Day One

Iain and I are to find/extract some zeolite for use in a vacuum pump. The idea is for the Team to build a vacuum-driven water-cooling system that can be used to cool down a spacesuit. At low pressures, water will “boil” at a lower temperature than it does at atmospheric pressure. The process of boiling/evaporation should be able to cool a water supply that can be circulated round the spacesuit. The role of the zeolite is to lower the pressure in the vacuum system even more by adsorbing the evaporated (boiled) water. Zeolites are microporous materials containing lots of little cavities and channels (much like the activated charcoal and pumice in Programme 1). This porosity provides a huge surface area onto which small molecules like water can adhere.

Iain and I have two sources of zeolite – mine will be the packet of washing powder that Kate has provided in the chest. Iain will go and look for a more natural zeolite source. It should be easy enough for me to extract the zeolite from the washing powder; it is, after all, the only component of the powder that is insoluble in water. The problem is that the zeolite is so finely powdered, it won’t simply be a matter of dissolving everything else in water and filtering off what doesn’t dissolve – I’d need especially fine filter papers to do that, and I don’t have them.

One potential way round the problem would be to thoroughly shake the washing powder up in water and let what doesn’t dissolve (the zeolite) settle out overnight under the effect of gravity. Tomorrow morning I could then decant off the water above the settled solid and dry the solid outside in the heat of the day. That’s what I decide to do. Tomorrow's going to be quite an easy day … or so I think!

Day Two

I suspected it would be more difficult that I’d imagined. Although some of the zeolite settles out overnight, it’s so finely powdered that much of it stays suspended in the water. Separating the zeolite out this way won’t produce as much as I need. I'll have to find an alternative method.

Out here in California it gets pretty hot during the day. The temperature inside the workshop can top 38 degrees Celsius at times. We’ve thoughtfully been provided with a couple of large electric fans to keep us cool, and over an early lunch, I entertain the idea of converting one of them into a centrifuge. That would be a much more effective way of getting the undissolved zeolite to settle out from a ‘solution’ of the detergent. Because of the size of the fan, I’d only be able to process smallish quantities of detergent at a time, but at least I’d be able to get a much more efficient separation this way.

The problem, of course, is that I’m depriving colleagues of 50% of their cooling system for a while. I only need the fan for a few hours though – surely they won’t mind. As it turns out, no-one notices the fan has gone missing.

By early afternoon I’ve dismantled one of the fans, and knocked together a centrifuge of sorts. It’s taken a while to get the balance right, and I’ve soaked myself in the process, but at last I can get on with separating out the zeolite from the washing powder more efficiently now.

    next > Page 1 of 2

Content last updated: 18/07/2006