Mariner 10 and MESSENGER.
Messenger
By the space race
it has neither. also there are no man made orbiting spacecrafts.
mariner 10 and MESSENGER
No. Because of its proximity to the Sun, Mercury is one of the least-studied planets - because terrestrial observations are so difficult. Only two spacecraft have studied Mercury; the Mariner 10 and the more recent Messenger. No landers have been sent there.
Marnier 10 studied 2 planets, Venus and Mercury. It studied Venus on it's way to Mercury. Marnier 10 managed 3 fly-bys on Mercury before running out of maneuvering gas.
As of 2021, only two spacecraft have visited Mercury: Mariner 10, which flew by three times in the 1970s, and MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging), which orbited the planet from 2011 to 2015. The European Space Agency's BepiColombo mission is currently en route to Mercury as well.
Mars
Planets that have been visited by spacecrafts include Mars, Venus, Mercury, Jupiter, Saturn, Uranus, and Neptune. Additionally, the spacecraft Voyager 2 has conducted flybys of both Uranus and Neptune.
No spacecraft has ever landed on Mercury, but it was studied by Mariner 10 and MESSENGER.
Spacecrafts studying Mercury have revealed a variety of fascinating findings. Some notable discoveries include its heavily cratered surface, presence of water ice in permanently shadowed craters, a large iron core contributing to its strong magnetic field, and extreme temperature variations with highs of over 800 degrees Fahrenheit.
Term used they are docking.