UPSC IAS Prelims 2022 Material| Science and Tech Current Affairs | Space technology – Nov. 2021- 31st March, 2022

Dear Friends,

This post is a part of our current affairs series for the UPSC IAS Prelims 2022. In this post, we have covered the Science and tech current affairs of the Space technology section. This post covers current affairs from Dec. 2021 to 15th March 2022. In the 2nd part, we will cover the rest of the current affairs of July 2021 to 31st April 2022.

Science and Tech Current Affairs 2021-22

Space technology

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SARAS 3 Radio Telescope

News: Indian astronomers have refuted the recent claim of a discovery of a radio wave signal from Cosmic Dawn, the time in the infancy of our Universe when the first stars and galaxies came into existence.

About SARAS 3 Radio Telescope: SARAS 3 radio telescope was invented and built by the astronomers at Raman Research Institute, an autonomous research institute engaged in research in basic sciences.

The telescope was designed, built, and deployed in India to detect extremely faint radio wave signals from the depths of time, from our “Cosmic Dawn” when the first stars and galaxies formed in the early Universe.

Giant Metrewave Radio Telescope(GMRT)

News: Astronomers of the National Center of Radio Astrophysics(NCRA-TIFR) in Pune and the University of California in the US have used the Giant Metrewave Radio Telescope(GMRT) to map the distribution of atomic hydrogen gas from the host galaxy of a Fast Radio Burst (FRB) for the first time.

What is the Giant Metrewave Radio Telescope(GMRT)?

GMRT is an array of thirty fully steerable parabolic radio telescopes of 45-meter diameter, observing at meter wavelengths.

Purpose: It is a very versatile instrument for investigating a variety of radio astrophysical problems ranging from the nearby Solar system to the edge of the observable Universe

Operated by: It is operated by the National Center for Radio Astrophysics (NCRA), a part of the Tata Institute of Fundamental Research, Mumbai.

Location: Pune

Fast Radio Bursts (FRB)

News: Astronomers of the National Center of Radio Astrophysics (NCRA-TIFR) in Pune and the University of California in the US have used the Giant Metrewave Radio Telescope (GMRT) to map the distribution of atomic hydrogen gas from the host galaxy of a Fast Radio Burst (FRB) for the first time.

About Fast Radio Burst (FBRs): FRBs are extremely bright bursts of radio waves (radio waves can be produced by astronomical objects with changing magnetic fields) that blaze for a few milliseconds before vanishing without a trace. FRBs generate as much energy in a thousandth of a second as the Sun does in an entire year

They are spotted in various and distant parts of the universe as well as in our own galaxy. However, their origins are still unknown, and their appearance is highly unpredictable.

The first FRB was spotted in 2007. Since then, scientists had only caught sight of around 140 bursts in their telescopes.

Source: Magnetars could be the source of some fast radio bursts (FRBs).

Earth Observation Satellite

News: Indian Space & Research Organization (ISRO) has successfully the EOS-04 Satellite on board the Polar Satellite Launch Vehicle(PSLV-C52).

About EOS-04: EOS-04 is the fourth in the series of earth observation satellites. It is a Radar Imaging Satellite. It weighs about 1710 kg and will be placed in a sun-synchronous polar orbit.

The satellite is designed to provide high-quality images under all weather conditions for applications such as agriculture, forestry and plantations, soil moisture & hydrology, and flood mapping.

The satellite will complement the data from Resourcesat, Cartosat, and RISAT-2B series of satellites that are already in orbit.

Previous EOS Satellites:

EOS-01: It was launched in 2020. It is in orbit right now.

EOS-02: It is yet to be launched. It is a microsatellite to be flown on a new launch vehicle called SSLV (Small Satellite Launch Vehicle).

EOS-03: It ended in a failure in August 2021.

Other satellites launched along with EOS-04

INSPIREsat-1: It is a student satellite. It is aimed at improving the understanding of ionosphere dynamics and the Sun’s coronal heating processes.

INS-2TD: It is a precursor to the first India-Bhutan joint satellite [INS 2-B] and will assess land and water surface temperatures, delineation of crops and forest, and thermal inertia.

