SPACE-TECHNOLOGY

- HIMABINDU
 Major events
1957: First artificial satellite Russian Sputnik 1 launched.

1958: Explorer 1, first US satellite launched.

1962: Indian National Committee for Space Research (INCOSPAR) formed by the Department of Atomic Energy under the
leadership of Dr. Vikram Sarabhai

1969: Indian Space Research Organization (ISRO) formed under Department of Atomic Energy.

1972: Department of Space (DoS) established and ISRO brought under it.

1975: First Indian satellite, Aryabhata, launched into space April 19. It was completely designed in the country and
launched from a Russian facility.

1979: Bhaskara-I, an experimental remote sensing satellite for earth observations, launched from Russia into LEO.

1993: PSLV carried out its first mission, became the Indian space mission’s most reliable workhorse.

For the next 20 years, it launched various satellites for historic missions such as the Chandrayaan and Mangalyaan. PSLV
remains a favourite among various organizations as a launch service provider.
How Do Objects Stay in Orbit?
An object in motion will stay in motion unless something pushes or pulls on it. This
statement is called Newton's first law of motion. Without gravity, an Earth-orbiting
satellite would go off into space along a straight line. With gravity, it is pulled back
toward Earth. A constant tug-of-war takes place between the satellite's tendency to
move in a straight line, or momentum, and the tug of gravity pulling the satellite
back.
An object's momentum and the force of gravity have to be balanced for an orbit to
happen. If the forward momentum of one object is too great, it will speed past and
not enter into orbit. If momentum is too small, the object will be pulled down and
crash. When these forces are balanced, the object is always falling toward the
planet, but because it's moving sideways fast enough, it never hits the planet.
Orbital velocity is the speed needed to stay in orbit. At an altitude of 150 miles (242
kilometers) above Earth, orbital velocity is about 17,000 miles per hour. Satellites
that have higher orbits have slower orbital velocities.
Geo synchronous (GSO) / Geo stationary orbit (GEO)

• Satellites in geostationary orbit (GEO) circle Earth above the equator

from west to east following Earth’s rotation – taking 23 hours 56
minutes and 4 seconds – by travelling at exactly the same rate as Earth.
• This makes satellites in GEO appear to be ‘stationary’ over a fixed
position.
• If such orbit circles exactly above the equator, it is called
Geostationary and if it is inclined, it is called Geosynchronous.
• In order to perfectly match Earth’s rotation, the speed of GEO satellites
should be about 3 km per second at an altitude of 35 786 km.
• This is much farther from Earth’s surface compared to many satellites.
• GEO is used by satellites that need to stay constantly above
one particular place over Earth, such as telecommunication
satellites. This way, an antenna on Earth can be fixed to always
stay pointed towards that satellite without moving.
• Also used for India’s navigation satellites.
• It can also be used by weather monitoring satellites, because
they can continually observe specific areas to see how weather
trends emerge there.
• Satellites in GEO cover a large range of Earth so, as few as
three equally-spaced satellites can provide near global
coverage. This is because when a satellite is this far from
Earth, it can cover large sections at once.
Low Earth orbit (LEO)

• A low Earth orbit (LEO) is, as the name suggests, an orbit that is relatively
close to Earth’s surface.
• It is normally at an altitude of less than 1000 km but could be as low as 160
km above Earth – which is low compared to other orbits, but still very far
above Earth’s surface.
• Unlike satellites in GEO that must always orbit along Earth’s equator, Low
earth orbits can be tilted. This means there are more available routes for
satellites in LEO, which is one of the reasons why LEO is a very commonly
used orbit.
• LEO’s close proximity to Earth makes it useful for several reasons. It is the
orbit most commonly used for satellite imaging, as being near the surface
allows it to take images of higher resolution.
• It is also the orbit used for the International Space Station (ISS), as
it is easier for astronauts to travel to and from it at a shorter
distance.
• Satellites in this orbit travel at a speed of around 7.8 km per
second; at this speed, a satellite takes approximately 90 minutes to
circle Earth, meaning the ISS travels around Earth about 16 times a
day.
• However, individual LEO satellites are less useful for tasks such as
telecommunication, because they move so fast across the sky,
communications satellites in LEO often work as part of a large
combination or constellation, of multiple satellites to give constant
coverage.
Medium Earth orbit (MEO)

• Medium Earth orbit comprises a wide range of orbits

anywhere between LEO and GEO.
• It is similar to LEO in that it also does not need to
take specific paths around Earth, and it is used by a
variety of satellites with many different applications.
• It is very commonly used by navigation satellites &
some communication satellites.
Polar orbit and Sun-synchronous orbit (SSO)
• Satellites in polar orbits usually travel past Earth from north to south rather
than from west to east, passing roughly over Earth's poles.
• Satellites in a polar orbit do not have to pass the North and South Pole
precisely; even a deviation within 20 to 30 degrees is still classed as a polar
orbit.
• Polar orbits are a type of low Earth orbit, as they are at low altitudes
between 200 to 1000 km.
• Sun-synchronous orbit (SSO) is a particular kind of polar orbit.
• Satellites in SSO are synchronous with the Sun. This means they are
synchronised to always be in the same ‘fixed’ position relative to the Sun. This
means that the satellite always visits the same spot at the same local time – for
example, passing the city of Paris every day at noon exactly.
Geostationary transfer orbit (GTO)

• Transfer orbits are a special kind of orbit used to get from one orbit to
another.
• A GTO is highly elliptic. Its perigee (closest point to Earth) is typically as
high as low Earth orbit (LEO), while its apogee (furthest point from Earth) is
as high as geostationary / geosynchronous orbit. That makes it a Hohmann
transfer orbit between LEO and GSO.
• Using this system, the satellite is placed into a low earth orbit with an altitude
of around 180 miles. Once in the correct position in this orbit rockets are
fired to put the satellite into an elliptical orbit with the perigee at the low
earth orbit and the apogee at the geostationary orbit as shown. When the
satellite reaches the final altitude the rocket or booster is again fired to retain
it in the geostationary orbit with the correct velocity.
Satellite Launchers

