Get UPSC Prelims Ready: Is your topic of ‘Space Missions and Technology in India’ well prepared? Check your progress through 4 R strategy

Today, let’s check our progress on the ‘Space Missions and Technology in India’ — using the 4R Strategy: READ – REVISE – RECALL – RETAIN.

#1. READ

Key Missions and initiatives: Let’s first refresh some major Indian missions and initiatives in the spotlight as UPSC often targets their technical details.

(a) NISAR (NASA-ISRO Synthetic Aperture Radar): A joint Earth-observation mission. It is unique for being the first to use dual-band (L and S) radar. It employs advanced, novel SweepSAR technique, which provides high resolution and large swath imagery.It will map the entire globe every 12 days to monitor changes in ecosystems, ice mass, and natural hazards. NISAR mission will help to: measure the woody biomass and its changes, track changes in the extent of active crops, understand the changes in wetlands’ extent, map Greenland’s & Antarctica’s ice sheets, dynamics of sea ice and mountain glaciers, characterize land surface deformation related to seismicity, volcanism, landslides, and subsidence & uplift associated with changes in subsurface aquifers, hydrocarbon reservoirs, etc. Orbit: Sun Synchronous Polar Orbit

(b) Gaganyaan: India’s flagship Human Spaceflight Programme. It aims to demonstrate indigenous capability to send a 3-member crew to a 400 km Low Earth Orbit (LEO) for a 3-day mission. Vyommitra is an AI-powered, female-looking “half-humanoid” robot developed by ISRO to fly uncrewed missions for the Gaganyaan program aboard. The Union Cabinet expanded the Gaganyaan programme to include the development of the Bharatiya Antariksh Station (BAS)

(c) Aditya L1: India’s first space-based solar observatory. It is placed in a Halo Orbit around the Sun-Earth Lagrange Point 1 (L1). This allows it to view the Sun continuously without any occultations or eclipses. It is expected to provide the most crucial information to understand the problem of coronal heating, coronal mass ejection, pre-flare and flare activities and their characteristics, dynamics of space weather, propagation of particles and fields etc.

(d) Chandrayaan-3: It is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface. It consists of a Lander and Rover configuration. It was successfully launched onboard using LVM-3 on 14th July, 2023 from the Satish Dhawan Space Centre, SHAR.  The propulsion module has the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and polarimetric measurements of Earth from the lunar orbit. With Chandrayaan-3, India became the 4th country to achieve a soft landing on the Moon (after the US, Russia, and China) and the first to land near the lunar south pole region. The landing site was named Shiv Shakti Point, and the Pragyan rover conducted in-situ experiments. Later, Japan became the 5th country to soft-land on the Moon with SLIM.

(e) SPADEx (Space Docking Experiment): A technology demonstrator of docking where two spacecraft (Chaser and Target) rendezvous and dock. Docking is a process by which two fast-moving spacecraft are brought to the same orbit, brought closer to each other manually or autonomously, and finally joined together. With this, India becomes the fourth country to achieve the feat after the US, Russia, and China. SPADEx mission lifted off from the Satish Dhawan Space Centre in Sriharikota in December 2024 by PSLV-C60 and successfully placed two satellites in the desired lower Earth orbit (below 2000 Km). This technology is crucial for setting up the Bharatiya Antariksh Station(BAS). BAS is supposed to have five modules, which are expected to be launched separately and brought together in space.

(f) Navigation with Indian Constellation (NavIC): To meet the positioning, navigation, and timing requirements of the nation, ISRO has established a regional navigation satellite system called Navigation with Indian Constellation (NavIC). NavIC was earlier known as the Indian Regional Navigation Satellite System (IRNSS). NavIC is designed with a constellation of seven satellites and a network of ground stations operating 24×7. Three satellites are placed in geostationary orbit, while four are placed in inclined geosynchronous orbit. NavIC offers two services: the Standard Positioning Service (SPS) for civilian users and the Restricted Service (RS) for strategic users. These services are provided in both L5 and S bands. The NavIC coverage area includes India and extends up to 1,500 km beyond India’s boundaries. A new civilian signal is being introduced in the L1 band. NavIC SPS signals are interoperable with other Global Navigation Satellite System (GNSS) signals, namely GPS, GLONASS, Galileo, and BeiDou.

(g) XPoSat (X-ray Polarimeter Satellite): India’s first dedicated mission to study the “polarisation” of cosmic X-rays from sources like pulsars (neutron stars) and black holes.  It is the world’s second dedicated mission to study X-ray polarisation. Following NASA’s Imaging X-ray Polarimetry Explorer (IXPE). 

