Colonising Space/Access to space

We now have access to space using rockets although this is still expensive (over $5000 per pound of material launched^[1]) and the failure rate is quite high. This severely limits what we can do in space; it is the main obstacle to space solar power and the colonisation of space. So far, we have only dipped our toes, if we want to really dive in we have to make spaceflight cheap and reliable.

It may be that using abundant solar energy and seawater and advanced automation, mature rocket technologies like liquid oxygen and hydrogen fuelled rockets actually end up becoming cheap and common-place, likely in conjunction with solid-rocket boosters like the Space Shuttle uses that employ metal fuels and inorganic oxidizers made from common elements.

Skylon single-stage-to-orbit (SSTO) hybrid air-breathing space-plane capable of carrying 40 tonnes of cargo or 40 passengers to low earth orbit

However many alternative and interesting launch systems are thought to be technically (or at least theoretically) feasible ranging from single stage to orbit hybrid air-breathing space-planes (SSTOs), electromagnetic and balloon platform launch assist to more exotic space fountains, launch loops and geosynchronous space elevators. It may be that launch strategies that can have their power systems decoupled from the propellant/propulsion systems and installed on the ground may end up being more economical and efficient in terms of energy expended per unit weight lofted into space.

Information on these alternative launch methods are covered in more detail in this WP article .