Context: The Indian Space Research Organisation (ISRO) successfully carried out the landing mission of its Reusable Launch Vehicle (RLV) named 'Pushpak' in the Reusable Launch Vehicle – Landing EXperiment (RLV LEX-02) on March 22, 2024.
Major Highlights:
The RLV LEX-02 landing experiment, is the second of the series, was conducted at Aeronautical Test Range (ATR), Chitradurga in Karnataka.
The RLV-LEX-01 mission was accomplished in April 2023.
RLV-LEX-02 demonstrated the autonomous landing capability of RLV from off-nominal initial conditions at release from Chinook Helicopter.
Pushpak Viman is a winged vehicle built like a space plane/ shuttle which has the capacity to take the payloads to the Low Earth Orbit and return it back to the Earth.
The vehicle was lifted by an Indian Airforce Chinook helicopter and was released from 4.5 km altitude.
After release at a distance of 4 km from the runway, Pushpak autonomously approached the runway, and landed precisely using its brake parachute, landing gear brakes and nose wheel steering system.
This mission successfully simulated the approach and high-speed landing conditions of RLV returning from space.
Significance:
With the mission, ISRO has re-validated indigenously developed technologies in the areas of navigation, control systems, landing gear and deceleration systems essential for performing a high-speed autonomous landing of a space-returning vehicle. This would be a critical step towards developing future Orbital Re-entry missions.
Developing essential technologies for a fully reusable launch vehicle aims to enable low-cost access to space.
Further, the vehicle can be configured to act as a flying test bed to evaluate various technologies, namely, hypersonic flight, autonomous landing and powered cruise flight.
About Indian Astronomical Observatory/ Hanle Dark Sky Reserve:
The Indian Astronomical Observatory (IAO) or Hanle Observatory is a high-altitude astronomical observatory located in Hanle valley, UT Ladakh, India.
It is operated by the Indian Institute of Astrophysics.
Located atop Mt. Saraswati in the Nilamkhul Plain, at an altitude of 4500 metres, it is one of the highest and best sites in the world for optical, infrared and gamma-ray telescopes.
The observatory holds the title of India's first dark-sky reserve, due to the minimal light pollution, reduced atmospheric interference, low atmospheric water vapour and exceptionally clear (cloudless) skies in the region. This makes it a prime location for astronomers to study the universe (galaxies, nebulae, stars gazing etc.)
Dark Sky Reserves:
A Dark Sky Reserve is a designated area that aims to preserve and protect the quality of its night skies by minimising light pollution orrestricting artificial light pollution. These reserves are recognised for their exceptional natural darkness and starry skies, and are specifically protected for scientific, natural, educational, and cultural purposes, primarily to advance astronomy.
International Dark-Sky Association (IDA) is a U.S.-based non-profit organisation that designates places as International Dark Sky Places, Parks, Sanctuaries and Reserves, depending on the criteria they meet.
Why does Dark Sky preservation matter?
Light pollution not only obscures our view of the stars but also disrupts ecosystems and affects human health. With over 80% of the world's population living under light-polluted skies, the need to preserve our night sky heritage has never been more urgent. Initiatives like the Hanle Dark Sky Reserve in Ladakh, India, underscore the importance of combating light pollution and promoting awareness about the significance of dark skies.
Key Fact:
In January 2024, The Pench Tiger Reserve (PTR) in Maharashtra was certified as India’s first-ever Dark Sky Park (DSP) for protecting the night sky and preventing light pollution, making the facility ideal for astronomy enthusiasts.
Context: Vikram Sarabhai Space Centre (VSSC), the Indian Space Research Organisation (ISRO) facility at Thumba in Thiruvananthapuram, has developed the multi-purpose app SAKHI that will help astronauts on Gaganyaan space flight mission carry out a range of tasks.
About SAKHI App:
The Space-borne Assistant and Knowledge Hub for Crew Interaction (SAKHI) is a digital platform integrated to the space suits of astronauts that will assist the astronauts as follows:
Looking up vital technical information: Give assistance to the astronauts regarding technical documents and training manuals digitally at short notice, thereby, preventing the need to carry manual documents.
