A crack has reportedly been uncovered on a Russian rocket during pre-launch preparations, a second defect in less than a year.

The U.S. microsatellite startup OneWeb was scheduled to send its first satellite into orbit on a Russian launch vehicle on Feb. 19 as it arrived in French Guiana last week. It was the second hole found on a Russian-made spacecraft in less than six months, following an incident last August in which cosmonauts found a 2 millimeter-wide hole on the Russian Soyuz capsule docked at the International Space Station, which undocked and landed safely on Earth last month.

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However, a crack was found in the Russian Soyuz rocket’s Fregat upper stage, the state-run RIA Novosti news agency reported Wednesday, citing three space industry sources.

Another unnamed space industry source told the state-run TASS news agency the “pinhole most likely appeared due to the upper stage’s lengthy transportation to the launch site.”

The launch date could be postponed until March while Fregat’s manufacturers work to fix the defect, the source was quoted as saying.

OneWeb plans to deploy dozens of satellites – “routers in space” – to provide global internet coverage by 2021. The project is scheduled to go fully online by 2027.

The platform struck a deal with Russian space agency Roscosmos in 2015 to send the satellites into orbit and clinched a joint venture with a subsidiary of the agency to service Russia.

Russia’s Federal Security Service (FSB) branded the project a threat to national security.

Reuters contributed reporting to this article.