Не напомните, что там были за приземления на кометы, кажется год или 2 назад. Вроде Япония не то аппарат послала, не то аж космонавта. И если человек ухитрился приземлиться на комету, тогда в чём проблема с полётом на Марс?
Извите за невнятную тему - целый день мучает похмелье. Башка болит подлая.
Приземление на кометы
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Мыслитель
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Приземление на кометы
GM cars are EVIL, they are the work of the devil, made to collect your souls and turn you into brainless slaves of hell.
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Polar Cossack
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Re: Приземление на кометы
Возвращаться пора. Японец.Мыслитель wrote:Извите за невнятную тему - целый день мучает похмелье. Башка болит подлая.
"Я хотел бы устроиться в вашу мусарню… Я хочу ходить с волыной и шмалять в людей." "Триод и Диод"
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Иоп
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KP580BE51
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Иоп wrote:А комета твердая? Я почему-то думал, что это просто газ.
http://deepimpact.jpl.nasa.gov/index.cfm
Газ тоже может твердым быть.
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Polar Cossack
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MaxSt
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Re: Приземление на кометы
Мыслитель wrote:Вроде Япония не то аппарат послала, не то аж космонавта.
Аппарат, причем малобюджетный. Он у них от немягкой посадки слегка поломался, и неизвестно еще, сумеет ли он доползти черепашьим ходом обратно...
Мыслитель wrote:И если человек ухитрился приземлиться на комету, тогда в чём проблема с полётом на Марс?
Не ухитрился. Японцы пока еще даже на орбиту своих космонавтов не отправляли, какой уж там Марс...
Даже привести пробу грунта с Марса - чрезвычайно сложный и дорогой проект. По крайней мере NASA отложила его в долгий ящик.
War does not determine who is right - only who is left.
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NightFlier
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In December, NASA astronaut Edward Lu told Space.com that plans under study include landing on an asteroid and retrieving rock samples for return to Earth before 2020.
And at NASA's Ames Research Center, lab chief Simon "Pete" Worden, a longtime advocate of such exploration, has set aside $10 million for designing small spacecraft that could visit asteroids, according to the Jan. 19 Science magazine.
The space agency does have a few asteroid missions already planned. In its just-released 2008 budget, NASA said it is studying a mission, dubbed the Origins Spectral Interpretation, Resource Identification and Security (OSIRIS) probe, to return rock samples from an asteroid.
In June, NASA will launch the Dawn mission to orbit the two largest asteroids, Ceres and Vesta, in the main asteroid belt between Mars and Jupiter.
And outside NASA, others also see asteroids' scientific potential.
"They are pristine in a way, vagabonds of the solar system, leftovers from the era of the formation of the planets," says American Museum of Natural History astrophysicist Neil deGrasse Tyson, host of PBS' NOVA scienceNOW, and author of the new book Death by Black Hole and Other Cosmic Quandaries. "And as for landings, they are low-hanging fruit, or low-hanging rocks, in this case, for space exploration."
Too close for comfort?
The International Astronomical Union has given identifying numbers to nearly 150,000 asteroids; about 5,000 are discovered every month. A mix of sand piles, dust balls, metal-rich rocks and burned-out comets, they mostly congregate in the asteroid belt between Mars and Jupiter.
Closer to home, NASA has, as of November, tracked 855 potentially dangerous Near-Earth asteroids. These pass within about 30 million miles of Earth, with a diameter of approximately 1 kilometer (.62 miles) or larger. Astronomers regard that size as the point at which impact with Earth would threaten civilization, says Richard Binzel of the Massachusetts Institute of Technology.
NASA operates a program, the Spaceguard Survey, to track this "cosmic shooting gallery," in the words of NASA scientist David Morrison, aiming to identify 90% of the estimated 1,100 civilization-buster Near-Earth asteroids lurking overhead before 2009. Congress has further told NASA to catalogue 90% of all Near-Earth asteroids less than 460 feet wide by 2020, and figure out ways to deflect any headed for Earth.
Tyson says such asteroids offer an intriguing array of midway points between the four-day trip to the moon and the six-month voyage to Mars.
"As steppingstones to Mars, (asteroids) are a really good way to learn to leave the comfort of the Earth-Moon system," says Binzel. "There are literally hundreds of Near-Earth asteroids that are probably easier to reach than the moon, in terms of the propellant you need to go there and back."
