Capitolism is the impediment. Communism is Star Trek's answer to this problem. Don't be offended... these are economic terms, not political. Thru the years, their meanings have become misconstrued.
But as leftist as I am, "cost" doesn't cease to exist in a socialist framework.
I disagree with Sojourner, too--money isn't a paper representation of the labor theory of value. It's a paper representation of the market's determination of worth.
In addition to economics/money being a limiting factor there is also politics coming into play. Government sector vs. Corporate sector vs. Private sector also factor in to our development and expansion. Why does the government limit this or that?
For example why haven't any private companies ventured to the moon? Were there private space programs in the 50s, 60s and 70s or was it just the government?
Aren't there some areas of research and development that still need government approval before the private sector can proceed? As long as any government doesn't want to give up power or give permission for non-governmental agencies to work in various areas, government will hinder growth and expansion.
How much hindrance is due to money, how much is due to resources and how much is due to governments wanting power or control?