The first strike came overnight on October 8 in Sasovo, Ryazan region, home to Chervonenkis, the IT giant's most powerful machine, and Lyapunov, its third most powerful. The following night, drones hit the data center in Kaluga, Yandex's largest and one of the biggest in Russia. Overnight on October 11, a drone attacked the data center in Vladimir housing the Galushkin supercomputer.

Four computing-systems specialists interviewed by T-invariant said the company's computing capacity had been seriously damaged. The equipment's vulnerability stems from its direct free-cooling system: cooling by outside air, which intake fans force through filters before it passes through server racks.

Even if fire did not reach the racks, air carrying soot and ash could have reached the server boards, with the finest particles settling on the circuit boards. Carbon conducts electricity, and because of the high density of traces on the boards, the particles act as conductive "bridges" between contacts, causing short circuits and the burnout of motherboards. Combustion products can also corrode conductors and contact connections.

According to the specialists, cleaning smoke, soot and grime from supercomputer components could take up to six months. If components need replacing — including scarce NVIDIA chips or their analogues — restoring full operation of the machines could take one to two years.

In the summer, Yandex said it was starting to introduce liquid cooling systems. To integrate the technology into free-cooling data centers, the company's engineers developed a solution — sidecars, additional racks with liquid-air radiators that avoid the need for large-scale reconstruction of buildings. According to the experts, any liquid cooling elements are more effective during fires, but the company is unlikely to have finished rebuilding all of its data centers.

One of T-invariant's sources, who works at a global AI technology giant, was skeptical about the supercomputer cooling technologies Yandex uses. Liquid cooling systems of the kind NVIDIA uses are usually employed, and less often immersion liquid cooling systems.

Before the full-scale war, Chervonenkis ranked 19th out of 500 in the world supercomputer ranking. According to T-invariant's assessment, Russia risks losing out to Kazakhstan in the AI race as early as November. Yandex is not commenting on the state of its supercomputers after the attacks.

Russian users have been encountering disruptions for more than a week in the services of Yandex's cloud partners and other B2B partners of the company, as well as outages in the company's own services — above all Yandex Disk and Yandex Pay.

In Kaluga, after the attack on the data center, which halted several modules of the facility, a prayer service was held on October 14 before the icon of the "Burning Bush," which is considered miracle-working. The rector of the Church of Saint Prince Vladimir, Priest Kirill Khlanta, together with Priests Dimitri Novikov and Ilya Potemkin, drove around the Pravoberezhye microdistrict with the image of the Mother of God and sprinkled the streets with holy water, according to the church's page on VKontakte. "We are now living through a difficult time. Our city, and Pravoberezhye among it, is being bombarded, drones are flying. It is precisely in such times that our ancestors turned to God and the Mother of God for intercession and help," the church's post says. According to The Moscow Times, a total of 30 buildings were damaged in Kaluga, including residential buildings. At the same time, after drone debris fell, the AGR automobile plant, which assembles Chinese Tenet cars, halted operations.

Similar prayer services and religious processions have been growing in popularity in Russia since the invasion of Ukraine. In the winter of 2025, priests flew with icons over the Ryazan region, home to the Dyagilevo nuclear bomber base and a Rosneft plant.

On October 14, drones attacked an unfinished Sberbank data center in Balakovo, Saratov region.