Which spacecraft was launched by ESA to investigate Halley's Comet?

The spacecraft launched by the European Space Agency (ESA) to investigate Halley's Comet is Giotto. This mission, which took place in the mid-1980s, successfully traveled close to the comet during its 1986 apparition. Giotto provided valuable data about the comet's structure, composition, and behavior, capturing remarkable images and generating insights that significantly improved our understanding of comets in general.

In contrast, the other mentioned spacecraft had different targets and missions. The Mars Global Surveyor was designed for Mars exploration and mapping, Galileo was intended for studying Jupiter and its moons, and Cassini was a mission to investigate Saturn and its rings. Each of these missions focused on their respective celestial bodies rather than Halley's Comet, highlighting Giotto's unique role in that specific investigation.