Monitor the health of the astronauts: SAKHI will also keep a close watch on their physical condition/ vitals by providing information on key parameters like blood pressure, heart rate and oxygen saturation and alert them about their dietary schedules, hydration level, sleep patterns throughout their mission.
Maintain mission log: Astronauts can use the app to maintain a log on the mission in multiple formats including voice records, texts and images.
Help them stay connected with Earth: SAKHI will keep the crew connected with the onboard computer and ground-based stations, guaranteeing a seamless communication link.
Gaganyaan Human Spaceflight Mission:
Gaganyaan mission envisages demonstration of human spaceflight capability by launching a crew of 3 members to a Low earth Orbit of 400 km for a 3 days mission and bring them back safely to earth, by landing in Indian sea waters. ISRO is hoping to launch the Gaganyaan human spaceflight mission in 2025.
The crewed flight is planned on the Human Rated Launch Vehicle Mark 3 (LVM3) as the launch vehicle. It comprises solid, liquid and cryogenic stages.
Human Space Flight Centre will coordinate the Indian Human Spaceflight Programme. The agency will be responsible for implementation of the Gaganyaan project.
ISRO has already performed a Crew Module Atmospheric Re-entry Experiment and a Pad Abort Test for the mission. The project will cost less than Rs. 10,000 crore.
India has revealed the identities of the four astronaut-designates, all IAF test pilots at the VSSC in February 2024. The final crew for the mission will be picked from among the four.
If completed on schedule, India will become the world's fourth nation to conduct independent human spaceflight after the Soviet Union/Russia, United States and People's Republic of China.
Context: The IceCube neutrino observatory is a device at the earth’s South Pole that detects subatomic particles called neutrinos. It was built and is maintained by the IceCube Collaboration, which consists of many universities worldwide led by the University of Wisconsin, Madison.
Neutrinos:
Neutrinos are elementary subatomic particles with no electric charge and very little mass (nearly massless).
They very rarely interact with matter and that is why they’re called “ghost particles”.
Source of Neutrinos: Stars, Supernovae, Galaxies, Nuclear reactions.
About IceCube Neutrino Observatory:
IceCube is the world’s biggest ‘neutrino telescope’; its sensors are distributed throughout a cubic kilometre of ice.
IceCube consists of thousands of sensors buried more than 1.4 km beneath the ice plus multiple detectors above the surface. The larger the detector’s collecting area, the higher the chances of spotting neutrinos.
Regular Telescopes vs. Neutrinos: Traditional telescopes work by collecting light (photons) emitted by celestial objects. Neutrinos, however, are incredibly elusive and rarely interact with matter, including light. So, a regular telescope would not be able to detect them directly.
Indirect Detection: Neutrinos are very difficult to detect because they rarely interact with matter. However, when a neutrino interacts with an atom in the ice, it creates a secondary particle that travels faster than light in ice. This faster-than-light travel creates a faint blue light called Cherenkov radiation.
The IceCube Neutrino Observatory is a cubic kilometre in size and contains thousands of sensors called Digital Optical Modules (DOMs). These DOMs are spaced out over a large area of ice and are designed to detect the Cherenkov radiation produced by neutrinos.
When a neutrino interacts with an atom in the ice, the DOMs will detect the Cherenkov radiation and send a signal to the surface. By studying the pattern of Cherenkov radiation, scientists can learn about the energy and direction of the neutrino that caused it.
Context: The Prime Minister of India laid the foundation stone for India’s new spaceport for small satellite launch vehicles at Kulasekarapattinam, Tamil Nadu.
Kulasekarapattinam spaceport:
Location: Kulasekarapattinam in Thoothukudi district, southern Tamil Nadu. The project will come up across 2,233 acres in Padukkapathu, Pallakurichi, and Mathavankurichi villages in Kulasekarapattinam and Sathankulam taluks.
Will launch: Smaller payloads like Nano and Microsatellites.
Project cost: ₹950-crores. The construction is expected to take nearly two years to complete.
India has Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh spread over 145 sq km that has two launch pads for PSLV and GSLV flights (heavier satellites).