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1. Satellite Launch Vehicle-3:
• (SLV-3) was India's first experimental satellite launch vehicle,
which was an all solid, four stage vehicle weighing 17 tons with a
height of 22m and capable of placing 40 kg class payloads in Low
Earth Orbit (LEO).
• While building upon the experience gained from the SLV-3
missions, ISRO developed the “Augmented Satellite Launch
Vehicle” (ASLV), designed to augment the payload capacity to 150
kg for Low Earth Orbits (LEO). It is a five stage, all-solid
propellant vehicle.
Polar Satellite Launch Vehicle (PSLV):
• It is the third generation launch vehicle of India.
• It is the first Indian launch vehicle to be equipped with liquid stages.
• It is a four-staged launch vehicle with first and third stage using solid
rocket motors and second and fourth stages using liquid rocket
engines.
• It also uses strap-on motors to augment the thrust provided by the first
stage and depending on the number of these strap-on boosters, the PSLV
is classified into its various versions like core-alone version (PSLV-CA)
with no strap-on boosters, PSLV-G with six strap-on boosters (9 tons
each), and PSLV-XL variant with 6 strap-on boosters (12 tons each).
• New variants such as PSLV-DL (2 strap on motors) & PSLV-QL (4 strap
on motors) are also being used.
• PSLV is designed mainly to deliver the “remote-sensing”
satellites with lift-off mass of up to about 1750 Kg to Sun-
Synchronous circular polar orbits.
• After its first successful launch in October 1994, PSLV emerged as
the reliable and versatile workhorse launch vehicle of India by
launching the satellites of lower lift-off mass of up to about 1400 Kg
to GEO transfer orbit (GTO). Besides, the vehicle successfully
launched two spacecrafts – Chandrayaan-1 and Mars Orbiter
Spacecraft.
3. Geosynchronous Satellite Launch Vehicle (Fat boy):
• (GSLV) is the fourth generation launch vehicle developed by India. Two
versions of the GSLV are being developed by ISRO.
• The first version, GSLV Mk-II, has the capability to launch satellites
of lift-off mass of up to 2,500 kg to the GTO and satellites of up to
5,000 kg lift-off mass to the LEO.
• GSLV MK-II is a three-staged vehicle with first stage using solid
rocket motor, second stage using Liquid fuel and the third stage,
called Cryogenic Upper Stage, using cryogenic engine.
• GSLV Mk III, chosen to launch Chandrayaan – 2 spacecraft and will
be used to carry Gaganyaan.
• For one of its recent launch, ISRO redesignated GSLV-MK III to LVM-
III (Launch Vehicle – Mark III)
• It is a three-stage heavy lift launch vehicle developed by ISRO. The
vehicle has two solid strap-on boosters (S200 strap-ons) on either side
of its core. Each carry 204 tons of composite solid propellant and their
ignition results in vehicle lift off. Considered as stage 1
• Stage 2 is L110 liquid stage
• It has a cryogenic upper stage (C25).
• It is designed to carry 4-ton class of satellites into Geosynchronous
Transfer Orbit (GTO) or about 10 tons to LEO, which is about twice the
capability of GSLV Mk II.
 Small Satellite Launch Vehicle (SSLV)
• Low-cost alternate to launch small satellites
• Produced through New space India Limited (NSIL,Nodal agency for SSLV)
• 3-Stage Solid propulsion
• Pay load capacity of 300 kg to Sun synchronous orbit & LEO 500 kg to
Low earth orbit.
Planned launches:
• In March 2022, ISRO has successfully conducted ground testing of
SSLV's solid booster stage-SS1, completing the ground testing of all 3
stages.
• SSLV-D1 (demonstration) launch has taken place in August 2022, but
failed due to a sensor failure and placed Earth Observatory satellite
(EOS)-2 and a student satellite into a wrong orbit.
• The second developmental flight of SSLV, SSLV-D2 is successfully
launched.
 AGNILET: World’s first single-piece 3D-printed rocket
• On 4th November 2022, Chennai-headquartered space-tech start-up Agnikul had
successfully test-fired its single-piece 3D-printed engine, Agnilet.
• It is the world’s first single-piece 3D-printed rocket engine fully designed
and manufactured in India, which was successfully first test-fired at IIT Madras in
2021.
• The current test was conducted at Thumba Equatorial Rocket Launching Station
(TERLS), at Vikram Sarabhai Space Center (VSSC), Thiruvananthapuram.
• The test was carried out as part of MOU signed between ISRO and Agnikul
Cosmos Pvt. Ltd. to provide opportunity for Indian space start-ups to use facilities
of ISRO through (Indian National Space Promotion and Authorization Centre)
IN-SPACe.
• This engine is going to be used in Agniban, a highly customizable two-stage
rocket with 100 kg payload capacity to orbits around 700 km high (low Earth
orbits). It is going to use semi cryogenic engine that run on Kerosene as fuel and
Liquid oxygen as oxidizer.
 Vikram-S: India's first privately made rocket launched
(Mission Prarambh)
• Vikram is a family of small lift launch vehicles being developed by
Hyderabad based startup, Skyroot Aerospace.
• It became the first Indian company to be authorised for launching a rocket
by Indian National Space Promotion and Authorisation Centre (IN-
SPACe).
• Skyroot has been developing 4 variants of the Vikram rocket, named after Dr.
Vikram Sarabhai.
• Vikram-S, a sounging rocket (used for probing the upper atmospheric regions
and for space research with their suborbital flights). was launched by Skyroot
Aerospace on 16th Nov 2022, from the sounding rocket launch complex at
Satish Dhavan Space Centre. The Mission titled 'Prarambh’ carried three
payloads. It marks the first launch of launch vehicle built by a private
company in India. It reached an altitude of 89.5 km. It was fuelled by 3-
stage all solid engine.
• Vikram-I can carry 480 kilograms of payload to Low Earth Orbit.
• Vikram-II is equipped to lift off with 595 kilograms of cargo.
• Vikram-III can launch with an 815 kg to 500 km Low Inclination Orbit.
● Skyroot's first privately developed, fully cryogenic rocket engine, Dhawan-I, for its
Vikram II was successfully test fired in 2021.
● Skyroot Aerospace test-fired its 3D-printed Dhawan II engine. The engine was
developed by the company for its updated version of, Vikram II.
● Dhawan-II is completely indigenous and used a super alloy for 3D printing the engine,
which reduced the manufacturing time by 95%. It will use Liquid Natural gas (LNG)
and Liquid Oxygen (LoX) as propellants.
● LNG is more than 90% methane and is considered the rocket fuel of the future.
● The engine development was partly supported by NITI Ayog’s ANIC-ARISE program
which promotes technologies including the use of green rocket propellants.
 Reusable Launch Vehicle (RLV)

• ISRO is also working on a reusable launch vehicle

(RLV) is to achieve low cost, reliable and on-demand
space access.
• RLV-TD (technology demonstration) was successfully
flight tested in 2016 from Sriharikota High Altitude
Range (SHAR) validating the critical technologies such
as autonomous navigation, guidance & control, reusable
thermal protection system and re-entry mission
management.
• ISRO tested the landing capabilities of RLV TD, It was
taken to a height 4.5 km by an Indian Air Force (IAF)
Chinook helicopter and & dropped the from there.
Other Agencies Using RLV or Partial RLV:
● Reusable spacecraft have been around for a while; the NASA
space shuttles have completed numerous human space flight
missions.
● With its Falcon 9 and Falcon Heavy rockets, SpaceX has been
demonstrating partially reusable launch systems since 2017.
● Starship is a system of fully reusable launch vehicles that SpaceX
is also developing.
Source: The Hindu, 3 April , 2023.
 Fuels used in Launchers
Solid propellant:
• They consist of mixture of solid compounds (both fuel and oxidizer) that burn at a
rapid rate after ignition.
• The fuel is usually organic material (hydroxyl-terminated polybutadiene) or
powdered aluminum.
• The oxidizer is most often ammonium perchlorate.
• Solid rocket motors once ignited burn their fuel until it is exhausted.
Liquid propellant:
• Liquid fuels can range from ordinary kerosene, which can be used at ground
temperature, to liquid hydrogen, which must be maintained at extremely cold
temperatures.
• In order to burn, liquid rocket fuel must be mixed in the combustion chamber of a
rocket engine with an oxidizer. Liquid Oxygen is commonly used as oxidizer.
• Liquid engines can be turned off after ignition and provide better control than solid
fuels.
Cryogenic Engines:

• Cryogenic rocket stage is more efficient and provides more thrust for every
kilogram of propellant it burns compared to solid and liquid propellant rocket
stages.
• Liquid Hydrogen and Liquid Oxygen are commonly used as cryogenic
propellants.
• Cryogenic stage is technically a very complex system compared to solid or
liquid propellant stages due to its use of propellants at extremely low
temperatures and other designing requirements.
• Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C.
 COMMUNICATION SATELLITES

The Indian National Satellite (INSAT) system

• One of the largest domestic communication satellite systems in Asia-Pacific
region
• Established in 1983 with commissioning of INSAT-1B.
• 9 communication satellites placed in Geo-stationary orbit (5 operational
now).
GSAT (Geosynchronous satellites)
• India’s indigenously developed communication satellites.
• First launch in 2001.
• Launched by GSLV or foreign launchers (mostly Ariane-5).
• Over 20 GSAT satellites of ISRO have been launched, out of which,14 are
operational.
They contain instruments like transponders (A wireless communication &
monitoring device that pics up and responds to a signal) serving in various
bands for TV broad casting, cameras, Radiometers (Detects and measures
electromagnetic radiation) for Meteorological imaging.
Applications:
Telecommunication, Television broadcasting, Satellite news gathering,
Meteorology (Weather forecasting), Disaster warning, Search and Rescue
operation services.
Theme based communication satellites:
• ‘EDUSAT’(GSAT-3), India’s first thematic satellite dedicated
exclusively for educational services.
• Telemedicine.
REMOTE SENSING SATELLITES (IMAGING)

• Starting with IRS-1A in 1988, ISRO has launched many

operational remote sensing satellites.
• Today, India has one of the largest constellation of remote
sensing satellites in operation. Currently 13 operational
satellites are in Sun synchronous orbit & 4 in
Geostationary orbit.
• The satellites use variety of instruments to provide
necessary data in a diversified fields.
 Theme based Remote Sensing Satellites

(i) Land/water resources applications

➢ RESOURCESAT series and RISAT series
(ii) Ocean/atmospheric studies
➢ OCEANSAT series, INSAT-VHRR (Very High-Resolution
Radiometer), INSAT-3D, Megha-Tropiques and SARAL