Satellite Internet

News: Jio Platforms has launched a joint venture (JV) with European satellite-based broadband service company SES to enter the satellite internet space. Jio will use geostationary (GEO) and medium earth orbit (MEO) satellites, while Starlink and OneWeb use low earth orbit (LEO) satellites.

About Satellite Internet: Satellite Internet is the technology that beams the internet down from a satellite that’s orbiting the earth. Jio, Bharti Airtel OneWeb, and Starlink want to send thousands of these satellites to orbit.

Difference between GEO, MEO, and LEO satellites?

LEO satellites are cheaper to make and deploy but require a satellite constellation working in sync to offer coverage on earth.

On the other hand, GEO and MEO Satellites are larger, deployed in higher orbits and cost more. These satellites cover a larger area and require fewer ground stations, which makes them ideal for targeted coverage.

Advantages of satellite internet

Militaries across the world have depended on satellite communications for a long time. The reason telecom firms want to explore satellite internet is that there are areas where fiber connections just can’t reach. Hence, satellite networks are being used to bring connectivity to such areas, which include hills and remote islands.

Disadvantages of satellite internet

The satellite internet has the following limitations,

High latency: Latency is all about internet speed, while bandwidth determines how many devices can connect to a network at the same time.

Low bandwidths: Experts say current satellite connections will bring only about 1-2 MB bandwidth.

Troubleshooting can also be a problem because it needs specialized knowledge.

India-based Neutrino Observatory (INO)

News: The Tamil Nadu government has filed an affidavit in the Supreme Court stating that it would not permit the construction of the proposed Indian Neutrino Observatory at Bodi West Hills in Theni district.

About India-based Neutrino Observatory (INO)

The India-based Neutrino Observatory (INO) is a proposed Pure-Science underground laboratory. Its primary goal is to study the properties and interactions of neutrinos.

The observatory is jointly supported by the Department of Atomic Energy (DAE) and Department of Science & Technology (DST) with DAE acting as the nodal agency.

The proposed site of the observatory is in Bodi West Hills, in Theni district. The site is spread across Kerala and Tamil Nadu.

Why is the observatory being opposed by the Tamil Nadu Government?

Firstly, the observatory, if constructed, will affect the flora and fauna of the Periyar Tiger Reserve and Mathikettan Shola National Park in the Western Ghats.

Secondly, the tunneling works for the proposed project involve blasting hard and composite rock in the Western Ghats. This would impact the conservation efforts in the Western Ghats.

Thirdly, the project area links the Periyar Tiger Reserve in Kerala with Srivilliputhur Meghamalai Tiger Reserve. Quarrying and construction activities will upset wild animals which use the corridor for seasonal migrations.

Various Moon missions

News: Moon will be the focus of multiple missions through 2022 and the following decade.

About various Moon missions

NASA: It has a sequence of missions codenamed Artemis scheduled for the next few years. The first would test a new unmanned rocket and associated systems. The second would put a team of astronauts into orbit around the moon. The third would land a team (including at least one woman) on the moon.

European Space Agency: It is also shortlisting six astronauts for training. The six chosen ones will be trained to live on the International Space Station (ISS) before being laun­c­hed on a lunar mission.

India: It will send Chandrayaan-3 to the moon in late 2022 and the ISRO is also testing and building equipment for the Gaganyaan mission, which would be its first manned mission.

Russia-China Joint Venture: They are planning to build a permanent lunar habitat as a joint venture. But this won’t happen before 2027 at the very least.

South Korea: It is also targeting the launch of its first lunar mission, the Korea Pathfinder Lunar Orbiter, from Cape Canaveral (USA).

Roscosmos, the Russian space agency also plans to launch a robotic mission to the moon’s South Pole.

Why is the moon a ‘Test-lab’ for various technologies?

The Moon is Earth’s only natural satellite. The Moon’s distance from Earth is about 240,000 miles (385,000 km). The Moon’s surface is cratered and pitted from comet and asteroid impacts. The moon is airless, with gravity around one-sixth that of Earth.

