Lagrange Points and Satellites | Science & Technology for UPSC CSE PDF Download

Lagrange Points

In the realm of space exploration, achieving the right orbit is crucial for the success of missions. While proximity to Earth is essential for some spacecraft, it can prove disruptive for others, especially those tasked with capturing images of deep space. This article delves into the significance of Lagrange points, often referred to as L-points, in space missions and how they enable stable orbits that are far removed from Earth.

The Challenge of Proximity to Earth

• Disruption to Space Observatories: Space-based observatories and telescopes aiming to photograph distant celestial objects face a significant challenge when positioned too close to Earth.
• Interference from Earth's Emissions: Earth emits visible light and infrared radiation naturally, which can hinder the telescopes' ability to detect faint lights such as distant galaxies.
• Analogy of Hopelessness: Capturing images of dark space from a telescope located near our radiant Earth is akin to attempting to photograph stars from Earth in broad daylight.

The Role of Lagrange Points

• Stable Remote Orbits: Lagrange points provide a solution by offering orbits that are exceptionally distant from Earth, extending over a million kilometers away.
• Gravitational Balance: These points are specific locations in space where the gravitational forces of both Earth and the Sun interact harmoniously.
• Anchoring Spacecraft: Spacecraft positioned at Lagrange points remain stable and can be effectively "anchored" relative to Earth.
• Minimized Effort for Positioning: Unlike other distant points in space where spacecraft would naturally fall into orbits around the Sun, spacecraft at Lagrange points stay fixed with minimal effort, ensuring proximity to Earth without entering different orbits.

Key Lagrange Points

• L1 and L2: The most commonly used Lagrange points are L1 and L2.
• Significant Distance: These points are situated four times farther away from Earth than the Moon, approximately 1.5 million kilometers from Earth.
• Comparison to GEO Orbit: In contrast to the geostationary orbit (GEO) at 36,000 kilometers from Earth, L1 and L2 are only about 1% of the distance from Earth to the Sun.

Conclusion

In the dynamic world of space exploration, understanding Lagrange points is essential for optimizing the success of missions. These points offer a strategic solution for spacecraft, allowing them to maintain stable positions far from Earth while minimizing the challenges associated with long-distance communication and interference from Earth's emissions. Among the various Lagrange points, L1 and L2 stand out as vital locations for space-based observatories and telescopes, enabling them to capture the mysteries of the universe with unparalleled clarity.

Satellites

Satellites are celestial bodies that orbit around other celestial bodies in space. There are two main categories of satellites: natural and man-made.

Natural Satellites

• Natural satellites are celestial bodies that occur naturally in space.
• Examples include the Earth and the Moon.
• The Earth orbits around the Sun, while the Moon orbits around the Earth.

Man-Made Satellites

• Man-made satellites are machines launched into space to orbit around celestial bodies.
• Examples of man-made satellites include the Hubble Space Telescope and the International Space Station.

Types of Man-Made Satellites

1. Astronomical Satellites

• Purpose: Observing distant planets, stars, galaxies, and objects in the universe.
• Description: Space telescopes like Hubble capture images of celestial objects in space.

2. Biosatellites

• Purpose: Conducting research on the effects of space on living organisms like animals and plants.
• Description: Animals and plants are placed in space to study their behavior and adaptation.

3. Communication Satellites

• Purpose: Support telecommunication services such as telecasting, phone calls, internet connectivity, radio broadcasting, and remote connectivity.
• Impact: Enabling global communication and connectivity.

4. Earth Observation Satellites

• Purpose: Study the environment, monitor climate changes, and create non-military maps of the Earth.
• Impact: Environmental monitoring, disaster management, and resource assessment.

5. Navigation Satellites

• Purpose: Trace the exact location of objects on Earth, leading to the development of new applications and technologies.
• Impact: GPS and navigation services for various sectors.

6. Killer (Military) Satellites

• Purpose: Deployed for offensive actions to attack enemy satellites and space assets during wartime.
• Description: Part of military strategies for space dominance.

7. Space Stations

• Purpose: Designed for human habitation and conducting research on celestial objects.
• Description: International Space Station (ISS) is an example where astronauts live and work in space.

8. Reconnaissance Satellites

• Purpose: Used for spying, surveying, and scouting enemy territory during wartime.
• Impact: Gathering crucial intelligence.

