To the best of my knowledge, the double-slit experiment has not been conducted in the vacuum of space The double-slit experiment is a fundamental experiment in quantum physics that demonstrates the wave-particle duality of matter and the interference phenomenon.
The experiment involves passing particles, such as electrons or photons, through a barrier with two narrow slits and observing the resulting pattern on a screen placed behind the barrier. When particles are sent through the slits one at a time, they can behave as if they are waves and create an interference pattern on the screen, indicating their wave-like nature. This interference pattern is not observed when the particles are observed or when their path through the slits is detected, indicating their particle-like nature.
While the double-slit experiment has been extensively performed in laboratory settings using various particles, such as electrons, photons, and even larger molecules, I am not aware of any reports or scientific experiments specifically conducted in the vacuum of space.
However, it is worth noting that space-based experiments have been carried out to explore quantum phenomena and test the foundations of quantum mechanics. For example, experiments have been conducted on the International Space Station (ISS) to investigate quantum entanglement, quantum communication, and other aspects of quantum physics. These experiments leverage the unique environment of space to achieve long coherence times, precise control, and isolation from external disturbances.
It is possible that in the future, space-based experiments may include variations of the double-slit experiment or explore other aspects of wave-particle duality in the vacuum of space. Advances in technology and space exploration may provide opportunities to investigate quantum phenomena in such environments, but it would depend on the specific goals and objectives of future research missions.