The James Webb Space Telescope won't launch as scheduled on Halloween this year—which is definitely a trick rather than a treat for the space community. However, the delay may only be a few weeks.

Last summer, NASA and the European Space Agency (ESA) set an October 31, 2021, launch date for the $10 billion telescope. The instrument, which is the largest science observatory ever placed into space, will launch on a European Ariane 5 rocket from a spaceport in French Guiana. Now, however, three considerations have pushed the launch into November or possibly early December.

During a press briefing with reporters on Tuesday, the telescope's director for launch services, Beatriz Romero, said that there are a "combination of different factors" to consider when setting a new launch date. These factors include shipment of the telescope, the readiness of the Ariane 5 rocket, and the readiness of the spaceport in South America as well. Romero said she did not expect to identify a new launch date until later this summer or early fall.

NASA plans to ship the telescope to the launch site by boat late this summer. (NASA is keeping precise plans vague due to concerns about piracy at sea. Seriously.) The space agency's chief of science, Thomas Zurbuchen, said Tuesday that "we don't have a lot of reserve" left in the schedule to prepare for shipment. However, he added that NASA and Webb's primary contractor, Northrop Grumman, are close to folding up the telescope and putting it into a shipping container. He said that this should happen toward the "end of August."

The launch campaign, which begins when the telescope arrives in French Guiana, requires 55 days. Asked whether this means that Webb will not launch until mid-November at the earliest, Zurbuchen said this assessment was correct.

The rocket is also not ready. The Ariane 5 booster, a venerable rocket in service for more than 25 years, has been grounded since August 2020 due to a payload fairing issue. However, officials with Arianespace, which manages launch for the Ariane 5, said the fairing issue's cause has been diagnosed and addressed with a redesign. Two Ariane 5 launches are scheduled before Webb's launch to ensure that the fairing issue has been fixed. (Those launches are scheduled for July and August, but delays are possible.)

Finally, there are concerns about the spaceport itself, where operations have been limited by COVID-19. Vaccines are not yet widely available in French Guiana, and officials have said that if virus activity worsens, it could further slow operations.

While it is not pleasant to hear about further delays to launching the James Webb Space Telescope, it is nonetheless clear that NASA is finally bringing this project closer to space. Webb's launch has been delayed for more than a decade by technical problems and by the need for extensive testing. Some of this is understandable, however. Launching and deploying Webb successfully would be a masterful feat—unfurling it in deep space requires 50 major deployments and 178 major release mechanisms. All of these must work, or the instrument will fail.

So if NASA needs just a little more time to get Webb into space, and if ESA needs a little more time to ensure the safety of its ride, these are perhaps not such bad precautions to take.