NASA stalls $8bn James Webb Space Telescope again

The telescope designed to look at stars formed soon after the Big Bang as well as closer objects – was scheduled to launch in October this year. Technical problems pushed that back to May 2019. Now NASA says that will slip to May 2020 at the earliest, and indicated that the $8bn plowed into the project may not be enough to complete it.
“With all the flight hardware 100 per cent complete, we’re approaching the finish line for launch readiness. However, it looks like we have a ways to go before we cross that finish line,” said Thomas Zurbuchen, NASA associate administrator for science.
The telescope is being put together by Northrop Grumman. The team has run into various problems, particularly with the propulsion system. In testing, a transducer was found to be incorrectly powered and in need of replacement, which set the project back three months.
A section of the propulsion unit was also found to have used the incorrect solvent, so certain valves had to be stripped out and replaced. A catalytic heater was also accidentally "overstressed," and had to be ripped out and replaced.
Dennis Andrucyk, deputy associate administrator for NASA’s Science Mission Directorate, said these were avoidable errors, however, they happened because humans are human, and, well, we all make mistakes.