Std X Science 1 Chapter 10: Space Missions (Space Missions  Artificial satellites Classification of artificial satellites Orbits of artificial satellites)

Title : Std X Science 1 Chapter 10: Space Missions

• Space Missions , Artificial satellites , Classification of artificial satellites ,Orbits of artificial satellites

Maharashtra state board solutions for class 10 SSC board science part STD X-Science 1 Space Missions

 Know everything about; Space Missions .Maharashtra state board class 10 SSC .Get detailed Questions and answers for chapter 10 Science 1, Space missions Satellite launch vehicles , Space missions away from the Earth, part 2

Q.1) What is the difference between space and sky?

Answer: The sky is the region in which sunlight is scattered in the Earth's atmosphere, making it visible from the surface of the planet, while space is everything beyond that. The sky also includes all objects as far as we can see outside of the Earth. For example, Mars is far away but we consider it in our night sky.

Q.2) What are different objects in the Solar system?

 Answer: The Sun

. · The Planets and Dwarf Planets.

· Moon, Satellites and Rings.

· Asteroids.

· Meteoroids.

· Comets, the Kuiper Belt, and the Oort Cloud

. · Interplanetary Medium.

 · Artificial satellites etc.

 Q.3) What is meant by a satellite?

 Answer: A celestial body orbiting the earth or another planet or an artificial body placed in orbit round the earth or moon or another planet in order to collect information or for communication.

Q.4) How many natural satellites does the earth have?

 Answer: The earth only has one natural satellite the moon.

 Space missions

Q.1) What are the two categories of space missions?

Answer: We can classify the space missions into two categories. In one type of missions, the objective is to put artificial satellites in orbits around the earth for research and various other useful applications. The objective of second type of missions is to send the spacecrafts to outer space for close observations and understanding of the objects in solar system, or even outside the solar system.

 Q.2) Yuri Gagarian

 Answer: The first person to go into the space in a spacecraft was Yuri Gagarin of the then USSR. He orbited the earth in 1961. The first person to step on the Moon (1969) was Neil Armstrong of USA. Rakesh Sharma of India orbited the earth in 1984 in a Russian spacecraft. Kalpana Chawla and Sunita Williams of Indian origin also participated in space explorations through missions organized by NASA (National Aeronautics and Space Administration) of USA.

 Q.3) In which year did India orbited space.

Answer: India orbited the earth in 1984 in a Russian spacecraft.

Q.4) Name the two female astronauts to be included in space missions.

 Answer: Kalpana Chawla and Sunita Williams of Indian origin also participated in space explorations through missions organized by NASA (National Aeronautics and Space Administration) of USA.

Q.6) What is the need and importance of space missions?

 Answer: The world has become a global village due to space missions. Today, we can contact a person in any part of the world within a second. We can gather information about worldwide events sitting at home. You all know the importance of internet. Due to internet, every information is available at our fingertips. It has become possible to get advance alert about natural calamities and take proper precautions.

Artificial Satellites

Q.1) Write a short note on communication satellites.

Answer: During war, it is possible to get information about the actions of the enemy through aerial surveillance using satellites. It is also possible to explore the fossil reserves and minerals in the earth. Thus, there are unlimited applications of space missions. Today, space technology is an inevitable part for development of a nation.

Q.2) What is a natural satellite?

 Answer: A natural satellite is an astronomical object orbiting the earth or any other planet. The moon is the only natural satellite of the earth. Some other planets in the solar system have more than one natural satellites

Q.3) What is an artificial satellites?

Answer: if a manmade object revolves around the earth or any other planet in a fixed orbit it is called an artificial satellite.

Q.4) Which was the first artificial satellite?

Answer: The first artificial satellite ‘Sputnik’ was sent to space by Soviet Union in 1957. Sputnik

Q.5) How does satellites work?

Answer: Today, more than thousand satellites are orbiting the earth. The satellites work on solar energy. So, solar photovoltaic panels are attached on both sides of these satellites like wings. Instruments are installed in the satellites to receive and transmit signals from and to the earth. The satellites have various other types of instruments, depending on their functions. Signals transmitted from the earth to the satellite and from the satellite to a mobile tower and mobile phone are also shown. These satellites are sent into the space to perform various functions.

 Q.6) Classify the satellites depending on their functions.

Answer: Type of satellite Function of the satellite Weather satellite Study and prediction of weather. Communication satellite Establish communication between different location in the world through use of specific waves. Broadcast satellite Telecasting of television programs. Navigational satellite Fix the location of any place on the earth’s surface in terms of its very precise latitude and longitude. Military Satellite Collect information for security aspects. 6 Earth Observation Satellite Study of forests, deserts, oceans, polar ice on the earth’s surface, exploration and management of natural resources, observation and guidance in case of natural calamities like flood and earthquake.

 Q.7) Give the full forms of

• INSAT: Indian National Satellite
• GSAT: Geosynchronous Satellite
• IRNSS: Indian Regional Navigation Satellite System
• IRS: Indian Remote Sensing Satellite
• GSLV: Geosynchronous Satellite Launch Vehicle
• PSLV: Polar Satellite Launch Vehicle

Q.8) What does the nature of artificial satellite decide?

 Answer: All artificial satellites do not revolve in similar orbits around the earth. The functions of the satellite decide the height of the satellite’s orbit from the earth’s surface, the nature of the orbit (circular/elliptical) and whether the orbit shall be parallel to equator or making some angle with it.

Q.9) What do you mean by critical velocity?

 Answer: To put the satellite in its proper orbit at specific height above the earth’s surface, the satellite is taken to that height using a satellite launcher. Then the satellite is given a specific velocity known as the critical velocity (vc) in a tangential direction to the orbit. The satellite then starts revolving around the earth.

Q.10) Write a note on High Earth Orbits.

 Answer: If the height of the satellite’s orbit above the earth’s surface is greater than or equal to 35780 km, the orbit is called High earth Orbit. a satellite revolving in an orbit 35780 km above the earth’s surface, will take around 24 hours to complete one revolution. the earth also takes almost 24 hrs for one revolution. If the satellite is revolving in an orbit parallel to the equator, the time of revolution for the earth around itself and that for the satellite to revolve around the earth being the same, the satellite will appear to be stationary with respect to the earth. For a passenger in one vehicle, another vehicle, moving parallel to him with equal velocity, appears to be stationary. This is what happens here also. These satellites are, therefore, called geosynchronous satellites. Since, these satellites are stationary with reference to the earth, they can observe a specific portion of the earth, continuously. Therefore, they are used in applications like meteorology and for carrying signals for telephone, television, radio etc.

 Q10) Write a note on Medium Earth Orbit.

Answer: If the height of the satellite orbit above the earth’s surface is in between 2000 km and 35780 km, the orbits are called medium earth orbits. The geostationary satellites orbit above the equator. These are, therefore, not useful in the study of polar regions. For this purpose, elliptical medium earth orbits passing over the polar region are used. These orbits are called polar orbits. In these orbits, the satellites complete one revolution in 2 to 24 hours. Some of these satellites revolve in circular orbits at a height of around 20,200 km above the earth’s surface. Global positioning satellites revolve in such orbits.

 Q.11) Write a note on Low Earth Orbits.

 Answer: If the height of the satellite orbit above the earth’s surface is in between 180 km and 2000 km, the orbits are called Low earth Orbits. The satellites used for scientific experiments and atmospheric studies revolve in low earth orbits. Depending on the height of their orbits, they complete one revolution in around 90 minutes. International Space Station and Hubble telescope also revolve in Low earth Orbits.

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