Uranus

Kalpana Chawla

(March 17, 1962^[ – February 1, 2003) was born in Karnal, India. She was the first Indian-American astronautand first Indian woman in space. She first flew on Space Shuttle Columbia in 1997 as a mission specialist and primary robotic arm operator. In 2003, Chawla was one of the seven crew members killed in the Space Shuttle Columbia disaster.

Kalpana Chawla was born in Karnal, India. She completed her earlier schooling at Tagore Baal Niketan Senior Secondary School, Karnal and completed her Bachelor of Engineering degree in Aeronautical Engineering at Punjab Engineering College at Chandigarh in 1982. She moved to the United States in 1982 where she obtained a Master of Science degree in aerospace engineering from the University of Texas at Arlington in 1984. Determined to become an astronaut even in the face of the Challenger disaster, Chawla went on to earn a second Masters in 1986 and a PhD in aerospace engineering in 1988 from the University of Colorado at Boulder.

Jean-Loup Jacques Marie Chrétien

(Born August 20, 1938) is a French retired Général de Brigade (brigadier general) in the Armée de l'Air (French air force), and a former CNES spationaut. He flew on two Franco-Soviet space missions and a NASA Space Shuttle mission. Chrétien was the first Frenchman and the first western European in space.

Born 20 August 1938, in the town of La Rochelle, France. Married to and then divorced from Amy Kristine Jensen of New Canaan, Connecticut. Chrétien was educated at L'École communale à Ploujean, the Collège Saint-Charles à Saint-Brieuc, and the Lycée de Morlaix. He entered the École de l'Air (the French Air Force Academy) at Salon-de-Provence in 1959, and graduated in 1961, receiving a master’s degree in aeronautical engineering.In April 1979, the Soviet Union offered France the opportunity to fly a cosmonaut on board a joint Soviet-French space flight, along the same lines as the agreement to fly non-Soviet cosmonauts from member countries of the Intercosmos program. The offer was accepted, and France began a spationaut selection process in September 1979. Chrétien was one of two finalists named on 12 June 1980. He started training at the Yuri Gagarin Cosmonaut Training Center in September 1980. The following year he was named as the Research Cosmonaut for the prime crew of the Soyuz T-6 mission.

Takao Doi

(Born September 18, 1954) is a Japanese astronaut and a veteran of two NASA space shuttle missions.

Doi holds a doctorate from the University of Tokyo in aerospace engineering, and has studied and published in the fields of propulsion systems, and microgravity technology. He researched at the Institute of Space and Astronautical Science and was selected by NASDA as an astronaut candidate in 1985 for the Japanese manned space program while also conducting research in the United States at NASA's Lewis Research Center and the University of Colorado at Boulder. Doi flew as a mission specialist aboard STS-87 in 1997, during which he became the first Japanese astronaut to conduct a spacewalk.

He received a Ph.D in Astronomy from Rice University in 2004.

Takao Doi visited the International Space Station in March 2008 as a member of the STS-123 crew. STS-123 delivered the first module of the Japanese laboratory, Kibō, and the Canadian Dextre robot to the space station. During this mission, he became the first person to throw a boomerang in space that was specifically designed for use in microgravity during spaceflight.

Doi retired from the astronaut duty and he works as the chief of Space Applications Section of United Nations Office for Outer Space Affairs starting September 2009

URANUS

Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System.

Discoverer: William Herschel.

Radius: 25,362 km

Surface area: 8,083,079,690 km²

Mass: 86.81E24 kg (14.54 Earth mass)

Distance from Sun: 2,877,000,000 km

Time to spin on Axis 17 hours, 14 minutes ( Earth: 23 hours, 56 minutes )

Time to orbit the Sun 84 years ( Earth: 365 days, 6 hours )

Distance planet travels to complete one orbit 18,026,802,831 km / 11,201,335,967 miles ( Earth: 924,375,700 km / 574,380,400 miles )

Gravity (Earth = 1) 0.91

Escape Velocity : 76,968 km/h /47,826 mph ( Earth: 40,248 km/h / 25,009 mph )

