Kerbal Space Program is a wonderful game about space and landing on the moon that is as inspiring as it is painfully inaccessible to people who don't understand how orbital mechanics work (so, everyone). It's the hero we need, but not the hero we deserve, and Mars Horizon is here to offer an alternative.
Released today, Mars Horizon is a game where you are in charge of a space agency at the dawn of humanity's journey into the stars. You need to research new vehicle parts to create more complex spacecraft, but you also need to research the missions these craft will be used on. There is also a more interactive base-building element, and you can research new building options to expand your space agency's facilities.
You'll be competing against other global agencies to achieve key milestones, such as the first EVA, first moon landing, and so on, with the ultimate goal of being the first agency to land a crewed mission on the surface of Mars. To get there, you'll have to make sure you're hitting enough research bonuses and generating enough revenue to get their first, although choosing to focus on tech as opposed to flashy missions is a legitimate way to go.
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Mars Horizon review - a modest leap for mankind
Mars Horizon is basically Kerbal Space Program Tycoon, and it hits Steam in November
Mars Horizon will hold a beta next month, and you can sign up now