In the sunshine, temperatures hit 125 degrees Celsius. At night, it drop to minus 175 degrees Celsius. This is far more variation than on Mars, where temperatures mostly range between 20 degrees Celsius and minus 75 degrees Celsius.

The moon has large deposits of metals. It also contains large quantities of oxygen embedded in various compounds, and isotopes of helium in larger quantities than on Earth.

There is also water ice on the moon, and there may even be liquid water under the surface.

Hence, these harsh conditions make it a “test-lab” for technologies that may allow humans to survive on Mars.

Upcoming ISRO Missions

First unmanned mission of Gaganyaan: It is expected to be launched before the 75th anniversary of India’s independence (August 15, 2022).

Disha: It is a twin-satellite system that will study Earth’s aeronomy, the uppermost layer of Earth’s atmosphere.

Trishna: It stands for Thermal Infrared Imaging Satellite for High-resolution Natural resource Assessment. It is a joint mission of ISRO and CNES, the French space agency. It is meant for accurate mapping of land surface temperature. It is scheduled for a 2024 launch.

EOS-4 and EOS-6: These are Earth Observation Satellites. They will be launched onboard the Polar Satellite Launch Vehicle (PSLV).

NISAR [NASA-ISRO SAR] mission: It is scheduled for launch in 2023. It is optimized for studying hazards and global environmental change and can help manage natural resources better and provide information to scientists to better understand the effects and pace of climate change.

X-ray Polarimeter Satellite (XPoSat): It is an ISRO planned space observatory to study polarization of cosmic X-rays. It is planned to be launched in the second quarter of 2022. The telescope is being developed by the Indian Space Research Organisation (ISRO) and the Raman Research Institute.

Aditya-L1: It is India’s first solar mission.

Chandrayaan-3: It is a third lunar mission of ISRO. It is planned to demonstrate India’s capability of soft landing on a celestial body, with the rover then communicating with Earth via the existing orbiter from Chandrayaan-2. It is planned to be launched in the third quarter of 2022.

Shukrayaan Mission: It is expected to be launched in 2024 by ISRO. It will study Venus for four years.

Small Satellite Launch Vehicle (SSLV)

News: ISRO Chairman has said that the Small Satellite Launch Vehicle (SSLV) named “SLV-D1 Micro SAT” will be launched in April 2022.

About Small Satellite Launch Vehicle (SSLV): It is an all-solid three-stage vehicle with the capability to launch up to 500 kg satellite mass into 500 km Low Earth Orbit (LEO).

It will cater to a market for the launch of small satellites into low earth orbits.

The demand for small satellites has emerged in recent years on account of the need for developing countries, private corporations, and universities for small satellites.

Until now, the launch of small satellites is dependent on ‘piggy-back’ rides with big satellite launches on ISRO’s Polar Satellite Launch Vehicle, which has had over 50 successful launches so far.

Advantages of SSLV

The SSLV would help in a) Reduced Turn-around Time b) Launch on Demand c) Cost Optimization for Realization and Operation d) Flexibility in accommodating Multiple Satellites and e) Minimum launch infrastructure requirements.

Significance of SSLV Satellites

The development and manufacture of the SSLV are expected to create greater synergy between the space sector and private Indian industries – a key aim of the space ministry.

Dhawan-1 – India’s First private Cryogenic Engine

News: Skyroot Aerospace, a Hyderabad-based space technology startup, has successfully test-fired the Dhawan-1 engine and is planning to launch Vikram-1 and Vikram-2 launch vehicles in a few years.

About Dhawan-1: Dhawan-1 is India’s first privately developed, fully cryogenic rocket engine. It runs on two high-performance rocket propellants — liquid natural gas (LNG) and liquid oxygen (LoX). The engine was developed using 3D printing with a super alloy.

About Vikram: Vikram is a series of launch vehicles to be launched by Skyroot space. These vehicles are specially crafted for the small satellite market.

Vikram-1:  It is based on a solid propulsion engine. After Skyroot successfully designed and developed the solid propulsion rocket engine, it became the first private firm in the country to do so.

