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Message Subject "Curiosity Mars "landing" BIGGEST HOAX EVER!!!"
Poster Handle nomuse (not logged in)
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See: [link to www.braeunig.us]
to understand Cd and how it relates to
super/sub sonic speeds for various shapes.

For a round nose projectile, such as the
it looks like the range is about:

Subsonic: Cd = 0.2
Supersonic: Cd = 0.6 (maybe .65 @ Mach 1.5 or so)

The Curiosity protective shell looks more flat than a round nose projectile and probably has a Cd MUCH higher as supersonic speeds, dropping very quickly at subsonic speeds, more similar to the cylinder and sphere than a round nose projectile. But we don't have that data to my knowledge.

Unfortunately, my communication with Earth is about the same speed as Curiosity, 32kbps, so I am not so informed with graphical data as most, and no video data at all.

I see many physics types trying to calculate everything with math and energy formulas, but :) That's not really possible. Physicists create formulas like computer programs that model relationships we see in nature, so we can put numbers into them, and get other numbers out of them. But especially in Aeronautics, physics has it's limits - there are some things in this world that become too mind-bogglingly complex with fluids - fluids have too many variables, they change too quickly, in all directions, with a different set of physics for every change and direction. Playing with air/water isn't exactly like playing with billiard balls and beams of iron. NASA would not be able to do much at all without extensive real-world testing and real-world measurements, refining things in the real-world to get the results they are looking for.

That is why we use wind-tunnels to find coefficients of drag, it's just too complex for physics. Anyway, I will try to think of some way to approach a sanity check for high-altitude deceleration due to friction. It would be helpful if anyone has data on the "shell" or "pod" that is carrying the Curiosity assembly, also the height when it was released, it's velocity, etc. Gotta go for now, maybe a few days.
 Quoting: Engineer 694654


Yup. Sanity check is all that's really appropriate here; formula may not be completely applicable in the specific domain, modeling is complex (and can also be incomplete), and if you are assuming malfeasance you have already determined not to accept empiricism (at least, not from the usual suspects).

One simplification that may help; according to NASA the parachute deploys at supersonic speed. So it is a pretty good assumption that the entire performance of the heat shield is in the supersonic regime.
 
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