Ask an Aquanaut: Waves and the moon pool?
Richard asks: If there is a storm above Aquarius with high waves overhead, Does that high wave cause an increase in water pressure and does the livel in the moon pool rise and fall?
Dear Richard
You are correct, the height of the waves overhead affects the pressure at depth, and the change is sometimes very noticeable to the aquanauts. Because Aquarius is constantly adding air for atmospheric makeup, the water level is kept at the bottom edge of the wet porch. If we were to shut off our constant vent, each large wave would “burp off” some of the air inside, and the water level would creep up. You may see that burping at times on the web cams, in fact a diver entering the wet porch will also displace air, some of us more than others unfortunately! Sometimes when we return after a non-mission weekend that included 4-6′ or higher waves, we might find the water level up 18″ or so, but it would need to rise far greater than that to get up to the wet porch floor. Throughout the mission you can notice the tidal changes as well, with the depth changing from 43 to 47 fsw on our Labview monitoring back at the Watch Desk. One thing that happens during missions with waves in excess of 6-7′ is that aquanauts notice the change in pressure with a constant ear popping, so in those cases we close the wet porch door and allow the change to vent through an open equalization valve, that dampens the effect of the pressure change and allows the aquanauts to sleep more comfortably. When it does get rough, the swoosh of air burping out of Aquarius is the first sign before “Topside” has to tell you the seas are getting rough.
Thanks for that question Richard, hopefully we’ll have calm seas for the science mission starting June 10.
Craig Cooper
Operations Director
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