Just why do we need to make space travel a common thing?
Well there a lot of reasons but the main reasons are:
- Technological advancement
- Human species survival
Our everyday appliances and devices run on electrical energy, which is obtained from fossil fuels or other types of fuels. Our cars run on fossil fuel energy. Our bodies rely on chemical energy and so on. Everything in our world that we have today is based on energy. With the invention of agriculture we were able to achieve more food which is more energy for our bodies and minds. That gave us more free time to think about ways to better ourselves.
To travel into space efficiently we have to have to great amounts of easy to produce energy. Traveling efficiently means to travel fast, because distances in space are of the order of billions of kilometers. You don't want to travel from point A to point in B in space in years because you will die of boredom, so you'll have to move faster. To make an object move faster you need energy.
Currently we are not very efficient at producing and storing energy. Reaching space means that our millennial fight with finding a way of cheaply producing and storing massive amounts of energy will probably come to an end. Rockets are actually a pretty inefficient way of traveling because for a useful payload you need huge amounts of propellant.
2. Interplanetary space is very inhospitable. There's no air. It's cold. It's full of radiation. And the distances are abyssal. To survive in the harsh environment of space we need technology. If somebody gets sick on a space ship that is light years away from the nearest hospital you need technology that can diagnose and cure diseases fast with very few resources. You need a way to efficiently grow or produce food. You need novel and efficient ways to repair or construct needed devices.
3. It's nice and warm on planet Earth. The problem is that some stay stray comet, asteroid, planeton or runaway neutron star can hit the earth and wipe us out. Chances are quite high because it happened in the past. When sh*t hits the fan we need a way to abandon ship and the only way is by going into space.
If you ever wondered what are the principles behing rockets just remember that it's all about Newton's 3rd principle, action and reaction.
I have written a nice post on the principles of Newtonian Mechanics:
please check out these 2 sources :