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Author Topic: Perseverance lands on Mars tomorrow!  (Read 1075 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...

https://youtu.be/M4tdMR5HLtg

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...

https://youtu.be/UEO77UEFGT4

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...

https://youtu.be/MobwYuhkSVE

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...

https://youtu.be/rzmd7RouGrM

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...

https://youtu.be/ZEyAs3NWH4A

https://youtu.be/W7FcE7yZl4M

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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