The Rosetta Mission
Launched on March 2, 2004, from Kourou, French Guiana, by the European Space Agency (ESA), a spacecraft designed to fulfill the goals of the Rosetta Mission is set to send a lander to hitch a ride on a comet ten years later (2014). It will study the comet for two years before it launches its lander. Then in 2014 it releases its 220-pound lander, called Philae, which will ride the comet for a year as it travels past Jupiter and flies by the sun.
In the first phase of the project, in order to overcome the effects of gravity, it will circle Earth and Mars three times in March 2005, November 2007, and November 2009. From 2008 to 2009 it will begin to pass through two asteroid belts where it will study the asteroids, Steins and Lutetia. From 2011 to 2013 it begins to reach its maximum orbit, 540 million miles from the sun, and then shuts down its engines. In this phase it studies the comet's coma (the principal part of most comets consisting of a diffuse cloud of gas and dust which surrounds the nucleus) until November 2014 when it delivers its lander.
The technique used to land Philae on the comet Chury and keep it in place for its perilous ride on a comet's back is remarkable. As soon as it touches down, two harpoons will anchor the probe to the surface. A self-adjusting landing gear will then keep it upright even if it is on a slope. The lander's feet will then drill into the ground. All these manuevers are designed to help the lander deal with the low gravity found on comets.
The International Rosetta Mission was approved in November 1993 by ESA. Originally it was set to meet Comet 46p/Wirtanen but after a delay in the launch time it was reset to meet comet 67p/ Churyumo-Gerasimenko (Chury). Studying the two asteroids is also one of Rosetta mission's secondary objectives. It will gather images of these rocks and learn more about their composition, subsurface temperature, and surrounding gas and dust.
The mission takes its name from the Rosetta Stone which was used to decipher Egyptian Hieroglyphics. Just as this stone helped to teach Egyptologists more about ancient Egyptian history, so the Rosetta Mission's probe should help astronomers decipher the history of the solar system as well as the underlying forces that govern planetary systems in relation to their stars.
The lander is called "Philae" after the obelisk that helped decode the Rosetta Stones . If the Rosetta Mission succeeds it will be:
the first to land on a comet;
the first to fly to Jupiter on solar power alone;
the first to fly alongside a comet and orbit its nucleus;
the first to analyze a comet's composition from its surface;
and the first to see a comet transform from a rock to a hot ball of gas and dust.
In February 1999, NASA launched a spacecraft named Stardust which gathered information from comet Wild 2. Since Stardust's launch it has traveled 4 billion kilometers (2.5 billion miles), looping through the inner solar system three times before arriving at Wild 2. It swung by Earth in January 2001 and in November 2002 came close to the asteroid Annefrank, as a kind of test run for its encounter with Wild 2. It then took pictures while scientists studied and modified its orbit.
Then on January 2, 2004, the Stardust spacecraft flew by Comet Wild 2 scooping up grains of dust and ice from the comet's tail. It came within 230 kilometers (143 miles) of the comet's 5.5-kilometer-wide (3.4-mile-wide) core, the closest approach ever to a comet by a spacecraft.If its mission is successful, the craft will return with the first sample ever taken directly from a comet.
Stardust also captured 72 detailed pictures of Wild 2's core, about one every ten seconds, as it swung by. The pictures showed dust and gas venting from various cracks and openings in the core, forming a tail, as in most comets. But the photographs also revealed Wild 2's surface to be strewn with craters, pockmarks and sinkholes. Scientists were shocked by the varied terrain, which was far different from the surface of the comets Halley and Borrelly pictured by othe spacecraft.
As comets approach the Sun they heat up and begin to boil, leaving a trail of dust, ice and other particles in their wake. Stardust flew through this, scooping some of these particles from behind its heavy shields with an outstretched net shaped like a tennis-racket. About an ounce of material was caught in a compound called aerogel, a spongy silicon. Stardust is due to drop these samples back to Earth by parachute in January 2006. The heat-protected package should land near an air force base in the Utah desert.
Scientists are eager to study this material. Comets are assumed to have formed at the outer edges of the solar system and, except when their orbits have brought them close to the Sun, to have remained frozen since then. They assume the dust Stardust captured has remained unchanged since our solar system formed 4.6 billion years ago. Studying this dust could reveal conditions during that period. Some scientists think a torrent of comets may have seeded Earth with water and organic molecules essential to the planet's evolution in its first 500 million years.
Other than moon rocks, this will be the first material from outer space that scientists have brought back for study. Meteorites from Mars and more distant reaches of the solar system have landed on Earth, but they all passed through Earth's atmosphere, heating up so much that their chemical composition could have been changed
Stardust is the fifth spacecraft to have met up with a comet. In 1985, the International Cometary Explorer zoomed by Comet Giacobini-Zimmer, and one year later, the Giotto and Vega spacecraft had their rendevous with Comet Halley.
The comet Chury will have Philae on it until it becomes a fireball. It reaches its perihelion (the nearest distance of a comet's orbit to the sun) in October 2015. Rosetta monitors the comet with its hitchhiker until the mission ends in December of 2015.
Jordan P. Richman, Ph.D.