Considerations for selecting a rocket launch site in India:
The primary considerations for selecting a rocket launch site in India are the site’s proximity to the equator and its location on the Eastern coastline.
Proximity to Equator (Provides initial boost, saves cost):
When seen from the North Pole, the Earth rotates counterclockwise, or from west to east. The surface velocity of rotation varies from point to point on the Earth.
It is about 1600 km per hour or about 465 metres in a second near the equator.
The velocity gradually reduces as we move to the poles and it is practically zero at the poles.
A satellite launched from the sites near the equator towards the east direction will get an initial boost equal to the velocity of the Earth surface. The initial boost helps in cutting down the cost of rockets used to launch the satellites.
However, this benefit can be taken only for such satellites which are placed in geo-stationary orbit or which circle the Earth parallel to the equator. Such satellites are usually communication satellites or satellites used for scientific research such as the International Space Station. Polar satellites (placed in polar orbits moving across the equator in north south direction) are generally launched in southward or northward direction and therefore cannot take advantage of the Earth’s rotation.
Location on Eastern coast (Safety considerations):
The launching stations are generally located near the eastern coastline of India so that, just in case of failure of the launch, any debris of the satellite falls harmlessly in Bay of Bengal or Indian Ocean and does not fall on the main hinterland.
Strategic advantage of Kulasekarapattinam:
The geographic location of the country’s second spaceport to be set up at Kulasekarapattinam in Tamil Nadu has a strategic advantage over launch pads in Sriharikota.
During polar missions, big launch vehicles follow a trajectory where they fly in the southeast direction after lift-off from Sriharikota to avoid flying over Sri Lanka, protecting the landmass from rocket debris.
The rocket then takes a sharp manoeuvre and proceeds towards the south pole. This manoeuvre results in the rocket deviating from a straight flight path requires more fuel that results in loss of rocket’s payload capacity.
The payload loss in big launch vehicles is manageable, But for small satellite launch vehicles, such manoeuvres will leave minimal payload capability.
Kulasekarapattinam gives the benefit of launching straight in the southward direction. Hence, when launched from Kulasekarapattinam, the manoeuvre is not required thereby saving the rocket’s fuel as well as improving the payload capability.
Significance:
India, by the establishment of the new spaceport, seeks to leverage the private sector in making it a self-reliant spacefaring nation. The global market for small satellites is projected to have a CAGR of 16.4 per cent — from $3,215.9 million in 2020 to $13,711.7 million by 2030. By allowing easier access to polar orbits, the location will help make launches cheaper for both private players and ISRO.
In 2020, the Centre permitted private companies to enter the space sector, which was hitherto under the complete control of ISRO. The new policy aims to enable ISRO to focus on scientific space missions rather than routine activities like weather and communication satellite launches.
The Central Government has allowed 100 per cent FDI in the space sector. The Indian Space Policy 2023 allows satellite launches by non-government entities (NGEs), subject to technical feasibility and range safety.
Context: Plasma Analyser Package for Aditya (PAPA) payload onboard Indian Space Research Organisation’s (ISRO) Aditya-L1 has detected the impact of coronal mass ejections (CMEs) on solar wind.
Aditya-L1 is India's first solar mission aimed at studying the sun from a distance of about 1.5 million km from the Earth. It has seven payloads, including Plasma Analyser Package for Aditya.
CMEs can disrupt the solar wind and cause disturbances in Earth's magnetic field, leading to geomagnetic storms that can damage systems on Earth's surface and near-Earth.
Plasma Analyser Package for Aditya(PAPA):
PAPA is an energy and mass analyser designed for in-situ measurements of solar wind electrons and ions in the low energy range.
Solar wind is a stream of charged particles (protons, electrons, and alpha particles) flowing outward from the Sun at high speeds.
It has two sensors which can measure the mass, energy distribution, and even the direction of arrival of solar wind particles.
Solar Wind Electron Energy Probe (SWEEP, measuring electrons in the energy range of 10 eV to 3 keV)
Solar Wind Ion Composition Analyser (SWICAR, measuring ions in the energy range of 10 eV to 25 keV and mass range of 1-60 amu).
