Rosetta Mission sets November 12th as the Landing Date for Philae
canada goose alternative uk ESA Rosetta mission planners have selected November 12th, one day later than initially planned, for the historic landing of Philae on a comet’s surface. The landing on67P/Churyumov Gerasimenko will be especially challenging for thewashing machine sized lander. While mission canada goose coats on sale scientists consider their choiceof comet for the mission to be an incredibly good one for scientific canada goose black friday sale investigation and discovery, the canadian goose jacket irregular shape and rugged terrain alsomake cheap canada goose for a risky landing. The whole landing is not unlike the challenge one faces in shooting a moving target in a carnival arcade game; however, this moving target is 20 kilometers below and it is also rotating. canada goose alternative uk
canada goose outlet houston At 8:35 GMT (3:35 AM EST), the landing sequence will begin with release of Philae by Rosetta at an altitude of 20 kilometers above the comet. The expected time of touchdown is seven hours later 15:35 GMT (10:35 AM EST). During the descent, Philae’s ROLIS camera will take a continuous series of photos. The comet will complete more than half arotation during the descent; comet P67’s rotation rate is 12.4 hours. The landing site will actually be on the opposite side of the comet when Philae is released and will canada goose uk outlet rotate around, and if all goes as planned, meet Philae at landing site J. canada goose outlet houston
Before November 12th, mission planners will maintain the option of landing at Site C. If the alternate site is chosen, the descent will begin at13:04GMT also on November 12 but from an altitude of 12.5 kilometers, a 4 hour descent time.
canada goose trillium parka uk NAVCAM image of the comet on 21 September, which includes a view of primary landing site J. Click for more details and link to context image. (Credits: ESA/Rosetta/NAVCAM)Rosetta will ejectPhilae with an initial velocity of approximately 2 1/2 kilometers per hour. Because the comet is so small, its gravity will add little additional speed to Philae as it falls to the surface. Philae is essentially on a ballistic trajectory Canada Goose Outlet and does not have any means to adjust its path. canada goose trillium parka uk
The actions taken by Philae’s onboard computer begin only seconds from touchdown. It has a landing propulsion system but unlike conventional systems that slow down the vehicle for soft landing, Philae’s is designed to push the lander snugly onto the comet surface. There is no guarantee that Philae will land on a flat horizontal surface. A slope is probably more likely and the rocket will force the small lander’s three legs onto the slope.
A model of the buy canada goose jacket cheap comet P67/Churyumov Gerasimenko created using images from the Rosetta OSIRIS narrow field camera. Mouse click on the image to start the animated GIF. (Credit: ESA)Landing harpoonswill be fired that are attached to cables that will be pulled in to also uk canada goose outlet help Philae return upright and attach to the surface. Philae could actually bounce up or topple over if the rocket system and harpoonsfail to do their job.
The Philae Lander anchoring harpoon with the integrated MUPUS accelerometer and temperature sensor. (Credit: “Philae Lander Fact Sheet”, ESA)However, under each of the three foot pads, there are ice screws that will attempt to drill and secure Philae to the surface. This will depend on the harpoons and/or rockets functioning as planned, otherwise the action of the drills could experience resistance from hard ground and simply push the lander up https://www.fcvfrankfurt.de rather than secure it down. Philae also has a on board gyro to cheap Canada Goose maintain its attitude during descent, and an impact dampener on the neck of the vehicle which attaches the main body to the landing struts.
Ten landing siteswere picked, then canada goose store down selected to five, and then finally on September 15th, they selected Site J on the head of the smaller lobe canada goose factory sale the head of the rubber duck, with site C as a backup. Uncertainty in the release and the trajectory of the descent to the comet’s surface means that the planners needed to find a square kilometer area for landing. But comet67P/Churyumov Gerasimenko simply offered no site with that much flat area clear ofcliffs and boulders. Philae will be released to land at Site J which offers some smooth terrain but only about a quarter of the area needed to assure a safe landing. Philae could end up landing on the edge of a cliff or atop a large boulder and topple over.
canada goose factory sale A ‘color’ view of Comet 67P, from a September 24, 2014 NavCam image. This is how it had to be because the light travel time for telecommunications from the spacecraft to Earth does not permit real time control. The execution time and the command sequence will be delivered to Rosetta days before the November 12th landing. And ground control must maneuver Rosetta with Philae still attached to an exact point in space where the release of Philae must take place. Any inaccuracy in the initial release point will be translated all the way down to the surface and Philae would land some undesired distance away from Site J. However, ground controllers have a Canada Goose Coats On Sale month and a half to practice simulations of the landing many times over with a model of the comet’s nucleus. With practice and more observational data between now and the landing, the initial conditions and model of the comet in the computer simulation will improve and raise the likelihood of a close canada goose clearance sale landing to Site J. canada goose factory sale
Previous Universe Today articles on Rosetta’s Philae:
How do you land on a comet? Very carefully.
uk canada goose Rosetta’s Philae Lander: A Swiss Army Knife of Scientific Instruments uk canada goose
canada goose shop vancouver Comet’s Head Selected as Landing Site for Rosetta’s Historic Philae Lander canada goose shop vancouver
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