Though space and air flight are as distinct from each other, as air flight and ship transport are from each other, many people do group them together. Therefore we’ll discuss in this post the future of aviation on Earth.
Of all types of aircraft air-planes are the most well-known and together with helicopters the most popular ones. Most air-planes are powered by burning kerosene. Unfortunately petroleum, of which kerosene is made, is going to be depleted in a few decades. And given that simultaneously the amount of air traffic is increasing, flying will become more and more expensive.
For other modes of transportation the depletion of oil is less a problem, ships can be powered by wind, by using kites. Land based vehicles can be powered by electricity and can be recharged along the route. An electric plane is possible but a commercial air plane would need very heavy batteries, which would mean that fewer passengers and cargo can be transported at a flight.
An easy solution would be to replace petroleum-based kerosene by bio-fuels or synthetic fuels. Bio-fuels have they big disadvantage that the production of it will compete with food production, and hence will increase the price of food and lower people’s access to food.
Another option would be to reconsider airships. Since the disaster with the Hindenburg airships have fallen out general use, but modern version use inert helium rather than flammable hydrogen as buoyant. Only helium is on Earth are rare resource, and much of our helium reserves is wasted in, for instance, helium balloons at parties.
Fortunately there might be good news. With the prospect of oil depletion, more people are turning to fusion power as a method of energy production. And the primary waste product of fusion power happens to be helium. With more fusion power plants, also more helium will be produced. And hence more airships can be produced.
But wouldn’t be nice if we could use solar energy to power air planes? Well, NASA just did that, their Pathfinder planes are basically flying wings covered by solar arrays. But these are small, unmanned planes designed for research purposes rather than for transportation. For commercial air planes huge solar panels would be required.
The Canadian company Solarship has developed an aircraft which combines airship technology with solar energy. Their hybrid airship, while being heavier than air, gets a substantial part of its lift from buoyancy and therefore reducing its fuel consumption.
The people behind Solarship claim that the main benefit of their product is that increase the accessibility of many parts of the world, because no infrastructure is required for the operation of their airship. Though they intend to use their airship for cargo, it seems also to be usable for transporting people.
A totally different approach more suitable for mass transport along predetermined routes, is the vacuum tube train also known as “vactrain“. The idea is to drive maglev trains through long vacuum tubes, because it takes less energy to remove air from a tube than for a maglev to overcome air resistance. This approach would allow speeds up to 8,000 km/h. Vacuum tube trains might be powered by fusion power plants.