Grade 10 Q&A: Chapter 10: Space Missions

Concept Questions

Q1: What is the primary objective of space missions?

Answer: The primary objective of space missions is to explore the unknown, expand human knowledge about the universe, and utilize space technology for various useful applications on Earth.

Q2: Name the two main categories of space missions.

Answer: The two main categories of space missions are missions to put artificial satellites in Earth's orbit for various applications, and missions to send spacecrafts to outer space for observation and understanding of celestial objects.

Q3: Who was the first person to go into space?

Answer: The first person to go into space was Yuri Gagarin of the then USSR, in 1961.

Q4: Who was the first person to step on the Moon?

Answer: The first person to step on the Moon was Neil Armstrong of USA, in 1969.

Q5: What is an 'artificial satellite'?

Answer: An artificial satellite is a man-made object that revolves around the Earth or any other planet in a fixed orbit.

Q6: What is the first artificial satellite sent to space?

Answer: The first artificial satellite sent to space was Sputnik, launched by the Soviet Union in 1957.

Q7: How do artificial satellites primarily get their energy?

Answer: Artificial satellites primarily work on solar energy, using solar photovoltaic panels attached to them.

Q8: What is 'critical velocity' in the context of satellite orbits?

Answer: Critical velocity is the specific tangential velocity given to a satellite to place it into its proper orbit at a specific height above the Earth's surface, allowing it to revolve around the Earth.

Q9: Name the three main classifications of satellite orbits based on height.

Answer: The three main classifications of satellite orbits are High Earth Orbits (HEO), Medium Earth Orbits (MEO), and Low Earth Orbits (LEO).

Q10: What is a 'geosynchronous satellite'?

Answer: A geosynchronous satellite is a satellite revolving in an orbit parallel to the equator at a height of 35780 km, taking approximately 24 hours to complete one revolution, thus appearing stationary with respect to the Earth.

Q11: What are 'polar orbits'?

Answer: Polar orbits are elliptical medium Earth orbits that pass over the polar regions, used for studying these areas, as geosynchronous satellites are not useful for this purpose.

Q12: What is the primary function of a 'satellite launch vehicle'?

Answer: The primary function of a satellite launch vehicle is to place satellites into their specific orbits.

Q13: On what principle is the functioning of a satellite launch vehicle based?

Answer: The functioning of a satellite launch vehicle is based on Newton's third law of motion (action and reaction).

Q14: What is 'escape velocity'?

Answer: Escape velocity is the minimum initial velocity an object must have to escape the gravitational force of a planet and not fall back to it.

Q15: What is the escape velocity on Earth?

Answer: The escape velocity on Earth is approximately 11.2 km/s.

Application-Based Questions

Q16: Explain why multi-stage satellite launch vehicles are beneficial.

Answer: Multi-stage satellite launch vehicles are beneficial because they allow the weight of the vehicle to be reduced step by step after launching. As each stage's fuel is exhausted, the empty fuel tank and engine are detached, making the remaining vehicle lighter and enabling it to achieve higher speeds and reach the desired orbit more efficiently with less fuel consumption overall.

Q17: Describe how geosynchronous satellites are used for communication.

Answer: Geosynchronous satellites are used for communication because they appear stationary relative to a specific point on Earth. This allows ground stations to continuously point their antennas at the satellite, enabling uninterrupted transmission and reception of signals for telephone, television broadcasting, and radio services across vast distances.

Q18: How do Earth Observation Satellites contribute to natural resource management and disaster management?

Answer: Earth Observation Satellites (like those in the IRS series) contribute to natural resource management by providing data for studying forests, deserts, oceans, and polar ice, and for exploring mineral and fossil reserves. For disaster management, they offer real-time observation and guidance during natural calamities like floods and earthquakes, helping in early warning and response efforts.

Q19: Why do space travelers and objects in a spacecraft appear to be floating?

Answer: Space travelers and objects in a spacecraft appear to be floating because they are in a state of free fall. Although the spacecraft is at a height from Earth's surface, the gravitational force is still significant. However, the spacecraft, travelers, and objects are all continuously falling around the Earth due to their orbital velocity, creating a sensation of weightlessness.

Q20: What was the most important discovery made by India's Chandrayaan-1 mission?

Answer: The most important discovery made by India's Chandrayaan-1 mission was the presence of water on the Moon's surface, making India the first country to discover this.

Higher-Order Thinking Questions

Q21: "The world has become a global village due to space missions." Elaborate on this statement.

Answer: The statement "The world has become a global village due to space missions" highlights the profound impact of space technology on connectivity and information exchange. Communication satellites enable instant contact with anyone across the globe, facilitating international business, education, and social interaction. Earth observation satellites provide real-time data for weather forecasting, disaster management, and resource mapping, making information universally accessible. This interconnectedness, driven by space missions, has shrunk geographical distances and fostered a sense of global community, much like a small village where everyone is connected and informed.

Q22: Discuss the challenges posed by 'space debris' and the importance of its management.

Answer: Space debris, consisting of non-functional satellites, detached launcher parts, and fragments from collisions, poses significant challenges: 1. Collision Risk: It can collide with operational satellites and spacecrafts, causing damage or destruction, which is a major threat to ongoing and future space missions. 2. Increased Debris: Each collision generates more debris, creating a cascading effect (Kessler Syndrome) that could make certain orbits unusable. 3. Difficulty in Launching: The increasing density of debris makes it difficult and risky to launch new spacecrafts. Therefore, managing space debris is crucial to ensure the sustainability of space activities, protect valuable assets in orbit, and preserve access to space for future generations. Efforts include tracking debris, developing removal technologies, and designing missions to minimize new debris.

Q23: Compare and contrast the benefits of Low Earth Orbits (LEO) and High Earth Orbits (HEO) for different satellite functions.

