Falcon Heavy

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nsaspook

Joined Aug 27, 2009
16,325
Q. (Serious): what is the velocity at which pressurized gas particles expand in a vacuum of infinite volume?
https://articles.adsabs.harvard.edu//full/1966must.conf..269Y/0000269.000.html

A tricky question that depends on initial PE pressure (original volume of gas), jet size aperture and the level of vacuum.
https://www.physicsforums.com/threads/free-expansion-of-gas.687051/

I don't deal with rockets but I've seen a few vacuum implosions in ultra high vacuum chambers several meters long. The estimated wave velocities were supersonic judging on the damage seen.
 

joeyd999

Joined Jun 6, 2011
6,281
https://articles.adsabs.harvard.edu//full/1966must.conf..269Y/0000269.000.html

A tricky question that depends on initial PE pressure (original volume of gas), jet size aperture and the level of vacuum.
https://www.physicsforums.com/threads/free-expansion-of-gas.687051/

I don't deal with rockets but I've seen a few vacuum implosions in ultra high vacuum chambers several meters long. The estimated wave velocities were supersonic judging on the damage seen.
So, the final velocity of the gas molecules must possess a total kinetic energy equal to the original PE of the pressurized gas, yes?
 

joeyd999

Joined Jun 6, 2011
6,281
So, the final velocity of the gas molecules must possess a total kinetic energy equal to the original PE of the pressurized gas, yes?
Which is interesting in that the final velocity, given the same initial pressure, will be an inverse function of the molecular weight of the gas. Neat.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
16,325
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Thread Starter

nsaspook

Joined Aug 27, 2009
16,325
https://www.youtube.com/live/227WGGFeDoc?si=HS-lhWpprIfCtZQI&t=2451
SpaceX Falcon Heavy Launches GOES-U

GOES-U is amazing technology. In the late 70's we would receive GOES from GEO orbit using a WEFAX analog signal receiver on the ship connected to a special receiver and dish to the top of the ships mast.
1719440244475.png
Carrier mast example:
The dish/LNA/downconverter was slaved to the ships gyro for pitch/roll/yaw stability to the bird in the sky.
1719440433938.png
http://wd4eui.com/GOES_WEFAX_Receiver.html
For generat SATCOM we were using leased birds that are still operational. It was wide open so, 'anyone' could use it with the right equipment.
 
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Thread Starter

nsaspook

Joined Aug 27, 2009
16,325

joeyd999

Joined Jun 6, 2011
6,281
https://spacenews.com/eumetsat-moves-weather-satellite-from-ariane-6-to-falcon-9/
Eumetsat moves weather satellite from Ariane 6 to Falcon 9

Reliability, price and a solid launch schedule are good reasons why.
Musk took a lot of personal risks with SpaceX. I'm glad to see it paying off for him. This is the way capitalism is supposed to work.

I've always had doubts about Starship, both the tech itself and the mission. I'll be happy to find out I was wrong, if that's the case.
 

ApacheKid

Joined Jan 12, 2015
1,762
13 Things You Thought Were American But Really Aren't

Not to mention the Jet engine, radar, radio, penicillin, helicopters, ballistic missiles...

Really if Elon Musk has had intellectual property "stolen" he needs to get a better security system installed. The entire US rocket industry is based on "stolen" secrets extracted from Nazi war criminals and developed by Jewish slave labor, so lets have less of this pot calling a kettle black.
 
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