Depends on whether you say Pluto is a planet or not.
If you say it isn't, then there are no planets that haven't been visited by a spacecraft.
If you say it is, then there is one that hasn't been visited yet, but one is on the way.
yes, spacecraft have visited Mars, but the results haven't always been positive. More than half of the attempts to send a spacecraft to the planet have failed.
No human has really visited any planet other than Earth; the Moon isn't a planet. However, spacecraft have visited other planets, such as the Spirit and Opportunity rovers, who went to Mars
Mars has constantly been visited by spacecrafts. The first spacecraft to visit Mars was the Mariner 4. After that Mars has been visited by numerous spacecrafts like: Mars Pathfinder, Mars Global Surveyor, Mars Odyssey, Mars Express and the Mars 2 which was the first spacecraft to land on Mars.
The answer is mars.
Pluto has yet to be visited by a spacecraft because it is so far away.
No spacecraft has visited all the planets.
All of the eight planets have been visited or orbited by space probes.
April 2008 At present the only planet in our solar system that has not been visited (either by an orbiting spacecraft or flyby spacecraft) has been the recently planet downgraded body of Pluto. There is a mission currently in motion to visit this distant outpost.
venus was the first planet visited by the American spacecraft
All 8 of the planets in our solar system have been visited by spacecraft, either fly-bys, or actual landings. The dwarf planet pluto has yet to be visited, but a space probe called New Horizons is on its way and should reach Pluto in 2015.
hi
yes
Currently no clear pictures if any dwarf planet exist, as none have been visited by a spacecraft. In 2015, however, the New Horizons spacecraft will fly by Pluto, and the Dawn spacecraft will enter orbit around Ceres.
yes, spacecraft have visited Mars, but the results haven't always been positive. More than half of the attempts to send a spacecraft to the planet have failed.
yes
No human has really visited any planet other than Earth; the Moon isn't a planet. However, spacecraft have visited other planets, such as the Spirit and Opportunity rovers, who went to Mars
Pluto will be visited by the spacecraft New Horizon in 2015