Mercury

1860

Earth based

Giovanni Sciaparelli

First maps of Mercury

circa 1900

Earth based

Spectroscopic analysis detects thin atmosphere with sodium and potassium possibly diffusing from Mercury's crust

1919

May 29

Earth based / miscellaneous

Eddington / Einstein

Eddington went to Principe off the coast of West Africa to observe the eclipse that proved the theory of relativity and explained Mercury’s perturbations.

1991

Earth based

Earth based telescopes detect polar ice sheets

1974

Flyby

Mariner 10

 Mariner 10 passes Mercury in first of three flyby's, Feb 1974, Sept 1974 and March 1974. The probe detects a temperature of 430c on the sunlight side and -180 on the dark side, it also detects craters and on September 1974 detects a magnetic field 10% Earth

1992

Sample returned

Mission Sample Return

Mission named Sample Return scheduled but cancelled due to lack of funding, no immediate plans to reinstate project.