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How would I calculate the terminal velocity of Mars?

What is the terminal velocity of a balloon entering Mars' atmosphere?

Would a balloon pop if dropped from space?

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    $\begingroup$ The atmospheric pressure of Mars is about 0.636 kPa, that is 0.63 % of atmospheric pressure on Earth. At a height of about 35 km, the pressure is the same at Mars ground. We should be able to build a glider for 35 km height first. $\endgroup$ – Uwe Sep 23 '18 at 15:17
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    $\begingroup$ Felix Baumgartner exceeded sound speed in his jump from 39 km height. So the terminal velocity at Mars surface should be supersonic too. $\endgroup$ – Heopps Sep 23 '18 at 16:26
  • $\begingroup$ Terminal velocity applies to falling objects. Is this balloon falling? $\endgroup$ – Organic Marble Sep 23 '18 at 17:26
  • $\begingroup$ @OrganicMarble If just "dropped" it would have this nasa.gov/larc/expert-panel-assesses-inflatable-spacecraft-tech on the bottom of the bottom possibly a streamer to keep it down right once terminal velocity has be reached and cooled to temp expand the balloon to a buoyant size. The balloon would fit inside this vacuum. ichef.bbci.co.uk/wwfeatures/wm/live/1280_640/images/live/p0/1t/… $\endgroup$ – Muze Sep 23 '18 at 18:00
  • $\begingroup$ @uhoh updated question $\endgroup$ – Muze Sep 25 '18 at 19:32
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How to calculate terminal velocity in general:

$$ V_t = \sqrt\frac{2W}{\rho C_d A} $$

where

$V_t$ = terminal velocity
$W$ = weight (mass times local gravity)
$C_d$ = the coefficient of drag of the object
$\rho$ = atmospheric density
$A$ = frontal area of the object

Comparing Mars to Earth, weight is $\approx 0.38$ and atmospheric density is $\approx 0.0167$ that of Earth, so terminal velocity is $\sqrt{23} = 4.8$ times faster on Mars. (Assuming $C_d$ doesn't change, which it would, but this is close.)

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    $\begingroup$ A reasonable choice for Cd assuming a spherical blimpish structure would be 0.5, otherwise there are various tables a search engine will find. Strange things happen to Cd above mach 1 but this will at least get an approximation. $\endgroup$ – GremlinWranger Sep 23 '18 at 23:12

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