Coronal Mass Ejections (CME):
CMEs are large bursts/expulsions of plasma and magnetic fields that can erupt from the Sun’s corona and cause significant disturbances in the solar wind.
Compared to solar flares (bursts of electromagnetic radiation that travel at the speed of light), CMEs travel at a more leisurely pace with their highest speeds reaching 3,000 kilometres per second. These relatively slower travel times may give more time to prepare for such an arrival.
Impacts of CMEs on Earth:
CMEs can produce a geomagnetic storm which in turn can disrupt power grids, telecommunication networks and orbiting satellites, disrupt radio communication and expose astronauts to dangerous doses of radiation.
Charged particles from CMEs can interact with Earth's atmosphere near the poles, and produce colourful displays of light known as auroras or the northern and southern lights.
Key Terms:
Solar Flares: Solar flares are intense bursts of energy and light that originate from the Sun's surface. They are caused by the release of magnetic energy stored in the Sun's atmosphere.
Solar Wind/Storm: Solar wind is created by the outward expansion of plasma (a collection of charged particles) from the Sun's corona (outermost atmosphere). This plasma is continually heated to the point that the Sun's gravity cannot hold it down. It then travels along the Sun's magnetic field lines that extend radially outward.
Geomagnetic storms: A geomagnetic storm is a disturbance in the Earth's magnetic field caused when a solar wind shock wave or cloud of the magnetic field interacts with the Earth's magnetic field.
Comparison between Solar winds, Solar flares and Coronal Mass Ejections:
Context: European Council for Nuclear Research, popularly known as CERN, plans to build a 91-kilometer-long largest particle collider underneath the Earth below the French and Switzerland borders.
About Future Circular Collider
Future Circular Collider is a proposed 91 km long at the CERN. It will overtake the 27 km long Large Hadron Collider (LHC) facility LHC is currently world’s largest particle collider.
Construction of the machine will require drilling a circular tunnel 200 metres underground. The facility will also have four experimental halls.
The facility will be used to collide electrons with their antimatter particles, positrons, with the aim of generating and studying in precise detail around one million Higgs bosons and other Standard Model particles.
FCC-hh: for hadron-hadron collisions, including proton-proton and heavy ion collisions.
FCC-ee: for electron-positron collisions
FCC-eh: for electron-hadron collisions
The second step would be an energy frontier collider, offering collision energies of 100 TeV or higher (i.e., 8 times the energy of the LHC) following developments in the superconducting and magnet technologies.
The final approval for the Future Circular Collider (FCC) will be given by CERN Council
Concerns against the Future Circular Collider
High cost of constructing the facility: Future Circular Collider facility will cost around 15 billion Swiss Francs. Bulk of the funding will come from the existing CERN budget. But the project will still require financial contributions from the countries that are full members of CERN (European Countries, USA & Japan etc.)
Criticism of design: A section of physicists have argued against the FCC’s design which aims to collide electrons with positrons. They have argued for colliding beams of muons instead of electrons or protons. Muons are much more massive than electrons, allowing for higher-energy collisions.
Other Proposed Particle Accelerators
High Luminosity LHC: High Luminosity Large Hadron Collider project aims to crank up the performance of the LHC to increase by increasing the integrated luminosity by a factor of 10 beyond the LHC’s design value. Luminosity is an important indicator of the performance of a particle accelerator as it is proportional to the number of collisions that occur in a given amount of time. The HL-LHC will produce at least 15 million Higgs bosons per year, compared to around three million from LHC. It is expected to be operational from 2029.
International Linear Collider (Japan): A proposed linear particle accelerator with a planned collision energy of 500 GeV with a possibility for a later upgrade to 1000 GeV. The ILC would collide electrons with positrons with length between 30 & 50 km. This will be more than 10 times as long as the 50 GeV Stanford Linear Accelerator, longest existing linear particle accelerator. Japan has shown interest in hosting the long planned International Linear Collider.
Circular Electron Positron Collider (China): A proposed Chinese electron positron collider. It would be world’s largest particle accelerator with a circumference of 100 kms.
Muon Collider: Particle Physicists in the US have called for building a muon collider. Muons are like electrons but about 200 times heavier. However, muons are unstable and quicly decay into other particles.
