ESA indicates that the first bounce lasted two hours and reached a height of 1 km. With the extremely weak surface gravity and low escape velocity of the body (< 1 m/s), and other publicly available information regarding the comet's mass properties and the landing site location, can we estimate how close the lander came to drifting away into space?
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How close was Philae to escape velocity during its first bounce?
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asked Nov 13 '14 at 14:50
pericynthion
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It was never close. Rosetta did not have escape velocity when it ejected Philae. So as long as Philae was ejected in the retrograde direction, Philae would not have escape velocity either. After the bounce, Philae would have even less energy due to landing gear attenuation and would therefore be even farther from escaping than it was pre-bounce.
answered Nov 15 '14 at 2:06
Erik
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The new report says Philae was moving at 38 cm/s.
Using Russell's figure of 0.886 m/s as escape velocity, we have 43% of escape velocity.
answered Nov 14 '14 at 13:00
SF.
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How close was Philae to escape velocity during its first bounce?
up vote
14
down vote
ESA indicates that the first bounce lasted two hours and reached a height of 1 km. With the extremely weak surface gravity and low escape velocity of the body (< 1 m/s), and other publicly available information regarding the comet's mass properties and the landing site location, can we estimate how close the lander came to drifting away into space?
asked Nov 13 '14 at 14:50
pericynthion
9,4181 gold badge38 silver badges57 bronze badges
9,4181 gold badge38 silver badges57 bronze badges
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It was never close. Rosetta did not have escape velocity when it ejected Philae. So as long as Philae was ejected in the retrograde direction, Philae would not have escape velocity either. After the bounce, Philae would have even less energy due to landing gear attenuation and would therefore be even farther from escaping than it was pre-bounce.
answered Nov 15 '14 at 2:06
Erik
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They are that simple. As long as the separation impulse was small -- which it must have been since Rosetta is still captured -- then nothing else matters. The only other thing that I can think of that might cause Philae to escape would be geyser impingement. - Erik Nov 15 '14 at 2:18
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