Which spacecraft was specifically launched to explore the Sun's poles?

The spacecraft that was specifically launched to explore the Sun's poles is Ulysses. Launched in 1990, Ulysses was a joint project between NASA and the European Space Agency (ESA) designed to study the Sun from a unique high-inclination orbit, allowing it to observe the solar poles for the first time.

This mission provided critical data on solar wind, magnetic fields, and cosmic rays, significantly enhancing our understanding of solar activity and its effects on the solar system. Ulysses' orbit took it over the Sun's poles, which was essential for gathering information that cannot be observed from Earth's orbit or even from other locations in the inner solar system.

The other spacecraft mentioned—Mariner, Galileo, and Skylab—were designed for different missions. Mariner explored various planets, Galileo studied Jupiter and its moons, and Skylab was a space station focused on scientific research in microgravity rather than solar observation. Thus, Ulysses stands out as the only mission specifically aimed at investigating the Sun's poles.