Gleaming red in the night sky, it caught eyes of many. Water ice polar caps, valleys, volcanoes, marks of tributaries, permafrost, hills, avalanches, alluvial fan regions, are synonymous to not just Earth but Mars too. Surprising at first glance, the God of War, seems most unlikely as a place where life could’ve existed : with exceedingly thin atmosphere, no net magnetic field that can protect it from solar winds, a desolate silicate, oxide filled land scattered with rocks and lifelessness, freezing cold temperature (-80 degrees F on an average and -184 degree F on the south polar ice cap) and frequent dust devils raging across the planet.
But beyond these, lie similarities which are most striking. Water is quintessential for life as we know it on Earth. It facilitated conditions for life from early stromatolites which were the first to photosynthesize 3.4 billion years ago to ancient civilizations that developed near rivers. With evidence of water ice caps on Mars and permafrost region of about 5000km, signs of life hid in them (explorations in Antarctica and study of permafrost have proven that microbes can still be alive after 10 million years with temperature of -20 degree Celsius). Rocks scattered that spoke only of a desolated area, are actually signs of life for geologists like Jim Rice confirm its similarity to regions in Iceland. They are formed when volcanoes inside glaciers erupt, leading to floods and waters rise upto 10km, but leave behind these typical rocky terrains on their recession. Marks of canals and similarities to Grand Canyon on earth can only have been caused when water flowed through the Martian surface once. Also sediment mountains such as Mount Sharp on Mars hold explainations about different eras trapped in its various strata of rocks, examples of it on earth are Himalayas, Alps etc.
Critical to the above ideas and basis of our study on Mars have been the various Mars missions since 1960s. Two third of the missions have failed : some lost contact, some had a launch vehicle failure, some had landing failure. No wonder why Mars is called the Bermuda triangle of Space. But successful missions such as Viking, Mars Global surveyor, Mars Pathfinder, Mars Odyssey, Spirit and Opportunity, Reconnaissance Orbiter and Phoneix, have returned large amounts of data about elementary composition of soil and the atmosphere, mapping Mars to great detail. However, none can compare to the most audacious mission to Mars yet : The Mars Science Laboratory (Curiosity). Being twice as long and five times heavier than Spirit and Opportunity, driven on energy via plutonium decay that’ll last one Martian year or 687 earth days compared to solar powered energy of past that only lasted months, its ChemCam laser eye, sophisticated robot arm which will collect samples, Cams that will provide multiple spectra imaging, ability to detect potential obstacles at a distance, terrain overview, Easter Eggs (wheels) that can easily roll over 26 inch high rocks and that which leaves a track behind with “JPL” written in Morse code ;) , an inbuilt laboratory (APXS, SAM, CheMin, SAM, RAD, DAN, REMS) that will conduct the analysis and also the intelligence to decide which places are worth digging in for more information about possible habitable grounds, designed and engineered for a decade, the billion dollar rover, Curiosity is certainly one of a kind.
Apart from the ingenuity of the rover, how to get it to surface of mars, in this case inside gale crater (carefully chosen from 60 landing site possibilities because of presence of hydrated clay minerals and sulphate salts indicating substrates for possible preservation of fossils, also, it has the 6km high Mount Sharp, what’ll contain most information being a sediment mountain) with zero margin error calls for an equally unconventional landing. The spacecraft needs to be slowed down from 13,000 miles per hour to zero with an atmosphere that is too thin for parachute and aerobraking alone to be effective while reaming thick enough to create impingement problems when decelerating rockets. Airbag landing of previous missions can’t work due to heavy weight of curiosity. So the novel EDL system (Entry, descent and landing) was devised as a result of reasoned engineering although the concept looked crazy : it’s guided entry into the Martian atmosphere while heatshield glows with a whooping 1600 degree Celcius due to aerodynamic drag, then the largest and strongest supersonic parachute built yet that would sustain 65000 tones of force when the parachute itself weighs only 100 pounds, then removal of heatshield because it blocks the view of the ground from the radar which will take just the right measurements of velocity and altitude at just the right time, now since the parachute reduces spacecraft only to 200 miles per hour, the spacecraft must be separated from the parachute, that’s when the spacecraft is maneuvered using rockets, but it needs to be diverged sideways instantly else it’ll bounce back to the parachute. Now, using the radar, spacecraft will place itself right above the landing spot, but it can’t hover all the way down to the surface as dust blown by it would enter the rover destroying the instruments within. This was solved using a bizarre concept : skycrane landing, wherein 20m above the surface the rover is tethered down 21 feet with help of 3 nylon tethers and one electrical cable. Now, as the rover is gently touched down on the surface, the cables must be cut instantly else the crane will be on a collision course with the rover. The detachment of cables happens after 2 seconds of touchdown, in which confirmation of detection of weight on wheels will fire pyros activating cable cutters. And, ALL of this, from entering the atmosphere to touchdown happens in 7 minutes, which was quite rightly phrased as "7 minutes of terror" : that which requires perfect sequence, choreography and timing else its ALL GAME OVER. Since it takes 7 minutes for information to reach Earth via Mars orbiter Odyssey, its actually those 14 torturous minutes.
But today, we can quite proudly and happily state that we were successful with the landing (Bradbury Landing) less than 2.4km away from centre of planned ellipse landing site (credits to NASA, JPL engineers).
Since Curiosity’s launch on 26th November 2011, to final touch down on August 6th 2012 : it was more than a journey of just a few months, rather a work of a decade hanging on this one mission. It is a journey that’ll answer questions about life on another planet, that’ll travel back in time with its observations and one that’ll hold answers if earth’s fate is to be the same : one that’ll answer to our curiosity.
Curiosity is our best shot in unveiling mysteries of the red globe, that, which has intrigued us for centuries. For more information log on to : www.mars.jpl.nasa.gov and follow Curiosity’s updates on twitter ;)
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