That's because asteroids have hardly any gravity. So fuel costs for blasting out of each one's "gravity well" are minimal. Eros, a hefty near-Earth asteroid, some 20 miles long by 8 miles across, has such light gravity that a person could toss a baseball off its surface and into orbit. In comparison, a rocket needs a 5,370 mph escape velocity to leave the moon.
And NASA's plans include building a rocket capable of sending astronauts to the moon, called Ares 1, which is scheduled to be ready for flight testing in 2014. The rocket designers aim to overcome the Earth's 39,600 mph escape velocity and deliver a 25-ton astronaut capsule to the moon, complete with the fuel needed to return. That capability should put a variety of asteroids within reach.
For something a bit sooner, Morrison will describe a Near-Earth Asteroid Trailblazing (NEAT) probe, low-cost landers designed to flit among nearby asteroids, scouting their surfaces, at a March American Institute of Aeronautics and Astronautics meeting.
"Landing on one would be more like docking with the international space station than a moon landing," says astronomer Daniel Durda of the Southwest Research Institute in Boulder, Colo. Astronauts would most likely "swim" over the surface of an asteroid, he says, so lightly do things fall on a typical one, which essentially has zero gravity.
A proposal to rein them in
Of course, there is also the impact threat to consider. In 1980, geologist Luis Alvarez suggested in the journal Science that a comet or asteroid impact ended the Age of Dinosaurs. Many researchers believe the impact landed off the Yucatan peninsula in the Gulf of Mexico, and fears that there will be another such mass-extinction event stock the cabinet of modern worries.
"From a practical point of view, some time in the future, one of these things is going to threaten Earth with an impact and we'll need to do something about it," Durda says. So why not visit one to get the hang of herding them? he asks.
The Harvard-Smithsonian Minor Planet Center predicts there will be more than 5,300 "close" asteroid encounters, within 18.4 million miles, by 2040.
One of the most interesting, Apophis, grabbed headlines three years ago because of the possibility that it would smack into Earth in 2036. Improved observations lower the odds to a 1 in 45,000 chance, Binzel says, "nothing to lose sleep over."
But the asteroid's close approach in 2029 to within 22,600 miles of Earth, closer than the moon, may offer an exploration opportunity.
In 2005, Lu and another astronaut, Stanley Love, proposed a "gravity tractor" design for deflecting Apophis and other asteroids from Earth. "Our suggested alternative is to have the spacecraft simply hover above the surface of the asteroid. The spacecraft tows it without physical attachment by using gravity as a towline," they wrote in the journal Nature.
Once in orbit and gravitationally bound to a dangerous asteroid, the space tractor would gently fire its thrusters to slowly "tug" the threatening rock onto a safer trajectory. Apophis, for example, would require a one-ton tug to orbit the asteroid for a month before its 2029 close pass by Earth to put it onto a safer path.
Are they hollow or solid?
One of the great uncertainties about asteroids is what they are made of, something that might make astronauts piloting robotic surveyors more likely than actual manned landings. Some, like Eros, appear to be fairly solid objects, based on their gravity, albeit intensely dust-covered ones. The slowly-rotating Mathilde, which the NEAR-Shoemaker probe flew past in 1997, appears three times less heavy than its size would indicate, suggesting it may be hollow. And the asteroid Itokawa is just a rubble pile, a surprise that explains the 2005 failure of Japan's Hayabusa probe to land there.
As Tyson says, asteroids are thought to mostly be leftovers from the era of planetary accretion 4.6 billion years ago in the solar system. Weathered by eons of orbits around the sun and impacts with other space rocks, they still offer clues to the ingredients of today's planets and moons. "Each asteroid is a piece in the puzzle of how the planets formed," Tyson says.
Broadly speaking, inhabitants of the main asteroid belt between Mars and Jupiter are thought to come in three flavors: dark carbon-rich "carbonaceous" ones that make up about 75% of the total, iron-rich "metallic" asteroids, and fairly bright "silicaceous" asteroids built from a mix of iron and sand.
But nobody knows for sure, Binzel says, which makes exploring asteroids an exciting prospect. A few are likely burned-out comets plying their retirement years in the placid depths of space. "Water or ice might be inside them," handy for space travelers, he says. "Others might have minerals that might be useful future resources."
