Exploring the planets is risky business. A spacecraft must first survive the rigors of launch and then endure the extremes of heat, cold, and radiation throughout the rest of its mission. It must also cope with the wear and tear of its components and software glitches over time. Once the spacecraft arrives at its target world it then has to work flawlessly to either fly by, orbit, land, or rove to carry out a successful mission. In spite of these risks, many spacecraft have returned terabytes of data from the planets and are often tough enough to continue for years on extended missions. We have learned more about the planets in the past five decades than we did in the past four centuries. New technology is carefully and thoroughly tested often with startling successes, but there have been painful and costly failures. It is interesting to note where the failures have occurred considering the varying environments of the planets. Note the missions that have been launched to date to the planets and the success rates:

_______Missions Flown......Successful.....Success Rate

Mercury.................2..............2.............100%

Venus...................28.............22............79%

Mars.....................42.............18............43%

Jupiter...................5...............5.............100%

Saturn...................4...............4.............100%

Uranus..................1...............1..............100%

Neptune................1...............1..............100%

Total.....................83..............53............64%

The above includes all spacecraft from the U.S., Russia, the European Space Agency (ESA), Great Britain, and Japan. Mercury is currently being revealed in rich detail thanks to the highly successful MESSENGER orbiter mission. The only other spacecraft to explore Mercury was Mariner 10 when it flew past it three times during 1974-75 in spite of rocket problems. Voyager 2 had problems with various components, but survived the rigors of time and the hostile environment of the outer Solar System to give us our only views of Uranus and Neptune. Success rates at Jupiter and Saturn were perfect in spite of radiation hazards, risky ring particles, and, in the case of the Galileo spacecraft at Jupiter, a stuck main antenna and balky tape recorder. The Cassini orbiter at Saturn is the crown jewel of orbiters as it continues to make awesome discoveries. It also deployed ESA’s Huygens probe that successfully landed on Titan in 2005. The Venus missions only suffered from the experimental beginnings of the Space Age and the hostile surface conditions. Once those were overcome, there was not a Venus mission lost since 1965 until Japan’s Akatsuki spacecraft failed to go into orbit around Venus in 2010 due to rocket problems, but this mission may still be recovered and recounted as a success instead of a failure in 2015. What is going on with Mars? Is there really a Martian Ghoul trying to destroy spacecraft? Consider this complete list of Mars missions with the year of launch given:

U.S.:

1964: Mariner 3 - booster failure.

1969: Mariner 6 & Mariner 7 - both were successful photographic flybys.

1971: Mariner 8 - booster failure.

1971: Mariner 9 - successful orbiter mission. Photographed most of Martian surface. First photos of Phobos and Deimos.

1975: Viking 1, Viking 2 - successful orbiter and lander missions. First soft landings and surface photos.

1992: Mars Observer - contact lost upon arrival at Mars.

1996: Mars Pathfinder - successful lander and rover mission. Deployed Sojourner Rover, the first wheeled vehicle on Mars.

1996: Mars Global Surveyor - successful orbiter mission.

1998: Mars Climate Orbiter - navigation error, destroyed in Martian atmosphere.

1999: Mars Polar Lander - crashed while landing.

1999: Deep Space 2 - penetrators, crashed with Mars Polar Lander.

2001: Mars Odyssey - successful orbiter mission. Still functioning.

2003: Spirit - successful rover mission. Traveled nearly 5 miles.

2003: Opportunity - successful rover mission, confirmed existence of ancient seas. Still roving and traveled nearly 24 miles so far.

2005: Mars Reconnaissance Orbiter - successful orbiter mission. Still functioning.

2007: Phoenix - successful polar lander mission. Discovered water ice.

2011: Curiosity - successful rover mission in progress.

Russia:

1960: Mars 1960A, Mars 1960B - both failed to reach Earth orbit.

1962: Mars 1962A - failed to leave Earth orbit.

1962: Mars 1 - contact lost enroute.

1962: Mars 1962B - failed to leave Earth orbit.

1964: Zond 2 - contact lost enroute.

1969: Mars 1969A, Mars 1969B - both failed to reach Earth orbit.

1971: Mars 2 - orbiter successful, but lander failed.

1971: Mars 3 - orbiter successful, but lander failed after 110 seconds on surface.

1973: Mars 4 - retrorocket failure, orbiter missed the planet, no lander flown.

1973: Mars 5 - successful orbiter mission, no lander flown.

1973: Mars 6 - orbiter successful, contact with lander lost before landing.

1973: Mars 7 - orbiter successful, lander missed the planet.

1988: Phobos 1 - contact lost enroute.

1988: Phobos 2 - contact lost shortly after going into Martian orbit.

1996: Mars 1996 - booster failure.

2011: Phobos Grunt - failed to leave Earth orbit.

Japan:

1998: Nozomi – rocket problems. Destroyed by a powerful solar flare.

ESA: 2003: Mars Express - successful orbiter mission. Still functioning.

U.K: 2003: Beagle 2 - crashed while landing.

The most obvious is the stunning failure rate for Russia. Mars 5 was the only complete success and the orbiters for Mars 2, 3, 6, and 7 also succeeded to account for partial successes making a dismal success rate of 16%. There have been no successes since the 1973 missions. All of the flybys and landings failed and Phobos Grunt was the latest failure. The U.S. success rate is far better at 70% with perfect luck in this new century especially with its rovers. In spite of this, Mars missions still have a high failure rate. If Mars has one of the most benign environments in the Solar System, what is going on?

The main answer is quality control. While the U.S. rigorously designs, tests and retests everything before it flies, Russia is willing to take more risk to keep costs down, but unfortunately they have paid the price having been lucky to get any Mars spacecraft beyond Earths orbit, especially since the fall of the Soviet Union. Topnotch scientists left for other jobs back then or even left the country. Japan is new to space exploration and they are on a learning curve like the U.S. was back in the 1960s and they will eventually succeed. In the earlier days the U.S. missions often failed shortly after leaving Earth, sometimes only moments after launch. We have overcome that with Mariner 8 in 1971 being the last such failure for the U.S.

Highly intelligent rovers have arrived with Curiosity and eventually there will be a sample return mission, which will ultimately lead to astronauts on Mars. There will always be risk with planetary missions, especially when carrying new or advancing technology. It is up to us to accept the risks involved in exploration, like our pioneering forefathers did when they sailed the Atlantic Ocean for the New World or explored the American West. We must be brave, for only then can we advance our knowledge of Mars and further enrich our existence in our universe.