Temperature at Cloud Tops : -216 °c / -357 °F / 57 K ( Earth's average temp: 15 °c / 59 °F / 288 K )

Contents of Atmosphere :Hydrogen, Helium, Methane

Known moons There are at least 27 moons known to orbit Uranus - : Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda, Perdita, Puck, Mab, Miranda, Ariel, Umbriel, Titania, Oberon, Francisco, Caliban, Stephano, Trinculo, Sycorax, Margaret, Propero, Setebos and Ferdinand

Discovery of Uranus :

The third of the gas giants. Uranus was discovered in 1781 by Caroline Herschel and her brother William. William thought it was a comet at first and his calculations showed it getting bigger and bigger as he thought it approached the Earth. When observations and calculations from other astronomers in different countries came in, it was realised by them all that the Herschels had discovered a planet, and William hastily revised his data.
Some wanted to call the planet Herschel, but the Herschels called it Georgius Sidus (George's Star in Latin) after King George III who funded them. Bode suggested Uranus after the Greek God of the Heavens who had been castrated by his son Chronos the God of Time (see Saturn). Eventually this was to be accepted internationally as the planet's name.

About Uranus :

Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both are of different chemical composition than the larger gas giants Jupiter and Saturn. For this reason, astronomers sometimes place them in a separate category called "ice giants". Uranus's atmosphere, although similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, contains more "ices" such as water, ammonia, and methane, along with traces of hydrocarbons. It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (-224.2 °C), and has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane the uppermost layer of clouds. In contrast, the interior of Uranus is mainly composed of ices and rock.
It is the only planet whose name is derived from a figure from Greek mythology rather than Roman mythology like the other planets, from the Latinized version of the Greek god of the sky, Ouranos. Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration among those of the planets because its axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun. Its north and south poles therefore lie where most other planets have their equators. In 1986, images from Voyager 2 showed Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants. Terrestrial observers have seen signs of seasonal change and increased weather activity in recent years as Uranus approached its equinox. The wind speeds on Uranus can reach 250 meters per second (900 km/h, 560 mph).

Rotation

Uranus revolves around the Sun once every 84 Earth years. Its average distance from the Sun is roughly 3 billion km (about 20 AU). The intensity of sunlight on Uranus is thus about 1/400 that on Earth. Its orbital elements were first calculated in 1783 by Pierre-Simon Laplace. With time, discrepancies began to appear between the predicted and observed orbits, and in 1841, John Couch Adams first proposed that the differences might be due to the gravitational tug of an unseen planet. In 1845, Urbain Le Verrier began his own independent research into Uranus's orbit. On September 23, 1846, Johann Gottfried Galle located a new planet, later named Neptune, at nearly the position predicted by Le Verrier.

Inside Uranus :

Uranus's mass is roughly 14.5 times that of the Earth, making it the least massive of the giant planets. Its diameter is slightly larger than Neptune's at roughly four times Earth's. A resulting density of 1.27 g/cm3 makes Uranus the second least dense planet, after Saturn. This value indicates that it is made primarily of various ices, such as water, ammonia, and methane.] The total mass of ice in Uranus's interior is not precisely known, because different figures emerge depending on the model chosen; it must be between 9.3 and 13.5 Earth masses. Hydrogen and helium constitute only a small part of the total, with between 0.5 and 1.5 Earth masses. The remainder of the non-ice mass (0.5 to 3.7 Earth masses) is accounted for by rocky material.
The standard model of Uranus's structure is that it consists of three layers: a rocky (silicate/iron-nickel) core in the center, an icy mantle in the middle and an outer gaseous hydrogen/helium envelope. The core is relatively small, with a mass of only 0.55 Earth masses and a radius less than 20% of Uranus's; the mantle comprises its bulk, with around 13.4 Earth masses, whereas the upper atmosphere is relatively insubstantial, weighing about 0.5 Earth masses and extending for the last 20% of Uranus's radius. Uranus's core density is around 9 g/cm3, with a pressure in the center of 8 million bars (800 GPa) and a temperature of about 5000 K. The ice mantle is not in fact composed of ice in the conventional sense, but of a hot and dense fluid consisting of water, ammonia and other volatiles. This fluid, which has a high electrical conductivity, is sometimes called a water–ammonia ocean.

