Throughout my career as an aerospace engineer and physics professor, I keep coming back to the concept of a cable stretching from Earth to space, along which people and cargo can easily travel.In recent years I and other researchers have found new ways to tinker with designs and answer questions about how space elevators could work.That will be hard.The real issue is that the portion of cable between the climber and the Earth experiences a drop in tension (like if you held an elastic band vertically in tension, and then affixed a mass halfway along it).Me: While the synthesis of potentially suitable materials has progressed in recent years, we are still at least 10 years away from a material solution (one having adequate properties, and that can be manufactured reasonably quickly at a reasonable cost)."