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Six reasons the Mars Science Laboratory 'Curiosity' could fail before its mission begins
By Marshall Connolly (Catholic Online)
June 27th, 2012
Catholic Online (www.catholic.org)
The Mars Science Laboratory, a.k.a. Curiosity, is about to touch down on Mars. On earth, NASA scientists and researchers are waiting the event, set firmly for August 6, with bated breath. And they have good reason to be a bit nervous; slightly more than half of all attempted Mars missions have ended in failure for reasons as simple as a mix-up between metric and imperial units.
Here are six reasons why the Curiosity mission could fail before the science even starts.
#6. Bad weather - Scientists on Earth have a hard enough time predicting Earth weather, and it's all the more difficult to predict weather on a planet millions of miles away. Mars is notorious for long, cold winters and dust storms that can blanket the entire planet. While the mission is scheduled to land during a good weather period, anything can happen. Previous landers have suffered reduction in capability due to dust coating their solar panels. The already feeble sunlight cannot penetrate a very thick layer of dust, which is the eventual doom of all solar-powered Mars rovers.
However, Curiosity has its own internal power supply so it will not need to worry about dust storms cutting off its electricity. Still, static charges, extra-cold weather, and fine dust particles can still wreak havoc on the craft, especially over the long term. Unfortunately, bad weather is the least of Curiosity's worries.
Read More: Mars Rover lifts off without a hitch.
#5. Getting stuck - The surface of Mars is sandy and rocky which makes it difficult for rovers to move on the surface. The most famous example is the Mars Spirit rover, which despite its amazing success, eventually got stuck on the planet and engineers were unable to free the craft. Scientists have a good idea how to drive on Mars and choose their routes meticulously. In addition, Curiosity has much larger wheels than its predecessors, making successful maneuvers more likely. However, the possibility remains that the lander could get stuck. And getting stuck could put an early end to a very expensive mission.
#4. Instrument failure - Should Curiosity safely land, the mission won't be out of danger. The possibility of hardware or software failure remains a concern. Several missions to Mars have suffered instrument failures. While the most common instrument failure seems to be failures of communication equipment, scientific instruments can fail too. A failed boom or probe or a broken instrument can kill at least one key component of a scientific mission. The more instruments there are, the more complications, and the more possibility of breakage, and Curiosity is packed with instruments.
Other famous examples include the failure of Skylab's solar panels to deploy properly and the mirror for the Hubble Space Telescope. Luckily in those cases, astronauts were able to intervene directly and conduct repairs. That won't be possible for Curiosity.
#3. Communications failure - The distance between Earth and Mars varies greatly (between 36 and 250 million miles!) Earth regularly catches up to, then overtakes and leaves behind the red planet as both orbit the Sun at different periods. The Martian year is almost 687 Earth-days long. As the separation between the two planets changes, so does the amount of time needed to communicate with the orbiters and landers there. Messages can arrive in as little as three minutes or take as long as 22.
In addition to distance, the both planets are rotating with craft frequently passing behind Mars (from our perspective) and being unable to communicate. In fact, any number of dynamic factors can interrupt communications.
Communications failures claim space missions from time to time. At least seven of the 49 attempted Mars missions have been lost due to communication difficulties that couldn't be overcome. A number of other satellites sent into space have also been lost because of communication problems.
A number of things cause these failures, but the extreme nature of space is certainly a factor. Although satellites are built to withstand the harsh space environment, a number of things can go wrong. The extreme forces of launch, the deep freeze of space, or blasts of solar radiation can break, freeze, or fry electronics. The impact of landing can be worse than expected and something can come lose. Or get stuck. The most famous example of this was the Galileo mission to Jupiter. The orbiter's high-gain antenna became stuck and never fully deployed. Luckily, engineers were able to come up with a solution by repurposing the satellite's low-gain antenna to transmit scientific data. While speculation abounds, nobody will likely know the real reason why the antenna became stuck.
Until Curiosity is on the ground transmitting data, communications failure is a real possibility.
#2. Surface crash - Not counting the probes that failed to even attempt landings because of various problems, five of the 49 previous missions have ended in a man-made impact crater on the surface of Mars. The precise nature of each crash remains unknown but all can be chalked up to a miscalculation or hardware failure. Much like the communications hardware, the apparatus required for landing is often elaborate and susceptible to damage.
Curiosity needs a mix of parachutes and rockets to slow its descent enough to land. It will also be a mission of firsts, which increases its risk. The landing sequence is so new and complex, NASA is referring to the final landing sequence as "seven minutes of terror."
Curiosity will use a new landing trajectory that is designed to be much more precise than previous approaches. It will be protected by a 15 ft. diameter heat shield, the largest to ever fly in space (excluding the space shuttle). It must guide its own landing (communications from to and from Mars will take at least 13 minutes to arrive) and will use ballast weights, which it will jettison during reentry. The craft must autonomously do these things while slowing from the dramatic speed of 3.7 miles per second to just under Mach-2. Assuming the slowdown goes well and the heat shield separates, a specially designed supersonic parachute will deploy. This must slow the spacecraft further. At just over a mile in altitude, the lander will deploy rockets to slow its descent to landing speed. Finally, a revolutionary new design known as the "sky crane" will actually lower the rover to the Martian surface. Once the rover touches down, the sky crane must detach itself and crash land away from the lander.
The risk of complication is high because the Martian variables are being combined with design variables - bold designs that have never been attempted before.
#1. Human error - Whether it's failing to convert imperial units to metric or sending the wrong command to the craft, humans probably represent the greatest threat to the mission. Humans are an essential component in any space mission. No matter how automated and autonomous a spacecraft is, human interaction is always necessary at some point, and to err is quintessentially human.
In fact, most of the above failures are the result of human mistakes, or a lack of understanding. Sadly, errors in human judgment aren't limited to unmanned missions tens of millions of miles away. The losses of shuttles Challenger and Columbia were at least partially ascribed to human error in judgment. And if manned spacecraft can be lost just miles above the surface of the Earth, imagine a lander that's so far away it takes several minutes to communicate with it.
The Curiosity rover is certainly a well designed, quality built, and carefully managed mission. The best and brightest minds have labored over how to land a fully functional scientific laboratory on Mars and how to conduct scientific experiments to help unlock the secrets of the Red Planet. If any mission enjoys strong odds of success, it is this one. However, lest we be emboldened too much by hubris, it is important to remember that other, carefully crafted and less ambitious missions have failed.
Until we have the hard data and images in our hands and the science is complete, it will be premature to declare success. In the meantime all we can do is hope and trust that this multimillion dollar project provides a return on investment paid in knowledge and understanding beyond our greatest imaginings.
Life on Mars? These scientists say 99 percent yes!
Learn more about the Mars Science Laboratory Curiosity from the official JPL/NASA website!
© 2012, Distributed by NEWS CONSORTIUM.
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