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Subject: Shuttle cloud that is present before liftoff?

Date: Sun Nov 7 19:47:04 1999
Posted by Bret Underwood
Grade level: undergrad School: No school entered.
City: No city entered. State/Province: No state entered. Country: No country entered.
Area of science: Astronomy
ID: 942022024.As Message:
I work at COSI in Columbus, and we have a computer that can run video real slow. On this computer we have a clip of the space shuttle taking off. Right before the space shuttle engines light up, a cloud rises from the launch pad. I have heard two conflicting explanations: that the cloud is steam from water; or that the cloud is from liquid nitrogen. Both had in common the idea that the cloud is the product of some coolant of some kind. What is it really?

I think what you are seeing is the sound suppression system. It was found early on in the Shuttle missions that the tremendous noise from the solid rocket boosters could damage the Shuttle. To absorb the noise, valves are opened 6.6 seconds before liftoff which release water from a nearby tower. The tower contains 300,000 gallons of water which gets dumped into a cavity below the launch pad. The water absorbs the sound from the boosters and dampens the vibrations, making the Shuttle liftoff safer. It lacks subtlety, but it works!

You can read more about the sound suppression system at Space Shuttle Reference Manual, which has a huge amount of info about the Shuttle.

©2008 Phil Plait. All Rights Reserved.

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