Currently all missions to Mars are unmanned. The only human aspect of these missions are the scientist and engineers that build the satellites or rovers/landers and the people that control them (mission control).
Yes, Voyager II has. (Voyager II is an unmanned space probe).
Yes, there are 44 missions.
Many American spacecraft have reached Mars. All were unmanned, however.
One of the best places for one to find images of Mars is on the NASA website. NASA has had numerous unmanned missions to Mars and has a vast collection of pictures of the planet. The latest such mission is the Mars Curiosity Rover.
Humans, no. Unmanned spacecraft, yes.
VoyagerCassiniHuygensLunaSputnik
Curiosity is unmanned.
I am not sure if by "space mission" You mean a mission to a distant object or into deep space or manned or unmanned. Voyager I and II are unmanned deep space missions, both launched in 1977. More than thirty years later they are both still running (as of today: March 10, 2010). The unmanned Mars Exploration Rovers Spirit and Opportunity were rover launched to Mars in 2004. Opportunity is still running fine but Spirit is stationary because two of its six main wheels have stalled. The Apollo Missions were manned moon missions in the nineteen-sixties and seventies. They were also very successful.
yes
Familiarity with orbital mechanics would be an excellent idea. That, and some really big engines. Our unmanned missions to Mars have all been launched on the civilian equivalent of Intercontinental Ballistic Missiles.
No one went to Mars. It was an unmanned robotic expedition.
The Russians did not make any successful moon landings, it was all unmanned.