As the cost of access to low Earth orbit falls, one of the main business opportunities will be the growth of passenger travel services. Market research has shown that there is a very large unsatisfied demand for trips to orbit, and it is known that suitable vehicles could be developed with the investment of some billions of dollars - a fraction of current annual government expenditure on space activities. If developed soon, passenger space travel could become for the 21st century what air travel was for the 20th century, with great benefits for the world economy. The economic benefits of this development will be so great that steps should be taken to realize it as soon as possible.