Information taken from Wikipedia and Books by Stephen and Lucy Hawking



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Wrist Mirror
A spacewalker cannot see the front of the Displays and Control Module while wearing the spacesuit. To see the controls, astronauts wear a wrist mirror on the sleeve. Look at the settings on the front of the module. They are written backward. But "backward" is "forward" in a mirror.


 
 





Layers
The spacesuit arm has 14 layers of material to protect the spacewalker. The liquid cooling and ventilation garment makes up the first three layers. On top of this garment is the bladder layer. It creates the proper pressure for the body. It also holds in the oxygen for breathing. The next layer holds the bladder layer to the correct shape around the astronaut's body and is made of the same material as camping tents. The ripstop liner is the tear-resistant layer. The next seven layers are Mylar insulation and make the suit act like a thermos. The layers keep the temperature from changing inside. They also protect the spacewalker from being harmed by small, high-speed objects flying through space. The outer layer is made of a blend of three fabrics. One fabric is waterproof. Another is the material used to make bullet-proof vests. The third fabric is fire-resistant.


 




Cuff Checklist
On their wrists, astronauts wear a short checklist of the tasks they will do during the spacewalk.

 




Safety Tethers
One end of these straps is attached to the spacewalker. The other end is connected to the vehicle. The safety tethers keep the astronauts from drifting away into space.



Satellites
Space Exploration
Robotic Space Travel
A space probe is a robotic spacecraft that scientists send out on a journey across the solar system in order to gather more information about our cosmic neighbourhood. Robotic space missions aim to answer specific questions like “What does the surface of Venus look alike?” “Is it windy on Neptune?” “What is Jupiter made of?”
While robotic space missions are much less glamorous than manned space flight, they have several big advantages :


  1. Robots can travel for great distances, going farther and faster than any astronaut. Like manned missions, they need a source of power – most use solar arrays which convert sunlight to energy, but others which are travelling long distances away from the Sun take their own on-board generators. However, robotic spacecrafts need far less power than a manned mission as they don’t need to maintain a comfortable living environment on their journey.

  2. Robots also don’t need supplies of food or water and they don’t need oxygen to breathe, making them much smaller and lighter than a manned mission.

  3. Robots don’t get bored or homesick or fall ill on their journey.

  4. If something goes wrong with a robotic mission, no lives are lost in space.

  5. Space probes cost far less than a manned space flight and robots don’t want to come home after their mission ends.

Space probes have opened up the wonders of the Solar System to us, sending back data which has allowed scientists to understand far better how the Solar System was formed and what conditions are like on other planets. While human beings have to date travelled only as far as the Moon – a journey averaging 378,000 kilometers, space probes have covered billions of miles and shown us extraordinary and detailed images of the far reaches of the Solar System.


In fact, almost 30 space probes reached the Moon before mankind did! Robotic spacecrafts have now been sent to all the other planets in our Solar System, they have caught the dust from a comet’s tail, landed on Mars and Venus and travelled out beyond Pluto. Some space probes have even taken information about our planet and the human race with them. Probes Pioneer 10 and Pioneer 11 carry engraved plaques with the image of a man and a woman on them and also a map, showing where the probe came from. As the Pioneers journey onward into deep space, they may one day encounter an alien civilization!

The Voyager probes took photographs of cities, landscapes and people of Earth with them as well recorded greetings in many different Earth languages. In the incredibly unlikely event of these probes being picked up by another civilization, these greetings assure any aliens who manage to decode them that we are a peaceful planet and we wish any other beings in our Universe well.