Vikram-2: This vehicle is using a cryogenic engine. It will be launched into orbit in the next 2 years.

Imaging X-ray Polarimetry Explorer (IXPE) Mission

News: NASA has launched a new mission named Imaging X-ray Polarimetry Explorer (IXPE). The mission was launched from SpaceX’s Falcon 9 rocket.

About the IXPE Mission: IXPE observatory is a joint effort of NASA and the Italian Space Agency.

Aim: To study the most extreme and mysterious objects in the universe – supernova remnants, supermassive black holes, and dozens of other high-energy objects.

Duration: The mission’s duration is 2 years.

Instruments used: IXPE carries three state-of-the-art space telescopes. Each of the three telescopes hosts one light-weight X-ray mirror and one detector unit. These will help observe polarized X-rays from neutron stars and supermassive black holes.

By measuring the polarization of these X-rays, we can study where the light came from and understand the geometry and inner workings of the light source.

The mission will complement other X-ray telescopes such as the Chandra X-ray Observatory and the European Space Agency’s X-ray observatory, XMM-Newton.

Importance of the mission

The mission will help scientists answer questions such as:

1. How do black holes spin?
2. Was the black hole at the center of the Milky Way actively feeding on surrounding material in the past?
3. How do pulsars shine so brightly in X-rays?
4. What powers the jets of energetic particles that are ejected from the region around the supermassive black holes at the centers of galaxies?

James Webb Telescope

News: NASA has launched the James Webb Telescope.

About the James Webb Telescope: It is an international project of collaboration between NASA, European Space Agency (ESA), and the Canadian Space Agency.

The telescope will complement and is considered the successor of the Hubble Space Telescope.

The telescope will be launched on an Ariane 5 ECA rocket.

Once in space, the telescope will be situated near the second Lagrange point of the Earth-Sun system, which is around 1,500,000 km from Earth and directly opposite the Sun.

Purpose of the James Webb Telescope

The telescope will allow us to a) look deeper into our solar system than ever before, b) give us a clearer view of exoplanets in the solar system, c) help us understand how the universe itself was formed and d) help to get a detailed atmospheric characterization of potentially habitable exoplanets.

Working of the telescope

The telescope works in the infrared spectrum, collecting infrared light from the object it is focused on.

Infrared light is electromagnetic radiation with longer wavelengths than visible light. This particular trait of the telescope would help it look farther back in time more effectively than other telescopes. It will also help scientists look into the atmosphere of stars, which is usually shrouded with dust and gas during formation.

Note: Infrared light can easily penetrate through such cosmic dust and gas.

OSCAR-1 Satellite

News: 12^th Dec 2021 marked the launch date of the first amateur radio satellite called OSCAR 1.

Background

Sputnik 1 was launched successfully by the Soviet Union in 1957. This marked the beginning of the space age.

Not willing to be left lagging behind, the U.S. launched their own satellite, Explorer 1 in 1958.

Barely four years after that, OSCAR-1(Orbiting Satellites Carrying Amateur Radio) satellite was launched in December, 1961.

About OSCAR-1 Satellite: OSCAR 1 was the first amateur radio satellite launched by Project OSCAR. It was launched into low Earth orbit (LEO). This satellite was the world’s first non-governmental satellite.It was also the first satellite constructed by a collection of private individuals.

The satellite lasted for around 22 days, and transmitted the letters “HI” in Morse code. These letters were chosen in particular over other possibilities because the letters “HI” was and still remains – an internationally recognised friendly greeting between radio amateurs.

Magnetars

News: An international group of astronomers has obtained the first clues about extremely rare giant eruptions lasting 3.5 milliseconds that emerged from a magnetar located 13 million light years away.

About Magnetars: When massive stars like supergiant star with a total mass of between 10 and 25 solar masses collapse, they might form neutron stars. Among neutron stars stands out a small group with the most intense magnetic field. These are known as magnetars.