And at NASA's Ames Research Center, lab chief Simon "Pete" Worden, a longtime advocate of such exploration, has set aside $10 million for designing small spacecraft that could visit asteroids, according to the Jan. 19 Science magazine.
The space agency does have a few asteroid missions already planned. In its just-released 2008 budget, NASA said it is studying a mission, dubbed the Origins Spectral Interpretation, Resource Identification and Security (OSIRIS) probe, to return rock samples from an asteroid.
In June, NASA will launch the Dawn mission to orbit the two largest asteroids, Ceres and Vesta, in the main asteroid belt between Mars and Jupiter.
And outside NASA, others also see asteroids' scientific potential.
"They are pristine in a way, vagabonds of the solar system, leftovers from the era of the formation of the planets," says American Museum of Natural History astrophysicist Neil deGrasse Tyson, host of PBS' NOVA scienceNOW, and author of the new book Death by Black Hole and Other Cosmic Quandaries. "And as for landings, they are low-hanging fruit, or low-hanging rocks, in this case, for space exploration."
Too close for comfort?
The International Astronomical Union has given identifying numbers to nearly 150,000 asteroids; about 5,000 are discovered every month. A mix of sand piles, dust balls, metal-rich rocks and burned-out comets, they mostly congregate in the asteroid belt between Mars and Jupiter.
Closer to home, NASA has, as of November, tracked 855 potentially dangerous Near-Earth asteroids. These pass within about 30 million miles of Earth, with a diameter of approximately 1 kilometer (.62 miles) or larger. Astronomers regard that size as the point at which impact with Earth would threaten civilization, says Richard Binzel of the Massachusetts Institute of Technology.
NASA operates a program, the Spaceguard Survey, to track this "cosmic shooting gallery," in the words of NASA scientist David Morrison, aiming to identify 90% of the estimated 1,100 civilization-buster Near-Earth asteroids lurking overhead before 2009. Congress has further told NASA to catalogue 90% of all Near-Earth asteroids less than 460 feet wide by 2020, and figure out ways to deflect any headed for Earth.
Tyson says such asteroids offer an intriguing array of midway points between the four-day trip to the moon and the six-month voyage to Mars.
"As steppingstones to Mars, (asteroids) are a really good way to learn to leave the comfort of the Earth-Moon system," says Binzel. "There are literally hundreds of Near-Earth asteroids that are probably easier to reach than the moon, in terms of the propellant you need to go there and back."
That's because asteroids have hardly any gravity. So fuel costs for blasting out of each one's "gravity well" are minimal. Eros, a hefty near-Earth asteroid, some 20 miles long by 8 miles across, has such light gravity that a person could toss a baseball off its surface and into orbit. In comparison, a rocket needs a 5,370 mph escape velocity to leave the moon.
And NASA's plans include building a rocket capable of sending astronauts to the moon, called Ares 1, which is scheduled to be ready for flight testing in 2014. The rocket designers aim to overcome the Earth's 39,600 mph escape velocity and deliver a 25-ton astronaut capsule to the moon, complete with the fuel needed to return. That capability should put a variety of asteroids within reach.
For something a bit sooner, Morrison will describe a Near-Earth Asteroid Trailblazing (NEAT) probe, low-cost landers designed to flit among nearby asteroids, scouting their surfaces, at a March American Institute of Aeronautics and Astronautics meeting.
"Landing on one would be more like docking with the international space station than a moon landing," says astronomer Daniel Durda of the Southwest Research Institute in Boulder, Colo. Astronauts would most likely "swim" over the surface of an asteroid, he says, so lightly do things fall on a typical one, which essentially has zero gravity.
A proposal to rein them in
Of course, there is also the impact threat to consider. In 1980, geologist Luis Alvarez suggested in the journal Science that a comet or asteroid impact ended the Age of Dinosaurs. Many researchers believe the impact landed off the Yucatan peninsula in the Gulf of Mexico, and fears that there will be another such mass-extinction event stock the cabinet of modern worries.
"From a practical point of view, some time in the future, one of these things is going to threaten Earth with an impact and we'll need to do something about it," Durda says. So why not visit one to get the hang of herding them? he asks.
