How to get to Space - cheap...

There are many reasons why exploring and later living in space will be expensive.

However, perhaps the greatest obstacle which needs to be overcome for the door to be opened so that humanity can freely travel from the earth will be the fact that here on our planet we live at the bottom of a gravity well; each kilogram of material going into orbit must be hauled up out of the earth’s gravitational influence.

Currently, the price-to-orbit starts at around US$19,000 per kilogram – and that’s for inanimate mass - the cost for lifting humans to orbit is much higher due to the fact that we require air, food, water and a controlled environment, all of which need to travel with us; the total price will need to include training, ground support crew, earth based recovery teams and infrastructure.

At every space launch a very large amount of the mass that is lifted into earth orbit comprises of the fuel needed by rocket engines. Are there any other methods of moving material off the surface of the earth? What can be done to lower the costs of flinging mass into earth orbit?

One alternative is the concept of a ‘space elevator’.

The basic idea is a structure of some kind that reaches from the surface of the earth into space. Getting to – or from – earth orbit will be achieved by travelling up and down the structure. At this date, it’s difficult to imagine construction materials that would allow for the erecting of what most of us would imagine as a traditional ‘building’ – bricks or some other material compressing themselves down to the ground and thereby maintaining overall structural integrity. It is extremely unlikely that the construction of such a tower will ever be achieved that will raise a mass to geostationary orbit – 35,786 km. A slightly more realistic solution involves the production of a long, strong cable, extending at least to geosynchronous orbit where it might be tethered to a counterweight such as a space station or captured asteroid. Material can then be ferried to and from orbit by riding down the tether.

Once the space elevator has been constructed, the theoretical cost for moving mass to orbit dramatically decreases – by some conservative estimates to as little as US$ 500 per kilogram – and by other estimates, far less.