Science chapter practice

Space Science and Astronomy MCQs

Practise 81+ Space Science and Astronomy MCQs for UPSC Prelims in Science, including 45+ previous year questions. The sample set below is shown with correct answers and explanations.

81
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45
PYQs
12
visible samples

Sample Space Science and Astronomy questions

12 sample questions are shown here; sign up free to practise all 81.

Q1ScienceSpace Science and AstronomyPYQ 2026

Consider the following statements with regard to involvement of private entities in India’s space programme: 1. The Indian National Space Promotion and Authorisation Centre (IN-SPACe) is an autonomous agency formed to facilitate participation of private entities. 2. Agnikul Cosmos launched the world’s first flight using 3D-printed rocket engine. 3. Skyroot Aerospace has developed liquid fuel for GSLV. Which of the statements given above is/are correct?

  • A1 only
  • B2 and 3 only
  • C1 and 2 onlyCorrect
  • D1, 2 and 3

Explanation

UPSC provisional key: (C), Series A question 46. Statements 1 and 2 are accepted. IN-SPACe facilitates private participation, and Agnikul flew Agnibaan SOrTeD with a single-piece 3D-printed engine in May 2024. That single-piece qualifier matters: this was not the first rocket ever to use any 3D-printed engine components. Statement 3 is not the Skyroot achievement identified by official sources.

Sources: UPSC provisional answer key · PIB: Agnikul launches rocket with fully 3D-printed engine, 30 May 2024 · ISRO: Mission Prarambh and Skyroot Vikram-S · IN-SPACe: autonomous agency role and private-sector participation

Why the other options are incorrect
Option A

Statement 1 correctly identifies IN-SPACe’s role in enabling and authorising private space activity. It misses statement 2, which the key accepts with reference to Agnikul’s flight using a single-piece 3D-printed engine.

Option B

Statement 2 is accepted, but statement 3 wrongly attributes GSLV fuel development to Skyroot. Skyroot is associated with its Vikram launch-vehicle programme, whereas GSLV is an ISRO vehicle. Statement 1 should be included instead.

Option D

The incorrect Skyroot–GSLV claim in statement 3 invalidates this combination. Keep the organisations and achievements separate: IN-SPACe enables private participation, Agnikul demonstrated the single-piece printed engine, and Skyroot developed Vikram vehicles.

Q2ScienceSpace Science and AstronomyPYQ 2025

With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements: 1. All types of UAVs can do vertical landing. 2. All types of UAVs can do automated hovering. 3. All types of UAVs can use battery only as a source of power supply. How many of the statements given above are correct?

  • AOnly one
  • BOnly two
  • CAll three
  • DNoneCorrect

Explanation

Correct. Fixed-wing UAVs cannot do vertical landing or automated hovering, and many UAVs use internal combustion engines or hybrid power, not batteries alone.

Why the other options are incorrect
Option A

None of the statements is universally true for all types of UAVs.

Option B

Fixed-wing UAVs cannot hover or land vertically, and many UAVs use fuel engines, so none of the statements holds for all types.

Option C

Fixed-wing UAVs require runways; many large UAVs use combustion engines. None of the three statements applies universally.

Q3ScienceSpace Science and AstronomyPYQ 2025

Consider the following space missions: 1. Axiom-4 2. SpaDeX 3. Gaganyaan How many of the space missions given above encourage and support micro-gravity research?

  • AOnly one
  • BOnly two
  • CAll threeCorrect
  • DNone

Explanation

Correct. Axiom-4 conducts micro-gravity experiments on the ISS, SpaDeX demonstrates docking for future space station modules, and Gaganyaan is India's crewed mission with micro-gravity research payloads.

Why the other options are incorrect
Option A

All three missions involve or support micro-gravity research environments, not just one.

Option B

All three missions, not just two, are designed to support micro-gravity experiments in space.

Option D

All three missions have micro-gravity research as a significant component of their objectives.

Q4ScienceSpace Science and AstronomyPYQ 2024

Consider the following statements: Statement-I: Giant stars live much longer than dwarf stars. Statement-II: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions. Which one of the following is correct in respect of the above statements?

