Many American spacecraft have reached Mars. All were unmanned, however.
As of yet, there have been no manned Mars spacecraft at all.
Not yet, only probes have. In the future, NASA are hoping to reach Mars.
No spacecraft has been built yet that's capable of transporting human beingsto Mars, particularly if they're the kind of people who'd be expecting to breatheduring the trip, and to wrap it up some day by returning to earth alive.
No person has yet walked on mars.
Not yet.
No, as of yet there is no evidence of any life existing on Mars but they are still looking.
Nope. They all survived. We have not yet sent any humans to Mars, if that was what you meant. Except for Hollywood, they've sent tons of people to Mars
There have been several unmanned spacecraft that have landed on mars (look at http://en.wikipedia.org/wiki/Exploration_of_Mars), but as yet, no manned missions. several space agencies have projected possible manned attempts in the 2030s, (http://en.wikipedia.org/wiki/Manned_mission_to_Mars), but as yet, no formal plans have been decided on.
no human has landed on mars yet. just a few machines taking pictures
We have not yet found any evidence of life on Mars, let alone footprints.
Not yet, but the "New Horizons" space craft was launched in January 2006. It is expected to reach Pluto some time in 2015 if nothing goes wrong.
Astronomers have not yet made any findings regarding the possibility of life on Mars.