About CERN
CERN is an intergovernmental organisation that operates the largest particle physics laboratory in the world.
Established in 1954.
Based in Meyrin, western suburb of Geneva, on the France-Switzerland border.
Governance: CERN Council is the highest authority of the organisation.
CERN is an official UNGA observer. CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research – consequently, numerous experiments have been constructed at CERN through international collaborations.
Member States of CERN: Currently, there 23 member states of CERN: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovak Republic, Spain, Sweden, Switzerland and the UK. Israel is the only non-European full member. (Cyprus, Estonia and Slovenia are Associate Member States in pre-stage to membership).
Associate Members of CERN: Croatia, India, Latvia, Lithuania, Pakistan, Turkiye and Ukraine. (India is also Associate member of CERN).
Context: In a major milestone for India’s space sector, Indian Space Research Organisation (ISRO) has accomplished the human rating of its cryogenic engine (CE-20), which powers the cryogenic stage of the human-rated LVM3 launcher for India’s first human space flight mission Gaganyaan.
Human-rating refers to rating a system that is capable of safely transporting humans.
Major Highlights:
The ground qualification tests for the human rating of the CE-20 engine involved life demonstration tests, endurance tests and performance assessment under nominal operating conditions as well as off-nominal conditions with respect to thrust, mixture ratio and propellant tank pressure.
ISRO has also successfully completed the acceptance tests of the flight engine identified for Gaganyaan mission, tentatively scheduled for the second quarter of 2024. The engine will power the upper stage of the human-rated LVM3 vehicle and has a thrust capability of 19 to 22 tonnes with a specific impulse of 442.5 seconds.
Gaganyaan Mission:
The Gaganyaan project envisages demonstration of human spaceflight capability by launching a crew of three members to an orbit of 400 km for a three-day mission, and bring them back safely to the Earth, by landing in the sea.
Launch Vehicle Mark-3 or LVM3 (previously referred as the Geosynchronous Satellite Launch Vehicle Mark III or GSLV Mk III) is a three-stage medium-lift launch vehicle developed by the Indian Space Research Organisation (ISRO).
Stages: GSLV Mk III is a three-staged launch vehicle.
First stage- Solid fuel S200 stage. Two rocket boosters use 200 tonnes of solid fuel to lift off the rocket.
Second stage- Liquid fuel L110 stage.
Third stage- Cryogenic fuel C25 stage uses 25 tonnes of a mixture of liquid hydrogen and liquid oxygen.
This upper stage, developed entirely in India, uses the CE-20 cryogenic engine.
This high-thrust engine burns liquid hydrogen and liquid oxygen at very low temperatures for exceptional efficiency and payload capacity.
Primarily designed to launch communication satellites into geostationary orbit. It is also due to launch crewed missions under the Indian Human Spaceflight Programme (Gaganyaan Mision).
The LVM3 is one of the most powerful rockets in ISRO's fleet, and it is capable of launching heavier payloads than its predecessors (GSLV-MKII).
Payload capacity:
4,000 kilograms to geosynchronous transfer orbit (GTO).
10,000 kilograms to low Earth orbit (LEO).
Indigenous cryogenic engine technology in India:
India has managed to develop its own cryogenic engine, a result of decades of research and development. This engine has an entirely Indian design, developed within ISRO, and uses a different process to burn the fuel.
This indigenously developed cryogenic engine is deployed in LVM3, ISRO’s most powerful rocket so far, which carried the Chandrayaan-2 and Chandrayaan-3 missions, among others. LVM3 has had seven flights till now, without any trouble.
Some important reasons why cryogenic engines are used in rockets:
High specific impulse: Cryogenic engines use liquid hydrogen and liquid oxygen as propellants. These propellants are stored at extremely low temperatures (around -253°C for hydrogen and -183°C for oxygen), which gives them a high energy density, i.e, they pack a lot of energy in a small amount of mass.
When these propellants burn, they release a lot of energy compared to their mass, or have high specific impulse.