(iii) Large scale mapping applications

➢ CARTOSAT series
 Remote Sensing - Applications
Agriculture Resources & Environment
• Crop area estimation • Forest Cover & Type mapping
• Crop production Forecast • Wetland Inventory & Conservation plans
• Biodiversity Characterization
• Crop health / damage assessment
• Desertification Status mapping
• Soil mapping
• Snow & Glacier studies
• Horticulture development

Rural Development Disaster Management Support

• National Drinking Water Mission • Realtime analysis of natural disasters like
• Wastelands Mapping/ Updation Flood, Cyclone, Drought, Landslide,
• Watershed Development & Earthquake and Forest Fire
Monitoring • R&D Studies on Early warning Systems,
• Land Records Modernization Plan Decision Support Tools

Urban Development Geology & Mineral Resources

• Urban Mapping of Major Cities • Landslide Hazard Zonation
• Master/ Structure Plans • Mineral/ Oil Exploration, Mining Areas,
• Comprehensive Development Plans • Seismo-tectonic Studies
Cartography Ocean and Meteorology
• Visualization of spatial information. • Ocean State Forecast (OSF)
• Large Scale Mapping • Regional Weather prediction
 NAVIGATION SATELLITES
Navigation: The process of accurately ascertaining one's position and planning and
following a route”
Indian Regional Navigational Satellite System (IRNSS): independent Indian
Satellite based positioning system for critical national applications. Objective is to
provide Reliable Position, Navigation and Timing services over India and its
neighborhood, 1500 kilometers around the Indian mainland.
• 9 satellites launched, one unsuccessful, eight satellites are currently in orbit (3 in
Geo stationary orbit and remaining in Geosynchronous orbits).
• The IRNSS constellation is known as Navigation with Indian Constellation
(NavIC)
• IRNSS-1I is the latest (eighth) member of the NavIC system, launched on 12th
April, 2018, into Geosynchronous orbit.
• ISRO has recently revealed its plans to add new navigation satellites in Medium
Earth Orbits to increase coverage.
The IRNSS will help India enter the club of select countries which have their own
positioning systems. Following countries have global coverage:

• USA’s GPS (31 satellites in a constellation)

• Russia’s GLONASS (over 24 satellites)
• European Union’s Galileo (Over 24 satellites)
• China's BeiDou (Full global services launched in July 2020 with constellation of 35
satellites)
• Japan's Quasi Zenith (QZSS) regional system (planned to launch 7 satellites).

The system was developed partly because access to foreign government-

controlled global navigation satellite systems is not guaranteed in hostile situations, as
happened to the Indian military in 1999 when the United States denied an Indian request
for Global Positioning System (GPS) data for the Kargil region, which would have
provided vital information. The Indian government approved the project in May 2013.
 Navigation satellites - Applications

➢ Terrestrial, Aerial and Marine Navigation

➢ Disaster Management
➢ Vehicle tracking and fleet management
➢ Integration with mobile phones
➢ Precise Timing and Mapping
➢ Terrestrial navigation aid for hikers and travellers
➢ Visual and voice navigation for drivers
 GPS Aided Geo Augmented Navigation (GAGAN)
• Developed by ISRO and Airports Authority of India (AAI)
to deploy satellite-based augmentation system (SBAS) for
civil aviation applications.
• Replace ground-based navigation systems using radars.
• More efficient use of available airspace.
• GAGAN GEO coverage extends from Africa to Australia
and has expansion capability for seamless navigation services
across the region.
• GAGAN is already operational through GSAT-8, GSAT-10,
and GSAT 15 satellites.
Uses: Additional accuracy, availability, and integrity necessary
for all phases of flight.
MOON MISSIONS
 Chandrayaan-1
• Launched on 22nd October 2008.
• India became the 4th country (USA, RUSSIA, JAPAN) to land a probe on the
moon.
• Distance: 386,000 km from the earth
• PSLV-XL (C11) (320-ton lift-off weight)
• Cost: $ 80 million (~400 cr)
• The mission included a lunar orbiter and an impactor.
• Expected duration: 2 years , Lasted for ~ 10 months.
• Confirmed water ice on the surface using NASA’s instrument, Moon minerology
mapper, M3.
• Carried 11 scientific instruments (payloads), 5 from ISRO, remaining from other
countries.
• Findings: confirmed the presence of lunar waters, lunar caves, tectonic activity,
Faults and fractures.
HIMA BINDU
 Chandrayaan-2
• Launched on 22nd July 2019.
• GSLV Mk III-M1
• Cost : ~ 1000 Cr
• 3 parts: Orbiter, Lander and Rover.
• Could have become the first-ever
mission to land a rover near
the lunar south pole (Unexplored).
• Lander crashed during the soft
landing.
• Only US, Russia and China have
been able to soft-land spacecraft on
lunar surface so far.
HIMA BINDU
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2379 kg
Pragyan (27kg) 7yrs life,
6-wheeled robotic vehicle for Vikram (1471 kg)
Observe the lunar surface 14-days Life
In situ analysis Relay communication between
14-days Life Earth and Lander
HIMA BINDU
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Indian Express
Why ISRO want to explore the Moon’s South Pole:
Water Resources: The south pole region is believed to have water molecules in substantial
amounts, possibly trapped as ice in the permanently shadowed craters. Exploring and
confirming the presence of water is essential for future human missions and the potential
utilization of lunar resources.
Scientific Discoveries: The extreme environment and the presence of permanently
shadowed regions provide a preserved record of the Moon’s history and the early Solar
System.
Clues to Earth’s History: The Moon is thought to have formed from debris generated by a
giant impact between a Mars-sized object and the early Earth. By studying the lunar south
pole, scientists can gain insights into the materials and conditions that existed during the
formation of the Earth-Moon system.
Technological Advancements: By undertaking missions to this region, ISRO can develop
and demonstrate innovative technologies for soft landing, navigation, resource utilization,
and long-duration operations that can be applied in future space missions.
 HIMA BINDU

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Hindustan Times
 CHANDRAYAAN-3
● Chandrayaan-3 is India’s third moon mission and is a follow-up of Chandrayaan-
2 (2019) which aimed to land a rover on the lunar South Pole.
● It aims to be the world’s first mission to soft-land near the lunar South Pole.
About the Mission:
The Mission will have three major modules-
a) The Propulsion module (will carry the lander and rover configuration till 100 km
lunar orbit).
b) Lander module (capability to soft land and deploy Rover).
c) Rover (will carry out in-situ chemical analysis of the lunar surface).
Unlike Chandrayaan-2, it will not have an orbiter and its propulsion module will
behave like a communications relay satellite.
Chandrayaan-3 payloads:
The propulsion module:
● It has Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to look
for changes that a life supporting atmosphere make to the star light that is passing
through it, there by analysing possibility of life in nearby planets.
The Lander payloads:
● Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere
(RAMBHA) – to measure near surface plasma density and and its changes with
time.
● Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure the
thermal conductivity and temperature.
● Instrument for Lunar Seismic Activity (ILSA) for measuring the seismicity
around the landing site.
● Langmuir Probe (LP) to estimate the plasma density and its variations.
● A passive Laser retroreflector array from NASA to help accurately measure the
distance between Earth and moon.
The Rover payloads:
● Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown
Spectroscopy (LIBS) for deriving the elemental composition in the vicinity of the
landing site.
Chandrayaan - 3 landed on Moon on 23rd August. Rover separated. And lost contact after
14 days.
Global Collaborations:
● ISRO-NASA successfully confirmed the presence of water from the data taken by
Chandrayaan-1.
● Indo-Japan collaboration, LUPEX aims to send a lander and rover to the Moon’s
south pole around 2024.
Findings of Chandrayaan 3:
• Chandrayaan-3 ‘unambiguously confirmed’ the presence of sulphur in the lunar
surface near south pole. Other elements like Aluminum (Al), Calcium (Ca), Iron
(Fe), Chromium (Cr), Titanium (Ti), Manganese (Mn), Silicon (Si), and Oxygen (O)
are also detected. The space agency further added that the search for Hydrogen (H) is
underway.
• 2. 4-meter diameter crater on Moon's surface
• Temperature recorded on the Lunar surface is 50-700C and at a depth of 8cm (-)100C
• Vikram lander studied the Moon’s Ionosphere to provide insights into developing
future communication technology suitable for Moon.
• Vikram lander detected seismic activity which could be either due to a moon quake
or an Asteroid hit.
• Pragyan Rover covered 100 meters distance of Lunar terrain.
• Found that near surface plasma environment (Charged particles) to be relatively
sparce means it will not cause much disturbance to radio communication.
• Vikram lander performed a hop experiment indicating that the space craft could be
used to bring samples back in future.
 RUSSIA’S LUNA 25
● The race to send a spacecraft to the moon
has taken an exciting turn as Russia's
Luna 25 mission, launched on a Soyuz
rocket on August 11, 2023, aims to soft-
land on Moon’s south pole a few days
before India's Chandrayaan-3.
● Luna 25 marks Russia's return to lunar

