As far as we know, the farthest that human beings have gone from the earth's surface has been in the Apollo command modules that orbited around the far side of the moon. Give them credit for maybe a quarter million miles from earth ... 250,000 miles. -- about 1 percent of the distance to Venus when it's closest to earth; -- about 1/2 percent of the distance to Mars when it's closest to earth; -- about 1/4 percent of the distance to the sun.
No. The Hubble Space Telescope was built on Earth and launched into space. It is about the size of a bus.
Mercury orbits very close to the Sun and looking near to the Sun could damage the telescope.
Otherwise it won't remain pointed at the same spot in space any longer.
Impossible to answer !... The Hubble Space Telescope is not located at a fixed point (geo-stationary orbit). It orbits the earth once every 95 minutes (approx) - at an inclination of 28.5 degrees. Therefore - although its position relative to the equator is fixed - it travels across the visible sky.