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We are bidding farewell to an epic year for space explorers, who for the past 12 months have been graced with some of the best images and best science ever to come down from another planet. With no slight to Cassini, Voyager or the others, which are also still sending many happy returns, 2012 was all about Mars.
Many of you were glued to your livestreams and Twitter feeds in August–and through the onset of winter–for the touchdown and first rolls of the Mars rover Curiosity. Its intrepid sibling, Opportunity, also made some crazy new finds this year. There is a lot more to come in 2013, of course. But click through our gallery to see some of the best highlights from the Year In Mars.
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The Mars Science Laboratory launched Nov. 26, 2011, and spent the next eight months traveling to the Red Planet. While on the way, the Curiosity rover and its descent stage were safely tucked in this chicken-pot-pie-shaped aeroshell, designed to protect it from radiation and from the first stages of atmospheric entry. Curiosity’s radiation-sensing equipment picked up plenty of signals from a massive solar eruption in mid-January. The Radiation Assessment Detector, or RAD, was designed to measure radiation on Mars, but NASA turned it on for the long journey there just to see what it would find. Scientists are still parsing through the data from the solar flare, which could help set baselines for possible radiation exposure to humans when we head to Mars someday.
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Just before passing the baton of public attention to its larger, younger sibling, the Opportunity rover hit a milestone that brought it closer to marathon distance. This is an incredible feat, given that Opportunity and its late twin, Spirit, were designed to drive about one-third of a mile in total. Opportunity drives about 160 to 330 feet a day, so it’s no wonder it took nearly nine years to get this far.
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After a few months of cruising, the Mars Science Laboratory’s entry finally began on Aug. 5. The mission’s approach phase started 45 minutes before the spacecraft entered the Martian atmosphere, according to NASA. For navigation purposes, the atmospheric entry point was 2,188 miles above the center of the planet. The weather was even cooperating that day–NASA’s forecast called for dry, cloudless skies and calm winds for the landing site at Gale Crater.
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The fireball surrounding the Mars Science Laboratory reached 3,800 degrees Fahrenheit as it screamed into the atmosphere at 13,200 miles per hour. Within seven minutes, the spacecraft had to come to a safe stop on the surface. These “seven minutes of terror” was one of the most audacious attempts in space history–too beefy to bounce around with airbags, the rover needed a guided descent. NASA devised the sky crane, a hovercraft that fired retro-rockets toward the surface to slow the spacecraft down and drop it onto the surface, wheels first. Although NASA engineers were confident it would work–they said it was the only thing that would–it was terrifying to think about. A mile from the surface, the spacecraft cut its chute and shed its aeroshell, free-falling to the surface. After a few seconds, the retro-rockets fired up, with Curiosity’s belly exposed to the ground as the hovercraft continued lower and lower. A few meters from the surface, tethers unspooled to drop Curiosity onto the ground. The worst thing? NASA couldn’t even hear it in real time. It takes a while for radio signals to reach Earth from Mars, and in this case it was even worse because just as the parachute deployed, Earth set below the Mars horizon. No direct contact was possible through the Deep Space Network. Instead, the trusty Mars Odyssey orbiter served as a vent pipe, funneling data from the rover to Earth.
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And it all worked! From the Jet Propulsion Laboratory to Times Square, spectators cheered Curiosity’s safe landing. “It’s the wheel! It’s the wheel!” an engineer cried upon seeing the first image from Curiosity (inset). Just before the cheers erupted, a JPL engineer cried out, “Tango Delta nominal.” This was a code for T-D, as in touchdown–meaning touchdown was a success. But no one cheered until the word came from Allen Chen, Flight Dynamics and Operations Lead for the EDL team: “Touchdown confirmed. We are safe on Mars.”
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Curiosity has some amazing cameras, and already it has sent the best-detailed images of Mars humans have ever seen. This photo shows massive Mount Sharp, Curiosity’s ultimate destination in the heart of Gale Crater. The mound at the center of the image is about 1,000 feet across and 300 feet high. If it was in the frame, Curiosity would look like a speck of dirt by comparison.
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One of the best parts of Curiosity is @SarcasticRover, a lonely, wisecracking alter ego on Twitter. To NASA’s enduring credit, the rover has an official yet witty Twitter feed–“GALE CRATER, I AM IN YOU!” the official-rover said right after landing. But the sarcastic version just nails it. Writer Jason Filiatrault, who runs the account, started it as a celebration and commentary on the mission. Curiosity seems to hate Mars, a lot, but loves doing a science there. “Let’s do a science!” has become somewhat of an anthem. You should just really follow this account.
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Curiosity first tried out its laser on this innocent rock, which Tweeted the attack live. The rover’s laser, ChemCam, is designed to superheat samples into a plasma and detect their contents with a sensitive spectrograph. For five nanoseconds, the laser directs the energy of a million light bulbs into the area the size of a pinhead. It’s the workhorse of the mission, and can do preliminary research to help determine which other instruments, like the drill, should look at rocks in greater detail.
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Opportunity (and its late twin, Spirit) have found plenty of evidence for a watery Martian past. But this fall, Opportunity spotted something unusual that had scientists buzzing. These strange spherules could be the work of water, they could be left over from a major crater-causing impact, or something else scientists still don’t understand. They are made of basalt and apparently crunchy on the outside but soft on the inside. If they are evidence of sedimentary deposits, that’s an indication that water once moved through the rocky outcrops where Opportunity has been exploring, along the rim of a crater called Endeavour. Mars Exploration Rover mission scientists said it was one of the most exciting finds in the nearly nine-year-old mission.
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As we know, Opportunity and Spirit saw lots of evidence for water, largely in their exploration of minerals inside rocks. But with this image, scientists have the first observation of flowing water’s influence. Right after Curiosity landed and sent its first pictures back, scientists thought they may have put down in an alluvial fan–an ancient runoff site, and a bullseye for the type of science Curiosity is designed to do. Very early in its mission, Curiosity found this gravel, which was once part of an ancient stream bed. This image shows the Martian rock outcrop where that gravel is found.
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It might not have been Earth-shaking, but Curiosity did see something very interesting already: Signs of carbon on Mars. It’s still not clear where this came from, however–whether it’s indigenous to Mars or if the rover took it there inadvertently. Curiosity is designed to find evidence of environments that could have played host to life at some point, and finding organic molecules would be an interesting step on that path. There is still plenty to do in the rover’s two-year primary mission, however–so stay tuned.
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NASA will provide money for Curiosity as long as it works, the space agency said earlier this month. It may still be rolling by the time NASA sends its next Mars rover in 2020. It likely won’t return to Earth–although you never know–but it does leave a piece of Earth with it on Mars. Curiosity’s tracks spell out JPL in Morse code, a nod to the Jet Propulsion Laboratory engineers who built it. The mission is designed to last at least a full Martian year, which is two years on Earth–so really it’s still the very, very beginning. 2013 is sure to have much more in store.