  • ABoth Statement-I and Statement-II are correct and Statement-II explains Statement-I
  • BBoth Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  • CStatement-I is correct, but Statement-II is incorrect
  • DStatement-I is incorrect, but Statement-II is correctCorrect

Explanation

Correct. Giant stars have higher nuclear reaction rates (Statement-II is true) but this causes them to exhaust fuel faster, giving them shorter, not longer, lifespans (Statement-I is false).

Why the other options are incorrect
Option A

Statement-I is actually incorrect; giant stars burn fuel faster and have shorter lifespans despite their larger mass.

Option B

Statement-I is wrong. Giant stars consume their nuclear fuel at much higher rates than dwarf stars and die sooner.

Option C

Statement-II is correct; massive stars have far higher core temperatures and nuclear reaction rates.

Q5ScienceSpace Science and AstronomyPYQ 2023

Consider the following pairs: Objects in space : Description 1. Cepheids — Giant clouds of dust and gas in space 2. Nebulae — Stars which brighten and dim periodically 3. Pulsars — Neutron stars that are formed when massive stars run out of fuel and collapse How many of the above pairs are correctly matched?

  • AOnly oneCorrect
  • BOnly two
  • CAll three
  • DNone

Explanation

Correct. Only pair 3 is correct. Cepheids are variable stars (not dust clouds), nebulae are gas-dust clouds (not variable stars), and pulsars are indeed rapidly rotating neutron stars formed from collapsed massive stars.

Why the other options are incorrect
Option B

Pairs 1 and 2 have their descriptions swapped; Cepheids are variable stars and nebulae are gas-dust clouds.

Option C

Pairs 1 and 2 are incorrectly matched; their descriptions are interchanged.

Option D

Pair 3 is correctly matched; pulsars are neutron stars that emit beams of radiation as they rotate.

Q6ScienceSpace Science and AstronomyPYQ 2023

Which one of the following countries has its own Satellite Navigation System?

  • AAustralia
  • BCanada
  • CIsrael
  • DJapanCorrect

Explanation

Correct. Japan operates the Quasi-Zenith Satellite System (QZSS), a regional satellite navigation system that augments GPS coverage over Japan and the Asia-Oceania region.

Why the other options are incorrect
Option A

Australia does not operate its own satellite navigation system; it relies on GPS and augmentation systems.

Option B

Canada does not have an indigenous satellite navigation constellation.

Option C

Israel has advanced satellite capabilities but does not operate an independent navigation system.

Q7ScienceSpace Science and AstronomyPYQ 2022

If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth? 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 over much of the planet. 6. Orbits of the satellites could be disturbed. 7. Shortwave radio communication of aircraft flying over polar regions could be interrupted. Select the correct answer using the code given below:

  • A1, 2, 4 and 5 only
  • B2, 3, 5, 6 and 7 only
  • C1, 3, 4, 6 and 7 onlyCorrect
  • D1, 2, 3, 4, 5, 6 and 7

Explanation

Correct. Solar storms can disrupt GPS, damage power grids via geomagnetically induced currents, trigger intense auroras, alter satellite orbits through atmospheric drag, and interrupt polar shortwave radio. They do not cause tsunamis or forest fires.

Why the other options are incorrect
Option A

Solar storms do not cause tsunamis or widespread forest fires; these are unrelated geophysical and terrestrial events.

Option B

Tsunamis and forest fires are not caused by solar storms. However, GPS failure (1) and auroras (4) are valid effects.

Option D

Tsunamis (2) are caused by seismic events, and large-scale forest fires (5) are not a consequence of solar storms.

Q8ScienceSpace Science and AstronomyPYQ 2022

Which one of the following statements best reflects the idea behind the 'Fractional Orbital Bombardment System' often talked about in media?

  • AA hypersonic missile is launched into space to counter an asteroid approaching the Earth and explode it in space
  • BA spacecraft lands on another planet after making several orbital motions
  • CA missile is put into a stable orbit around the Earth and deorbits over a target on the EarthCorrect
  • DA spacecraft moves along a comet with the same speed and places a probe on its surface

Explanation

Correct. A Fractional Orbital Bombardment System places a nuclear warhead into low Earth orbit and then de-orbits it onto a target, making its trajectory harder to predict than a conventional ICBM.

