Artificial "black hole" placed on orbit around Mars for the purposes of energy production and the terraforming of Mars.
The Dot is an artificial micro-singularity (and tiny black hole) fueled by asteroids and other space detritus sent along the Asteroid Highway by the massive multicorp Hooker ships for this purpose. When thrown into the Dot's gravity well, the rocky waste is converted into a massive energy source by a combination of gravitational forces, kinetic friction and (to a suprisingly trivial degree) mass conversion. That is, mostly they're squeezed and bumped into heat and light. This energy is routed towards Earth via string lasers, and radiated towards Mars, like a second, small, sun.
With this unlimited power, Mars is increasingly transformed into an Earth-like planet, and Earth is kept rich with energy for manufacturning, heating jacuzzis and awesome laser shows.
As a bonus, some asteroids contain platinum, diamonds, and iridium - precious commodities that allow the business entities operating ex-Earth to generate trillions by stripping the ore, feeding the remaining mass to The Dot, and transporting the precious rare commodities back to planet Earth.