Eutelsat’s OneWeb constellation suffered a date-related meltdown last week while the rest of the IT world patted itself on the back for averting the Y2K catastrophe a quarter of a century ago.
The satellite broadband service fell over on December 31, 2024, for 48 hours. According to Eutelsat, “the root cause was identified as a software issue within the ground segment.” Issues began just after 0000 UTC, and it took until January 1 to get 80 percent of the network operational. By the morning of January 2, everything was working again.
A spokesperson told The Register: “We can confirm that the issue was caused by a leap year problem, related to day 366 in 2024, which impacted the manual calculation for the GPS-to-UTC offset.”
An issue related to the number of days in a leap year will have many software engineers stroking their chins thoughtfully. While it is usually the extra day itself that can cause the odd issue or two, failing to take it into account when rolling into a new year can also cause headaches, as evidenced by OneWeb’s woes.
Eutelsat OneWeb, a Starlink competitor, completed its low Earth orbit (LEO) constellation in 2023. The company has more than 630 satellites, far fewer than the thousands of Starlink spacecraft, but enough to maintain connectivity. Assuming the code on the ground knows about leap years.
The outage came on the 25th anniversary of the Y2K panic, in which the promised chaos did not unfold due in large part to the endeavors of IT teams working on the problem during the preceding years.
The issue faced by Eutelsat OneWeb was not due to two digits being used to store the year, which is what happened in the Y2K incident, but rather an oversight that meant the extra day in a leap year was not adequately accounted for. Since accurate timekeeping is required for communication and navigation systems, problems with the offset would cause an understandable – if not excusable – service outage.
The good news is that the problem was in the software in the ground segment, meaning that the hardware in orbit was unaffected. However, the incident is embarrassing for Eutelsat since it is one of the leaders of the SpaceRISE industry consortium, recently tapped by Eurocrats for the multibillion-euro IRIS² satellite broadband deal.
SpaceRISE has promised the project will be launched into service by early 2030. Luckily, that is not a leap year. ®
