The Case for Human Space Exploration

“We have been given hands to touch the miraculous. We have been given hearts to know the incredible. Can we shrink back to bed in our funeral clothes? Mars says we cannot.”

-- Ray Bradbury, Too Soon from the Cave, Too Far from the Stars

The Dragon spacecraft has completed its historic mission to the International Space Station and returned safely to Earth. Though SpaceX, its designer, says that the vehicle can be rapidly repurposed for manned missions in the future, there were no humans aboard.

The reasons to send robotic craft into space are numerous. The reasons to send human beings into space number very few: because we must; because it is our destiny. Because our history as a people is a history of exploration -- we will cease to be ourselves if we do not go to space, and we will be changed when we do; such is the nature of life.



But let me put it in more practical terms.

The prosperity of each of us depends in part on the benign self-interested neglect of our fellows. We hope that those around us will help us, or if not, will leave us alone. Sometimes that hope is disappointed: a woman is assaulted, a home is robbed, a city is attacked. Fortunately, the number of people who would do such things is small, the number of those who are capable of doing so is smaller still, and their power is limited.

The world is growing smaller. More people live closer together in greater interdependence all the time. If our propensity for evil and conflict remain constant, our risks therefore increase. Civil and military institutions strive to reduce the incidence of violence; the capabilities of bad actors simultaneously increase, so that those breaches that do occur cause more damage. A loan shooter murders a dozen people; a private army, relatively poorly equipped, kills thousands in less than a day, half a world away.

Let's be concrete: suppose we measure risk by the number of people who might pass within a quarter mile of us on any given day. Hypothetically, any of those people might kill or ruin us if they had the inclination. (Fortunately, almost none of them do, or I would not be writing this, and you would not be reading it.) Two centuries ago, many people could count them on their fingers and toes -- in fact they probably knew all of their names. Those who lived in large cities might count that high in a few minutes. Today, the people who do pass us by number in the hundreds of thousands; those who might, if they wished to, number in the hundreds of millions. And a century from now, we will measure them by the billions; they will be everyone, each of us living within a metaphorical arm's length of everyone else, all the time. In some small way, we must trust each of these people.

Space will be to us in the future what oceans and mountains were to us in the past: a way out, a way forward, a road to opportunity -- a high wall of separation between a vulnerable pilgrim people and their troubled homeland. One people will become many, separated by distances and costs sufficiently vast to protect each from the others' mistakes, mischief, and poor choices.


More of Sagan's "Pale Blue Dot" here and elsewhere online.