Posted: Tuesday, August 1, 2006
Today we accomplished an objective we called a "vehicle inspection." On the International Space Station and Space Shuttle we sometimes need to look at something externally to understand a problem we have or damage that has occurred. This is how the protective tiles on the Space Shuttle get inspected after launch now. The primary method for doing this is to use one of the Canadian-built robotic arms and maneuver it into position so that its video cameras can show the specialists on the ground what is going on. This is a primary method (as opposed to a spacewalk) for two reasons: risk to the crew, and "work efficiency" of a spacewalk (or "EVA" as we call them.)
We envision that periodic inspections of a lunar habitat will be required just as they are on our current space vehicles, and that a robotic system will have a prominent role once again (because spacewalks carry some additional risk by their very nature.) For instance, we may notice that there's a small leak because the pressure keeps slowly falling inside the habitat. A big enough leak into the vacuum of space might be visible from the outside - kind of like seeing your breath on a cold winter's day. In our scenario, to play the role of a robotic arm we used our trusty little ROV again. The crew flew it all around the exterior of Aquarius, taking care not to hit Aquarius, but also getting close enough to see little details in the video camera. As for the vehicle inspection, the crew was able to successfully and confidently fly it all around their habitat, and get high resolution imagery while doing so.
The crew was also able to conduct a ship-to-ship video linkup with the International Space Station today. Former NEEMO 3 crew commander Jeff Williams is currently on the ISS as a member of the Expedition 13 crew, along with Pavel Vinogradov and Thomas Reiter. For his NEEMO mission, Jeff (like our NEEMO 10 crew) was trained by our NEEMO 10 aquanaut Mark Hulsbeck. The crew reported this opportunity to swap stories of sea and space was the highlight of their day.
However, the clock is running out, and today the crew will began the 16+ hour process called "decompression" in order to allow them to safely "splashup" tomorrow. This is what we call "deco" day. As you now know, they have spent the last 6 days at a depth of 47 feet. At that depth, their bodies have taken on excess amounts of nitrogen which has been absorbed in their body tissues and must be removed.
Decompression is a very safe procedure which is accomplished in several steps: 1) The crew breathes pure oxygen for 3 short intervals to help decrease or "washout" the nitrogen in their blood; 2) the main living quarters are "locked out" from the "wet porch" area and the internal habitat pressure is slowly brought to the surface pressure by exhausting the internal air to the surface (14 hours); and finally 3) the habitat is "blown down" to the 47 foot level again in just a few minutes. Then the hatch is opened and the crew swims slowly to the surface under the watchful eye of escorting safety divers. They should be on the surface at ~ 9:42 am on Friday, where we will be waiting on the boat to take them home under the expert supervision of NURC Associate Director Otto Rutten. -
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