Planetary Probes: Where Are They Now?

The &39;Spirit&39; has given up the ghost. (Photo: NASA)

Much to the melancholy of stargazers the galaxy over, the wandering NASA rover Spirit has reportedly given up its ghost after six successful years on the red planet.

Before succumbing to the fatal task of searching Mars for signs of life, Spirit famously found evidence that the red, rocky soil was once a perfect home for Martian microorganisms.

The far-flung tourist also took the highest resolution photo ever snapped from the surface of another planet, as well as the first photo of Earth from a celestial body beyond the Moon.

This year, the waning Martian sun stopped pumping juice into Spirit’s solar panels, suffocating the craft. On March 22, 2010, the rover beamed its last message back to Earth, something perhaps reflective and bittersweet, or maybe a failed, yet earnest attempt at poetry.

Spirit is survived by its overachieving twin, Opportunity, which remains busy snapping photos of Mars's southern hemisphere.

Like Spirit, the following probes have braved the harsh outer reaches of the solar system to bring the mighty heavens that much closer to earthbound man.

Greetings from Earth&39;s forgotten tribe. (Photo: NASA)

Probe: Pioneer 10

Launched: March 3, 1972

Mission: Pioneer 10 was the first probe to take a close-up gander at Jupiter, and the first man-made object to take a one-way trip out of the solar system.

Its final stop is Alderbaran, an enormous star located in the constellation Taurus. If the destination doesn't get swept away by time, Pioneer 10 should reach its target in about 2 million years.

Status: The last transmission from Pioneer 10 was beamed back to Earth on January 23, 2003, when it was 7.5 billion miles from home. 

The lifeless probe is now a 570-pound paperweight drifting some 9.3 billion miles away in interstellar space.

A gold-anodized aluminum plaque fitted on the side of Pioneer 10 (and another on Pioneer 11) carries a pictorial history of the craft and a return address, just in case an alien scrapping metal finds it. Whether or not the space junkie can decipher the thing is anybody's guess.

&39;Mariner 10&39; set its controls for the heart of the sun. (Photo: NASA)

Probe: Mariner 10

Launched: November 3, 1973

Mission: The last craft in the enterprising Mariner program was the first to visit Mercury, the planet voted "Most Likely to Be Swallowed by an Angry Sun."

The probe set a standard by using gravity assist to get from point A to point B, rubber-banding off the orbit of Venus to make haste to Mercury. 

Mariner 10 was a bit of a problem child from the start, requiring more course corrections than any previous mission.

It did, however, serve as the solar system's first paparazzo, returning some 12,000 pics of Venus and Mercury. To date, none have been featured on TMZ. 

Status: On March 24, 1975, Mariner 10 swallowed the last of its altitude-control gas supply, and mission control pulled the plug. Last anyone's heard, the probe is still circling the sun in dire need of Coppertone. 

Neptune as seen by &39;Voyager 2.&39; (Photo: NASA)

Probe: Voyager 2

Launched: August 20, 1977

Mission: Taking advantage of a rare planetary alignment, ambitious Voyager 2 nailed the Grand Tour and knocked off Jupiter, Saturn, Uranus and Neptune all in one trip. It remains the only spacecraft to visit all of the outer planets. 

The mission has been manna from heaven for science. At its first stop alone, Voyager 2 found rings around Jupiter, volcanoes on Io, a possible ocean on Europa, and managed to solve the mystery of the planet’s Big Red Storm (better known as the Big Red Spot). To date, it remains the world's longest ongoing space mission. 

Status: Voyager 2's still ticking, though its jet-setting agenda bent its trajectory south of the Ecliptic plane. It's now off studying magnetic fields, charged particles, and Sanskrit 8.5 billion miles from a decent FM reception.

Pluto will have to wait for future &39;Voyagers.&39; (Photo: NASA)

Probe: Voyager 1

Launched: September 5, 1977

Mission: Voyager 2’s nomadic twin, Voyager 1, flew 217,000 miles from Jupiter, grabbed some photos of its clouds and moons, then sped over to Saturn for more of the same. 

It wrapped up its mission in 1980 with some gas left in the tank; so the probe ventured off to the termination shock and the heliosheath, where no one could hear it scream. 

Voyager coulda-woulda-shoulda visited lonely Pluto, but NASA engineers decided to use the craft’s resources for a closer look at Titan instead. 

Pluto remains the only planet in the solar system that’s never had company. To make matters worse, it's not even a planet; the International Astronomical Union (IAU) stripped the little guy of its title in 2006. 

Status:  On February 17, 1998, the craft hustled past Pioneer 10 to become the farthest man-made object from Earth. Now 10.6 billion miles away, Voyager 1 and its batteries should stall out somewhere in 2025, 12.5 billion miles from the closest AAA office.

The piano-sized &39;New Horizons&39; is already too far gone to ever come back. (Photo: NASA)

Probe: New Horizons

Launched: January 19, 2006

Mission: After decades of effort, the New Horizons team became the first to announce a space program to Pluto. 

The piano-sized probe left in a hurry, setting the fastest spacecraft launch from Earth at a record 36,733 mph. The nuclear-fueled New Horizons made it to the moon in just nine hours—the Apollo teams took three days to accomplish the same.

Months after the craft departed on its 3-billion mile journey, the IAU pulled the ol’ bait-and-switch and downgraded Pluto’s membership status. The probe was purposely left in the dark, and still believes it’s headed to the Solar System’s ninth planet, not its second dwarf planet.  

Status: New Horizons swung by Jupiter for a little gravity assist in 2007, and is now cruising through interplanetary space somewhere near the orbit of Neptune.

The craft will pass 6,200 miles from Pluto on July 14, 2015, and then move on to study the Kuiper Belt, an enormous junkyard of rock and metal parts leftover from the Solar System’s infancy.

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