Note: Neutron stars are the remnants of giant stars that died in a fiery explosion known as a supernova. They have a mass of about 1.4 times that of the sun

Magnetars experience violent eruptions or intense bursts in the form of transient X-ray pulses which are several orders higher than that of the Sun. Even inactive magnetars can be thousands of times more luminous than the Sun.

So far, only 30 magnetars located within the Milky Way have been discovered.

What did the scientists find out?

Like earthquakes on Earth, magnetars suffer starquakes produced on their crust due to high instability prevailing in their magnetospheres.

This instability triggers Alfven waves that are also common in the Sun. The interactions between multiple Alfven waves ultimately release massive energies, appearing as giant flares lasting for a few milliseconds.

 Laser Communications Relay Demonstration (LCRD)

News: NASA has launched its new Laser Communications Relay Demonstration (LCRD).

About Laser Communications Relay Demonstration (LCRD): LCRD is NASA’s first-ever laser communications system launched to demonstrate the benefits of space-to-ground laser communications also called optical communications.

Currently, most NASA spacecraft use radio frequency communications to send data. But with the LASER communications capability further proven, NASA can start to implement laser communications on more missions, making it a standardized way to send and receive data.

Difference between Laser vs Radio Communications

Firstly, laser communications and radio waves use different wavelengths of light. The laser uses infrared light and has a shorter wavelength than radio waves. This will help the transmission of more data in a short time.

Examples:

1. It would take roughly nine weeks to transmit a completed map of Mars back to Earth with current radio frequency systems. With lasers, it can accelerate that to about nine days.
2. Using lasers, LCRD can send data to Earth at 1.2 gigabits-per-second (Gbps). At this speed, it will take less than a minute to download a movie.

Secondly, Optical or Laser communication systems are smaller in size, weight, and require less power compared with radio instruments. A smaller size means more room for science instruments. Less weight means a less expensive launch. Less power means less drain on the spacecraft’s batteries. Hence, LCRD enabled missions will have unparalleled communications capabilities.

Third, unlike radio frequency communications, optical signals cannot penetrate cloud coverage. That’s why, LCRD will transmit data to two ground stations, located in California and Hawaii. These locations were chosen for their minimal cloud coverage.

Science behind jets of plasma

News: Scientists have unraveled the science behind the jets of plasma.

About Plasma: Plasma is often called the fourth state of matter (beyond the conventional solids, liquids and gases).

What are Jets of Plasma?

Jets or spicules appear as thin grass-like plasma structures that constantly shoot up from the surface of the sun and are then brought down by gravity.

The amount of energy and momentum that these spicules can carry is of fundamental interest in solar and plasma astrophysics.

However, the processes by which plasma is supplied to the solar wind and the solar atmosphere is heated to a million degrees Celsius still remain a puzzle.

What did the scientists find out about these Jets of Plasma?

Scientists have explained the origin of ‘spicules’ or ‘jets’ on the Sun.

They explained that the plasma right below the visible solar surface (photosphere) is perpetually in a state of convection, much like boiling water in a vessel heated at the bottom. This is ultimately powered by the nuclear energy released in the hot-dense core.

The convection serves almost periodic but strong kicks to the plasma in the solar chromosphere, the shallow semi-transparent layer right above the visible solar disk. The chromosphere is 500 times lighter than the plasma in the photosphere.

Therefore, these strong kicks from the bottom shoot the chromospheric plasma outward at ultrasonic speeds in the form of spicules or jets.

Leonids Meteor Shower

News: The annual Leonids Meteor Shower has begun on 6th November, 2021.

About the Leonids Meteor Shower

It was originally discovered in 1833. It contains debris that originated from a small comet called 55P/Tempel-Tuttle in the constellation Leo, which takes 33 years to orbit the sun.

Every 33 years, a Leonid shower turns into a meteor storm, which is when hundreds to thousands of meteors can be seen every hour.

The Leonids are also called fireballs and earth grazer meteors. Fireballs, because of their bright colors and earthgazer because they streak close to the horizon.

Moreover, Leonids meteors showers are also some of the fastest that are seen on Earth traveling at speeds of 71 km per second.