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reclaim its reputation in space exploration.
● Russia's space agency, Roscosmos asserts
that Luna 25's landing would not impact
Chandrayaan-3, as their landing regions
are distinct.
Reason for Luna 25 reaching the Moon Earlier than Chandrayaan-3:
• Direct Trajectory Advantage for Luna 25
• Luna 25's lift-off mass of 1,750 kg is significantly lighter than Chandrayaan-3's
3,900 kg, facilitating a quicker journey.
● Luna 25 benefits from an earlier lunar dawn at its landing site, ensuring full Solar
panel power for its payloads during the lunar day (equal to 14 Earth days).
Soft landing to moon:
● Only three countries have managed to complete a soft landing on the Moon in history:
the United States, the Soviet Union, and China.
Other Differences between Luna 25 and Chandrayaan 3:
Luna 25 is lighter and lacks a rover, The lander has eight payloads to study the soil
composition, dust particles in the polar exosphere, and detect surface water.
Chandrayaan-3 carries a rover capable of moving 500 meters, aims to study lunar soil,
and has instruments to detect water-ice in shadowed craters near the lunar South Pole.
Luna 25 is designed for a year-long mission, equipped with heating mechanisms
and a non-solar power source. In contrast, Chandrayaan-3 is built for a single lunar day
due to lack of heating during lunar nights.
Status of India Russia Space Collaboration:
● India’s first satellite, Aryabhata was launched by the Soviet Union in 1975.
● Only one Indian citizen has ever flown to space- Rakesh Sharma flew to the
Salyut 7 space station on a Soyuz rocket in 1984 as part of the USSR’s
Interkosmos program (a program designed to help allies with crewed and uncrewed
missions).
● In 2004, the two countries signed a protocol to boost cooperation in space. This
included the development of the GLONASS navigation system and the launching
of Russian GLONASS satellites by Indian rockets.
● Chandrayaan-2 was initially supposed to be a collaboration between India
and Russia.
● However, Russia withdrew from designing the lander-rover for
Chandrayaan-2 leading India to develop it independently.
● Also, four astronauts who will be part of India’s first crewed space
mission: Gaganyaan have been trained in Russian facilities.
Source: IE, 16 Aug 2023.
 China’s Chang’e-4 Mission
• On January 2 nd , 2019, China has successfully landed a robotic
spacecraft on the far side of the Moon, the first ever such landing.
• Previous Moon missions have landed on the Earth-facing side, but this is
the first successfully landing on the unexplored far side.
• It is carrying instruments to analyse the unexplored region's geology, as
well to conduct biological experiments.
• The area where the probe has landed faces away from Earth, meaning it is
free from radio frequencies. As a result, it is not possible for a lunar rover
to communicate directly with ground control.
• Hence, China launched a dedicated satellite (Queqiao) orbiting to relay
information from the rover to Earth.
Tidal locking: The moon takes about 29 days to
complete one revolution around the Earth, the same
time it takes to make one rotation on its own axis. As
a result, we see the same side of the moon irrespective
of when and where on Earth we look at it from.

The reason for this is a phenomenon called “tidal

locking”. The Earth’s gravitational pull on the moon
and Moon’s gravitational pull on earth, slowed down
the moon’s rotation down to the time it takes to orbit
the Earth. (Lunar day = Lunar year)
 China’s Chang’e-5 Mission
• Lunar sample return mission launched on November 24th, 2020.
• It made China just the third country to have retrieved lunar samples, after
the US and the former Soviet Union (1976).
• The mission carried a lunar orbiter, a lander, and an ascent probe.
• In December 2020, it successfully brought approximately 2 kilograms of
lunar samples – the first to be returned in 44 years.
• It provided first on-site evidence of water.
• Lunar material will help scientists understand more about the moon's origin
and formation.
• It marked a successful conclusion of China’s current three-step lunar
exploration programme of orbiting, landing, and sample collection,
which began in 2004.
 New International Moon missions

• NASA’s VIPER rover: Planned to be launched on the Moon's south

pole in 2023 to study water ice.
• South Korea launched Danuri (also known as the Korean Pathfinder
Lunar Orbiter or KPLO) to the Moon on August 5, 2022, to study the
Moon's surface and help plan future missions to the lunar poles.
• Beresheet2: Israeli non-profit organization, SpaceIL’s plan to the
Moon targeting 2024 to conduct scientific experiments.
 NASA's ARTEMIS MISSION
• Artemis is the ambitious plan of NASA to relaunch its human missions to Moon
after 5 decades
• The Artemis program comprises of three missions:
• Artemis I, launched on 16th November 2022, is an uncrewed mission, with human
models to test the functioning of the rocket and effects on Human body.
• NASA's SLS rocket carried Orion spacecraft into space to travel past the moon and
cover 1.3 million miles before ending its 42-day journey back to earth.
• Artemis II will be the first crewed flight test of the SLS rocket and the Orion
spacecraft around the Moon taking humans to their farthest point yet in space.
• Artemis III will make history by landing humans on the Moon.
• With this Mission, NASA is planning to establish long-term presence on Moon by
setting up a human base camp, a series of nuclear reactors, and a mineral mining
operation.
• It is going to be stepping stone of its journey to Mars and then further exploration of
deep space.
INTER PLANETARY MISSIONS
 Mangalyaan (MOM)
• Launch vehicle : PSLV XL (C25) (1350 Kg)
• Launched on 5th Nov 2013
• Cost: $ 75 million (~ 450 crore)
• Payload: 1350 kg
• Mangalyaan traveled for ~300 days, covering ~ 680 mn kilometers, and
reached Martian orbit in September 2014.
• Objective: To study the composition of Mar’s SAM (Surface – Atmosphere
– Minerals), using 5 different payloads.
• It made India the 4th space agency to orbit mars after ROSCOSMOS, NASA,
ESA & the first nation to send a satellite into Martian orbit on its first attempt.
• The Mars Color Camera (MCC) has produced more than 1000 images and
published a Mars Atlas.
• ISRO is planning another orbiter mission (MOM-2) as the Mars Orbiter craft
has attained end-of-life.
 NASA’s Perseverance
• It is a NASA’S MARS ROVER, launched on 30th July 2020
• It reached on: 18th Feb 2021
• Took 7 months and traveled ~ 480 million Km.
• It is part of NASA’s Mission 2020 to collect samples from Mars.
• Landing site: Jezero Crater
• It uses the Mars Reconnaissance Orbiter (designed to study geology and climate
on Mars, reached MARS in 2006) to send images back to Earth.
• Samples will be studied to learn if life has ever existed on Mars.
• An experimental helicopter called Ingenuity, a small drone was sent along with
Perseverance to test if helicopter can fly in Mars’ atmosphere.
• In December 2021, NASA announced that Perseverance detected Carbon
containing organic compounds on Martian rocks – indicating past life on MARS,
but it needs to be confirmed through sample verification in future.
 HOPE (Al-Amal)
• United Arab Emirates' (UAE’s) first-ever interplanetary mission
• This orbiter/probe, developed by UAE scientists in the USA and was launched on 19th
July 2020 from the Tanegashima Space Centre in Japan.
• Has successfully entered orbit around Mars in February 2021.
• UAE became the fifth country to reach the Red Planet, joining NASA, the Soviet
Union, the European Space Agency and India.

