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Couldn't find this in the article: How is it expected to reach the Earth in 2020 when it took 3.5 years to get to the asteroid? Will it begin its return when th
by uprasad 8y ago
Couldn't find this in the article: How is it expected to reach the Earth in 2020 when it took 3.5 years to get to the asteroid? Will it begin its return when the asteroid is closer to the Earth?
- canadaj 8y agoI couldn't either, but on the Wikipedia page[1] for Hayabusa-2, there is a gif of the flight path. Maybe it took 3.5 years to achieve proper alignment/speed to land on the asteroid, but due to the larger size of earth and the position of Hayabusa-2 when it begins its return, it will be much more straightforward? [1] https://en.wikipedia.org/wiki/Hayabusa2 https://en.wikipedia.org/wiki/Hayabusa2
- wongarsu 8y agoGetting into an orbit next to some other small object is kind of hard. In the GIF you can see Hayabusa-2 making multiple orbits below the asteroid's orbit to catch up (lower orbits are faster) before it raises its orbit to the height of the asteroid. Once it reached the asteroid it had to do another correction to the orbit to make sure they stay together. In comparison, meeting something massive like a planet is very single: go into any orbit that nearly hits the planet, and when you are there slow down enough to let charit gravity pull you into an orbit around that planet. tl;dr: more gravity makes rondevous easier and quicker
- zamadatix 8y agoThe craft uses ion engines for propulsion. Extremely efficient but also extremely week. As a result it took a long time for the craft to match it's orbit. Had it not done this it would have either flown by or smashed into the asteroid at extraordinary speed. To return samples to Earth it does not need to match it's orbit since the atmosphere provides a convenient way to slow the samples without powerful engines and large amounts of fuel.