About Meteor Shower

When Earth encounters many meteoroids at once, it is termed a meteor shower.

Meteor showers and their damages: The vast majority of meteors burn up long before they hit the ground, posing no threat to property or people. Occasionally, a small amount of material survives entry into Earth’s atmosphere and explodes above the planet’s surface.

DART Mission

News: NASA will launch its first planetary defense test mission, named the Double Asteroid Redirection Test (DART). The mission will be launched on a SpaceX Falcon 9 rocket.

About the DART Mission

DART is the first technology demonstration of the kinetic impactor technique. If successful, this technique could be used to mitigate the threat ​​in case an asteroid heads towards Earth in the future.

Key aspects of DART Mission

The mission will test this newly developed technology by allowing a spacecraft to crash into an asteroid and change its course.

After the spacecraft has collided with the asteroid, scientists will study its impact on the trajectory of the asteroid with a range of telescopes deployed on different regions of the planet.

This study will help scientists understand whether the kinetic effect of a spacecraft impact could successfully deflect an asteroid on a collision course with Earth.

Target Asteroid

The target of the spacecraft is a small moonlet called Dimorphos (Greek for “two forms”). Dimorphos orbits a larger asteroid named Didymos (Greek for “twin”).

Reason for choosing Dimorphos

Firstly, the Didymos and Dimorphos do not pose any threat to Earth.

Secondly, Didymos is an eclipsing binary, which means it has a moonlet that regularly orbits the asteroid, and scientists can see it when it passes in front of the main asteroid. Due to this, Earth-based telescopes can make the most precise measurement possible.

Black Hole

News: A paper published in The European Physical Journal C has said that M87* (a compact object that was imaged by the Event Horizon Telescope) is not necessarily a black hole. It could be a “naked singularity with a gravitomagnetic monopole”.

About the research

In 2019, astronomers of the Event Horizon Telescope captured the first-ever image of a supermassive black hole (M87*) which was located at the center of a galaxy Messier 87 (M87).

This black hole was calculated to be 6.5 billion times the Sun’s mass and is 55 million light-years away from the Earth.

This discovery also found mention in the “popular information” section of the announcement of the Nobel Prize in physics for 2020.

However, recent research has said that M87 is not necessarily a black hole but could even be a “naked singularity with a gravitomagnetic monopole”.

About the Black Hole

The simplest definition of a black hole is an object that is so dense that not even light can escape its surface.

Formation of Black Hole: When stars much more massive than the Sun reach the end of their lives, they collapse under their own gravity, and the product of this collapse, most astronomers believe is a black hole.

Parts of Black Hole: A black hole has two parts:

• Singularity: At the core of a black hole is a singularity. It is a point that is infinitely dense, as all the remnant mass of the star is compressed into this point.
• Event horizon: It is an imaginary surface surrounding the singularity, and the gravity of the object is such that once anything enters this surface, it is trapped forever. Not even light can escape the pull of the singularity once it crosses the event horizon.

About Naked Singularity

In many scenarios of stellar collapse, the event horizon does not form, and the singularity is exposed to the outside without any event horizon shielding it. This has been called “naked singularity” or a “troublesome sibling” of a black hole.

About Gravitomagnetic Monopole

In the 19th Century, James Clerk Maxwell unified electricity and magnetism as one combined phenomenon, showing that light is an electromagnetic wave.

But there is an asymmetry between electricity and magnetism. While positive and negative electric charges can be found to exist independently, the poles of a magnet are always found in pairs, north and southbound together.

Hence, the researchers [Newman, Unti, and Tamburino (NUT)], based on this analogy between gravitational force and electromagnetism, proposed a theoretical concept called a “gravito-magnetic charge” also called a gravitomagnetic monopole.

A magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). It cannot be created from normal matter such as atoms and electrons, but would instead be a new elementary particle.

Kamo’oalewa

News: A study in the journal Communications Earth and Environment has provided details about Kamo’oalewa.

About the Kamo’oalewa

Kamo’oalewa is a quasi-satellite. This means that it is a near-Earth object that orbits the Sun and yet remains close to the Earth.

