UPSC Prelims 2020 · Question 3 of 100
UPSC Prelims 2020 question on Elisa Space Antenna
- ExamUPSC CSE
- Year2020
- PaperGeneral Studies Paper I
- SubjectScience and Technology
- TopicSpace Technology
- DifficultyMedium
- TypeDirect
The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one million kilometers long, with lasers shining between the craft. The experiment in question refers to
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Answer: D. Evolved LISA
The description refers to the Evolved Laser Interferometer Space Antenna (eLISA) project — a plan of setting into space three spacecraft (a mother and two daughter spacecraft), which will fly in a triangular formation, trailing the Earth in its orbit around the sun at a distance of over 50 million km.
Each arm of the imaginary triangle, from the mother to each daughter spacecraft, will measure about a million km. Laser interferometers will accurately measure changes in the distance between these spacecraft. If affected by a gravitational wave, the minute changes in this distance are measured by the interferometer.
This followed the success of the LISA Pathfinder experiment after the second detection of gravitational waves by the LIGO detector.
Hence option (d) — Evolved LISA — is the correct answer.
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