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Author Topic: Perseverance lands on Mars tomorrow!  (Read 2411 times)

Jeremy McCreary

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Perseverance lands on Mars tomorrow!
« on: February 17, 2021, 11:16:37 AM »

Same bonkers EDL (entry, descent, and landing) sequence used by Curiosity...



Took a lot of hutzpah to think that EDL would ever work, but it did last time -- flawlessly! And the entry vehicle at 0:52 looks a lot like our favorite toy.

How to watch...

https://mars.nasa.gov/mars2020/timeline/landing/watch-online/
« Last Edit: February 17, 2021, 04:01:08 PM by Jeremy McCreary »
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ta0

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Re: Perseverance lands on Mars tomorrow!
« Reply #1 on: February 17, 2021, 03:58:44 PM »

Thanks for the heads up. I'll try to watch tomorrow at 1:15 PM CST
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Texture

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Re: Perseverance lands on Mars tomorrow!
« Reply #2 on: February 17, 2021, 07:24:22 PM »

That'll be fun to watch. Thanks for letting us know.
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jim in paris

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Re: Perseverance lands on Mars tomorrow!
« Reply #3 on: February 18, 2021, 01:25:44 AM »

Wahoo ! 13 000 mph before entry!

Mad!☻

Jim
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ta0

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Re: Perseverance lands on Mars tomorrow!
« Reply #4 on: February 18, 2021, 03:44:58 PM »

A few minutes!
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ta0

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Re: Perseverance lands on Mars tomorrow!
« Reply #5 on: February 18, 2021, 03:59:48 PM »

Landed successfully!  8)
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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #6 on: February 18, 2021, 06:19:14 PM »

One mission bigwig just said that every time they have a landing, there's a plan and a contingency plan. He then held up the latter and tore it up to great applause in Mission Control. :)

America at its best -- doing the hard things with science and engineering as our guides. Hope the rest of the US government gets back into that habit soon.
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the Earl of Whirl

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Re: Perseverance lands on Mars tomorrow!
« Reply #7 on: February 18, 2021, 10:03:47 PM »

Yes!  Science is not a four letter word.
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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #8 on: February 19, 2021, 10:02:19 AM »

Excellent comparo of the Mars Science Laboratory and Mars 2020 rovers we call Curiosity and Perseverance, respectively...



The engineering on both machines is beyond incredible. As for the new stuff, gotta love that sample-handling robotic arm tucked in Perseverance's belly.
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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #9 on: February 19, 2021, 11:21:04 AM »

If we didn't have snow on the ground, I'd celebrate by taking my toy rover for another walk...



The NASA rocker-bogie mobilty system modeled here schematically turns out to be amazingly effective at any scale. But snow's not its long suit.
« Last Edit: February 20, 2021, 04:01:28 PM by Jeremy McCreary »
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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #10 on: February 20, 2021, 01:33:52 PM »

NASA's getting really good at these animations of how a mission is supposed to go. Perseverance's improbable EDL sequence in its entirety with the actual scenery it will encounter...



Never gets old. With both Perseverance and Curiosity, EDL went exactly as planned. Boggles the mind.

During Curiosity's 6-month shakedown process, only one function out of thousands failed to meet its performance goals  -- a mast-mounted weather instrument of minor importance that still produced some useful data.

Hoping Perseverance's shakedown goes as smoothly -- only much faster. Ready for this rover to get roving!
« Last Edit: February 20, 2021, 02:54:36 PM by Jeremy McCreary »
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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #11 on: February 20, 2021, 02:45:33 PM »

Sorry to keep posting this stuff, but I can't help myself, as I came down with FPPD (Fulminant Perseverance Perseveration Disorder) on Thursday.

Mars is a place of stark beauty, with evidence of active wind- and fossilized water-driven motion everywhere you look. Stunning 2-part documentary compiled in 4K from scenery shot by the Curiosity, Spirit, and Opportunity rovers...





Think private National Park tour on Mars!
« Last Edit: February 20, 2021, 03:26:57 PM by Jeremy McCreary »
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ta0

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Re: Perseverance lands on Mars tomorrow!
« Reply #12 on: February 20, 2021, 03:32:10 PM »

Am I the only one who looks at those amazing images and searches for a good spot to spin a top?  ;D ;D ;D

By the way, with lower gravity a top would spin longer before falling. Also it will provide more time in the air to catch the top on a trick. But slower precession will require some adjustments. Texture is young enough that he could try one day ;)

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Jeremy McCreary

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Re: Perseverance lands on Mars tomorrow!
« Reply #13 on: February 20, 2021, 06:15:02 PM »

Am I the only one who looks at those amazing images and searches for a good spot to spin a top?  ;D ;D ;D

By the way, with lower gravity a top would spin longer before falling. Also it will provide more time in the air to catch the top on a trick. But slower precession will require some adjustments. Texture is young enough that he could try one day ;)

Pretty sure you'd have to pay a big extra baggage fee for Figaro.

Wouldn't it be fun to turn down the gravity in a physically correct top simulator?

Though precession rates and critical speeds would decrease, nutation rates wouldn't change -- at least not directly.

The von Karman aerodynamic braking torque is proportional to air density and the square root of the air's kinematic viscosity. The viscosity is ~100 times larger on Mars than on Earth, while the density is ~100 times smaller.

Net effect: The von Karman torque on Mars would be ~10% that on Earth.

I say we go to Mars ASAP!
« Last Edit: February 20, 2021, 07:06:30 PM by Jeremy McCreary »
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ta0

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Re: Perseverance lands on Mars tomorrow!
« Reply #14 on: February 21, 2021, 01:21:01 AM »

The von Karman aerodynamic braking torque is proportional to air density and the square root of the air's kinematic viscosity. The viscosity is ~100 times larger on Mars than on Earth, while the density is ~100 times smaller.

Net effect: The von Karman torque on Mars would be ~10% that on Earth.

This table from Aerodynamics of Mars 2020 Rover Wind Sensors:



gives the kinematic viscosity 35 times bigger and the density 64 times lower on Mars than the Earth, but the end result is the same: about 10% the von Karman drag torque.
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