space hard MCQ

Nuclear thermal propulsion (NTP) achieves higher specific impulse than chemical rockets by heating propellant via _______.

  1. Electric arc
  2. Nuclear fission reactor
  3. Radioactive decay
  4. Fusion plasma

Answer: Nuclear fission reactor

NTP uses fission reactors to heat liquid hydrogen to ~2500 K, achieving Isp ~900 s vs ~450 s for LH2/LOX chemical engines, enabling faster Mars transit.

Topic Space Technology - Propulsion
Exam Relevance ISRO Scientist Exam, UPSC Prelims
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