Prelims · Science & technology · 22 questions

Space technology

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Prelims 2022 · Q34

Medium

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

Answer & explanation

Answer: (c) A missile is put into a stable orbit around the Earth and deorbits over a target on the Earth.

A Fractional Orbital Bombardment System (FOBS) sends a warhead into a low Earth orbit and brings it down over the target before it completes a full circuit — hence 'fractional'. Because it can approach from any direction, even over the South Pole, it is hard for early-warning radars to track. The Soviet Union built one in the 1960s, and it returned to the news in 2021 after reports of a Chinese test.

✓ (c) FOBS places a weapon in orbit around the Earth and then deorbits it onto a target, instead of following the arcing path of an intercontinental ballistic missile.
✗ (a) Deflecting or destroying an incoming asteroid is planetary defence (for example NASA's DART mission), not a bombardment system aimed at Earth.
✗ (b) Orbiting a planet several times before landing describes a planetary landing mission, unrelated to weapons.

Remember · FOBS: nuclear warhead put into low partial Earth orbit, deorbited onto target — evades radars facing the usual ICBM routes; Soviet system banned under SALT II (1979).

Sources

US Congressional Research Service, Defense Primer: Hypersonic Boost-Glide Weapons (updated May 2026) ↗ “a ballistic missile booster that carried the HGV into orbit before the HGV de-orbited and approached its target. Experts assert that this type of system might provide China with the ability to launch HGVs over the South Pole, thus evading U.S. early warning assets that track threats over the North Pole”
US Department of State: Treaty Between the USA and the USSR on the Limitation of Strategic Offensive Arms (SALT II), 1979 ↗ “After entry into force of the Treaty, fractional orbital missiles shall be removed and shall be destroyed pursuant to the provisions of subparagraph 1(c) of Article IX and of Article XI of the Treaty”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q40

Medium

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 the aircraft flying over polar regions could be interrupted.

Select the correct answer using the code given below:

Answer & explanation

Answer: (c) 1, 3, 4, 6 and 7 only

Items 1, 3, 4, 6 and 7 are genuine effects of a strong solar storm: it disturbs GPS, damages power grids, brightens auroras, drags on satellites and blacks out high-frequency radio near the poles. Tsunamis (item 2) come from undersea earthquakes and forest fires (item 5) are not an effect of space weather, so they are ruled out.

✓ 1. Solar-flare disturbances of the ionosphere range from errors of a few metres to complete loss of the GPS signal.
✗ 2. A tsunami needs an earthquake tremor centred below the ocean; solar storms do not generate them, at the equator or anywhere else.
✓ 3. Geomagnetic storms drive large ground currents (GICs) that can damage high-voltage transformers and have caused widespread power outages.
✓ 4. The same storms create the aurora borealis and aurora australis, and a strong one can push the northern lights as far south as Florida.
✗ 5. None of the recognised effects of space weather (radio, GPS, satellites, power lines, pipelines) is a ground-level fire hazard.
✓ 6. A strong storm heats and expands the upper atmosphere, raising drag on low-Earth-orbit satellites, which can slow them or make them lose altitude.
✓ 7. Near the poles, Earth's magnetic field funnels charged particles down. Severe space weather can cut radio contact with aircraft on transpolar routes, so they may need to reroute.

Remember · Solar storms hit technology: GPS, HF radio, satellites, power grids; and give auroras. They do not cause tsunamis or forest fires.

📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 3 (practise this chapter)

Sources

NOAA NESDIS, The Effects of Space Weather On Earth (Internet Archive copy) ↗ “The effects of solar flare disruptions can range from errors of a few meters to the complete loss of GPS signal. … GICs can flow into conductors such as power lines and damage high-voltage transformers. In the past, they have led to widespread power outages. … Extra drag can slow satellites in their orbit, or even cause them to lose altitude. … Planes flying on high-altitude transpolar routes must be aware of the space weather forecast before taking flight, as a loss of radio signal can prevent pilots from speaking with ground control. … a strong solar storm can cause the northern lights to appear as far south as Florida.”
NCERT Class 11 · Fundamentals of Physical Geography, Chapter 3 “The effect of tsunami would occur only if the epicentre of the tremor is below oceanic waters and the magnitude is sufficiently high.”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

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Class 11 Fundamentals of Physical Geography, Chapter 3cited in 1 explanation