There are different types of space probes and the type used for a particular mission will depend on the question that the probe is attempting to answer. Some probes fly by the planets and take pictures for us, passing by several planets on their long journey. Others orbit a specific planet to gain more information about that planet and its moons. Another type of probe is designed to land and send back data from the surface of another world. Some of these are rovers, others remain fixed wherever they land.
The first rover, Lunokhod 1, was a part of a Russian probe, Luna 17, which landed on the Moon in 1970. Lunokhod 1 was a robotic vehicle which could be steered from Earth, in the same way as a remote control car.
NASA’s Mars landers, Viking 1 and Viking , which touched down on the Red Planet in 1976, gave us our first pictures from the surface of the planet of War, which have intrigued people on Earth for millennia. The Viking landers showed the reddish-brown plains, scattered with rocks, the pink sky of Mars and even frost on the ground in winter. Unfortunately, it is very difficult to land on Mars and several probes sent to the red planet have crashed onto its surface.
Later missions to Mars sent two rovers, Spirit and Opportunity. Designed to drive around for at least three months, they lasted for far long and also, like other spacecrafts sent to Mars, found evidence that Mars had been shaped by the presence of water. In 2007, NASA sent the Phoenix Mission to Mar. Phoenix could not drive around Mars but it had a robotic arm to dig into the soil and collect samples. On board, it had a laboratory to examine the soil and work out what it contains. Mars also has three operational orbiters around it – the Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter, showing us in detail the surface features.
Robotic space probes have also shown us the hellish world that lies beneath the thick atmosphere of Venus. Once it was thought that dense tropical forests might lie under the Venusian clouds but space probes have revealed the high temperatures, heavy carbon dioxide atmosphere and dark brown clouds of sulphuric acid. In 1990, NASA’s Magellan entered orbit around Venus. Using radar to penetrate the atmosphere, Magellan mapped the surface of Venus and found 167 volcanoes larger than 70 miles wide! ESA’s Venus Express has been into orbit around Venus since 2006. This mission is studying the atmosphere of Venus and trying to find out how Earth and Venus developed in such different ways. Several landers have returned information from the surface of Venus, a tremendous achievement given the challenges of landing on this most hostile of planets.
Robotic space probes have braved the scorched world of Mercury, a planet even closer to the Sun than Venus. Mariner 10, which flew by Mercury in 1974 and again in 1975, showed us that this bare little planet looks very similar to our Moon. It is a grey, dead planet with very little atmosphere. In 2008, the Messenger mission returned a space probe to Mercury and sent back the first new pictures of the Sun’s nearest planet in 30 years.
Flying close to the Sun presents huge challenges for a robotic spacecraft but probes sent to the Sun – Helios 1, Helios 2, SOHO, TRACE, RHESSI and others have sent back information which helped scientists to develop a far better understanding of the star at the very centre of our Solar System.
Further away in the Solar System, Jupiter was first seen in detail when the probe Pioneer 10 flew by in 1973. Pictures captured by Pioneer 10 also showed the Great Red Spot – a feature seen through telescopes from Earth for centuries. After Pioneer, the Voyager probes revealed the surprising news about Jupiter’s moons. Thanks to the Voyager probes, scientists on Earth learnt that Jupiter’s moons are all very different to each other. In 1995, the Galileo probe arrived at Jupiter and spent eight years investigating the giant gas planet and its moons. Galileo was the first space probe to fly-by an asteroid, the first to discover an asteroid and the first to measure Jupiter over a long period of time. This amazing space probe also showed the volcanic activity on Jupiter’s moon, Lo, and found Europa to be covered in thick ice, beneath which ay lie a gigantic ocean which could even harbour some form of life!
NASA’s Cassini was not the first to visit Saturn – Pioneer 11 and the Voyager 1 and Voyager 2 had flown past on their long journey and sent back detailed images of Saturn’s ring system and more information about the thick atmosphere of Titan. But when Cassini arrived in 2004 after a 7 year journey, it showed us many more features of Saturn and the moons that orbit it. Cassini also released a probe, ESA’s Huygens, which travelled through the thick atmosphere to land on the surface of Titan. The Huygens probe discovered that Titan’s surface is covered in ice and and that methane rains down from the dense clouds.
Even further from Earth, Voyager 2 flew by Uranus and showed pictures of this frozen planet, tilted on its axis! Thanks to Voyager 2, we also know much more about the thing rings circling Uranus, which are very different to the rings of Saturn, as well as many details of its moons. Voyager 2 carried on to Neptune and revealed this planet is very windy – Neptune has the fastest moving storms in the Solar System. Voyager 2 is now 10 billion miles away from the Earth and Voyager 1 is 11 billion miles away! They should be able to continue communicating with us until 2020.
The Stardust mission – a probe which caught particles from a comet’s tail and returned to us in 2006 – taught us far more about the very early Solar System from these fragments. Capturing these samples from comets – which formed at the centre of the Solar System but have travelled to its very edge – has helped scientists to understand more about the origin of the Solar System itself!
Manned Space Flight
‘The Eagle has landed!’
This is the message US astronaut Neil Armstrong radioed back from the Moon to mission control in Houston, US on 20 July 1969. The Eagle was the lunar module, which had detached from the spacecraft Columbia, in orbit 60 miles above the surface of the Moon. While astronaut Michael Collins remained on board Columbia, the Lunar Excursion Module touched down on an area called the Sea of Tranquility – but there was no water on the Moon so it didn’t land with a splash. Neil Armstrong and Buzz Aldrin, the two astronauts inside the Eagle, became the first humans ever to visit the Moon.
NASA

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research. Since February 2006, NASA's mission statement has been to "pioneer the future in space exploration, scientific discovery and aeronautics research."

President Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 [6] with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, replacing its predecessor, the National Advisory Committee for Aeronautics (NACA). The agency became operational on October 1, 1958

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency's astronauts farther into space than ever before and provide the cornerstone for future human space exploration efforts by the U.S.



National Aeronautics and Space Administration




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