Orbiting Alpha Centauri B, Harvest, as it's colloquially known, was humanity's first foray into both paraterraforming of an entire world and the first attempt at large-scale agriculture outside the Solar System.
A small world in orbit around the K-type star, roughly halfway between Earth and Mars in size, Harvest was originally a barren rock with no water, no life and a thin atmosphere of toxic gases. The world was initially mined for minerals, but then a new project was considered thanks to its close proximity to its parent star.
This involved the creation of a worldhouse, an huge translucent sphere situated just above the Kármán line, which would serve to control the planet's temperature, shield the surface from cosmic radiation and provide a base of operations for the project.
Enclosed within this sphere, the planet's surface was mechanically eroded using lasers and grinders, creating soil that could then be infused with nutrients, while the atmosphere was artificially introduced using material from comets and nearby gas giants. The panels of the worldhouse can be lightened or shaded at will to encourage the development of wind and regulation of temperature, while clouds could be seeded to produce rains where they were needed.
Once this initial layer of topsoil was established, farming began on a massive scale. Within a few decades, the entire surface of Harvest became home to fields of crops, many of which are larger than whole countries back on Earth. These not only include food crops, but material ones such as cotton and medicinal ones such as willow.
Beneath the surface, vast cave systems are also home to farms of edible fungi and deeper flooded ones engaging in aquaponics. Harvest was designed as a self-contained testing ground for horticulture and agriculture, with many experiments visible from orbit.
The planet's equator is dominated by a large black belt, which may be mistaken for fire damage or even a body of water, but is actually a series of plants modified to produce black leaves and capture 99% of the light produced by the star. Seeds grown here have been sent to Proxima Centauri to see if they can grow under a red dwarf.
Harvest is sparsely populated by planetary standards, with less than 50 million residents both on the surface and in the worldhouse stations. Most of those on the surface either live in stationary communities resembling small farming towns on Earth or in mobile towns resting on enormous harvesters that run on Haber-Bosch reactors producing fertilizer for the fields. Settlements are never far from the space elevators tethering the worldhouse to the surface.
While many might view Harvest as a paradise, the planet's leadership is infamously strict. Because the biosphere is entirely artificial, as the world lacks any tectonics or water cycle, very few risks are allowed and unwelcome visitors are turned away. Should a serious threat arise, natural or artificial, the worldhouse is equipped with defensive lasers.
Anyone who wishes to visit Harvest must complete a long questionnaire, submit to thorough screening and are committed to 24-Earth month-long contracts. Of course, between the assistance from robots and high-quality medical care, it's not nearly as backbreaking as some might believe. Most who do work or settle there are people who prefer the quieter life and prefer to get their hands dirty.
Despite the strict regulations, Harvest is frequently visited by ships who seek to use the worldhouse's mass drivers for some extra acceleration to their destination. They're often given complimentary foodstuffs before being sent on their way.
With trillions of bushels of apples, grain bins, bales of hay, and countless billions of other crops produced every year, there's plenty to go around.
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