Mars exploration, past, present and future

On August 6, at 1:30 a.m. EDT a group of very smart people in JPL mission control will hopefully get very excited as the Mars Science Laboratory (MSL) rover Curiosity lands on the red planet. Launched last November, the latest and most advanced rover will have traveled 154 million miles.

Scientists and engineers gathered in Pasadena, Calif., wont know the result for about 14 minutes. The rover's "I'm here and ready to get to work" message takes that long to travel back to Earth.

Getting to Mars is not easy. Only about half of the 40 spacecraft sent there have actually made it there in one piece.

The race to study Mars started nine years before we landed on the moon.  The Soviet Union launched 10 missions before seeing any success with their Mars 2 orbiter. The others failed either during launch or enroute. During that time, NASA's Mariner program of flybys and orbiters produced four successful missions and two failures.

The Soviets didn't win the race to the moon, but they did beat the United States to the surface of Mars in 1971 with the Mars 3 rover, though success lasted only 15 seconds before the rover stopped transmitting. Their next five attempts over the following two decades failed or returned very limited data going silent.

NASA's Viking program placed two landers on opposite sides of the planet beginning on July 20, 1976, the seventh anniversary of the Apollo 11 landing. While these were the first spacecraft to produce significant data, their capabilities were limited, especially by Curiosity's standards. Even back then, they were known as the "Big Dumb Landers" (BDL). Curiosity has over 15,000 times more memory and about twice as much storage for images and other science data, though tape recorders have been replaced by flash memory similar to, but more durable, what we use in consumer digital cameras.

The Viking landers produced a complete view of the Martian surface, providing evidence of shaping by wind and past water. They produced the first color image from the surface of Mars showing the red surface and orange sky. That image has influenced how everyone from scientists to movie makers see Mars.

Over the two decades following 1990, Mars exploration was dominated by NASA. Most were successful with the notable exceptions of the Mars Climate Orbiter which was doomed by poor communication, not with the spacecraft but between the people designing it and the people controlling it. Software was written assuming metric units of force (Newtons) but was operated using imperial units (foot pounds). This mix up has led to strict controls inside NASA and has been an effective cautionary tale for teachers from elementary through college to use.

Russia tried to place a lander on Mars again in 1996 (launch failure).

Japan attempted to orbit the planet in 1998 (failed enroute) and no one is really sure what happened to Britain's Beagle 2 lander. What is left of China's orbiter Yinghuo-1 is likely at the bottom of (Earth's) Pacific Ocean after it's ride, the doomed Fobos-Grunt spacecraft was stranded in low Earth orbit before reentering over the South Pacific.

At the risk of jinxing August's MSL landing, NASA has had a string of successes with its rovers, beginning with the milk-crate-sized Pathfinder rover in 1997. Following the then guidance of "smaller, faster, cheaper," the rover was originally envisioned as the first in a swarm of small rovers deployed across the planet. The little rover provided valuable experience in how to get a rover there and literally scratched the surface of the geologic study that is possible.

2004's Mars Exploration Rovers (MER), Spirit and Opportunity set the standard for exceeding the planned mission duration. The planned nine-day mission of these rovers has entered an Energizer Bunny like marathon of over six and eight years respectively. Spirit ended her mission in 2010 after getting stuck in slick soft soil. Opportunity is still rolling along and still doing science. That's a bit like the family car lasting 250 years. NASA's science per dollar measurement of mission effectiveness is off the charts for the MER mission.

Both Pathfinder and MER missions utilized a grape-like cluster of kevlar-like airbags around the rover as it bounced to a stop. Curiosity weighs in at just under a ton, 2.5 times heavier than all three previous rovers combined. Air bags were not an option, and the resulting solution is pretty spectacular. More about that at the end of the month.

In the coming weeks leading up to Curiosity's landing, the WRAL Weather Center Blog will feature additional posts on Mars. They will also highlight events around the Triangle where you can learn more about Mars and its latest visitor:

* July 31 Seven minutes of terror, landing on Mars