"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
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Answer: D. Evolved LISA (eLISA) was the ESA design for a space gravitational-wave observatory with three spacecraft in a triangle with one-million-km arms, linked by lasers.
Watch for: LISA Pathfinder shares the name, but it was a single test spacecraft, not a trio.
Why the other options are wrong
- A. Wrong because Voyager-2 is a single probe that left the solar system.
- B. Wrong because New Horizons is a single probe that flew past Pluto.
- C. Wrong because LISA Pathfinder was one spacecraft that tested the technology.
Source to check: European Space Agency (esa.int), LISA and eLISA mission pages
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.