There are worlds out there cold enough to instantly freeze an unprotected explorer into a human popsicle. And others hot enough to boil a person into a wisp of steam in seconds flat. There's also poisonous air, steel-crushing atmospheric pressure and winds that make Earth's most intense tornados seem tame.
Spacecraft sent out to explore our solar system must endure all those intense environments while crossing mind-boggling distances. Even at speeds up to 80,400 kph (50,000 mph), the New Horizon's spacecraft will need about nine and a half years to reach distant Pluto and its moon, Charon.
Read on to learn more about the extreme machines exploring our solar system.
Long Arm of the Sun
Even though it is about 13,500,000,000 km (8,200,000,000 miles) out, NASA's Voyager 1 spacecraft is still within our Sun's sphere of influence. It has been more than 13 years since it passed the farthest point in the orbit of Pluto, our solar system's most distant known planet.
Made in the Shade
Even though it will be working in temperatures up to 450 degrees Celsius (about 840 degrees Fahrenheit), sensitive parts of the MESSENGER spacecraft will remain at a pleasant room temperature thanks to a heat-resistant ceramic cloth sunshade.
Image to right: The large curved panel in the middle of this artist's view of the MESSENGER spacecraft is a sunshade to protect it from the Sun's powerful energy. Credit: Johns Hopkins University Applied Physics Laboratory
Scientists weren't about to let dense clouds, extreme heat and intense pressure stop them from studying the surface of Venus. In 1990, they used the Magellan spacecraft's powerful radar to peer through the clouds and map most of the surface of the planet.
Astronauts planted six American flags on the Moon, but that doesn't mean the United States owns it. An international law written in 1967 prevents any single nation from owning planets, stars or any other natural objects in space.
Humans have studied the Moon for thousands of years, but we didn't see its far side until Russia's Luna 3 spacecraft got there in 1959. That's because the Moon rotates once on its axis in about the same time it orbits Earth. That means the same side faces Earth at all times.
To survive a landing on Mars, a spacecraft must shave three zeroes off its speed in only six minutes - from about 19,000 kph (12,000 mph) in space to less than 19 kph (12 mph) at the surface.
After NASA's NEAR spacecraft had completed its intensive study of Asteroid Eros, mission controllers decided to try to land the spacecraft. Despite the fact it wasn't designed for landing, NEAR successfully touched down on Eros in 2001 - and went into the record books as the first to land on an asteroid.
Image to left: An artist's impression of the NEAR spacecraft descending to the surface of asteroid Eros. Credit: NASA
There are no rockets powerful enough to hurl a spacecraft into the outer solar system and beyond. In 1962, scientists calculated how to use Jupiter's intense gravity to hurl spacecraft into the farthest regions of the solar system. We've been traveling farther and faster ever since.
If you retraced the 3.2 billion km (2 billion miles) Cassini traveled to reach Saturn in a car at 100 kph (62 mph), the ride would last about 3,653 years. Fortunately, spacecraft are much faster. Cassini made the trip in less than seven years.
Cassini is the largest interplanetary spacecraft ever built. With a total mass of about 5,650 kilograms (6 tons), the two-story tall spacecraft is roughly equal in mass to an empty 30-passenger school bus.
Image to right: Engineers finish assembly of the Cassini spacecraft at Kennedy Space Center in 1997. Credit: NASA
Only one spacecraft has visited distant Uranus. After traveling more than 3,000,000,000 km (1,800,000,000 miles) in nine years, NASA's Voyager 2 gathered much of its critical information about the mysterious planet in a scant six hours.
Even though it will travel at speeds 30 times greater than the fastest fighter jet, NASA's New Horizons spacecraft will still take 9 1/2 years to get to Pluto. If you could somehow fly an airliner to Pluto, the trip would take more than 800 years.
One Tough Robot
No one expected Europe's Giotto spacecraft to survive the beating it took from dust and rocks when it made a close pass by Comet Halley in 1986. Damaged, but far from dead, Giotto flew on to study a second comet.
The radio signal that a spacecraft uses to contact Earth has no more power than a refrigerator light bulb. And by the time the signal has traveled across space, the signal is only one-billionth of one-billionth of one watt!
Image to left: The Deep Space Network's 70-meter antenna at Goldstone, California. Credit: NASA
To detect those tiny signals, the Deep Space Network uses antennas with diameters of up to 70 meters (230 feet). That's almost as big as a football field.
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