Context (IE): India‘s first Venus mission is expected to launch in March 2028.
Objectives of the Venus Orbiter Mission (VOM)
Study Venus’s surface and subsurface geology.
Analyze atmospheric processes and composition. Investigate the ionosphere and its dynamics.
Examine the interaction of Venus with solar radiation.
Understand the evolutionary differences between Venus and Earth.
Instruments
Scientific Payloads: Approximately 100 kg, including:
Synthetic Aperture Radar: For detailed surface imaging.
Thermal Cameras: To monitor temperature variations.
Atmospheric Instruments: To study composition and dynamics.
Technical Aspects of the Venus Orbiter Mission (VOM)
Aero-Braking Technique:
For the first time, ISRO will employ aero-braking to adjust the spacecraft’s orbit around Venus.
It involves skimming the outer atmosphere to lower the orbit gradually, conserving fuel.
Orbit Details:
The spacecraft will initially enter a highly elliptical orbit (a satellite orbit around the Earth that follows the path of an ellipse).
It will be manoeuvred to a lower orbit for optimal scientific observations.
Importance of Studying Venus
Earth’s Evolution: Studying Venus, often called Earth’s twin due to its similar size, density and mass, can provide insights into the evolutionary paths of terrestrial planets and factors influencing habitability.
Climate Change Insights: Venus’s extreme greenhouse effect and climatic history offer valuable lessons on climate change processes that may also apply to Earth.
Atmospheric Composition and Dynamics: The planet’s thick atmosphere, primarily composed of carbon dioxide, allows scientists to explore atmospheric science and compare it with other celestial bodies.
Geological Activity: Investigating Venus’s geological features and volcanic activity enhances our understanding of the evolution of rocky planets, particularly processes like volcanism and tectonics.
Global Interest: The renewed focus on Venus by various space agencies, including ISRO, NASA, and ESA, fosters international collaboration and advances knowledge in planetary science.
About Venus
Venus is the brightest planet in the solar system and is the third brightest object visible from the earth after the sun and the moon. In ancient literature, Venus was often referred to as the morning & evening star.
It is the brightest among planets because it has the highest albedo due to the highly reflectivesulfuric acidthat covers its atmosphere. It is sometimes visible to the naked eye in broad daylight.
Venus is sometimes called Earth’s sister planet or Earth’s twin because of their similar size, mass, proximity to the Sun, bulk composition and presence of similar physical features such as high plateaus, folded mountain belts, and numerous volcanoes, etc.
It is radically different from Earth in other respects. The surface of Venus is totally obscured by a thick atmosphere composed of about 96%carbon dioxide, covered with clouds of highly reflective sulfuric acid.
It has the densest atmosphere of the four terrestrial planets. The atmospheric pressure at the planet’s surface is 92 times that of Earth, or roughly the pressure found 900 m underwater on Earth.
Venus is by far the hottest planet in the Solar System, even though Mercury is closer to the Sun. This is because of the greenhouse effect arising from high concentrations of CO2 and a thick atmosphere.
A day on Venus is equivalent to 243 earth days and lasts longer than its year (224 days). It rotates in the opposite direction (clockwise) to most other planets.
