Prelims 2025 · Q83
HardConsider the following space missions:
- I.Axiom-4
- II.SpaDeX
- III.Gaganyaan
How many of the space missions given above encourage and support micro-gravity research?
Answer & explanation
Answer: (b) Only two
UPSC's official answer: (b) · the answer UPSC accepted, and the one that counts in the exam
Also defensible: (c)
- Axiom-4 and Gaganyaan are counted on any reading: Axiom-4's first ISS experiment examined 'the impact of microgravity and space radiation on edible microalgae', and the Government lists 'Microgravity Experiments' among Gaganyaan's research benefits.
- SpaDeX's key objectives are 'precision rendezvous and docking manoeuvres', 'power transfer between docked spacecraft' and 'operating payloads post-undocking': a docking demonstration, not a microgravity mission. Judged by its objectives, UPSC's key counts two, option (b).
- But the Government's own SpaDeX release presents microgravity research as part of the mission: 'SpaDEX will also use PSLV's fourth stage, POEM-4, for experiments. The stage will carry 24 payloads from academic institutions and startups. These experiments will utilise the microgravity environment in orbit.' A reader who counts what the mission carried answers (c), all three.
UPSC's key counts Axiom-4 and Gaganyaan, judging SpaDeX by its docking objectives; counting the POEM-4 experiments that the Government's release folds into the mission gives (c). In the exam, judge a mission by its stated objectives, not by what else rode on the rocket.
- ISRO's year-end mission: SpaDeX, Department of Space, PIB: POEM-4 microgravity experiments ↗“SpaDEX will also use PSLV's fourth stage, POEM-4, for experiments. The stage will carry 24 payloads from academic institutions and startups. These experiments will utilise the microgravity environment in orbit.”
- ISRO's year-end mission: SpaDeX, Department of Space, PIB: key objectives ↗“Key objectives include Performing precision rendezvous and docking manoeuvres, Validating power transfer between docked spacecraft and Operating payloads post-undocking, with a two-year lifespan.”
- Shubhanshu Shukla to conduct Food and Nutrition experiments on the ISS, Department of Space, PIB ↗“the first ISS experiment will examine the impact of microgravity and space radiation on edible microalgae—a high-potential, nutrient-rich food source.”
This box is Minimalist IAS's analysis, with its sources; it does not change UPSC's answer.
UPSC's key counts two missions. Axiom-4 took Indian biology experiments to the International Space Station, and Gaganyaan is listed by the Government among its microgravity-experiment opportunities. SpaDeX is a docking technology demonstration, with rendezvous, docking, power transfer and payload operation as its key objectives, so it is not counted; the microgravity payloads on that launch flew on POEM-4, the PSLV's orbital platform.
- ✓ I Axiom-4 carried Indian biology experiments to the International Space Station, for example on how microgravity and space radiation affect edible microalgae.
- ✗ II SpaDeX's key objectives, as the Government describes them, are precision rendezvous and docking, power transfer between the docked craft and payload operation after undocking. The 24 microgravity payloads on the same launch belonged to POEM-4, the PSLV's fourth-stage platform, which is why the key leaves SpaDeX out.
- ✓ III The Government lists microgravity experiments among the research benefits of the Gaganyaan human-spaceflight programme.
Remember · Axiom-4 and Gaganyaan are tied to microgravity experiments; SpaDeX is a satellite-docking demonstration, and the microgravity payloads on its launch were POEM-4's.
Sources
- Shubhanshu Shukla to conduct Food and Nutrition experiments on the ISS, Department of Space, PIB ↗ “the first ISS experiment will examine the impact of microgravity and space radiation on edible microalgae—a high-potential, nutrient-rich food source.”
- ISRO's year-end mission: SpaDeX, Department of Space, PIB ↗ “These experiments will utilise the microgravity environment in orbit. SpaDEX will demonstrate docking and undocking capabilities between satellites. … Key objectives include Performing precision rendezvous and docking manoeuvres, Validating power transfer between docked spacecraft and Operating payloads post-undocking, with a two-year lifespan.”
- Status of Gaganyaan mission, Parliament question, Department of Space, PIB ↗ “Microgravity Experiments: Conducting experiments in microgravity can lead to breakthroughs in various fields, including materials science, biotechnology, and medicine.”
Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·