Which spacecraft became the first man-made object to escape the solar system after crossing Pluto's orbit?

The first man-made object to escape the solar system after crossing Pluto's orbit is Pioneer 10. Launched on March 2, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt and make a flyby of Jupiter, providing the first close-up images of the planet. It continued on its trajectory and became the first spacecraft to cross the orbit of Pluto and exit the solar system, completing its historic journey in 1983.

While Voyager II made significant contributions to our understanding of the outer planets and also left the solar system, it did so later than Pioneer 10. Explorer I was the first successful satellite launched by the United States but did not have the capabilities or trajectory to escape the solar system. New Horizons is also known for its mission to Pluto and beyond, but it does not precede Pioneer 10 in terms of escaping the solar system. Thus, Pioneer 10 holds the distinction of being the first man-made object to achieve this remarkable milestone.