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skyjames

supersonic parachute that's 110 feet in diameter

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LOS ANGELES (AP) — The skies off the Hawaiian island of Kauai will be a stand-in for Mars as NASA prepares to launch a saucer-shaped vehicle in an experimental flight designed to land heavy loads on the red planet.

For decades, robotic landers and rovers have hitched a ride to Earth's planetary neighbor using the same parachute design. But NASA needs a bigger and stronger parachute if it wants to send astronauts there.

Weather permitting, the space agency will conduct a test flight Tuesday high in Earth's atmosphere that's supposed to simulate the thin Martian air.

Cameras rigged aboard the vehicle will capture the action as it accelerates to four times the speed of sound and falls back to Earth. Viewers with an Internet connection can follow along live.

Engineers cautioned that they may not succeed on the first try.

"As long as I get data, I'll be very happy," said project manager Mark Adler of the NASA Jet Propulsion Laboratory.

Story link:http://news.yahoo.com/nasa-test-giant-mars-parachute-earth-144617685.html

"exit fast, fly smooth, dock soft and smile"
'nother james

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Supersonic is linked to the speed of sound through whatever medium it travels.

I would like to know what the speed of sound is up there.
You have the right to your opinion, and I have the right to tell you how Fu***** stupid it is.
Davelepka - "This isn't an x-box, or a Chevy truck forum"
Whatever you do, don't listen to ChrisD.

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1:45 p.m. (EST), Tuesday, June 3 - Live coverage of NASA's Low Density Supersonic Decelerator (LDSD) 2014 Flight Test - HQ/JPL/GSFC
Flight Test

http://www.nasa.gov/content/live-coverage-of-nasas-low-density-supersonic-decelerator-ldsd-2014-flight-test-hqjplgsfc[url]

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potatoman

Supersonic is linked to the speed of sound through whatever medium it travels.

I would like to know what the speed of sound is up there.

About 340 m/s at sealevel. At 120K, about 200 m/s. Unlike true airspeed that varies mostly as a function of pressure, the speed of sound varies as a function of temperature.

These figures are from a googled graph, but it showed a straight line function. I suspect the graph may not be accurate. At about 40K feet, the temp starts to rise again, so the speed of sound does too.

Edited: Just found another graph corrected for temp. At 320 155K, the top of the stratosphere, Mach 1 climbs back to 320 m/s due to the higher temperatures in the stratosphere. :)

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JohnMitchell

the speed of sound varies as a function of temperature



square root of absolute temperature -

constant coefficients in there depending on the units you start with and want to end with, and (I think) the gas you are in. It's a neat derivation, and the simplifications allow us to reduce it to the single variable of temperature that does a nice job

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

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rehmwa

***the speed of sound varies as a function of temperature



square root of absolute temperature -

Absolutely correct. I had it dumbed down for air traffic controllers. This bunch is smarter. ;)

A lot of controllers I worked with had a hard time wrapping their head around the concept of Mach speed reducing with altitude. :S:D

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Am I getting this right that they want to actually land with a chute on Mars?

Atmospheric pressure:
Earth 101.3 kilopascals against Mars 0.087

But gravitational force is only 37% as on earth.

Sure gonna make for a shithot landing, unless they use some kind of booster thingy to slow it down before touchdown.

B|

You have the right to your opinion, and I have the right to tell you how Fu***** stupid it is.
Davelepka - "This isn't an x-box, or a Chevy truck forum"
Whatever you do, don't listen to ChrisD.

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potatoman

Am I getting this right that they want to actually land with a chute on Mars?

Atmospheric pressure:
Earth 101.3 kilopascals against Mars 0.087

But gravitational force is only 37% as on earth.

Sure gonna make for a shithot landing, unless they use some kind of booster thingy to slow it down before touchdown.

I like the inflated bags to absorb some of the impact.

Saw it in a space movie.:$

B|


One Jump Wonder

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potatoman

Am I getting this right that they want to actually land with a chute on Mars?

Atmospheric pressure:
Earth 101.3 kilopascals against Mars 0.087

But gravitational force is only 37% as on earth.

Sure gonna make for a shithot landing, unless they use some kind of booster thingy to slow it down before touchdown.

B|



They already did.

The earlier rover missions landed with the "parachutes to slow you down and airbags to cushion the impact" plan.

Curiosity used a far more complex system because it was too big for the airbags to work.

Time Magazine story from a couple years ago:

http://science.time.com/2012/07/31/the-coolest-mars-landing-ever-attempted/
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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