Tianwen-1 (Questions to heaven)

• China’s first Mars mission, launched on 23rd July 2020.
• A robotic spacecraft, consisting of an orbiter, lander and rover.
• Has successfully entered orbit around Mars in February 2021 and landed a rover
(Zurong) in May 2021 on a massive plain in the northern hemisphere known as Utopia
Planitia.
• China became the second only country, after USA to land a rover on MARS.
 Mission to Venus (Shukrayaan)
• ISRO is also planning a mission to Venus.
• Both the Earth and Venus share similarities in size, mass, density, bulk
composition and gravity.
• ISRO is planning to send an orbiter that will be placed around 400 km over
Venus to conduct research and understand its formation, its atmosphere and its
interaction with the solar wind.
• The mission is expected to be launched by 2024 and expected to orbit for ~ 4
years.
• ISRO has been soliciting ideas for instruments for Venus mission since 2018.
• The flagship instrument will be a synthetic aperture radar to examine the
Venusian surface covered by thick clouds.
 EUROPEAN SPACE AGENCY SET TO LAUNCH JUPITER ICY
MOONS EXPLORER (JUICE)
● Recently, the European Space Agency is set to launch the Jupiter Icy Moons
Explorer (Juice) mission to explore Jupiter and its icy moons, namely
Ganymede, Callisto, and Europa.
● Two other spacecraft have examined Jupiter: NASA’s Galileo probe, which
orbited the gas giant between 1995 and 2003, and NASA’s Juno, which has
been circling the planet since 2016.
● Launched from French Guiana on an Ariane 5 launcher. The mission is set
to reach Jupiter in 2031.
● The spacecraft was constructed by Airbus Defence and Space, a division of
the Airbus group.
Main Objectives:
● To create detailed maps of the moons' surfaces and look beneath them to probe the
potential habitable environments by analyzing the water bodies underneath.
● To create a comprehensive picture of Jupiter by trying to understand its origin,
history, and evolution.
● To explore Jupiter’s complex environment in depth, and study the wider Jupiter
system as an archetype for gas giants across the Universe.
● The focus will be on Ganymede (the largest moon in the Solar System, which
generates its magnetic field).
● The three moons, Ganymede, Callisto, and Europa, are believed to hold
immense amounts of water, potentially making them habitable.
● Juice isn't equipped to detect life but can find out whether there could be
necessary conditions, such as water, biological essential elements, energy, and
stability, to sustain life.
 MARS missions

NASA European Space Agency

Perseverance Rover
MAVEN Orbiter ExoMars Trace Gas Orbiter
InSight Lander Mars Express
Curiosity Rover
MARS Reconnaissance orbiter
Odyssey orbiter (working for two decades)

BepiColombo
European & Japanese collaborative mission to Mercury. Launched in
October 2018 and expected to reach Mercury in 2025.
Akatsuki
Japan’s first interplanetary mission actively studying Venus’s atmosphere.
Juno
NASA’s mission exploring Jupiter (Reached Jupiter in 2016).
 VOYAGER TWIN SPACECRAFT
• The twin Voyager 1 and 2 spacecrafts launched in 1977 are continuing to explore where
nothing from Earth has flown before.
• The primary mission, Voyager 1 was the exploration of Jupiter and Saturn.
• Voyager 2 went on to explore Uranus and Neptune and is still the only spacecraft to
have visited those outer planets.
• In August 2012, Voyager 1 made the historic entry into interstellar space (the region
between stars), crossing the Heliopause (The boundary between solar wind and
interstellar wind). The interstellar space is filled with material ejected by the death of
nearby stars millions of years ago.
• Voyager 2 entered interstellar space on November 5, 2018 and scientists hope to learn
more about this region.
• Voyager’s power supply comes from a radioisotope thermoelectric generator (RTG)
which turns heat from the decay of radioactive material into electricity to power the
space craft.
• Twin Voyagers are likely to run out of power within 5 years.
 ISRO, BARC JOIN HANDS TO DEVELOP
NUCLEAR ENGINES FOR ROCKETS
● Recently, the Bhabha Atomic Research Center (BARC) and the Indian Space
Research Organization (ISRO) began working together to develop radio
thermoelectric generators (RTGs), a novel strategy meant to overcome the
limitations of traditional chemical engines for interplanetary travel.
● Chemical engines work well for satellite thrusters, but they are inadequate for
deep space travel due to fuel limitations and lack of solar power in distant regions.
● RTGs have been successfully employed by US spacecraft such as the Voyager,
Cassini and Curiosity, to power missions with exceptional achievements.
Radio Thermoelectric Generators (RTGs):
● Radioisotope Heater Unit (RHU) utilize radioactive materials, such as
Plutonium-238 or Strontium-90, to emit heat as they decay over time.
● This heat is harnessed and converted into electricity by the RTG component.
● This conversion takes place through a thermocouple, a material that generates
voltage when subjected to a temperature gradient.
● The voltage produced by the thermocouple is utilized to charge batteries
onboard the spacecraft.
● These batteries, in turn, power various systems, including propulsion mechanisms,
enabling interplanetary travel.
Advantages of RTGs for Space Missions:
Independence from Solar Proximity:
● Unlike solar-powered systems, RTGs operate effectively regardless of the
spacecraft's distance from the sun.
● This characteristic eliminates constraints related to launch windows and
planetary alignment.
Reliability and Consistency:
● RTGs offer a consistent and reliable source of power, essential for
sustaining prolonged deep space missions.
● The gradual decay of radioactive materials ensures a continuous supply of
heat and electricity.
Bhabha Atomic Research Centre:
● BARC is India’s premier nuclear research facility based in Mumbai,
Maharashtra.
● It is a multi-disciplinary research center with core mandate to sustain
peaceful applications of nuclear energy, primarily for power generation.
Source: BL, 16 July 2023.
 NUCLEAR-POWERED ROCKET
● NASA collaboration with the United States Defense Advanced Research Projects
Agency (DARPA) is seeking a nuclear propulsion system, a nuclear reactor that
utilizes the energy derived from the fission of uranium atoms that could
potentially cut down the travel time to Mars by half.
● This ambitious initiative, known as the Demonstration Rocket for Agile Cislunar
Operations (DRACO) and the launch is scheduled for late 2025 or early 2026.
Significance:
Minimized Exposure: The potential risks associated with extended space travel, such
as radiation exposure and isolation, could be mitigated through quicker journeys.
Military Applications: Nuclear propulsion can facilitate rapid maneuvers of
military satellites in Earth's orbit.
Concern:
• Safety Concerns: Accidents or malfunctions could release radioactive material
into space or back to Earth. Such incidents could have severe environmental and
health consequences.
• Launch Risks: There is always a chance of a launch failure or explosion, leading to
the dispersion of radioactive material over a wide area.
Historical Context of Nuclear Propulsion:
● Projects like Orion, Rover, and NERVA explored nuclear-powered propulsion
systems, although these initiatives were not fully realized.
● Notably, Project Orion considered using atomic bomb explosions for acceleration,
while Project NERVA aimed to develop a nuclear-thermal engine akin to the
DRACO engine.
DRACO’S advancement over its predecessors:
• Fuel Enrichment: Unlike Project NERVA, which used weapons-grade
uranium, DRACO employs a less-enriched form of uranium. This shift
enhances safety and minimizes the risks.
• In-Space Activation: The nuclear reactor within the DRACO engine
remains dormant until it reaches space. This mitigates the potential for
radioactive accidents during launch or on Earth.
Source: IE, 6 Aug 2023.
SOLAR PROBES
 Aditya L1 Mission
• Expected launch: 2023
• A 400-Kg Space craft will be launched using PSLV-XL in an orbit around the
Lagrange point 1 (L1) of the Sun-Earth system.
• Lagrange points are the positions where the centrifugal force due to the velocity
of orbiting satellite & the gravitational force / centripetal forces of two large
bodies, Sun and earth balance each other. There are 5 such points in Sun-Earth
system.
• It is placed at 1.5 million kms away from earth to provide continuous view of the
Sun without any occultation due to eclipses.
• It aims to study
➢ Solar corona (Visible and near infrared rays), Sun's Photosphere (soft and hard
X-ray) & Chromosphere (UV) solar emissions.
➢ Solar winds and flares, Coronal mass ejections ( significant release of plasma
and accompanying magnetic field from solar corona)
➢ Round the clock imaging of sun
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 Parker Probe
‘Parker Mission’ is a probe launched by NASA to study the Sun.
• Launched using Delta-IV Heavy rocket in August 2018. Cost: $ 1.5 bn
• Over the course of seven years, Parker will make 24 loops around the Sun-
getting as close as about 6 million km away from the Sun of 150 million km.
• First-ever mission to "touch" the Sun (as per NASA, the probe in December
2021 flown through the Sun’s upper atmosphere – the corona – and sampled
particles and magnetic fields).
• This probe is considered to be the fastest man made object with speeds around
190 km/s.
Key objectives:
• in situ measurements and imaging.
• Understanding of the corona and expanding our knowledge of the origin and
evolution of the solar wind.
• To forecast changes in Earth's space environment that affect life on Earth.
 The European Space Agency’s (ESA) Vigil mission
(formerly known as Lagrange)

