Humans pursue space exploration for five basic reasons.  The first emphasizes science, the second reason concerns national defense.

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Defense officials consume a large portion of their government’s overall space budget. In the United States, the federal government spends far more on defense related rockets, missiles, satellites, and associated space-age command and control systems than NASA spends on space science.  Little wonder that exploration enthusiasts are periodically attracted to defense entities as a source of support for the technologies that further their work – and sometimes get it.  If the science budget is meant to enlarge knowledge, the space defense budget projects force.

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For at least two thousand years, defense strategists have taught soldiers that they need to occupy battlefield positions that constitute the military “high ground.”  During the American civil war, Union forces (and confederates too) attached platforms to reenforced balloons and used them to observe opposing troops and the location of enemy artillery.  Military personnel on both sides of World War I purchased aero planes that conducted reconnaissance patrols over enemy-held territory. Shortly thereafter, pilots received weapons to defend themselves from opposing aviators, ushering in the era of air combat.