Hundreds of years ago, when most people thought that the universe ended somewhere just beyond Saturn and that one could acquire knowledge of all history, science and theology in a single lifetime, exploring space would've seemed like a much easier task.
Oh sure, it would be a few million miles in every direction but modern spacecraft can do it in just a few years. However, today, when we know the edge of the visible universe is actually closer to 558 billion trillion miles away and that evolution only braced us for existence on one planet, we're very aware that truly reaching beyond our cosmic cradle is an immense challenge. But despite having nature's deck stacked against us in this regard, we're still trying to set foot on Mars, the moons of Jupiter and Saturn, and beyond.
Today, we're doing it with robots but robots have their limitations. Lacking intelligence, they can only do what we tell them or pre-program them to do. Considering that true artificial intelligence needed to navigate new worlds is still a matter of thought experiments and semantic conflicts among computer scientists, and popular transhumanists ideas involving zapping our conscious minds across the universe into machines we already placed at our target destinations are virtually impossible given our current understanding of biology, there has to be a better way to travel to other worlds. We would need something that combines human curiosity, ingenuity and mental flexibility with the incredibly high tolerance for radiation, frigid cold and lack of food and air of robots. And come to think of it, we're taking the first steps towards that right now.
If you've been following some of the recent developments in the world of medicine, you know that humans today can use their thoughts to manipulate machines, ]artificial limbs which interact with their nervous systems, and even use voice synthesizers to quite literally speak their mind if their ability to talk has been take away from them.
Much of this technology is still experimental, but as it's proving to be effective and safe, we can use it to re-engineer the bodies of astronauts to handle the rigors of space other worlds. Basically, imagine space being explored not by people in space suits, but by cyborgs who were specially modified to cope with just about everything alien environments can throw at them.
Radiation? How about your own personal little magnetic field that repels most cosmic rays and maybe even some genetic engineering to repair damaged DNA via the same process used by extremophiles on Earth?
No air? Modified lungs that can recycle oxygen can help with that.
Bone loss? Not with artificial joints and bones made of carbon fiber or tungsten carbide. New generations of hardware and software that bridge the gap between humans and machines could enable travel into the harshest, most forbidding environments in our solar system and beyond. Technology could go as far as you try to push it before reaching biological and physical limits, and the biggest issues will be your requirements and finding those who would volunteer for all the radical surgeries involved in the process.
Of course there's a catch. Each of the procedures that would make all this possible would be a) incredibly invasive, b) exorbitantly expensive and c) require decades of highly focused research projects to make it all possible. While the benefits to those who suffered serious trauma to the brain, limbs and spine, or suffering from organ failure would be immense, there may be some serious pause about healthy individuals undergoing this sort of modification for the sake of traveling to other worlds. People who may never walk again without a prosthetic spine or mechanical legs would certainly volunteer for such procedures because being confined to a bed or a wheelchair for the rest of their lives is a far higher cost than the risks involved with the surgery.
But those who are healthy, strong and very active by our terrestrial standards, might have a hard decision on their hands and doctors would have plenty of second thoughts before replacing major parts of their skeletons and implanting electrodes in their brain. Using nanobots to facilitate these kinds of complex procedures and minimize the risks of infection and human error wouldn't make the decisions any easier either and having an astronaut fleet made up of people who were willing to make such drastic changes to their bodies would profoundly change how we view space exploration in general.
We could finally view exploring other planets as the next step in our technological advancement, but we would always wonder about the cost involved with leaving the only home our species has known so far...