Challenge: To make a Rough Science space suit, and provide it with a cooling system – the ultimate test – for Ellen to do a “space walk” in Death Valley.
This programme’s challenge could have been very awkward for all of us because none of us felt like we knew what we were doing, or at least none of us were experts in the area. But as it turned out it was a very good day and we all got a long way.
Kathy, Iain and Mike have made up a vacuum system, found zeolite in the hills around and have also tried extracting it from washing powder. This will be the basis for a fridge, which will cool the water for our cooling system. Ellen and I have made up a small pump which we hope will be able to move the cooled water to the suit.
At the end of the day Kathy had a vacuum system that could go to about 95% atmospheric pressure (i.e. the pump could remove 5% or so of the air) using just a small hand pump. Ellen and I were able to push water around a small loop of plastic and you could see the small air bubbles moving along nicely. We had decided to make one of those pumps that are used to make liquids flow. It works by a series of roller bars squashing a plastic tube in such a way that there is a forward squashing motion so that the water inside the tube is squeezed along.
We made use of an electric screwdriver to provide the power and fitted a large Allen key into the hexagonal shaft. This went to a small device we made up which looks like a small water wheel. This has six bolts that go across the wheel and it is upon these that the rollers are free to move. These parts were fixed to a piece of wood so that when the rollers moved they came close but did not quite touch the wooden base. A plastic tube was then threaded between the rollers and the base, so that as the driver turned, the rollers moved and the tube squashed, providing the "pumping action".
Such a hot day today. It was 38 degrees Celsius in the shade of the workshop and there was no breeze. Everyone was affected by it and in the worst time in the afternoon it makes you feel really strange and slightly irritated. I found that my brain just sort of slowly turned off!
After our success with the pump and the small closed loop we needed to see if it could pump water through all the equipment we were likely to use in the refrigerator and the suit. All in all, that amounts to about five or six metres of tubing. We filled the tubes with water and connected up to the type of device that we might use in the fridge and tried it out. Nothing happened. Tried it again, still no joy. Ellen even tried to blow the water through the system and found she couldn’t do it so our little pump would have no chance.
So we needed another plan to try and solve the problem. They filmed us chatting about other possible ways of pumping and we talked about perhaps using the foot pumps that were lying around.
Then it occurred to us that there might be an air lock in the system. We had tried to fill the tubes as best as possible but in all the bends and coils of tubing it is possible that there might be air trapped in one of the bends. So we carefully sucked water into the system and poor Ellen and I ended up having to drink quite a lot of it. After playing around for ten minutes or so we gave it another try and it worked! It was slower, of course, but we could see some small air bubbles passing really nicely through all the tubing. Ellen put some red dye into the water so that we could see it better.
There were still problems with the pump, though. For one thing, not all the rollers were identical and sometimes the drill would stall if the machine squashed the tube too much. We took it all apart to try and make the whole things more symmetrical and this helped. We then tracked down the cause of the problem to the tube itself. Yesterday, when the pump seemed to work so well it was really hot, and we had been filmed in the afternoon. All this time the equipment was in the Sun; consequently the tubing and the water were nice and hot and so this kept the tubing very flexible. Today it was cooler and the water is cooler and so the tube is stiffer - enough to jam the pump!
Once we had warmed the tube up it all worked well. It should be very hot in Death Valley so the tube should be nice and flexible - but of course we are aiming to pump cool water through the system so how will this affect the tube?
Kathy's first experiment didn’t get a good enough pressure / vacuum to cool the water. Found an air leak via the thermocouple wiring and after a few other mods we were getting 60 % atmospheric pressure / vacuum (roughly 400 Torr) which is pretty good for the simple equipment we were using. However still no joy getting the zeolite to do anything and the water just sits there; no cooling… A really good Rough Science test though.
There is still so much to do for this experiment that we bring equipment back to the rooms and have a takeaway and a drink and carry on. Mike B starts work on another method of cooling the fridge.
The morning sees a great RS team effort to try out the experiment again. We try alcohol instead of water, try modifying the connections to get better vacuum and even try modifying the apparatus so that the vacuum draws in air through a small tube and onto the liquid to blow-evaporate – this worked but only dropped the temp by a couple of degrees. Mike deploys his alternative “ammonium chloride” solution, and at last we have some cooling.
Ellen and I look at the problem of making the suit and making sure all the tubes out in the open are as insulated as possible. We all make up an insulated box on wheels for the equipment and cover it in aluminium foil – it looks “amazing”.
In the afternoon, feeling slightly under-prepared and wishing we had much more time, we pack all the equipment into the four wheel drives and head off to Death Valley. Its only 40 degrees Celsius in Death Valley today, amazing views coming down into the place and the scenery is very other worldly. On the way down Kathy puts the water container in a cloth bag and wets the bag periodically so that evaporation will cool the water.
We set up everything on site. The production team have chosen a salt pan in the middle of the Valley. Ellen puts on the suit and I wire a thermocouple to measure the temperature of the water close to her. Before we close the lid on the machine Mike B puts some ammonium chloride into the cool water which cools it down further. We pump out the device so that the water will remain insulated by the vacuum. Meanwhile, when we turn on the circulation pump Ellen immediately feels the cooling effect of the cool water being pumped around!!
So she starts to walk off into the distance the crew have a thermal imaging camera and it clearly shows the lower temps of Ellen’s body. Death Valley is at 40 degrees Celsius while Ellen is at 24 degrees Celsius – a result! The wheels on the fridge trolley weren’t so reliable though, and as Ellen moves away she end up having to drag the things over the salty pan …. A hilarious end to a grand three days.
The Next Day
Spent the day alone in the Alabama Hills (Mallory style) which are very near to Lone Pine. There is a nice breeze up hear and spectacular views. When I look south I have the High Sierra Nevada to my right, climbing to 3000m asl with perhaps 100 miles of peaks around me filling the panorama. To the left I have the open desert with the long empty road leading to the Rough Science mine and the distant Death Valley. Up here surrounded by the strange rock formations and fantastic views I can really relax. The winds are blowing on the desert floor a few miles away. It used to be a lake before the water was drained to supply Las Vegas with water. All that remains is a small brackish pond to the south. The salt and dust left behind is kicked up by the wind and as I observed the view a dust storm funnel moving slowly toward me. Storm clouds are brewing up on the Sierra Nevada’s and even though I am high up here it is so hot that the odd spot of rain is refreshing. However the downpour arrives and I head off to find shelter in a cave made out of three enormous rock boulders. I sit hear for an hour, perhaps two meditating and watching – just watching. In that place I would have liked to disappear for a month or two – to just watch / observe its ever-changing colours, animals and scenery.
Over the valley towards the desert there is a wonderful place. 10,000 years ago the lake was very deep and at that time this magical place was probably the lake side. Here there are marble cliffs and upon them are ancient carvings and drawings that the Native American peoples have carved so long ago. When I got back later on in the day I started to sketch out some designs based on the art work I had seen here and in books.