• It’s the first of its kind mission, with the aim of monitoring the unpredictable and
active Sun and help protect the Earth from its outbursts.
• Solar flares, coronal mass ejections, geomagnetic storms, and other space weather
incidences will be monitored by ESA Vigil.
• Monitoring of the space incidences will help in predicting the timing of its arrival
on Earth and any effect it might have on infrastructure.
• This mission plans to position two spacecraft in the L1 and L5 Lagrangian points.
• The spacecraft at L1 is to provide observations of the solar wind speed, density,
temperature and dynamic pressure, charged particle environment and the direction
and strength of the interplanetary magnetic field.
• The spacecraft at L1 would also monitor the solar
corona and measure solar energetic particles that may
be associated with solar flares and the onset
of coronal mass ejections.
• The spacecraft at L5 would complement
measurements made from L1 by providing a side-
view of the propagation of plasma clouds emitted by
the Sun toward Earth.
• The spacecraft at L5 would monitor of the solar disk
and corona and carry out measurements of
the interplanetary medium.
 SOLAR STORMS
• The Solar magnetic cycle that works in the deep
interior of the Sun creates regions that rise to the surface
and appear like dark spots. These are sunspots.
• Solar magnetic cycle: Every 11 years or so, the Sun's
magnetic field completely flips. This means that the
Sun's north and south poles switch places.
• One way to track the solar cycle is by counting the
number of sunspots. The beginning of a solar cycle is
a solar minimum, or when the Sun has the least
sunspots. Over time, solar activity—and the number of
sunspots—increases.
• They typically consist of a dark region called the
‘umbra’, which is surrounded by a lighter region called
the ‘penumbra’.
● Solar flares are highly energetic phenomena that happen when the energy
stored in the sun’s magnetic structures called sunspots is converted into light
and heat energy. This causes the emission of high energy electromagnetic
waves like radio waves, x-ray radiation, Gamma rays. They travel at a speed
of light. Takes 8 mins to reach Earth.
● There are five categories of solar flare according to their brightness in the x-
ray wavelengths, which include A, B, C, M, and X; each class is at least ten
times more potent than the one before it.
● (Current: Recently, the Sun emitted an X1.0 -class solar flare, disrupting
radio communications over parts of the United States and the Pacific Ocean).
● The solar wind is a stream of charged particles released from the
outer most layer of the Sun’s atmosphere called the corona. This
mostly consists of electrons, protons and alpha particles with kinetic
energy between 0.5 and 10 keV.
● A coronal mass ejections (CME) are significant release
of plasma and accompanying magnetic field from
the Sun's corona into the solar wind. They can harbour energies
exceeding that of a million atomic bombs. Take 1-3 days to reach
Earth.
● Solar flares occur in active regions and are often, but not always,
accompanied by coronal mass ejections.
• Geomagnetic storm: Major disturbance of Earth's magnetosphere due to the
heliospheric magnetic field (HMF) that is dragged out from the solar corona
by the solar wind. They are categorised as G1, G2,G3,G4,G5 in the increasing order
of their intensity.
• Solar storms occur when sun emits huge bursts of energy in the form of solar flares
and Coronal mass ejections. Solar storms can last only a few minutes to
several
hours, but the effects of geomagnetic storms can linger in the Earth's
magnetosphere and atmosphere for days to weeks. They are categorised as
S1,S2,S3,S4,S5 in the increasing order of their intensity
• (Note: Magnetosphere is that area of space, around a planet, that is controlled
by
the planet’s magnetic field.
• The interplanetary magnetic field (IMF) or heliospheric magnetic field (HMF), is
the component of the solar magnetic field that is dragged out from the
solar corona by the solar wind flow to fill the Solar System.)
 Effect of Solar storms:
• Judging by data from the NASA DSCOVR satellite, the scientists observed a
steep jump in transverse magnetic fields, density and speeds of the plasma
wind that are tell-tale signatures of the arrival of a coronal mass ejection shock
front. (The shock wave of travelling mass)
• The energy, radiation and high energy particles emitted by flares can affect Earth
bound objects and life on Earth – it can affect the electronics within satellites and
affect astronauts. International Space station ISS could also have been affected.
• Intermittent satellite navigation (GPS) problems.
• Very powerful Earth-directed coronal mass ejections can cause failure of power
grids and affect oil pipelines and deep-sea cables.
• They can also cause spectacular aurorae in the high-latitude and polar
countries.
• The last major blackout due to a coronal mass ejection recorded was in 1989.
 Predicting Solar Storms:
• The process of prediction takes place in two steps: First the researchers
analyse the possibility of a strong solar flare from an active region –
that is, clusters of sunspots using a machine learning algorithm which
has been developed in CESSI, IISER Kolkata.
• The second step is estimating the time of arrival on Earth of coronal
mass ejections and forecasting the geomagnetic storm.
• If there is an associated flare, its position on the Sun is used to extract
the location of origin of the CME. The location of the source of the
CME and the velocity are used as inputs in a model called the Drag
Based Ensemble Model to calculate the CME arrival times and
speed.
7)If a major Solar storm (Solar flare) reaches the Earth, which of the following are
the possible effects on the Earth? (UPSC 2022)

1. GPS and navigation systems could fail

2. Tsunamis could occur at equatorial regions
3. Power grids could be damaged
4. Intense auroras could occur over much of the earth
5. Forest fires could take place at much of the planet
6. Orbits of the satellites could be disturbed
7.Short wave radio communication of the aircraft flying over polar regions could
be interrupted.
Select the correct answer using the code given below:
a) 1,2,4 & 5 only
b) 2,3,5,6 & 7 only
c) 1,3,4,6 & 7 only
d) 1,2,3,4,5,6 & 7
SEARCH FOR GRAVITATIONAL
WAVES
LIGO (Laser Interferometer Gravitational-Wave Observatory):
• Einstein predicted gravitational waves about 100 years ago.
• Gravitational waves can be caused when stars explode or when two black
holes merge or when two large bodies orbit each other.
• In 2015, scientists detected gravitational waves for the very first time.
• They used a very sensitive instrument called LIGO (Laser
Interferometer Gravitational-Wave Observatory).
• These gravitational waves happened when two black holes crashed into
one another.
• The collision happened 1.3 billion years ago & the ripples reached earth
in 2015.
• When a gravitational wave passes by Earth, it squeezes and stretches
space. LIGO can detect this squeezing and stretching.
• Each LIGO observatory has two “arms” that are each more than 4
kilometers long.
• A passing gravitational wave causes the length of the arms to
change slightly. The observatory uses lasers, mirrors, and
extremely sensitive instruments to detect these tiny changes.

• Detection of gravitational waves was a very important event in

science. Before this our understanding of the universe was
only from studying waves of light. Now we have a new way to
learn about the universe—by studying waves of gravity.