The Harvard-Smithsonian Minor Planet Center predicts there will be more than 5,300 "close" asteroid encounters, within 18.4 million miles, by 2040.
One of the most interesting, Apophis, grabbed headlines three years ago because of the possibility that it would smack into Earth in 2036. Improved observations lower the odds to a 1 in 45,000 chance, Binzel says, "nothing to lose sleep over."
But the asteroid's close approach in 2029 to within 22,600 miles of Earth, closer than the moon, may offer an exploration opportunity.
In 2005, Lu and another astronaut, Stanley Love, proposed a "gravity tractor" design for deflecting Apophis and other asteroids from Earth. "Our suggested alternative is to have the spacecraft simply hover above the surface of the asteroid. The spacecraft tows it without physical attachment by using gravity as a towline," they wrote in the journal Nature.
Once in orbit and gravitationally bound to a dangerous asteroid, the space tractor would gently fire its thrusters to slowly "tug" the threatening rock onto a safer trajectory. Apophis, for example, would require a one-ton tug to orbit the asteroid for a month before its 2029 close pass by Earth to put it onto a safer path.
Are they hollow or solid?
One of the great uncertainties about asteroids is what they are made of, something that might make astronauts piloting robotic surveyors more likely than actual manned landings. Some, like Eros, appear to be fairly solid objects, based on their gravity, albeit intensely dust-covered ones. The slowly-rotating Mathilde, which the NEAR-Shoemaker probe flew past in 1997, appears three times less heavy than its size would indicate, suggesting it may be hollow. And the asteroid Itokawa is just a rubble pile, a surprise that explains the 2005 failure of Japan's Hayabusa probe to land there.
As Tyson says, asteroids are thought to mostly be leftovers from the era of planetary accretion 4.6 billion years ago in the solar system. Weathered by eons of orbits around the sun and impacts with other space rocks, they still offer clues to the ingredients of today's planets and moons. "Each asteroid is a piece in the puzzle of how the planets formed," Tyson says.
Broadly speaking, inhabitants of the main asteroid belt between Mars and Jupiter are thought to come in three flavors: dark carbon-rich "carbonaceous" ones that make up about 75% of the total, iron-rich "metallic" asteroids, and fairly bright "silicaceous" asteroids built from a mix of iron and sand.
But nobody knows for sure, Binzel says, which makes exploring asteroids an exciting prospect. A few are likely burned-out comets plying their retirement years in the placid depths of space. "Water or ice might be inside them," handy for space travelers, he says. "Others might have minerals that might be useful future resources."
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NightFlier
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433 Eros (ˈirɒs) is an asteroid named after the Greek god of love Eros (Greek Ἔρως). It is an S-type asteroid approximately 13 × 13 × 33 km in size, the second-largest near-Earth asteroid, belonging to the Amors. It is also a Mars-crosser asteroid. On January 31, 2012, Eros is expected to pass Earth at 0.1790 astronomical units (1 AU – about 93 million miles – is the average distance from Earth to the sun).
Eros was visited by the NEAR Shoemaker probe, which orbited it, taking extensive photographs of its surface, and, on February 12, 2001, at the end of its mission, landed on the asteroid's surface using its maneuvering jets.
Legal controversy
In an experimental legal case, Eros was claimed as property by Gregory W. Nemitz of OrbDev. According to the Homestead principle, Nemitz argued that he had the right to claim ownership of any celestial body that he made use of; he claimed he had designated Eros a spacecraft parking facility and wished to charge NASA a parking and storage fee of twenty cents per year for NEAR Shoemaker. Nemitz's case was dismissed and an appeal denied.
Eros was visited by the NEAR Shoemaker probe, which orbited it, taking extensive photographs of its surface, and, on February 12, 2001, at the end of its mission, landed on the asteroid's surface using its maneuvering jets.
Legal controversy
In an experimental legal case, Eros was claimed as property by Gregory W. Nemitz of OrbDev. According to the Homestead principle, Nemitz argued that he had the right to claim ownership of any celestial body that he made use of; he claimed he had designated Eros a spacecraft parking facility and wished to charge NASA a parking and storage fee of twenty cents per year for NEAR Shoemaker. Nemitz's case was dismissed and an appeal denied.
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tau797
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