Why the other options are incorrect
Option A

FOBS is a weapons delivery system, not a planetary defence mechanism against asteroids.

Option B

FOBS is a military concept involving Earth orbit, not interplanetary travel or landing.

Option D

This describes a cometary rendezvous mission like Rosetta, not a weapons delivery system.

Q9ScienceSpace Science and AstronomyPYQ 2021

Which one of the following is a reason why astronomical distances are measured in light-years?

  • ADistances among stellar bodies do not change
  • BGravity of stellar bodies does not change
  • CLight always travels in straight line
  • DSpeed of light is always sameCorrect

Explanation

Correct. The speed of light in vacuum is a universal constant (~3 × 10⁸ m/s), making it a reliable and invariant standard for defining large astronomical distances.

Why the other options are incorrect
Option A

Stellar distances do change over time due to proper motion; this is not why light-years are used.

Option B

Gravitational constancy is irrelevant to the choice of distance unit.

Option C

Light bends near massive objects due to gravity; it does not always travel in a straight line.

Q10ScienceSpace Science and AstronomyPYQ 2020

"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:

  • AVoyager-2
  • BNew Horizons
  • CLISA Pathfinder
  • DEvolved LISACorrect

Explanation

Correct. Evolved LISA (eLISA/LISA) is a space-based gravitational wave observatory using three spacecraft in a triangular formation with million-kilometre laser arms to detect gravitational waves.

Why the other options are incorrect
Option A

Voyager-2 is a single spacecraft on an interstellar trajectory, not a formation-flying experiment.

Option B

New Horizons is a Pluto flyby mission, not a laser interferometry experiment.

Option C

LISA Pathfinder was a single-spacecraft technology demonstrator, not the full three-spacecraft constellation described.

Q11ScienceSpace Science and AstronomyPYQ 2019

Recently, scientists observed the merger of giant black holes billions of light-years away from the Earth. What is the significance of this observation?

  • A'Higgs boson particles' were detected
  • B'Gravitational waves' were detectedCorrect
  • CPossibility of inter-galactic space travel through 'wormhole' was confirmed
  • DIt enabled the scientists to understand 'singularity'

Explanation

Correct. The LIGO and Virgo observatories detected gravitational waves produced by the merger of black holes, confirming a key prediction of Einstein's general theory of relativity.

Why the other options are incorrect
Option A

The Higgs boson was detected at CERN using particle accelerators, not through astronomical observations of black hole mergers.

Option C

No wormhole was confirmed; the observation detected gravitational wave signals from the merger event.

Option D

While black holes contain singularities, the observation's primary significance was the direct detection of gravitational waves.

Q12ScienceSpace Science and AstronomyPYQ 2019

For the measurement/estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the vegetation of a specific location 2. Greenhouse gas 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:

  • A1 only
  • B2 and 3 only
  • C3 only
  • D1, 2 and 3Correct

Explanation

Correct. Remote sensing satellites use spectral bands to measure vegetation chlorophyll (NDVI), thermal sensors for land surface temperatures, and methane-detecting instruments for greenhouse gas emissions from specific areas.

Why the other options are incorrect
Option A

Satellites can also measure greenhouse gas concentrations and land surface temperatures using infrared and thermal sensors.

Option B

Chlorophyll content is routinely measured by remote sensing using spectral reflectance data in the visible and near-infrared bands.

Option C

Remote sensing can also estimate chlorophyll content and methane emissions from rice paddies, not just surface temperature.

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Frequently asked questions

How many Space Science and Astronomy MCQs are available for UPSC Prelims practice?
PrelimsAI currently has 81+ Space Science and Astronomy MCQs under Science. This page shows 12 sample questions in full.
How many Space Science and Astronomy previous year questions are included?
45+ questions in this chapter are tagged as UPSC Prelims PYQs. PYQs are prioritised in the visible sample set when available.
Do these Space Science and Astronomy questions include explanations?
Yes. The 12 visible sample questions show the correct option and explanation on this page.
Where should I go after practising Space Science and Astronomy?
Continue with Biotechnology or Computers, ICT and Emerging Tech, or return to the Science subject page for more chapter-wise practice.

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