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2Mars Rover (Spirit)
Following mission completion and aided by cleaning events that resulted in higher power from its solar panels, Spirit went on to function effectively more than 20 times longer than NASA planners expected, as well as logging about 6 miles of driving. This is first color image compiled from images taken by Spirit when it landed in 2004. It was the highest resolution color image taken on another planet.
3Galileo
An unmanned spacecraft launched by NASA in 1989 to study the planet Jupiter and its moons, it arrived at the gas giant in 1995, where the spacecraft launched the first probe into Jupiter’s atmosphere. After completing 35 orbits around Jupiter throughout a nearly eight-year mission, the Galileo Orbiter was destroyed during a controlled impact with Jupiter in 2003.
4Voyager 2
The Voyager 2 space probe has been the most productive unmanned space voyage so far, visiting all four of the Outer Planets and their systems of moons and rings, including the first two visits to previously unexplored Uranus and Neptune (pictured here). Launched in 1977, it is now described as working on an interstellar mission, which NASA is using to find out what the solar system is like beyond the heliosphere, a bubble in space “blown” into the interstellar medium (the hydrogen and helium gas that permeates the galaxy) by the solar wind.
5Mariner 10
The Mariner program was a program that launched a series of robotic interplanetary probes designed to investigate Mars, Venus and Mercury. The program included a number of firsts, including the first planetary flyby, the first pictures from another planet, the first planetary orbiter, and the first gravity assist maneuver. Reprocessed Mariner 10 data was used to produce this image of Mercury; the blank area is where no photos were taken.
6Magellan
Sent to the cloud-covered planet Venus in 1989, Magellan created the first (and according to NASA, currently the best) near-photographic quality, high-resolution mapping of the planet’s surface features. It allowed for detailed imaging and analysis of craters, hills, ridges and other geologic formations. After five years orbiting and mapping the planet’s surface (shown here), it plunged to the surface as planned and partly vaporized; some sections are thought to have hit the planet’s surface.
7No Title
Launched in 1973, Pioneer 11 was the second mission of the Pioneer program (after its sister probe Pioneer 10) to investigate Jupiter and the outer solar system, and the first to explore Saturn and its main rings. Instruments on the Pioneer 11 probe studied the interplanetary and planetary magnetic fields, solar wind properties and cosmic rays. Using Jupiter’s mass in a gravitational slingshot, the probe altered its trajectory toward the gas giant Saturn, shown here.
8Ulysses
Ulysses was the first mission to survey the space environment above and below the poles of the sun. Launched in 1990, the spacecraft made the first direct measurements of interstellar dust particles and interstellar helium atoms in the solar system and the discovery that the magnetic field leaving the sun is balanced across latitudes, observations that helped redefine the way scientists think about space weather. This artist’s rendering depicts the spacecraft approaching the sun.
9Viking 2
This orbiter-lander combination first circled Mars after it was launched in 1976, and then landed on the surface. Due to radar misidentification, the thrusters fired longer than necessary before landing, cracking the surface and raising dust. The lander settled down with one leg on a rock, and the cameras began taking images immediately after landing. This image shows frost on the Martian landscape.
10Apollo 11
Certainly the best known of NASA’s missions, Apollo 11 needs no introduction. The mission to put a man on the moon was accomplished in 1969 as Neil Armstrong set foot on lunar soil with the famous proclamation “That’s one small step for man, one giant leap for mankind.” The astronauts also collected rock samples using scoops and tongs on extension handles. However, many of the surface activities took longer than expected, so they had to stop documenting sample collection halfway through the allotted time.
11Cassini-Huygens
Launched in 2007, the Huygens probe was separated from the orbiter and it reached Saturn’s moon Titan, when it made a descent into Titan’s atmosphere. The Cassini orbiter continued to transmit photos of the Saturn home. It was the first spacecraft to orbit the planet. Although the primary mission was to end in 2008, given the excellent condition of the orbiter the mission was extended through this year. Comparing this shot of Saturn in eclipse to those taken from Pioneer 11 demonstrates how far deep-space imaging technology has advanced.