High specific impulse means more thrust per kilogram of propellant (High thrust to weight ratio). This allows rockets to carry less fuel, reducing their overall weight and allowing them to carry heavier payloads or travel further. Higher thrust is beneficial for:
Overcoming Earth's gravity: Launching a rocket out of Earth's gravity well requires immense thrust. Cryogenic engines provide the necessary power to achieve this initial escape velocity.
Manoeuvring in space: Once in space, cryogenic engines allow for precise manoeuvring and course corrections due to their high thrust and controllability.
Throttling Capability: Cryogenic engines are designed to be throttleable, i.e., they have the ability to vary or adjust their thrust levels during flight. This capability is essential for precise control during ascent, orbit insertion, manoeuvring, controlled reentry and other critical phases of a rocket’s journey.
Greater fuel efficiency: The combustion process in cryogenic engines is cleaner and more complete, releasing more energy and generating more thrust. Rockets with cryogenic engines need less fuel to achieve the same results, making them more cost-effective.
Challenges:
Complexity: They require complex and expensive infrastructure to store and handle extremely cold propellants.
Cost: The initial development process of cryogenic engines is generally more expensive than other types.
Context: Astronomers have finally found a unique class of stars (Helium stars) they had been looking for, for a decade.
How do stars sustain?
Stars are giant balls of hot gas – mostly hydrogen, with some helium and small amounts of other elements. Every star has its own life cycle, ranging from a few million to trillions of years, and its properties change as it ages.
Newton’s law of gravity says all objects with mass attract each other. This should mean the Sun’s outer and inner layers should be attracted to each other, so the star should continuously fall inwards, and eventually simply collapse. However, the sun does not collapse as the nuclear fusion prevents the Sun from shrinking.
In the heart of the star, two hydrogen nuclei (protons) ultimately combine to form one helium nucleus, releasing enormous amounts of heat and energy in the form of gamma rays and neutrinos.
This energy endows all particles in the star with random motion, or pressure, which then fights against the pull of gravity and maintains the star in a state of equilibrium.
The fusion energy pushes the star out while gravity pulls it in, and they hold the balance for billions of years. Such stars are said to be in the main sequence.
Hydrogen devoid stars (Helium stars):
When a star no longer fuses material and allows gravity to gain the upper hand, it blows up in an explosion called a supernova when it is massive enough.
The light from supernovae contains signatures of the various elements it has passed through near the dying star’s surface.
Scientists have observed that some supernovae have shown no signs of hydrogen. (Hydrogen, the lightest of elements, makes up the outer layers of main-sequence stars). The only explanation is that the outer layers of some stars are stripped away before the supernova explosion.
An interesting mechanism happens if the star is part of a binary system — i.e. as one of two stars that are orbiting each other. (Most stars heavier than the Sun are in such binaries). Many binary systems start out with two main sequence stars. The gravitational attraction of one star can peel away the hydrogen layer off the other, resulting in one helium star and one main sequence companion.
Helium stars are Hydrogen depleted stars. They have a core of helium and their outer layers are stripped of Hydrogen. They are roughly 8-20 times the mass of our Sun and their surface gravity is about 1,000-times that of the earth. Helium stars are expected to be so hot that they emit more of their energy as ultraviolet radiation, which lies beyond the visible range.
These Helium stars will end their lives as hydrogen-poor supernovae that leave behind ultra-dense balls called neutron stars.
And these neutron stars may ultimately smash into each other in powerful kilonova explosions, releasing gravitational waves.
Context: Indian Space Research Organisation (ISRO) successfully launched the INSAT-3DS meteorological satellite onboard a GSLV-F14 from Satish Dhawan Space Centre in Sriharikota.
The new-generation meteorological satellite is meant to carry out enhanced monitoring of the Earth’s surface, atmosphere, oceans and environment.
INSAT-3DS will augment the capabilities of the existing two meteorological satellites, INSAT-3D and INSAT-3DR, and boost India’s weather and climate prediction services, early warnings, and disaster management services.
Geosynchronous Satellite Launch Vehicle (GSLV):
GSLV is one of the three main rockets used by ISRO for carrying its satellites, the other two being PSLV and LVM3 (earlier called GSLV-MkIII).
First Stage: Uses four strap-on solid boost motors (HS200) each carrying 127 tonnes of propellant. Provides the initial powerful thrust.
