Budget fight rages over James Webb Space Telescope, Washington Post

"But if Congress provides less than the $530 million that NASA says the project needs next year, the schedule will slip further and costs will continue to rise. In 2006, NASA estimated that Webb would cost $2.4 billion and could launch in 2014. In 2008, the price tag rose to $5.1 billion. A congressionally mandated report released last year found that NASA had underestimated costs and mismanaged the project. This summer, NASA said it had already spent $3.5 billion on the project and needed a total of $8.7 billion to launch in 2018."