(h) Venus Orbiter Mission (VOM): Also known as Shukrayaan-1, it will study Venus’s atmosphere and surface. It features the VSAR (Venus Synthetic Aperture Radar) for high-resolution mapping.

The ‘UPSC Prelims Traps’

TOPIC	The Statement (The Trap)	Why it is FALSE (The Reality)
Gaganyaan	“India will become the third country to launch a human spaceflight mission.”	India will be the fourth country after the USA, Russia, and China.
Aditya L1	“The mission is located 1.5 million km from the Sun’s surface.”	L1 is 1.5 million km from Earth (only 1% of the distance to the Sun).
NISAR	“NISAR is a lunar mission designed to study water ice on the Moon’s South Pole.”	It is strictly an Earth-observation mission. It does not study the Moon.
ChaSTE	“The ChaSTE payload on Chandrayaan-3 was used to detect the presence of water ice.”	It measured thermal properties (soil conductivity). Water ice was the target of LIBS and RAMBHA. (Note: ChaSTE is the first mission to successfully penetrate the soil of a celestial body to deploy a thermal probe.)
Aryabhata	“Aryabhata, India’s first satellite, was launched using the indigenous SLV-3 rocket.”	It was launched by a Soviet Kosmos-3M rocket from Kapustin Yar. (The satellite completed 50 years recently)
NavIC	“NavIC is a global positioning system that covers the entire Earth.”	It is a Regional system covering India and 1500 km beyond its borders.

#2. REVISE

Checkout if you know these facts:

(a) HOPE Analogue: Located in Leh, Ladakh (Tso Kar Valley). It is a “Space Analogue” mission to simulate Moon/Mars conditions (cold, dry, high UV) for testing life-support systems.

(b) NavIC NVS-01: This newer generation satellite introduced the L1 band for civilian use, making NavIC compatible with common smartphones and wearables.

(c) Kodaikanal Solar Observatory (KSO): Celebrating 125 years, it holds one of the world’s longest continuous records of solar data. It is famous for the discovery of the Evershed Effect (radial flow of gas in sunspots).

(d) AstroSat vs XPoSat: AstroSat is multi-wavelength (UV, Optical, X-ray); XPoSat is specialized for X-ray Polarimetry (measuring the direction of X-ray vibrations). Astrosat is the first dedicated Indian astronomy mission  aimed at studying celestial sources in X-ray, optical and UV spectral bands simultaneously. 

(e) Axiom-4: It was a private crewed spaceflight to the International Space Station (ISS) operated by Axiom Space in partnership with SpaceX and NASA. The four-person crew included commander Peggy Whitson, an Axiom Space employee and former NASA astronaut; pilot Shubhanshu Shukla of the ISRO; and mission specialists Sławosz Uznański-Wiśniewski, a European Space Agency (ESA) project astronaut from Poland, and Tibor Kapu, representing the Hungarian Space Office.

(f) CE20: The Indian Space Research Organisation (ISRO) has successfully demonstrated the boot-strap mode start test on the CE20 Cryogenic engine which powers the upper stage of the Launch Vehicle Mark -3 (LVM3) rocket.

#3. RECALL

Some connected tidbits for UPSC Prelims exam: 

(a) Coronal Mass Ejection (CME) : It is a massive burst of plasma (charged particles) and magnetic field released from the Sun’s outer atmosphere, called the corona. When a CME is directed toward Earth, it can cause geomagnetic storms, leading to: Disruptions in satellites and GPS, Radio communication disturbances, Power grid fluctuations, Enhanced auroras (Northern and Southern Lights). CMEs are closely monitored by missions like Aditya-L1 because they play a major role in space weather.

(b) Solar flare: It is a sudden and intense burst of solar energy from the Solar atmosphere. The phenomena is caused by Sun’s magnetic field. The magnetic field of the Sun is very dynamic in nature. Sometime they suddenly snap and release intense burst of energy – like a powerful, short flash. The energy is released in the form of light/radiation and high energy charged particles. Aditya L1 studies solar flare. During solar flare (as well as before the occurrence of solar flare) that particular region of the Sun generating flare becomes brighter in UV and X-ray. Aditya-L1 instruments such as SUIT, SoLEXS and HEL1OS can study these brightening and associated flash of radiation in greater details. This provides a detail picture of various phenomena related to Solar flares. It is to be noted that atmosphere of the Earth blocks these harmful radiations from the Sun to reach to the ground. Therefore, such study can be only made from space.