Second Stage: Liquid core stage (L110) powered by two Vikas liquid engines using hypergolic propellants (NTO/UDMH).
Third Stage: Cryogenic Upper Stage (CUS) with cryogenic engine using liquid hydrogen and liquid oxygen for high specific impulse and efficiency.
Specialises in placing heavier satellites (2,200 kg and above) into Geosynchronous Orbits (GEO), where they appear stationary relative to Earth. Ideal for large communication satellites.
GSLV is a more powerful rocket than PSLV and can carry much heavier satellites.
GSLV can carry more than 2,200 kg to geostationary orbits, and over 6,000 kg to low earth orbits.
Why ‘naughty boy'?
GSLV has had a rather patchy track record thus far, because of which it has been described as the ‘naughty boy’.
GSLV had flown 15 times before this, and four of these had been unsuccessful, a very high failure rate for any rocket.
PSLV, the rocket that ISRO has used the maximum number of times, has failed only twice in its 60 launches, including the first time it was tried way back in 1993.
LVM3 rocket has flown seven times and never failed.
What is the problem?
Its problems have mainly been with the cryogenic engine that powers the third and final stage of the flight.
Cryogenic engines use liquid hydrogen as the main fuel.
Hydrogen, the most efficient rocket fuel, is very difficult to handle in its natural gaseous form, but manageable in liquid state. However, it liquifies only at very low temperatures, nearly 250 degrees Celsius below zero.
Oxygen that is needed to burn this fuel also needs to be in liquid form. Oxygen is in a liquid state at about 90 degrees Celsius below zero.
The GSLV uses a cryogenic engine that is reverse-engineered on a Russian design.
The Russians had won a deal to supply cryogenic engines, and technology, to ISRO in the late 1980s, but that deal had come under pressure from the United States which claimed that it violated provisions of Missile Technology Control Regime, an international legal framework meant to stop the proliferation of missile technology.
The deal had to be thus called off. Russia did supply a few of those cryogenic engines but could not transfer the technology. India used those engines in some of its launches in the 2000s, and for later flights, tried to reverse-engineer that engine on its own. It is this reverse-engineered engine, used in the GSLV rockets, that has caused a few headaches for ISRO.
Indigenous cryogenic technology in India:
India has managed to develop its own cryogenic engine as well, a result of decades of research and development. This engine has an entirely Indian design, developed within ISRO, and uses a different process to burn the fuel.
This indigenously developed cryogenic engine is deployed in LVM3, ISRO’s most powerful rocket so far, which carried the Chandrayaan-2 and Chandrayaan-3 missions, among others. LVM3 has had seven flights till now, without any trouble.
Context: The National Aerospace Laboratories (NAL) in Bengaluru has successfully completed the first test of a solar powered “pseudo satellite”, a new age unmanned aerial vehicle (UAV) that can significantly increase India’s surveillance and monitoring capabilities in the border areas.
HAPS
High-altitude pseudo satellites, or HAPS, are unmanned air vehicles that can hold a fixed position.
It can fly at an altitude of 18-20 km from the ground- almost double the heights attained by commercial airplanes.
It has the ability to generate solar power, so it can remain in the air for months and even years-giving the advantage of a satellite.
Working of HAPS
They move at just about 80-100 km per hour at a height of 20 km above the Earth’s surface.
These features help it to gauge an area for a long time.
They can easily keep an eye over 200km and can observe everything even over a 400 sq km area with 5 cm resolution.
It can work like a geostationary satellite and can be easily redeployed at any location with a different payload.
Challenges with operating HAPS
Energy challenge-The primary challenge is to generate enough solar power to keep the aircraft flying, the payload operating and the batteries charging.
Design related challenges-The aircraft should be extremely lightweight to minimize the power requirement, but it also has to be stable.
That’s why this aircraft is meant to fly in the stratosphere.
In the stratosphere, the wind speed is very low, ideal for light weight aircraft to remain stable.
Challenges due to the stratosphere: Temperature is as low as -50 degree Celsius and even lower, which demands electronics devices to remain warm, this in turn leads to more power resources.
The low density of air in this layer creates complications in producing lifts and thrust.