9. Crewed Spacecraft

• Purpose: Transport astronauts to space and back to Earth, facilitating access to space stations.
• Description: Space shuttles and crew capsules are examples.

10. Recovery Satellites

• Purpose: Mainly used to recover bio, reconnaissance, and other satellites back to Earth.
• Description: Ensuring safe retrieval of valuable satellites.

11. Solar Power Satellites

• Purpose: Gather solar energy from the Sun and transmit it to Earth for consumption.
• Impact: Potential clean energy source.

12. Miniaturized Satellites

• Purpose: Smaller and lighter satellites launched at an economical cost for scientific data gathering and radio relay.
• Description: Cost-effective options for specific missions.

13. Tether Satellites

• Purpose: Connected to another satellite by a tether, often used as secondary payloads.
• Description: Utilized in student projects and smaller missions.

14. Weather Satellites

• Purpose: Measure and report Earth's weather conditions, contributing to weather forecasting.
• Impact: Improved weather predictions and disaster management.

Conclusion

• Satellites play a crucial role in various aspects of human life and scientific research.
• Understanding the different types and functions of satellites is essential for appreciating their significance in modern society and space exploration.

List Of Earth Observation Satellites

EOS-01

• Launch Date: Nov 07, 2020
• Launch Mass: Not specified
• Launch Vehicle: PSLV-C49/EOS-01
• Orbit Type: LEO (Low Earth Orbit)
• Application: Disaster Management System, Earth Observation

RISAT-2BR1

• Launch Date: Dec 11, 2019
• Launch Mass: 628 Kg
• Launch Vehicle: PSLV-C48/RISAT-2BR1
• Orbit Type: LEO (Low Earth Orbit)
• Application: Disaster Management System, Earth Observation

Cartosat-3

• Launch Date: Nov 27, 2019
• Launch Mass: Not specified
• Launch Vehicle: PSLV-C47 / Cartosat-3
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

RISAT-2B

• Launch Date: May 22, 2019
• Launch Mass: 615 Kg
• Launch Vehicle: PSLV-C46 Mission
• Orbit Type: LEO (Low Earth Orbit)
• Application: Disaster Management System, Earth Observation

HysIS

• Launch Date: Nov 29, 2018
• Launch Mass: Not specified
• Launch Vehicle: PSLV-C43 / HysIS Mission
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Cartosat-2 Series Satellite (Jan 12, 2018)

• Launch Date: Jan 12, 2018
• Launch Mass: 710 Kg
• Launch Vehicle: PSLV-C40/Cartosat-2 Series Satellite Mission
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Cartosat-2 Series Satellite (Jun 23, 2017)

• Launch Date: Jun 23, 2017
• Launch Mass: 712 kg
• Launch Vehicle: PSLV-C38 / Cartosat-2 Series Satellite
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Cartosat-2 Series Satellite (Feb 15, 2017)

• Launch Date: Feb 15, 2017
• Launch Mass: 714 kg
• Launch Vehicle: PSLV-C37 / Cartosat -2 Series Satellite
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

RESOURCESAT-2A

• Launch Date: Dec 07, 2016
• Launch Mass: 1235 kg
• Launch Vehicle: PSLV-C36 / RESOURCESAT-2A
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

SCATSAT-1

• Launch Date: Sep 26, 2016
• Launch Mass: 371 kg
• Launch Vehicle: PSLV-C35 / SCATSAT-1
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Climate & Environment

INSAT-3DR

• Launch Date: Sep 08, 2016
• Launch Mass: 2211 kg
• Launch Vehicle: GSLV-F05 / INSAT-3DR
• Orbit Type: GSO (Geostationary Orbit)
• Application: Climate & Environment, Disaster Management System

Cartosat-2 Series Satellite (Jun 22, 2016)

• Launch Date: Jun 22, 2016
• Launch Mass: 737.5 kg
• Launch Vehicle: PSLV-C34 / CARTOSAT-2 Series Satellite
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

INSAT-3D

• Launch Date: Jul 26, 2013
• Launch Mass: 2060 Kg
• Launch Vehicle: Ariane-5 VA-214
• Orbit Type: GSO (Geostationary Orbit)
• Application: Climate & Environment, Disaster Management System

SARAL

• Launch Date: Feb 25, 2013
• Launch Mass: 407 kg
• Launch Vehicle: PSLV-C20/SARAL
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Climate & Environment, Earth Observation

