Now, for the first time in 50 years, the future of human spaceflight is unknown.
Money for human spaceflight should go into building a new type of spacecraft instead, he said.
And human spaceflight is not the only enterprise to benefit.
This has introduced something never before seen in human spaceflight: market competition.
We need a debate on the real issues: What is our basic motivation for human spaceflight?
Life support functions and technology are also prominent in the field of human spaceflight.
George Abbey had more influence on human spaceflight than almost anyone in history, but few outside the field know his name.
So far, he added, scientists do not have that same sense of ownership about human spaceflight.
China's first efforts at human spaceflight started in 1968 with a projected launch date of 1973.
On June 21, 2004, it made the first privately funded human spaceflight.