The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one million km long, with lasers shining between the craft.” the experiment in the question refers to?
- Voyager-2
- New horizons
- LISA pathfinder
- Evolved LISA
Explanation
Option (d) is correct
- eLISA is a plan to place three spacecraft into space, 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. Inside these spacecraft, “freely falling” test masses will float – cubes with sides measuring about 46 mm. Laser interferometers will accurately measure changes in the distance between these cubes. If they should be affected by a gravitational wave, the minute changes in this distance are measure by the interferometer.
- The mission was proposed to the European Space Agency and selected as a science theme for the third large-class mission to be launched in 2034 within the agency’s Cosmic Vision science program.
- eLISA aims to measure gravitational waves in the frequency range from 0.1mHz to about 100 mHz.
- To do this, it is necessary for the interferometers to have an arm length of a million kilometres, and that is impossible to achieve with an Earth-based setup. Hence, it is necessary to have this elaborate experiment in space.
Option (a) is incorrect
- Voyager 2 is an unmanned space probe launched by NASA on August 20, 1977, just a few weeks before its sister craft, Voyager 1. Its mission was to study the outer planets of our solar system, including Jupiter, Saturn, Uranus, and Neptune. It was the first and only spacecraft to visit all four planets, and its observations revolutionised our understanding of these distant worlds.
- After completing its primary mission, Voyager 2 continued on its journey into interstellar space, where it is still sending back data on the interstellar medium and the heliosphere. Voyager 2 is currently the second most distant human-made object from Earth, after its sister craft, Voyager 1, and continues to communicate with NASA’s Deep Space Network.
Option (b) is incorrect
- NASA’s New Horizons was the first and, so far, the only mission to Pluto. It was also the first mission to explore the solar system’s recently discovered “third zone,” the region beyond the giant planets called the Kuiper Belt.
Option (c) is incorrect
- LISA Pathfinder was the European Space Agency (ESA) precursor mission to the LISA space-based gravitational wave observatory that the agency is developing within the Cosmic Vision Programme.
- The eLISA mission technology was being tested in space with LISA Pathfinder (LPF). LPF was launched successfully in December 2015 from Europe’s Spaceport, French Guiana.
