The launch of the $10bn (£7.5bn) James Webb space telescope has been delayed again, after an incident during the final preparations to place the telescope on top of its launch vehicle. The spacecraft was scheduled to be sent into orbit on 18 December but now it will not launch before 22 December. The space telescope is at Europe’s spaceport in Kourou, French Guiana, where it will be launched using an Ariane 5 rocket supplied by the European Space Agency (Esa). The project is an international partnership between Nasa, Esa and the Canadian Space Agency. The incident took place as technicians were preparing to attach Webb to the launch vehicle adaptor, which would then be used to fix the telescope to the upper stage of the rocket. According to Nasa, “a sudden, unplanned release of a clamp band” took place. The clamp band fixes the spacecraft to the launch adaptor and then releases in orbit, allowing the spacecraft to separate from the rocket. This unplanned release caused a vibration to travel through the telescope. To be absolutely certain the spacecraft remains in perfect shape, Nasa has convened an anomaly board to investigate and perform additional tests on the spacecraft to ensure nothing has been damaged. Once this is finished, assuming no damage, launch preparations will resume.