NASA officials said they delayed the launch, long scheduled for October 2018, after realizing that it will take more time than scheduled to integrate various elements of the telescope and test them to ensure they will survive the trauma of launching into space.
According to the United States space agency, the telescope is next great multi-purpose observatory and it will also be the world's most powerful space telescope ever built, serving thousands of astronomers worldwide.
NASA's James Webb Space Telescope (JWST), the spiritual successor to the Hubble Space Telescope (HST) and the most advanced space telescope ever built, will have to wait a little longer to get to orbit.
Integration "taking longer than planned" While tests of the telescope and its scientific instruments continue to "go well" and are said to be on schedule at NASA's Johnson Space Center in Houston, Texas, it is the spacecraft itself that is said to be responsible for the hold-up.
"The change in launch timing is not indicative of hardware or technical performance concerns", Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, said in a statement.
The rescheduling is the first major shift in planning for the telescope since 2011, when a new road map replaced one that culminated in an impossible and over-budget 2014 launch.
"Rather, the integration of the various spacecraft elements is taking longer than expected", he added.
Space fans (myself included) have been looking forward to James Webb for years.
These include the recently discovered TRAPPIST-1 planets-seven planets, of which three or four are believed to be potentially habitable. James Webb most likely won't find life, but it could tell us if the conditions for it are lurking in other star systems. Instead, an assessment of the schedule for the remaining work to be done on the telescope simply showed it would not be possible to launch JWST in October 2018.
The close co-ordination with ESA is required because the European agency is providing the Ariane 5 rocket to launch JWST, as part of its scientific collaboration with NASA.
"Webb's spacecraft and sunshield are larger and more complex than most spacecraft", JWST program director Eric Smith announced with NASA. Engineers have determined that integration activities, such as the installation of more than 100 sunshield membrane release devices, will require more time.