Today’s Science on File
Launched on March 2, 2004, from Kourou, French Guiana, by the European Space Agency (ESA), a spacecraft designed to fulfill the goals of the Rosetta Mission is set to send a lander to hitch a ride on a comet ten years later (2014). It will study the comet for two years before it launches its lander. Then in 2014 it releases its 220-pound lander, called Philae, which will ride the comet for a year as it travels past Jupiter and flies by the sun.
In the first phase of the project, in order to overcome the effects of gravity, it will circle Earth and Mars three times in March 2005, November 2007, and November 2009. From 2008 to 2009 it will begin to pass through two asteroid belts where it will study the asteroids, Steins and Lutetia. From 2011 to 2013 it begins to reach its maximum orbit, 540 million miles from the sun, and then shuts down its engines. In this phase it studies the comet's coma (the principal part of most comets consisting of a diffuse cloud of gas and dust which surrounds the nucleus) until November 2014 when it delivers its lander.
The technique used to land Philae on the comet Chury and keep it in place for its perilous ride on a comet's back is remarkable. As soon as it touches down, two harpoons will anchor the probe to the surface. A self-adjusting landing gear will then keep it upright even if it is on a slope. The lander's feet will then drill into the ground. All these manuevers are designed to help the lander deal with the low gravity found on comets.
The International Rosetta Mission was approved in November 1993 by ESA. Originally it was set to meet Comet 46p/Wirtanen but after a delay in the launch time it was reset to meet comet 67p/ Churyumo-Gerasimenko (Chury). Studying the two asteroids is also one of Rosetta mission's secondary objectives. It will gather images of these rocks and learn more about their composition, subsurface temperature, and surrounding gas and dust.
The mission takes its name from the Rosetta Stone which was used to decipher Egyptian Hieroglyphics. Just as this stone helped to teach Egyptologists more about ancient Egyptian history, so the Rosetta Mission's probe should help astronomers decipher the history of the solar system as well as the underlying forces that govern planetary systems in relation to their stars.
The lander is called "Philae" after the obelisk that helped decode the Rosetta Stones . If the Rosetta Mission succeeds it will be:
the first to land on a comet;
the first to fly to Jupiter on solar power alone;
the first to fly alongside a comet and orbit its nucleus;
the first to analyze a comet's composition from its surface;
and the first to see a comet transform from a rock to a hot ball of gas and dust.
In February 1999, NASA launched a spacecraft named Stardust which gathered information from comet Wild 2. Since Stardust's launch it has traveled 4 billion kilometers (2.5 billion miles), looping through the inner solar system three times before arriving at Wild 2. It swung by Earth in January 2001 and in November 2002 came close to the asteroid Annefrank, as a kind of test run for its encounter with Wild 2. It then took pictures while scientists studied and modified its orbit.
Then on January 2, 2004, the Stardust spacecraft flew by Comet Wild 2 scooping up grains of dust and ice from the comet's tail. It came within 230 kilometers (143 miles) of the comet's 5.5-kilometer-wide (3.4-mile-wide) core, the closest approach ever to a comet by a spacecraft.If its mission is successful, the craft will return with the first sample ever taken directly from a comet.
Stardust also captured 72 detailed pictures of Wild 2's core, about one every ten seconds, as it swung by. The pictures showed dust and gas venting from various cracks and openings in the core, forming a tail, as in most comets. But the photographs also revealed Wild 2's surface to be strewn with craters, pockmarks and sinkholes. Scientists were shocked by the varied terrain, which was far different from the surface of the comets Halley and Borrelly pictured by othe spacecraft.
As comets approach the Sun they heat up and begin to boil, leaving a trail of dust, ice and other particles in their wake. Stardust flew through this, scooping some of these particles from behind its heavy shields with an outstretched net shaped like a tennis-racket. About an ounce of material was caught in a compound called aerogel, a spongy silicon. Stardust is due to drop these samples back to Earth by parachute in January 2006. The heat-protected package should land near an air force base in the Utah desert.
Scientists are eager to study this material. Comets are assumed to have formed at the outer edges of the solar system and, except when their orbits have brought them close to the Sun, to have remained frozen since then. They assume the dust Stardust captured has remained unchanged since our solar system formed 4.6 billion years ago. Studying this dust could reveal conditions during that period. Some scientists think a torrent of comets may have seeded Earth with water and organic molecules essential to the planet's evolution in its first 500 million years.
Other than moon rocks, this will be the first material from outer space that scientists have brought back for study. Meteorites from Mars and more distant reaches of the solar system have landed on Earth, but they all passed through Earth's atmosphere, heating up so much that their chemical composition could have been changed
Stardust is the fifth spacecraft to have met up with a comet. In 1985, the International Cometary Explorer zoomed by Comet Giacobini-Zimmer, and one year later, the Giotto and Vega spacecraft had their rendevous with Comet Halley.
The comet Chury will have Philae on it until it becomes a fireball. It reaches its perihelion (the nearest distance of a comet's orbit to the sun) in October 2015. Rosetta monitors the comet with its hitchhiker until the mission ends in December of 2015.
Jordan P. Richman, Ph.D.
Today’s Science on File
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