Jonathan's Aerial Surveyor Diary

Production team

Day One

Kathy and I are to make a hot air balloon but it can’t be powered by a heater / burner - it has to be solar heated!

Apparently there are astronomers / physicists that are planning to send payloads to Mars and to get these machines to travel around the surface of the planet using a similar hot air balloon. It works like this: If the equipment lands at night, the air is cold. A dark coloured balloon will be made to inflate from the equipment using compressed gas. The whole thing waits till sunrise. As the Sun rises the gas in the balloon will heat up faster than the air around it. This will make it expand and so will become relatively less dense. This will make it rise.

Ideally this works best in the Polar Regions where there is the greatest difference in temperatures possible. We are to make a similar device. The production team have given us a wireless camera to put on the balloon as a payload.

Kathy and I talk about the science of this and then start to make up a couple of prototypes. We intend to use bin liner bags to make the balloon from. The first was a geodesic design – a spherical (12 pentagons called a dodecahedron) structure while a second quite different design was a sausage shape. As we have no previous experience we need to try out two very different designs. Both the balloons looked great and easily filled up with air by wafting using a board. The sausage was about five metres long while the round balloon was about two metres in diameter.

However apart from the beginning of the day there is always a breeze at the mine and our balloon bellowed and wriggled about far too much. Even when the breeze did die down and we could make sure the balloons were in the Sun nothing happened!

Finally we found out that the bags we had been using were too thick and too heavy. The production team got us some lighter bags and we started again.

Production team

Day Two

Tried out our balloon near to sunrise but still no joy. We decide that the round structure is a little more stable than the long sausage and so decide to make up a much larger spherical balloon using the light bags – about 4-5m in diameter.

The large spherical structure is composed of 12 pentagons cut-out from the bags and sticky-taped together to make up a sort of football shape. The idea was to make up the pentagons and then add them together to form two bowl shaped structures having six pentagons each, and then finally to fit these together to form the spherical structure. This seemed more logical as it is very easy to get lost in all the plastic sheet that ends up being on the ground! We started out really well and made good progress but when we had made up the two bowl shapes the problems began.

Kathy and I realised that the two halves needed to be joined together in the correct place, we couldn’t simply tape them together at any point and hope they would come together okay. So we thought about it and went ahead … and .. somehow got it wrong!

What should have been a nice round structure when filled with air turned into a horrible square-ish thing with knobbly bits! We carefully cut the two halves apart but got lost in the process and ended up having to take each pentagon apart and tape them up again. In the process our pentagons lost shape and it took ages to re-assemble the two halves. Then after carefully thinking about how they should go together we joined them up … only to find that once more we got it wrong!

We simply did not have the time to re-build the thing again and so we had to make do with a slightly square round balloon with tuffty bits like ears – in fact we called it ‘big ears’.

Kathy makes up a payload holder and we string it to the balloon. We are both exhausted having put everything into getting this damn design working. We are running out of time to do any changes and so we have to go with what we have got.

No more time left today and we only have tomorrow morning left for a Sun rise to test it out!

Production team

Day Three

Today we all get up really early so that we can be in place for sunrise. However, when we get to the location we find that it is getting cloudy and actually clouds are building up. What to do? We try it out. We fill the balloon and wait for the Sun to heat it. But we find that as the Sun rises and becomes hotter so do the clouds build up and obscure it!!

We pack everything away and decide to drive to another part of the desert about 30 minutes away to try there. We unpack everything at set everything up, the Sun is there and little cloud cover here which is good. The crew are ready to film and we are all ready to start. We are hanging around waiting to see when the best moment will be, to plan the filming, when all of a sudden the balloon takes off!!

It’s a fantastic moment because although we were all prepared and ready to go none of us were expecting it to go when it did!! As the Sun heated the black bin liners the air quickly heated and slowly and majestically the balloon came off the ground, lifted the weight of the payload and strings and rose elegantly into the sky! It went up about 40-50m and the little wireless camera sent back beautiful images.

Mike’s Triumph:
After unexpected behaviour and the success of the balloon we go back to the mine, almost as high as the balloon went. A funny, wonderful moment – and it wasn’t the last of the day.

The final challenge concerns Mike B’s experiment. He has to make a device that will extract carbon dioxide so that recycled air could be breathed safely. He sets up a complex experiment to prove his chemical filtration plant works. This is a big moment and a difficult one for all sorts of technical reasons that probably won’t come over on the program. Chemistry is often the most difficult of the Rough Science challenges as even if you can get the science to work often a lot of the real life changes are invisible on first inspection.

Mike B makes up a wonderful experiment to show as clearly as possible his challenge working. The idea is to make carbon dioxide and then use it to extinguish a candle. This experiment is repeated at the same time with an identical set up apart from that the second has a carbon dioxide filter in-line. So the candle with no filter should go out very quickly and the one with the filter should stay on for much longer. The carbon dioxide gas comes from a bottle, bubbles through water (to show it is there) and then it flows to a candle in a jam jar.

It is a nail-biting moment when it's time to film because there is only not much time to film and also because the experiment has to be built into the ending and so it’s a little tricky and complex TV wise.