinum that were found more abundantly in its depths than anywhere else in the system, while its proximity to the Sun provided the energy necessary to manufacture vast quantities of antimatter to use as starship fuel. Eventually, this activity dried up due to the exhaustion of Mercury's resources and to the development of reactionless drives that didn't require antimatter fuel, but the planet remains densely inhabited — most of its old dome cities are still intact and populated, and billions of people live in the layers of tunnels and caverns that were dug out to extract Mercury's metals.