Presence of jet streams in tropical areas also adds to challenges.
Need of HAPS
The need for development of high-endurance, high-altitude flying instruments arose from the desire to have continuous surveillance of border areas to detect changes or movements, particularly in the wake of the Doklam standoff in 2017.
Benefit over battery powered UAV and Satellite: Battery-powered UAVs can remain in air for a limited period of time and can scan relatively smaller areas.
Satellites placed in low-earth orbits and meant to observe the Earth usually move in their orbits and are not watching constantly.
Potential Benefits of HAPS
Search and rescue missions: HAPS vehicles travel closer to the earth than satellites but can loiter locally more readily than other aircraft. This means that they are excellent tools for observation, including search and rescue missions.
Disaster relief: HAPS vehicles can offer live situation reports and even replace failed communication networks, making them ideal for disaster relief. Interlinked HAPS vehicles offer potential advantages as they can provide services with minimal ground network infrastructure, which is ideal when a disaster is unfolding or expected to occur.
Environmental monitoring
Continuous, real-time monitoring of environmental areas is critical to protect against natural and human threats. Be it fire, flooding, poachers or other illegal activities; many things can happen without a watchful eye, especially in challenging terrain or when there is a lack of available human resources.
HAPS vehicles can fill in the gaps for environmental monitoring with a continuous flow of data with low latency. HAPS vehicles can cover a vast area, scanning, detecting, and tracking concerns. Any issues can be sent to a ground team, who can move in or take action.
Agriculture: HAPS vehicles work much like drones for agriculture, allowing monitoring and management. They again offer real-time information with reliable imagery and low latency, ensuring crops are as productive as possible.
Maritime monitoring: HAPS vehicles are vital for surveillance, including maritime monitoring. As outlined above, they can be used for pollution monitoring, vessel detection, and search and rescue missions.
Military intelligence: HAPS vehicles can do much for the military beyond search and rescue and maritime monitoring applications. HAPS vehicles can collect a lot of data, which along with their wide range and high altitude, can allow for military surveillance and reconnaissance.
Countries that are involved in developing HAPS.
NASA has been using solar-powered engines for its Pathfinder series of aircraft.
China, South Korea, and the UK are some of the other countries where this development is taking place.
Some private companies are also developing HAPS, even in India.
India and HAPS
HAPS is a still-developing technology, and the successful test flight puts India among a very small group of countries currently experimenting with this technology.
A Bengaluru-based NewSpace Research and Technologies, a deep-tech start-up, flew a similar solar-powered UAV, having developed the technology through the Innovation of Defence Excellence initiative of the Defence Ministry.
Context: In a study published by the Royal Astronomical Society, points out that the likely source of the mysterious zodiacal dust has been identified, and it has martian origin.
Zodiacal light:
Zodiacal light is the faint glow visible on completely dark nights from Earth. It is due to the sunlight scattered by interplanetary dust (Zodiacal dust).
Zodiacal light is present across the entire path of the ecliptic, which is the path along which the Sun moves in the sky over the course of a year.
Major Highlights of the study:
Scientists at the Physical Research Laboratory in Ahmedabad examined the data from the Juno spacecraft's encounter with dust particles between 1 and 5 astronomical units (AU) from the Sun. They found a peak in dust particle flux at 1.5 AU, suggesting a significant concentration of dust in that region.
AU’ stands for ‘astronomical unit’, which is the distance between the earth and the Sun. Mars is at a distance of 1.52 AU and Jupiter at 5.2 AU from the Sun.
Juno is a spacecraft that NASA launched in 2011 to study the gas-giant Jupiter and its moons.
By comparing the flux of dust near Mars and the number of particles escaping Mars's moons, Deimos and Phobos, the researchers concluded that these moons could be a major source of the interplanetary dust responsible for zodiacal light.
Mars’s two moons are called Deimos and Phobos. Phobos is the bigger of Mars’s two moons.
The low gravity of Deimos and Phobos allows smaller dust particles to easily escape into space. The smaller of these dust particles escape into space, while the larger particles are pulled in by Mars's gravity, leading to the formation of a dust ring around the planet.