• Gravitational waves will help us learn many new things about

our universe.
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• LIGO project operates three gravitational-wave (GW) detectors. Two are at Hanford
in the state of Washington, USA, and one is at Livingston in Louisiana, USA.
• Currently these observatories are being upgraded to their advanced configurations
(called Advanced LIGO).
• The proposed LIGO-India project aims to move one Advanced LIGO detector
from Hanford to India.
• LIGO-India project is envisaged as an international collaboration between the
LIGO Laboratory and Indigo (A consortium of Indian gravitational wave
physicists).
• The Union cabinet on 6th April 2023 approved the project at an estimated cost of
Rs 2600 crores. The facility’s construction is expected to be completed by 2030.
• LIGO India will cork in tandem with the twin LIGO observatories in USA.
• LIGO lab would provide the complete design and all the key detector components.
Indian scientists would provide the infrastructure to install the detector at a suitable
site in India and would be responsible for commissioning it.
• VIRGO detector is a 3 km interferometer in Italy.
• The KAGRA observatory is an underground 3 km interferometer in
Japan.
• They are managed by VIRGO collaboration and KAGRA collaboration,
respectively.
• LIGO-VIRGO-KAGRA (LVK) collaboration: These detectors need to be
operating simultaneously around the globe to localize a source of
gravitational waves anywhere in the sky.
• LIGO's success has led to ESA's plans of a future mission possibly by 2034.
The project is called Evolved Laser Interferometry Space Antenna / New
Gravitational Wave Observatory (eLISA/NGO) - or just LISA for short.
• The first step to ESA's space-based observatory has been taken. LISA
Pathfinder, which was a test-phase mission, ends on July 18, 2017, having
shown its technology works in space.
Laser Interferometer Space Antenna (LISA)
• The Laser Interferometer Space Antenna (LISA) is a proposed space
probe to detect and accurately measure gravitational waves from
astronomical sources.
• LISA would be the first dedicated space-based gravitational wave
detector.
• The LISA concept has a constellation of three spacecraft arranged in an
equilateral triangle with sides 2.5 million km long, flying along an Earth-
like heliocentric orbit.
• LISA will observe gravitational waves by measuring differential changes
in the length of its arms, as sensed by laser interferometry. (work by
merging two or more sources of light to create an interference pattern,
which can be measured and analysed.) Each of the three LISA spacecraft
contains two telescopes, two lasers and two test masses
• (each a 46 mm, roughly 2 kg, gold-coated cube of gold/platinum),
arranged in two optical assemblies pointed at the other two spacecraft
• Studying gravitational waves gives enormous potential for
discovering the parts of the universe that are invisible by other means,
such as black holes, the and other yet unknown, objects. LISA will
complement our knowledge about the beginning, evolution and
structure of our universe.
• The LISA project started out as a joint effort between NASA and
the European Space Agency (ESA). However, in 2011, NASA
announced that it would be unable to continue its LISA partnership
with the European Space Agency due to funding limitations.
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MANNED MISSIONS AND
SPACE STATIONS
 GAGANYAAN
• First-ever manned space mission of India – announced on 15th Aug,2018.
• Expected launch - in 2023
• Budget: 10,000 cr.
• India to become fourth country in the world to send manned missions to
space after USA, Russia and China.
• Planning to send 3 astronauts (using GSLV Mk-III) into LEO (300-400km).
They can see India from space while conducting experiments on
microgravity.
• Two unmanned test missions (delayed to 2023) will be launched before the
final manned mission.
• A humanoid robot (Vyom mitra) will be part of unmanned missions.
• Recently, ISRO has successfully integrated Vyom mitra with a computer
‘brain’ to enable it to ‘read’ control panels aboard the unmanned test flights
and communicate with its voice with the ISRO ground stations.
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• ISRO has begun work on the manned mission in 2004.
• Many of the critical technologies required for human spaceflight have
already been validated through various tests
✓ Space Capsule Recovery Experiment (from water bodies)
✓ Crew Module Atmospheric Re-Entry Experiment (CARE) in Dec-2014.
✓ Pad Abort Test (An ISRO launch escape system test of its crew module).
• Four Indian Air Force fighter pilots completed training in Moscow
Gagarin Research & Test Cosmonaut Training Center (GCTC) (Glavkosmos)
• Spacesuits are being made by Defence Bioengineering and Electromedical
Laboratory (DEBEL), an Indian defence laboratory under the DRDO.
 SPACE STATION FOR INDIA
• ISRO is planning to setup its own space station in about a decade.
• It would be similar to the International Space Station (ISS) but smaller in
size weighing about 20 tonnes.
• It would be placed in a low earth orbit (~ 400 km).
• The preliminary plan for the space station is to accommodate astronauts for
up to 15-20 days in space to conduct microgravity experiments.
• It may take about 5 to 7 seven years to construct, details will only emerge
after the Gaganyaan Mission is complete.
• China is also planning a large space station in the Lower Earth Orbit.
MISSIONS AND SATELLITE
LAUNCHES IN NEWS
 JAMES WEBB SPACE TELESCOPE
• Next Generation Telescope - successor to the Hubble Space Telescope.
• Developed by NASA—in collaboration with the Canadian Space
Agency and the European Space Agency (Cost: $9.7 billion).
• It will be the largest and most powerful telescope ever built for use in
space.
• Launched on 25th December 2021 by the Ariane 5 rocket from European
Space Agency's Spaceport in French Guiana.
• Maximum Life span estimated to be 10 years.
• After a 29 day-long journey, the spacecraft will arrive at Lagrangian point
2 (nearly 1.5 million km from Earth).
• The gravitational forces of the Sun and the Earth can nearly hold a
spacecraft at this point, so that it takes relatively little rocket thrust to keep
the spacecraft in orbit around L2.
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• It will have a much larger primary
mirror than Hubble (2.7 times larger
in diameter & 6 times larger in area), giving
it more light-gathering power.
• It has infrared instruments with longer
U
wavelength coverage and greatly
improved sensitivity than Hubble.
• Biggest feature is a tennis court sized five-
layer sunshield that attenuates heat
from the sun more than a million times.
• The telescope recently captured a clear
image of the planet Uranus and its rings.
(April 2023)
 NASA's DART (Double Asteroid Redirection) Test
• On September 27, 2022, NASA conducted DART (Double Asteroid Redirection
Test).
• It is a mission to demonstrate Kinetic impact/Kinetic kick method to deflect
an asteroid by changing its motion.
• For this test, NASA targeted Asteroid pair Didymos and its moonlet
Dimorphos.
• LICIACube (Light Italian CubeSat for Imaging Asteroids) was launched
from earth along side the DART impactor to take pictures of the Asteroid
before & after the collision.
• DART collided with the Dimorphos (just 160 meters wide) at a speed of 23,760
kilometers per hour, and changed its angular momentum and moved it in to
a closer orbit to Didymos – causing deflection.
• This method is expected to save the world in future by safely deflecting a
killer asteroid on its course towards earth.
 PSLV-C44 mission
• PSLV C-44 served as a test for a new variant of the launch vehicle, the
PSLV-DL, which has two strap-on motors.
• It will make use of the final stage of rocket as an experimental orbital
platform for Kalamsat, world’s smallest student satellite, built by
Chennai based school students. It will continue orbiting the earth at a
distance of 450km above it for six months, maybe more.
• PSLV C44 also carried an imaging and surveillance satellite called
Microsat for the Defence Research and Development Organisation
(DRDO).
• Microsat was targeted in Anti-satellite test (ASAT), Mission Shakti.
FUTURE MISSIONS OF ISRO
X-ray Polarimeter Satellite (XPoSat):
• It is a satellite that ISRO plans to launch on a Small Satellite launch
vehicle 2023.
• It will be placed in the Low Earth Orbit.
• It will measure polarisation of X-rays released from cosmic sources.
(Polarisation: An electromagnetic wave such as light consists of a
coupled oscillating electric field and magnetic field which are always
perpendicular to each other; by convention, the "polarization" of
electromagnetic waves refers to the direction of the electric field).
• X-ray polarisation measurements help understand the nature of
their source, including strength, distribution of its magnetic
field and the nature of other radiation around it ( As the
polarization of X-rays affect these factors).
The payloads to be carried:
• Polarimeter Instrument in X-rays (POLIX), developed by
Bengaluru-based Raman Research Institute.
• XSPECT (X-ray Spectroscopy and Timing).
 NISAR Mission
• NASA-ISRO Synthetic Aperture Radar.
• It will be the first satellite mission to use two different radar
frequencies (L-band and S-band) to measure changes in our planet’s surface.
• NASA will provide the mission’s L-band Synthetic Aperture Radar and
ISRO will provide S-band Synthetic Aperture Radar.
• This allows the mission to observe a wide range of changes, from the flow
rates of glaciers and ice sheets to the dynamics of earthquakes and volcanoes,
biomass, natural hazards, sea level rise, and groundwater etc.
• Likely to be launched by GSLV in 2024 from India after final assembly at UR
RAO Space centre into a sun synchronous orbit from Satish Dhawan
Space Centre .
 SPACE DEBRIS
• Space debris is the collection of defunct man-made objects in space — old
satellites, spent rocket stages and fragments from disintegration and collisions.
• It is estimated that there are about half a million pieces of man-made
substances orbiting the Earth.
• These space debris can really be dangerous as they travel at high speeds, which
turns even tiny pieces of junk into deadly shrapnel that can damage satellites,
space shuttles and even space stations.
• Kessler effect/syndrome: Proposed by NASA scientist Donald J. Kessler in
1978 - proposed that a chain reaction of exploding space debris can end up
making space activities and the use of satellites impossible for generations.
 Space debris – Steps taken by ISRO
• ISRO is a member of “Inter-Agency Space Debris Coordination
Committee” (IADC), which makes global efforts to reduce man-made and
natural space debris. They exchange information on space debris among
member space agencies and alert a respective space agency when any
satellite of that space agency is in danger due to space debris.”
• ISRO also banks on its sophisticated “Multi-Object Tracking Radar
(MOTR)”, operational since 2015, to track space debris.
• In 2019, ISRO initiated ‘Project NETRA’ (NEtwork for space object
TRacking and Analysis) – an early warning system in space to detect debris
and other hazards to Indian satellites.
• On 14th December 2020, ISRO inaugurated a dedicated space
situational awareness (SSA) Centre at ISRO Telemetry, Tracking
and Command Network (ISTRAC) in Bangalore under project
NETRA.
• The project NETRA with an estimated to cost of ₹400 crore, will give
India its own capability in space situational awareness (SSA) like
the other space powers — which is used to ‘predict’ threats from
debris to Indian satellites.
• Under “NETRA”, ISRO is planning to set up several observational
facilities: connected radars, telescopes; data processing units and
a control Centre.
Initial focus seems to be on debris in the Low Earth Orbit,
eventually ISRO wants to track the debris in GEO where the
communication satellites operate.

