{"id":16844,"date":"2014-11-11T17:22:51","date_gmt":"2014-11-11T09:22:51","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/unprecedented-cosmic-choreography-essential-to-landing-on-comet\/"},"modified":"2014-11-11T17:22:51","modified_gmt":"2014-11-11T09:22:51","slug":"unprecedented-cosmic-choreography-essential-to-landing-on-comet","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/unprecedented-cosmic-choreography-essential-to-landing-on-comet\/","title":{"rendered":"Unprecedented cosmic choreography essential to landing on comet"},"content":{"rendered":"
\"Artist's
Artist\u2019s concept of the Philae comet lander ejecting from Rosetta to begin its seven-hour descent. Credit: NASA<\/figcaption><\/figure>\n

 <\/p>\n

DARMSTADT, Germany \u2014 When a European landing probe goes for a daring touchdown on a comet Wednesday, officials say it would help to have a little luck on their side.<\/p>\n

The European Space Agency\u2019s Rosetta orbiter is set to deploy a lander named Philae on Wednesday for a seven-hour descent to comet 67P\/Churyumov-Gerasmimenko, an unexplored world that is rife with danger for the oven-sized landing craft.<\/p>\n

Nothing like it has ever been tried before.<\/p>\n

\u201cIt is realistic that there is a potential for failure, but I am very optimistic,\u201d said Fred Jansen, ESA\u2019s Rosetta mission manager.<\/p>\n

Going into the mission officials predicted about a 75 percent chance of a smooth landing by Philae. But that was before scientists saw the comet up close, a look that revealed its nucleus was scarred with cliffs, boulders, towering rock protrusions and possibly made of two parts joined together.<\/p>\n

\u201cIt\u2019s not a nice round potato,\u201d Jansen said. \u201cIt\u2019s rough, it\u2019s more difficult. But we\u2019ve analyzed the terrain. We\u2019ve analyzed the comet, and we are confident that the risks we have are still in the area of the 75 percent success ratio that we\u2019ve always felt.\u201d<\/p>\n

Philae hosts a suite of sensors designed to take panoramic and 3D imagery, measure the comet\u2019s mineral content, investigate the internal structure of the nucleus, and drill 23 centimeters \u2014 about 9 inches \u2014 into the comet\u2019s nucleus to extract a core sample for analysis by the lander\u2019s miniaturized internal laboratory.<\/p>\n

\u201cIf you decide you want to land on an object you know nothing about 10 years, 20 years ago, then you run risk,\u201d Jansen said. \u201cThat\u2019s clear because you\u2019re going somewhere where not everything might be the way you anticipated, and that\u2019s the way this comet is.\u201d<\/p>\n

\"Rosetta's
Rosetta\u2019s trajectory after releasing Philae is seen as the solid white line on this image. The orbiter will maneuver itself to be in view of the Philae lander \u2014 the shorter white line heading forward the comet\u2019s nucleus \u2014 to be a communications relay between the comet\u2019s surface and the ground. Credit: ESA<\/figcaption><\/figure>\n

With a cost of 200 million euros \u2014 or about $250 million \u2014 the lander will provide ground truth for groundbreaking observations already underway by Rosetta. The chief goal of the $1.7 billion Rosetta mission is to find out how comets work and whether they may have seeded Earth with water and the building blocks for life \u2014 like organic molecules, amino acids, and other life-forming material.<\/p>\n

Jansen described Philae as the \u201ccherry on the cake\u201d and said Rosetta itself will supply most of the mission\u2019s discoveries.<\/p>\n

\u201cIt\u2019s amazing to scientists and scary to engineers,\u201d said Art Chmielewski, who manages NASA\u2019s portion of the Rosetta mission.<\/p>\n

\u201cThis is not seven minutes of terror, OK?\u201d Chmielewski said, referencing the catchy slogan used to describe the landing of NASA\u2019s Curiosity rover on Mars. \u201cThis is seven hours of scary patience.\u201d<\/p>\n

\u201cWe cannot control this lander so accurately,\u201d Chmielewski said. \u201cAfter the release, the baby goes and we can\u2019t do anything about it.\u201d<\/p>\n

Philae\u2019s batteries only provide power to operate the probe for 64 hours before the lander switches off. If Philae has sufficient sunlight, it can recharge its batteries to support intermittent operations through March, when the craft is expected to overheat as the comet races closer to the sun.<\/p>\n

\u201cWe\u2019re doing something hugely ambitious, it\u2019s never been done before,\u201d said Mark McCaughrean, a senior advisor in ESA\u2019s science division. \u201cNobody\u2019s tried to land on an object like this and then stay there to do science. We\u2019ll see what tomorrow brings. We stand on the brink of something amazing, but we have a mission that\u2019s hugely successful already, and that will continue to be so.\u201d<\/p>\n

Getting Philae to the comet\u2019s surface requires an unprecedented cosmic ballet between the lander, the Rosetta mothership and the comet.<\/p>\n

Early Wednesday, Rosetta will fire its rocket thrusters to drive toward the comet, setting up for release of Philae at a distance of 22.5 kilometers, or about 14 miles from the center of the icy world\u2019s nucleus.<\/p>\n

If all goes according to plan, ground controllers here will receive confirmation of Philae\u2019s deployment from Rosetta at 0903 GMT (4:03 a.m. EST) Wednesday. Moments later, each spacecraft will turn their cameras toward each other to take a set of farewell photos.<\/p>\n

Flying on its own, the Philae lander is not able to control its path toward the comet. Its course is charted before it departs the mothership, which is responsible for aiming and ejecting the lander in exactly the right direction at the correct time.<\/p>\n