RISAT-1

• Launch Date: Apr 26, 2012
• Launch Mass: 1858 kg
• Launch Vehicle: PSLV-C19/RISAT-1
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Megha-Tropiques

• Launch Date: Oct 12, 2011
• Launch Mass: 1000 kg
• Launch Vehicle: PSLV-C18/Megha-Tropiques
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Climate & Environment, Earth Observation

RESOURCESAT-2

• Launch Date: Apr 20, 2011
• Launch Mass: 1206 kg
• Launch Vehicle: PSLV-C16/RESOURCESAT-2
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

CARTOSAT-2B

• Launch Date: Jul 12, 2010
• Launch Mass: 694 kg
• Launch Vehicle: PSLV-C15/CARTOSAT-2B
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Oceansat-2

• Launch Date: Sep 23, 2009
• Launch Mass: 960 kg
• Launch Vehicle: PSLV-C14 / OCEANSAT-2
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Climate & Environment, Earth Observation

RISAT-2

• Launch Date: Apr 20, 2009
• Launch Mass: 300 kg
• Launch Vehicle: PSLV-C12 / RISAT-2
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IMS-1

• Launch Date: Apr 28, 2008
• Launch Mass: 83 kg
• Launch Vehicle: PSLV-C9 / CARTOSAT – 2A
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

CARTOSAT – 2A

• Launch Date: Apr 28, 2008
• Launch Mass: 690 Kg
• Launch Vehicle: PSLV-C9 / CARTOSAT – 2A
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

CARTOSAT-2

• Launch Date: Jan 10, 2007
• Launch Mass: 650 kg
• Launch Vehicle: PSLV-C7 / CARTOSAT-2 / SRE-1
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

CARTOSAT-1

• Launch Date: May 05, 2005
• Launch Mass: 1560 kg
• Launch Vehicle: PSLV-C6/CARTOSAT-1/HAMSAT
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-P6 / RESOURCESAT-1

• Launch Date: Oct 17, 2003
• Launch Mass: 1360 kg
• Launch Vehicle: PSLV-C5 /RESOURCESAT-1
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

The Technology Experiment Satellite (TES)

• Launch Date: Oct 22, 2001
• Launch Vehicle: PSLV-C3 / TES
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Oceansat (IRS-P4)

• Launch Date: May 26, 1999
• Launch Mass: 1050 kg
• Launch Vehicle: PSLV-C2/IRS-P4
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-1D

• Launch Date: Sep 29, 1997
• Launch Mass: 1250 kg
• Launch Vehicle: PSLV-C1 / IRS-1D
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-P3

• Launch Date: Mar 21, 1996
• Launch Mass: 920 kg
• Launch Vehicle: PSLV-D3 / IRS-P3
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-1C

• Launch Date: Dec 28, 1995
• Launch Mass: 1250 kg
• Launch Vehicle: Molniya
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-P2

• Launch Date: Oct 15, 1994
• Launch Mass: 804 kg
• Launch Vehicle: PSLV-D2
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

IRS-1E

• Launch Date: Sep 20, 1993
• Launch Mass: 846 kg
• Launch Vehicle: PSLV-D1
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation

IRS-1B

• Launch Date: Aug 29, 1991
• Launch Mass: 975 kg
• Launch Vehicle: Vostok
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

SROSS-2

• Launch Date: Jul 13, 1988
• Launch Mass: 150 kg
• Launch Vehicle: ASLV-D2
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation, Experimental

IRS-1A

• Launch Date: Mar 17, 1988
• Launch Mass: 975 kg
• Launch Vehicle: Vostok
• Orbit Type: SSPO (Sun-Synchronous Polar Orbit)
• Application: Earth Observation

Rohini Satellite RS-D2

• Launch Date: Apr 17, 1983
• Launch Mass: 41.5 kg
• Launch Vehicle: SLV-3
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation

Bhaskara-II

• Launch Date: Nov 20, 1981
• Launch Mass: 444 kg
• Launch Vehicle: C-1 Intercosmos
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation, Experimental

Rohini Satellite RS-D1

• Launch Date: May 31, 1981
• Launch Mass: 38 kg
• Launch Vehicle: SLV-3D1
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation

Bhaskara-I

• Launch Date: Jun 07, 1979
• Launch Mass: 442 kg
• Launch Vehicle: C-1 Intercosmos
• Orbit Type: LEO (Low Earth Orbit)
• Application: Earth Observation, Experimental