Answer: Low Earth Orbits (LEO): * Height: 180 km to 2000 km. * Revolution Time: Around 90 minutes. * Benefits: Closer proximity to Earth allows for high-resolution imaging, detailed atmospheric studies, and scientific experiments. Used by the International Space Station (ISS) and Hubble Space Telescope. Lower latency for communication. * Drawbacks: Requires a large constellation of satellites for continuous coverage of an area due to rapid movement. High Earth Orbits (HEO) / Geosynchronous Orbits: * Height: Greater than or equal to 35780 km (geosynchronous at 35780 km). * Revolution Time: Approximately 24 hours (for geosynchronous). * Benefits: Appears stationary relative to Earth, providing continuous coverage of a large geographical area. Ideal for communication, broadcasting, and meteorology (e.g., INSAT, GSAT series). * Drawbacks: Higher latency due to greater distance. Not suitable for detailed Earth observation or polar region studies.

Q24: How does the concept of 'escape velocity' impact the planning and execution of interplanetary space missions?

Answer: Escape velocity is a fundamental concept for planning and executing interplanetary space missions because it determines the minimum initial velocity a spacecraft needs to permanently leave a planet's gravitational influence. For missions to other planets, a spacecraft must first achieve Earth's escape velocity (approx. 11.2 km/s) to break free from Earth's gravity. Then, it needs additional velocity to travel to its target planet, overcoming the Sun's gravity and the target planet's gravity. Calculating and achieving these precise velocities is critical for trajectory planning, fuel requirements, and ensuring the spacecraft reaches its destination without falling back or getting stranded in space.

Q25: Discuss India's significant contributions to space research, mentioning key organizations and satellite series.

Answer: India has made remarkable contributions to space research, primarily through the Indian Space Research Organization (ISRO). * Founding Fathers: Dr. Vikram Sarabhai is considered the father of the Indian space program, leading to the establishment of ISRO. * Launch Vehicles: India has developed indigenous launch vehicles like PSLV (Polar Satellite Launch Vehicle) and GSLV (Geosynchronous Satellite Launch Vehicle), capable of launching satellites into various orbits. * Satellite Series: * INSAT and GSAT: Used for telecommunication, television broadcasting, and meteorological services. * IRS (Indian Remote Sensing Satellite): Crucial for monitoring and managing natural resources and disaster management. * IRNSS (Indian Regional Navigation Satellite System): Provides precise location services. * EDUSAT: Specifically used for educational purposes. * Lunar and Mars Missions: India achieved significant success with Chandrayaan-1 (discovering water on the Moon) and Mangalyaan (Mars Orbiter Mission), which reached Mars orbit in its first attempt, demonstrating cost-effective space exploration.

Q26: What is the difference between 'space' and 'sky'?

Answer: The sky refers to the atmosphere above the Earth, which is visible to us and contains clouds, birds, and weather phenomena. It is a part of Earth's immediate surroundings. Space, on the other hand, refers to the vast, almost empty expanse beyond Earth's atmosphere and other celestial bodies. It is where planets, stars, galaxies, and other astronomical objects exist, and it is largely a vacuum.

Q27: How has space technology become an 'inevitable part for the development of a nation'?

Answer: Space technology has become an inevitable part of national development due to its wide-ranging applications: 1. Communication: Enables global connectivity for telecommunication, internet, and broadcasting. 2. Weather Forecasting: Provides crucial data for accurate weather prediction and climate monitoring, aiding agriculture and disaster preparedness. 3. Resource Management: Earth observation satellites help in mapping and managing natural resources like water, forests, and minerals. 4. Navigation: Satellite navigation systems (like GPS, IRNSS) are vital for transportation, logistics, and various location-based services. 5. Security and Defense: Military satellites provide surveillance and intelligence for national security. 6. Education: Satellites like EDUSAT facilitate distance learning and educational outreach. These applications directly contribute to economic growth, public safety, and improved quality of life, making space technology indispensable for modern nations.

Q28: Explain the concept of a satellite's orbit, including factors that determine its nature.

Answer: A satellite's orbit is the fixed path it takes around a celestial body, like Earth. Its nature (height, shape, and inclination) is determined by several factors: 1. Satellite Function: The purpose of the satellite (e.g., communication, weather, observation) dictates the required orbit. 2. Height from Earth's Surface: Different functions require different altitudes (LEO, MEO, HEO). 3. Nature of the Orbit (Circular/Elliptical): Most operational satellites are in near-circular orbits, but some, like those for polar studies, use elliptical orbits. 4. Inclination (Angle with Equator): Geostationary satellites are parallel to the equator, while polar satellites have high inclination to cover the poles. 5. Critical Velocity: The satellite must be given a precise tangential velocity at the desired height to maintain its orbit against Earth's gravity.

Q29: Describe the basic principle behind how a satellite launch vehicle works.

Answer: The basic principle behind a satellite launch vehicle's operation is Newton's third law of motion (for every action, there is an equal and opposite reaction). The vehicle carries a specific type of fuel. When this fuel undergoes combustion, it produces hot, high-pressure gases. These gases are forcefully expelled downwards through nozzles at the rear of the vehicle. As a reaction to this downward expulsion of gases, an equal and opposite upward thrust is generated, propelling the launch vehicle high into space. By continuously expelling mass (exhaust gases) downwards, the vehicle gains momentum and velocity upwards, overcoming Earth's gravity and reaching the required orbit.

References

1. MSBSHSE Class 10 Science and Technology Textbook Part 1 (2021-22 English) - Chapter 10: Space Missions
2. Maharashtra State Board 10th Standard Science Syllabus 2025-26
3. Balbharati Science and Technology Part 1 Textbook
4. Shaalaa.com Balbharati solutions for Science and Technology 1