An artist’s representation of the completed James Webb Space Telescope Northrop Grumman

The launch date for the James Webb Space Telescope (JWST) has been delayed again. This comes after a series of delays and budget overruns.

In a statement, NASA says they are now aiming to be ready to launch the space observatory in May 2020, and that it may exceed its budget. If it surpasses its current $8.8 billion budget, the project will have to be re-approved by the US Congress, says Thomas Zurbuchen of NASA’s Science Mission Directorate.

“We want this to work well in orbit, so we cannot afford to take any shortcuts,” he says. Since the project began in 1996, its scope has widened and its budget has ballooned from $0.5 billion to $8.8 billion. The recently passed US spending bill included $533.7 million for the James Webb Space Telescope, the amount requested.


Leaks and delays

By last year, the launch date had been pushed back to June 2019. In February, a report from the US Government Accountability Office suggested that the telescope’s launch seemed likely to be delayed and to exceed its budget. There were problems with its sunshield and thrusters, and little extra time built into the schedule to fix them – even with teams of contractors working 24 hours a day.

Acting NASA administrator Robert Lightfoot said in a press conference on 27 March that these issues will require more time for testing, effectively pushing back the launch date. He confirmed that the leaks in the thrusters affect the spacecraft that will place JWST in orbit, rather than the observatory itself.

JWST is NASA’s planned successor to the Hubble Space Telescope. Its mirror has a diameter of 6.5 metres – almost three times bigger than Hubble’s – which will be able to peer deeper into the early universe and capture data on the formation of the first stars and galaxies.

The space telescope is planned to be an exoplanet hunter, allowing us to see the atmospheres of planets beyond our solar system, and search for signs of life on other worlds.

Read more: We’ve just found a nearby exoplanet that could be right for life