July, 2015: After nine years of travel, we’ve reached Pluto!

After exploring 8 planets and an asteroid belt dwarf planet, we have finally reached the Kuiper belt, and its largest dwarf planet, Pluto, along with Pluto’s largest moon, Charon (also considered to be, as a pair, a double-dwarf planet)!

The era from 1962 to 2015, of planetary exploration has so many twists and turns that could take hours to follow, that it might be most easily summarized by lists.

NASA spacecraft missions spanning 1962 to 2015

The NASA missions have overlapped in time, but were launched in this order:

• Mariner (at least 10 missions)
• Pioneer 10 and 11
• Voyager 1 and 2
• Dawn (1 mission)
• New Horizons (1 mission)

Years we first saw the planets up close

• 1962 Venus (inner terrestrial planet)
• 1965 Mars (inner terrestrial planet)
• 1973 Jupiter (outer gas giant)
• 1974 Mercury (inner terrestrial planet)
• 1979 Saturn (outer gas giant)
• 1986 Uranus (outer gas giant)
• 1989 Neptune (outer gas giant)
• March, 2015 Ceres (dwarf planet, asteroid belt-between inner and outer planets)
• July, 2015 Pluto (dwarf planet, Kuiper belt, beyond Neptune’s orbit)

Mariner spacecraft, first mission launched in 1962

The “Era of planetary exploration,” 1962 to 2015, began with the Mariner. There were 10 missions, which explored what has been known as the “terrestrial” planets, the four planets in the “inner solar system,” just before the asteroid belt.

The Mariner series of U.S. spacecraft explored the inner solar system, obtaining information about Mercury, Venus, and Mars. Mariner 2 was the first successful space probe and the first spacecraft to visit a planet. It passed Venus at about 34,758 km on December 14, 1962.

Pioneer 10 and 11 spacecraft, launched 1972 and 1973

Next came the voyages of the Pioneer 10 and 11, traveling through the asteroid belt, to two of the four gas giants in the “outer solar system,” Jupiter and Saturn.

Launched over a year after its sister spacecraft, Pioneer 11 was the second spacecraft to explore the outer solar system. The spacecraft used Jupiter for a gravitational assist to slingshot it out to Saturn. Pioneer 11 studied the masses, interiors, atmospheres, moons and rings of Jupiter and Saturn

See also: Voyages of Pioneer spacecraft

Voyager 1 and 2, launched 1977

Next, Voyager 1 and 2 continued exploration of Jupiter and Saturn and went on to Neptune and Uranus. It’s been called the “interstellar” mission.

Between them, Voyager 1 and 2 explored all the giant planets of our outer solar system, Jupiter, Saturn, Uranus and Neptune; 48 of their moons; and the unique system of rings and magnetic fields those planets possess. Closest approach to Jupiter occurred on March 5, 1979 for Voyager 1; July 9, 1979 for Voyager 2.

The Voyager missions were renamed “interstellar” in midstream, in recognition that the probes eventually entered Interstellar space.

Voyager 2 encountered Uranus on January 24, 1986, returning detailed photos and other data on the planet, its moons, magnetic field and dark rings. Voyager 1, meanwhile, continues to press outward, conducting studies of interplanetary space. Eventually, its instruments may be the first of any spacecraft to sense the heliopause — the boundary between the end of the Sun’s magnetic influence and the beginning of interstellar space. (Voyager 1 entered Interstellar Space on August 25, 2012.)

Following Voyager 2’s closest approach to Neptune on August 25, 1989, the spacecraft flew southward, below the ecliptic plane and onto a course that will take it, too, to interstellar space. Reflecting the Voyagers’ new transplanetary destinations, the project is now known as the Voyager Interstellar Mission.

Source: The Voyagers eventually entered Interstellar Space

Dawn spacecraft, launched 2007

Next, the Dawn spacecraft entered the asteroid belt (between Mars and Jupiter) to explore the, dwarf planet, Ceres, as well as its largest asteroid, Vesta.

After a voyage of 3 billion miles, NASA’s Dawn spacecraft safely orbited the dwarf planet Ceres today (March 6, 2015)—the largest object in the asteroid belt between Mars and Jupiter.

New Horizons spacecraft, launched 2006

And now, in July, 2015, we have the New Horizons spacecraft, reaching beyond Neptune’s orbit, into the Kuiper belt, to explore its largest object, the dwarf planet, Pluto, and its moon, Charon (considered a dwarf planet, also).

VIDEOS (short and long): To see the New Horizons mission to Pluto in an overview, visit the next page. Choose either a 5-minute video summairzing the Pluto flyby, or a nearly hour-long video that examines what it took to actualize the New Horizons voyage and what discoveries and challenges might be encountered on the flyby of Pluto.