Discovered by: This quasi-satellite was discovered by the PanSTARRS telescope in 2006 in Hawaii.

Size: The asteroid is roughly the size of a Ferris wheel. Due to its small size (about 50 meters wide), this quasi-satellite has been difficult for scientists to study and little was known about it so far.

New findings about Kamo’oalewa

The study has offered insights into where this quasi-satellite could have come from. It has offered three possibilities, which are:

• Part of Earth-Moon: It could have broken away from the Moon due to a possible impact, and gone on to orbit the Sun rather than the Earth-like its parent does.
• Near-Earth Objects: Captured in its Earth-like orbit from the general population of Near Earth Objects.
• Earth’s Trojan Asteroids: It might originate from an as-yet-undiscovered quasi-stable population of Earth’s Trojan asteroids(Trojans are a group of asteroids that share an orbit with a larger planet).
  

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GSAT-7 Satellites

News: Defence Acquisition Council (DAC) has approved the procurement proposal of the Air Force for GSAT-7C Satellite and Ground Hubs for real-time connectivity of Software Defined Radios (SDRs).

About GSAT-7 Satellites

GSAT-7 (also known as Rukmini) is an advanced communication satellite built by ISRO. It was launched in 2013 for the Indian Navy to monitor the Indian Ocean Region and provide real-time data to all the Indian submarines, warships, and aircraft.

GSAT-7A is an advanced military communications satellite launched by ISRO in 2018. The satellite is currently being used by the Indian Air Force (IAF) and the Indian Army. The satellite allows IAF to interlink ground-based radars, airborne early warning and control aircraft for surveillance, gather intelligence by detecting aircraft.

GSAT-7C will be launched in the next 2 to 3 years by ISRO. It will be the 2nd dedicated satellite for the Indian Air Force (IAF).

The induction of GSAT-7C Satellite and Software Defined Radios (SDRs) will enhance the ability of the Armed Forces to communicate beyond Line of Sight (LoS) among one another in all circumstances in a secure mode.

About Software Defined Radios (SDRs)

Software Defined Radio (SDR) provides enhanced data transmission capability, enhanced voice clarity and data transmission accuracy in spectrally noisy environments.

PASIPHAE Project

News: Wide Area Linear Optical Polarimeter (WALOP) is being developed at Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India.

Note: WALOP is a vital instrument for PASIPHAE Project. It will be mounted on two small optical telescopes to detect polarised light signals emerging from the stars along high galactic latitudes.

About the PASIPHAE Project

Polar-Areas Stellar-Imaging in Polarisation High-Accuracy Experiment (PASIPHAE) is an international collaborative sky surveying project.

Aim: To study the polarisation in the light coming from millions of stars.

Key features of PASIPHAE Project

The survey will use two high-tech optical polarimeters to observe the northern and southern skies, simultaneously.

This will help us focus on capturing starlight polarisation of very faint stars that are so far away that polarisation signals from there have not been systematically studied. The distances to these stars will be obtained from measurements of the GAIA satellite.

By combining these data, astronomers will perform a maiden magnetic field tomography mapping of the interstellar medium of very large areas of the sky using a polarimeter instrument known as WALOP (Wide Area Linear Optical Polarimeter).

Significance of this Project

Since its birth about 14 billion years ago, the universe has been constantly expanding, as evidenced by the presence of Cosmic Microwave Background (CMB) radiation which fills the universe.

However, immediately after its birth, the universe went through a short inflationary phase during which it expanded at a very high rate, before it slowed down and reached the current rate.

A definitive consequence of the inflationary phase is that a tiny fraction of the Cosmic Microwave Background (CMB) radiation should have its imprints in the form of a specific kind of polarisation (known scientifically as B-mode signal).

All previous attempts to detect this signal met with failure, mainly due to the difficulty posed by our galaxy, the Milky Way, which emits enormous amounts of polarised radiation caused by large dust clouds that fill the galaxy.

Hence, PASIPHAE aims to remove these obstacles and enable astronomers to look for the elusive B-mode signal so that we can ultimately learn how things played out in the early universe.