I still remember the excitement and fear of April 12, 1961, the day Yuri Gagarin became the first human to travel into space. I was seven years old: too young to fully appreciate the thrill many people felt that the mysterious universe beyond Earth had suddenly been conquered and that the adventures of the swashbuckling Flash Gordon were now one step closer to reality. I was old enough, however, to vividly remember concern that the first person in space was Russian and not American.

The decade that followed Gagarin’s pioneering foray above the atmosphere seemed to validate all the promises of space travel I had gleaned from science fiction. Before the end of the decade men would walk on the moon, and the future, depicted most explicitly—and, we all thought, realistically—in 2001: A Space Odyssey, seemed so bright we needed shades. During each of the Apollo flights, I stayed home from school, huddled in the basement near the television with the diagrams of rockets I had cut out of local newspapers and magazines, transfixed by the images from space. I imagined the possibility that one day I, too, might experience the excitement of space travel.

Alas, it was not to be. Human space exploration has been reduced to visiting a $100-billion tin can orbiting closer to Earth than Washington is to Boston. No one except a billionaire or two has ever vacationed in space, and their “hotel” was a cramped, stuffy and at times smelly white elephant. The moon is not being mined for rare or expensive elements. Aside from communications satellites, space is devoid of industry.

What happened? Why did the dream of unlimited manned space travel and a vast new universe of possibilities for humanity dry up and fizzle? The answer is relatively simple: reality prevailed. Human space travel is expensive and dangerous, and there is almost no scientific justification for it (a sobering realization for the child-turned-scientist). All these factors stem from the same problem: most of the incredible cost of human space travel goes into keeping humans alive during the process, leaving little money for other things. This harsh reality leaves those of my generation in a position, 50 years hence, of having to reevaluate those childhood dreams.

It is important to acknowledge, first of all, that advances have been made. We have sent robots to places humans could never have survived and peered into the cosmos with instruments far more capable than our human senses, all for a small fraction of what it costs to send a living, breathing person into Earth’s orbit. The first rovers went to Mars for what it would cost to make a movie about sending Bruce Willis to Mars. And the Hubble Space Telescope, perhaps the most important and expensive unmanned device sent into space thus far, has captured our imagination in a way the International Space Station never has. And our robotic technology continues to improve.

This is not to say that sending humans into space is entirely pointless. If our species is to survive, our future will probably require outposts beyond our own planet. And having shared the stage with many an astronaut, I can attest to how inspiring they can be. Their exploits were precisely what got me so excited when I was a kid and helped to spur me to become a scientist.

Sending people into space for the sake of adventure and perhaps eventual habitation is a legitimate goal. But if we are to undertake it, we should be honest about our reasoning. Pretending that space voyages will push forward the frontiers of science or provide vast new opportunities to tap cheap or scarce resources is disingenuous. If inspiration is what we are after, let us do inspiring things—not orbit endlessly around Earth.

Figuring out how to inspire, in this age of preoccupation with debt and unemployment, is not going to be easy. We need new ideas. Establishing a permanent presence on Mars, to take one example, will cost many tens of billions of dollars. Such a mission is at present inconceivable, unless we can rethink it.

I have suggested, for example, sending astronauts on a one-way mission. Even if we consider the cost of keeping the crew alive indefinitely on the planet’s surface, a one-way trip would cost a mere fraction of a two-way trip, and I am sure volunteers would line up. If we are going to break the cycle of disappointment, we are going to need all the creative thinking we can muster.