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Galileo [9] [10] discovered the Galilean moons. These satellites were the first celestial objects that were confirmed to orbit an object other than the Sun or Earth. Galileo saw Io and Europa as a single point of light on 7 January 1610; they were seen as separate bodies the following night. [11] Callisto: Jupiter IV o: 8 January 1610 p: 13 ...
Mariner 10 first passed Mercury in 1974. The first probe to explore the outer planets was Pioneer 10, which flew by Jupiter in 1973. Pioneer 11 was the first to visit Saturn, in 1979. The Voyager probes performed a Grand Tour of the outer planets following their launch in 1977, with both probes passing Jupiter in 1979 and Saturn in 1980–1981.
The first telescopic observations of Mercury were made by Thomas Harriot and Galileo from 1610. In 1612, Simon Marius observed the brightness of Mercury varied with the planet's orbital position and concluded it had phases "in the same way as Venus and the Moon". [169]
Few missions have targeted Mercury because it is very difficult to obtain a satellite orbit around the planet. Mercury orbits the Sun very quickly (between 24.25 miles per second (39.03 km/s) and 30 miles per second (48 km/s)), so spacecraft must be travelling very fast to reach it.
Mars 3 – First Mars lander Pioneer 10 – First Jupiter flyby Mariner 10 – First Mercury flyby Voyager 2 – First Uranus/first Neptune flyby Mission name Launch date
First flyby and orbit of a dwarf planet . First spacecraft to orbit two separate celestial bodies. USA (NASA) Dawn [68] July 2015: First flyby of an object beyond Neptune (Pluto and its moons). First flyby in the Kuiper belt. First flyby of a trans-neptunian object. Last original encounter with one of the nine major planets recognized before 2006.
First Canadian satellite (on American rocket), first satellite not constructed by the US or USSR October 2 US: Explorer 14 (EPE-B) Thor-Delta A: Earth Success NASA spacecraft instrumented to measure cosmic-ray particles, trapped particles, solar wind protons, and magnetospheric and interplanetary magnetic fields. October 18 US: Ranger 5: Atlas ...
Originally presented as satellite planets orbiting the planet Uranus. [15] Planetary status later rescinded, leaving them only as satellites. Oberon: 1787 1700s Ceres: 1801 1867 Asteroid and dwarf planet: The first asteroids to be discovered were accepted as planets in the Copernican system, since they directly orbited the Sun.