Currently no human made objects are orbiting Neptune yet Neptune has eight satellites explain?

Answer 1

Neptune actually has 13 satellites,

Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Pasamathe, and Neso.

Also, you may note that your question is incomplete, so I'll try to give a "shot in the dark" at answering your question.

Though Neptune has 13 known satellites, it likely has more that are beyond the detection capabilities of modern telescopes. Out there at the edge of the Sol System, lighting isn't too good, so it's harder to find those small moons. With the exception of Triton, Neptune's moons are rather small. Triton orbits Neptune counter-clockwise, as opposed to the rest of the moons which orbit Neptune clockwise. This is because Triton is believed to have been captured earlier in the history of the Sol System.

It's believed Uranus had a large collision or two that resulted in enough debris being shot into orbit to generate several relatively large moons, and provided Uranus with a ring system. Neptune isn't believed to have any such event. So Neptune's satellites (with the exception of Triton, again) are generally smaller.

Answer 2

The satellites around Neptune are natural objects, not man-made. They are small bodies that have been captured by Neptune's gravitational pull and orbit the planet. Man-made objects have not been sent to orbit Neptune yet.