After a decade-long journey chasing its target, the European Space Agencys Rosetta, carrying three NASA instruments, became the first spacecraft to rendezvous with a comet today. The last of a series of 10 rendezvous maneuvers that began in May, to adjust Rosettas speed and trajectory to gradually match those of comet 67P/Churyumov-Gerasimenko, occurred today. After 10 years, five months and four days travelling towards our destination, looping around the sun five times and clocking up 6.4 billion kilometers, we are delighted to announce finally we are here, said Jean-Jacques Dordain, ESAs director General. Comet 67P/Churyumov-Gerasimenko and Rosetta are 252 million miles (405 million kilometers) from Earth, about halfway between the orbits of Jupiter and Mars. The comet is in an elliptical, 6.5-year orbit that takes it from beyond Jupiter at its farthest point, to between the orbits of Mars and Earth at its closest to the sun. Rosetta will accompany the comet for over a year as it swings around the sun and back out towards Jupiter again. Rosetta is 62 miles (100 kilometers) from the comets surface. Over the next six weeks, it will fly two triangular-shaped trajectories in front of the comet, first at the 62-mile (100-kilometer) altitude and then down at 31 miles (50 kilometers). At the same time, the spacecrafts suite of instruments will provide a detailed scientific study of the comet, scanning the surface to identify a target site for its comet lander, Philae. Eventually, Rosetta will attempt a close, near-circular orbit at 19 miles (30 kilometers) and, depending on the activity of the comet, may come even closer. Over the next few months, in addition to characterizing the comet nucleus and setting the bar for the rest of the mission, we will begin final preparations for another space history first: landing on a comet, said Matt Taylor, Rosettas project scientist from the European Space Agencys Science and Technology Centre in Noordwijk, The Netherlands. As many as five possible landing sites will be identified by late August, before the primary site is identified in mid-September. The final timeline for the sequence of events for deploying Philae -- currently expected for Nov. 11 -- will be confirmed by the middle of October. Comets are considered to be primitive building blocks of the solar system and may have helped to seed Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through a comprehensive, in situ study of the comet, Rosetta aims to unlock the secrets within. The three U.S. instruments aboard the spacecraft are the Microwave Instrument for Rosetta Orbiter (MIRO), an ultraviolet spectrometer called Alice, and the Ion and Electron Sensor (IES). They are part of a suite of 11 science instruments aboard the Rosetta orbiter. MIRO is designed to provide data on how gas and dust leave the surface of the nucleus to form the coma and tail that give comets their intrinsic beauty. Studying the surface temperature and evolution of the coma and tail provides information on how the comet evolves as it approaches and leaves the vicinity of the sun. Alice will analyze gases in the comets coma, which is the bright envelope of gas around the nucleus of the comet developed as it approaches the sun. Alice also will measure the rate at which the comet produces water, carbon monoxide and carbon dioxide. These measurements will provide valuable information about the surface composition of the nucleus. The instrument also will measure the amount of argon present, an important clue about the temperature of the solar system at the time the comets nucleus originally formed more than 4.6 billion years ago. Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation. Composed of an orbiter and lander, Rosettas objectives upon arrival at comet 67P/Churyumov-Gerasimenko in August are to study the celestial object up close in unprecedented detail, prepare for landing a probe on the comets nucleus in November, and track its changes as it sweeps past the sun. Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosettas lander will obtain the first images taken from a comets surface and will provide the first analysis of a comets composition by drilling into the surface. Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the suns radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life. For more updates on Astronomy and Space Exploration, follow us at Astronomy Today. #Rosetta #Comet #NASA #ESA #Spacecraft #Philae #Lander #Space #Exploration #Telescope #Astronomy #Astronomer #Share #Cosmos #Universe #TimeCapsule #Science #Education #PicoftheDay #FollowUs
Posted on: Thu, 07 Aug 2014 01:16:18 +0000