Russia lost access to Starlink and is building a replacement. What is known about the Rassvet system?

Russia is actively developing its own satellite internet system – a technology that has become well known to Ukrainians since 2022 thanks to Starlink terminals.
If Russia were a normal state, such a project would be seen as a logical step in technological development. In a country with such a vast territory, satellite internet could genuinely provide connection even to the most remote regions.
However, in the context of Russia's war against Ukraine, the story takes on a very different meaning. For Ukraine, it represents a significant potential threat to national security.
After losing access to Starlink, the Russian military has been searching for an alternative. Although Russia's attempts to develop its own systems have not always been successful, Moscow is trying to build a Starlink equivalent called Rassvet.
Little has been publicly disclosed about the project, which is being developed by Bureau 1440, but within a year it could become a major topic. If Russia succeeds, it will significantly improve military communications and, in the future, could use satellite internet to control drones – an idea that Kremlin ruler Vladimir Putin himself voiced in the spring.
If that happens, Russia's occupation forces will gain a new autonomous communications capability that is less dependent on ground infrastructure, foreign services and vulnerable communication channels. Can Moscow really build a Starlink equivalent? What threats would such a system pose to Ukraine? And what is known about Bureau 1440?