Irina K. Romanovskaya elaborates on the idea of using free floating (rogue) planets for space exploration and colonization. Extraterrestrial civilizations’ biological species, post-biological species or their technologies become Cosmic Hitchhikers when they ride free-floating planets to reach, explore and colonize planetary systems. The Cosmic Hitchhikers Hyptothesis:

I propose the Cosmic Hitchhikers hypothesis as follows. Advanced extraterrestrial civilizations may use free-floating planets as interstellar transportation for space exploration and interstellar colonization. Large groups or populations of their biological species, post-biological species, and technologies may become Cosmic Hitchhikers when they ride free-floating planets to reach, explore and colonize planetary systems. To get an interstellar ride, Cosmic Hitchhikers may travel to free-floating planets passing close by their home worlds. Otherwise, they may use astronomical engineering to steer free-floating planets toward their home planetary systems. Cosmic Hitchhikers may also ride objects native to the outer regions of their planetary systems, which become free-floating planets when ejected by astronomical engineering or by their stars during the asymptotic giant branch evolution. During interstellar travel, Cosmic Hitchhikers may apply astronomical engineering to steer their free-floating planets toward the planetary systems of their choice. Whereas riding free-floating planets may not save travel time, it avoids the technical challenges of interstellar spacecraft transporting large populations. Each civilization of Cosmic Hitchhikers may colonize several planetary systems. Its colonies may grow into autonomous civilizations, changing the number of civilizations in the Galaxy. Over the last 4 billion years, Cosmic Hitchhikers or their artifacts riding free-floating planets might have passed by the Solar System. Therefore, their artifacts might exist in the Solar System or in our stellar neighborhood. SETI and SETA should include the search for Cosmic Hitchhikers and their artifacts.

Romanovskaya, Irina K. ‘The Cosmic Hitchhikers Hypothesis: Extraterrestrial Civilizations Using Free-Floating Planets for Interstellar Colonization’. arXiv, 12 January 2022. https://doi.org/10.48550/arXiv.2202.03364.

Here is her paper published in the International Journal of Astrobiology, with empahsis on the technosignatures produced by Cosmic Hitchhikers….

I propose possible technosignatures and artefacts that may be produced by extraterrestrial civilizations using free-floating planets for interstellar migration and interstellar colonization, as well as strategies for the search for their technosignatures and artefacts.

Romanovskaya, Irina K. ‘Migrating Extraterrestrial Civilizations and Interstellar Colonization: Implications for SETI and SETA’. International Journal of Astrobiology, 28 April 2022, 1–25. https://doi.org/10.1017/S1473550422000143.

and a bit de-science-fictionalized (I guess after peer review ;).

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Featured Image, referred in How to become a space faring civilisation without leaving the armchair.