Need:
• Currently there are 15 functional Indian communication satellites
in the GEO, 13 remote sensing satellites in LEO & 8 navigation
satellites in MEO. Protecting them is important for India.
• This would make India a part of international efforts towards
tracking, warning about and mitigating space debris.
 SPACE DEBRIS –
INTERNATIONAL EFFORTS TO CLEANUP
1. “RemoveDEBRIS” has been deployed from the International Space Station
(ISS) that can capture and deorbit the debris.
2. European Space Agency with Swiss startup company “Clear Space” is
building a spacecraft equipped with four robotic arms to capture debris and
drag it into Earth’s atmosphere. This mission, known as ClearSpace-1, is
expected to launch by 2025.
3. NASA's Space Debris Sensor orbits the Earth on the International Space
Station.
4. The United Nations has established the Committee on the Peaceful Uses of
Outer Space (COPUOS).
PRIVATIZING SPACE
ACTIVITIES
• Department of Space announced Cabinet approval on reforms to boost private
participation in space activities on 24 June, 2020.
• GOI announced the establishment of a new autonomous body - Indian National
Space Promotion and Authorization Centre (IN-SPACe) that will take "decisions
to regulate and permit activities in the space sector - a facilitator, and also a
regulator.
❖ ISRO will be the main body for all the missions.
❖ IN-SPACE acts as a channel between private and government space sectors.
❖ NSIL works as marketing arm for ISRO
• Private companies can now produce their own satellites and rockets and use
ISRO’s launch facility to launch them for a fee.
• A large part of manufacturing and fabrication of rockets and satellites has also
begun in the private sector through NSIL.
 NSIL & ANTRIX corporation
• An agreement between Antrix corporation and Bengaluru based startup Devas
multimedia was signed in 2005 under which Antrix agreed to build, launch and
operate two satellites and lease our 90% of satellite transponder capacity to Devas
which had planned to use it to offer hybrid satellite and terrestrial communication
services throughout India.
• The deal included 70MHz of S-band spectrum (Restricted for the use by security
forces and government telecom entities like MTNL and BSNL) which was
priced at 1000 crore. A media expose claimed that incurred heavy loss to the
national exchequer (Treasurer or the treasury itself).
• The controversial deal was cancelled later.
• The long legal battle between Antrix and Devas ended up in the supreme court in 1st
Jan 2022 which ordered the winding up of the startup.
• NSIL is considered to be a move to protect the space industry in India from the
consequences of the Devas-Antrix mess.
 New Space India Limited
• It is a new commercial arm of ISRO, incorporated on 6 March 2019 (under the
Companies Act, 2013) is a wholly owned Government of India company, under the
administrative control of Department of Space (DOS).
• NSIL will have role in the following:
➢ Production of Polar Satellite Launch Vehicle (PSLV) and Small Satellite Launch
Vehicle (SSLV) through industry;
➢ Building of Satellites (both Communication and Earth Observation) as per user
requirements.
➢ Transfer of technology developed by ISRO centres/ units and constituent
institutions of Dept. of Space;
➢ Marketing spin off technologies and products/ services emanating out of ISRO
activities
ISRO is also willing to provide place for private players to build their own launchpad
within the Sriarikota launch station.
 SPACE X
• Space Exploration Technologies Corporation (Space X) is an American
aerospace manufacturer and space transportation services company.
•It was founded in 2002 by Elon Musk.
Crew Dragon spacecraft
• Space X has contract with NASA for Cargo and crew transportation to and
from the International Space Station.
• On 30th May 2020, Crew dragon Demo-2 mission took Two NASA astronauts
to ISS. It was the first crewed test flight of the crew dragon space craft and the
falcon 9 rocket.
• SpaceX Crew -1 mission: On 16th November 2020, SpaceX launched four
astronauts (3 Americans + 1 Japanese) to the International Space Station in the
first operational crewed flight of a “Crew dragon, resilience ”, spacecraft on a
Falcon 9 rocket. It was the first full-fledged taxi flight for NASA by a private
company.
• SpaceX broke the world record of the greatest number of satellites
carried by a single rocket as by sending 143 payloads into space
on 24th Jan 2021.
• With this it broke the record of ISRO’s 104 satellites being launched
in one go in February 2017.
• The reusable Falcon 9 rocket carried 133 commercial and
government spacecraft and 10 Starlink satellites to space - part of
the company’s Small Satellite Rideshare Programme.
• (Note: Starlink is a satellite internet constellation being constructed
by SpaceX providing satellite internet access)
 Space Race

SpaceX
(Elon Musk)
Inspiration-4

M A On 16th September 2021 flew the

automated Crew Dragon with four
HI civilian astronauts to an altitude
of 575 km.

They spent three days circling the

earth.
 PRELIMS QUESTIONS
1. For the measurement of which of the following are satellite images/remote
sensing data used? (UPSC 2019)

1. Chlorophyll content in the vegetation of a specific location.

2. GHG emissions from rice paddies of a specific location.
3. Land surface temperatures of a specific location. Select the correct
answer using the code given below.
a) 1 only
b) 2 and 3 only
c) 3 only
d) 1, 2 and 3
2) With reference to the Indian Regional Navigation Satellite System
(IRNSS), consider the following statements. (UPSC 2018)

1.IRNSS has three satellites in geostationary and four satellites in

geosynchronous orbits.
2. IRNSS covers entire India and about 5500 sq. km beyond its borders.
3.India will have its own satellite navigation system with full global
coverage by the middle of 2019.
Which of the statements given above is/are correct?
a) 1 only
b) 1 and 2 only
c) 2 and 3 only
d) None
3) With reference to the India's satellite launch vehicles, consider the following
statements: (UPSC 2018)

1.PSLV launch the satellites useful for earth sources monitoring where as GSLVs
are designed mainly to launch communication satellites.
2.Satellites launched by PSLV appear to remain permanently fixed in the same
position in the sky, as viewed from a particular location on Earth.
3. GSLV Mk III is four-staged launch vehicle with the first and third stages using
solid rocket motors; and second and fourth stages using liquid rocket engines.
Which of the statements given above is/are correct?
a) 1 only
b) 2 and 3 only
c) 1 and 2 only
d) 3 only
4) In which of the following areas can GPS technology be used? (UPSC 2018)

1. Mobile phone operations

2. Banking operations
3. Controlling the power grids.
Select the correct answer using the given below:
a) 1 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3
5) The Mangalyaan launched by ISRO (UPSC 2016)

1. is also called the Mars Orbiter Mission

2.made India the second country to have a spacecraft orbit the Mars after
USA
3.made India the only country to be successful in making its spacecraft
orbit the Mars in its very first attempt
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
6)The experiment will employ a trio of spacecraft flying in formation in
the shape of an equilateral triangle that has sides one million kilometres
long, with lasers shining between the craft.” The experiment in question
refers to (UPSC 2020)

a) Voyager-2
b) New Horizons
c) LISA Pathfinder
d) Evolved LISA