(c) Lagrange points : According to NASA, they are positions in space where objects sent there tend to stay put. At Lagrange points, the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them. These points in space can be used by spacecraft to reduce fuel consumption needed to remain in position. There are five special points where a small mass can orbit in a constant pattern with two larger masses. The Lagrange Points are positions where the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them. Of the five Lagrange points, three are unstable and two are stable. 

(d) Myogenesis: It was among key researches by ISRO in Axiom 4. Myogenesis is the biological process through which muscle tissue is formed during early stages of embryonic development from stem cells. These stem cells gradually differentiate into muscle precursor cells, which then multiply and fuse together to form muscle fibres. Myogenesis is crucial for the growth of the body, repair of muscle tissue, and regeneration of the musculoskeletal system (which includes bones, muscles and connective tissues).

(e) Launch Vehicles: They are used to carry spacecraft to space. India has three active operational launch vehicles: Polar Satellite Launch Vehicle (PSLV), Geosynchronous Satellite Launch Vehicle (GSLV), Geosynchronous Satellite Launch Vehicle Mk-III (LVM3).

• PSLV is configured with four variants like 6,4,2 solid rocket strap-on motors& core alone versions. Variants will be chosen based on the payload weights & orbit to be accomplished. PSLV has been a versatile launch vehicle deployed for launching all the three types of payloads viz. Earth Observation, Geo-stationary and Navigation. It has got highest success rate and considered as work horse of ISRO.
• GSLV with indigenous Cryogenic Upper Stage has enabled the launching up to 2 tonne class of communication satellites.
• The LVM3 is the next generation launch vehicle capable of launching 4 tonne class of communication satellites and 10 tonne class of payloads to LEOs. The vehicle was developed with completely indigenized technologies including the C25 cryo stage. The launch vehicle has a track record of all successful launches even from the first development flight. The Human rated LVM3 is identified as the launch vehicle for Gaganyaan mission, which is named as HRLV.
• The Small Satellite Launch Vehicle (SSLV) is being developed with complete indigenous technologies to meet the small satellite launch market on demand driven basis

(isro.gov.in)

#4. RETAIN

Brush up for UPSC Prelims with a quick look on one liner questions:

Q1. What did the ChaSTE payload reveal about the Lunar South Pole?

(It found that the lunar surface is a very strong thermal insulator. The temperature was ~50°C at the surface but dropped sharply to -10°C just 8 cm below the surface.)

Q2. Who is the lead partner for the L-band and S-band in NISAR?

(NASA provided the L-band SAR, while ISRO provided the S-band SAR.)

Q3. What is the significance of the SPADEx mission for India’s space station?

(It tests autonomous docking capabilities. Without docking, India cannot assemble the multiple modules required to build a permanent space station (BAS).)

Q4. Why is Tso Kar valley chosen for the HOPE Analogue Mission? 

(Tso Kar valley was specifically selected for this analog mission due to its striking environmental parallels with early Mars, due to high UV flux, low air pressure, cold extremes and saline permafrost.)

# 5. PRACTICE

Q1. With reference to ‘NavIC’, consider the following statements:

1. It provides coverage for the Indian mainland and up to 1500 km beyond its borders.

2. It currently provides global positioning services similar to GPS.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Q2. Which of the following missions is specifically designed to simulate Martian/Lunar conditions on Earth?

(a) SPADEx

(b) HOPE Analogue

(c) XPoSat

(d) Vyommitra

Q3. The ‘Evershed Effect’, a landmark discovery in solar physics, is associated with which Indian institution?

(a) Physical Research Laboratory (PRL)

(b) Kodaikanal Solar Observatory

(c) Raman Research Institute

(d) Indian Institute of Remote Sensing (IIRS)

Answers:

1. (a) Statement 2 is wrong; NavIC is a Regional system.

2. (b) HOPE (Himalayan Outpost for Planetary Exploration) in Ladakh.

3. (b) Discovered by John Evershed at KSO in 1909.  The Evershed effect refers to the phenomenon of characteristic Doppler shifts of photospheric spectral absorption (Fraunhofer) lines observed over the penumbrae of sunspots. Researchers from the Aryabhatta Research Institute of Observational Sciences (ARIES) recently analyzed over 100 years of digitized solar data from the Kodaikanal Solar Observatory (KoSO) (spanning roughly 1904–2017) to reconstruct the Sun’s historical polar magnetic field.

UPSC aspirants, while revising the theme of ‘Space Missions of India’, can you spot the other scientific facts within this topic? Let us know in the comments.

Also, tell us which subjects you would like to revise through the ‘4R’ strategy for the upcoming Prelims 2026 examination. Write to me at manas.srivastava@indianexpress.com.

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