Composition :

The composition of the Uranian atmosphere is different from its bulk, consisting mainly of molecular hydrogen and helium. The helium molar fraction, i.e. the number of helium atoms per molecule of gas, is 0.15 ± 0.03 in the upper troposphere, which corresponds to a mass fraction 0.26 ± 0.05. This value is very close to the protosolar helium mass fraction of 0.275 ± 0.01, indicating that helium has not settled in its center like it has in the gas giants. The third most abundant constituent of the Uranian atmosphere is methane (CH4). Methane possesses prominent absorption bands in the visible and near-infrared (IR) making Uranus aquamarine or cyan in color. Methane molecules account for 2.3% of the atmosphere by molar fraction below the methane cloud deck at the pressure level of 1.3 bar (130 kPa); this represents about 20 to 30 times the carbon abundance found in the Sun.The mixing ratio[h] is much lower in the upper atmosphere owing to its extremely low temperature, which lowers the saturation level and causes excess methane to freeze out. The abundances of less volatile compounds such as ammonia, water and hydrogen sulfide in the deep atmosphere are poorly known. They are probably also higher than solar values. Along with methane, trace amounts of various hydrocarbons are found in the stratosphere of Uranus, which are thought to be produced from methane by photolysis induced by the solar ultraviolet (UV) radiation. They include ethane (C2H6), acetylene (C2H2), methylacetylene (CH3C2H), and diacetylene (C2HC2H). Spectroscopy has also uncovered traces of water vapor, carbon monoxide and carbon dioxide in the upper atmosphere, which can only originate from an external source such as infalling dust and comets.

Mission on Uranus :
Voyager 2 (USA, 1977)

Interesting facts about uranus

1] After Saturn, a space-craft would have to travel 1,500,000,000 kilometres to reach Uranus. This means the planet is almost twice the distance from the Sun than Saturn is.

2] Voyager 2 was the first manmade object to reach Uranus. It had previously visited Jupiter and Saturn and had taken exciting close-up images of those two planets and their moons. However, when the first pictures of Uranus from Voyager 2 were received on Earth in January 1986, scientists were disappointed to see that it was a pale blue, featureless world. Six years of waiting and all they saw were images like the one on the left!

3] Uranus' pale blue colour is caused by the methane in its atmosphere which filters out red light.

4] If we were able to see Uranus' moons orbiting the planet, they would go over and under the planet like lights on a ferris wheel.

5] Uranus has 27 moons (so far discovered) orbiting the planet. Ten of these were discovered in 1986 by the Voyager 2 mission .

6] A day on Uranus is a few hours shorter than a day on Earth - the planet takes 17 hours to spin on its axis. However, a year on Uranus is much longer than a year on Earth. In fact, it takes 84 years on Earth for Uranus to complete one orbit around the Sun .

7] Because of Uranus' unique tilt, a night at one of its poles lasts for 21 Earth years, during which it will receive no light or heat at all from the Sun.

8] Uranus was the first planet in the Solar System to be "discovered". The planets known of at the time of the discovery of Uranus were Mercury, Venus, Earth, Mars, Jupiter and Saturn. Ancient astronomers were able to see these objects without telescopes or binoculars and named them after their Gods. Uranus was discovered much later using scientific instruments, in 1781, but was still named after an ancient god (in mythology, Uranus was the ruler of the Gods).

9] Uranus' pale blue colour is caused by the methane in its atmosphere which filters out red .

10] Almost all of the moons of Uranus are named after characters in plays written by Shakespeare. The moons of every other planet in the Solar System are named after characters in Greek and Roman mythology. The two moons of Uranus that are not named after Shakespearean characters (Arlel and Umbriel) are named after characters in a book called "The Rape of the Lock" written by Alexander Pope.