This weekend, NASA is set to launch a spacecraft that will journey to the asteroid belt that lies between Mars and Jupiter, a mission that involves a rendezvous with two of the solar system’s largest asteroids.
It is the ninth mission out of 10 planned in NASA’s Discovery program that employs unmanned vehicles to explore space, often focusing on asteroids. Dawn is scheduled to blast off Sunday on a Delta II rocket from Cape Canaveral base in US’ southern state of Florida.
NASA said the launch window for Dawn is set for 4:04 pm (2004 GMT) to 4:33 pm (2033 GMT)
Seeking clues about the birth of the solar system, the Dawn spacecraft will first encounter Vesta, the smaller of the two bodies, four years from now.
In 2015, it will meet up with Ceres, which carries the status of both asteroid and, like Pluto, dwarf planet.
“We’re trying to go back in time as well as to go out there in space,” said planetary scientist Christopher Russell of University of California, Los Angeles, who is heading up the mission.
Weather permitting, Dawn is set to blast off Sunday afternoon from Cape Canaveral, Florida, on a Delta II rocket.
The launch caps a tumultuous effort in which the $344 million mission was killed last year because of cost overruns and technical problems.
Ultimately, though, the Jet Propulsion Laboratory in Pasadena, which manages the spacecraft, appealed to NASA Administrator Michael Griffin and got the project revived.
Adding to the drama, Ceres briefly flirted with planethood during last year’s scientific debate about whether Pluto is a planet. Both Pluto and Ceres were classified dwarf planets.
Vesta and Ceres are believed to have evolved in different parts of the solar system more than 4.5 billion years ago around the same time as the formation of the rocky planets including Mercury, Venus, Earth and Mars.
Scientists believe the asteroids’ growth was stunted by Jupiter’s gravitational pull and never had the chance to become full-fledged planets.
Images by the Hubble Space Telescope show Vesta and Ceres as geologically diverse.
Mysteries abound: Why are Vesta and Ceres so different? How do size and water affect planet formation? What does the evolution of the asteroids say about Earth’s formation?
“We are interested in what our ancestors were like,” said Christopher Russell, Dawn’s principal investigator and a professor of geophysics and space physics at the University of California.
“We’re interested in what these early bodies did and how they evolved because those are the building blocks basically of the Earth,” Russell said.
Vesta, which measures 326 miles (525 kilometres) across, is dry and pocked with a deep impact crater in its southern hemisphere.
Scientists are especially interested in this enormous crater – 460 kilometres wide and 13 kilometres deep – on the south pole of Vesta, which is believed to be the result of a major collision.
Astronomers estimate that five per cent of all meteorites found on Earth are the result of this gigantic jolt.
By contrast, Ceres, about twice as large as Vesta, has a dusty surface covered by what appears to be an ice shell and may even contain water inside.
When Dawn reaches each asteroid, first Vesta in 2011, it will orbit each body, photographing the surface and studying the asteroid’s interior makeup, density and magnetism. Pictures and data will be sent back to Earth.
Dawn will be powered by ion propulsion instead of conventional rocket fuel, making it more fuel-efficient and allowing it to cruise between the asteroids and lower itself to about 125 miles (200 kilometres) above the surface to study them in depth.
Although previous spacecraft have explored smaller asteroids, researchers hope Dawn will shed light on the solar system’s origins.
“If you want to understand the Earth, it’s important to understand how it came to be and that’s where asteroids come in. They’re the building blocks,” said Jay Melosh, a planetary geologist at Arizona University who has no role in the Dawn mission.
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It is the ninth mission out of 10 planned in NASA’s Discovery program that employs unmanned vehicles to explore space, often focusing on asteroids. Dawn is scheduled to blast off Sunday on a Delta II rocket from Cape Canaveral base in US’ southern state of Florida.
NASA said the launch window for Dawn is set for 4:04 pm (2004 GMT) to 4:33 pm (2033 GMT)
Seeking clues about the birth of the solar system, the Dawn spacecraft will first encounter Vesta, the smaller of the two bodies, four years from now.
In 2015, it will meet up with Ceres, which carries the status of both asteroid and, like Pluto, dwarf planet.
“We’re trying to go back in time as well as to go out there in space,” said planetary scientist Christopher Russell of University of California, Los Angeles, who is heading up the mission.
Weather permitting, Dawn is set to blast off Sunday afternoon from Cape Canaveral, Florida, on a Delta II rocket.
The launch caps a tumultuous effort in which the $344 million mission was killed last year because of cost overruns and technical problems.
Ultimately, though, the Jet Propulsion Laboratory in Pasadena, which manages the spacecraft, appealed to NASA Administrator Michael Griffin and got the project revived.
Adding to the drama, Ceres briefly flirted with planethood during last year’s scientific debate about whether Pluto is a planet. Both Pluto and Ceres were classified dwarf planets.
Vesta and Ceres are believed to have evolved in different parts of the solar system more than 4.5 billion years ago around the same time as the formation of the rocky planets including Mercury, Venus, Earth and Mars.
Scientists believe the asteroids’ growth was stunted by Jupiter’s gravitational pull and never had the chance to become full-fledged planets.
Images by the Hubble Space Telescope show Vesta and Ceres as geologically diverse.
Mysteries abound: Why are Vesta and Ceres so different? How do size and water affect planet formation? What does the evolution of the asteroids say about Earth’s formation?
“We are interested in what our ancestors were like,” said Christopher Russell, Dawn’s principal investigator and a professor of geophysics and space physics at the University of California.
“We’re interested in what these early bodies did and how they evolved because those are the building blocks basically of the Earth,” Russell said.
Vesta, which measures 326 miles (525 kilometres) across, is dry and pocked with a deep impact crater in its southern hemisphere.
Scientists are especially interested in this enormous crater – 460 kilometres wide and 13 kilometres deep – on the south pole of Vesta, which is believed to be the result of a major collision.
Astronomers estimate that five per cent of all meteorites found on Earth are the result of this gigantic jolt.
By contrast, Ceres, about twice as large as Vesta, has a dusty surface covered by what appears to be an ice shell and may even contain water inside.
When Dawn reaches each asteroid, first Vesta in 2011, it will orbit each body, photographing the surface and studying the asteroid’s interior makeup, density and magnetism. Pictures and data will be sent back to Earth.
Dawn will be powered by ion propulsion instead of conventional rocket fuel, making it more fuel-efficient and allowing it to cruise between the asteroids and lower itself to about 125 miles (200 kilometres) above the surface to study them in depth.
Although previous spacecraft have explored smaller asteroids, researchers hope Dawn will shed light on the solar system’s origins.
“If you want to understand the Earth, it’s important to understand how it came to be and that’s where asteroids come in. They’re the building blocks,” said Jay Melosh, a planetary geologist at Arizona University who has no role in the Dawn mission.
http://www.mumbaimirror.com/net/mmp...&contentid=200707070257179534cc7dcaf&pageno=1