This project has been cancelled, due to a lack of interest from the students.
Hot-air balloons are a magical phenomenon to see. They achieve a deep human fantasy and they usually have beautiful colors. But really nice about these balloons, is the way they fly. They don’t use a motor and they fly very quietly. The only thing that’s unfortunate about a hot air balloon is that they need fuel to fly.
In June 2013, Google started testing the first thirty balloons of Project Loon. These balloons fly at an altitude of about 20 kilometres and are therefore almost unaffected by weather conditions or turbulence. They are used to deliver internet to countries that currently have poor or no coverage.
These balloons fly through helium. Each balloon is equipped with 12 helium tanks, which can be used to determine how fast a balloon has to descend or rise. The disadvantage of this is that the balloon has to be lowered when the tanks are empty.
If you don’t let the helium escape, the balloons don’t have to be brought to the ground anymore. This is only necessary if there is a problem with the balloon.
That’s why we’re going to build a new balloon that can do this. We do this by not adjusting the amount of helium, but the amount of air in the balloon. This changes the total density of the balloon and allows us to go up and down.
There are many purposes that you can think of for a balloon flying at 20 kilometers above your head. That’s why we want to open the balloon for research. We want to make it possible for researchers, students and companies to use the balloon themselves.
There is, however, a purpose that I would like to investigate myself. That’s use for real time communication. We can use this to control robots at relatively large bandwidths over long distances, for example.
There are several technical challenges that we expect to encounter. However, this is a small part of the challenges that we are really going to face. In practice, there will be many more problems that we cannot yet predict.
Ascending and descending
One of these problems is that the airtightness of the air around the balloon is as high as that of the balloon itself. This means that leaving extra air in the balloon does not increase the density of the balloon. The result is that we can’t lower the balloon.
That’s why we need to build a small compressor that we can use to compress the air. This increases the total density of the balloon and allows us to descend.
Of course, ascending is a lot easier. To do this, we simply let the air run out of the balloon again, so that the density decreases.
The balloon must be able to communicate with the people on the ground. This allows us to control the balloon, the balloon can get information (e.g. about the weather forecasts) and people can use the balloon for research.
However, communicating over these long distances is extremely challenging. We know it can be done, otherwise satellites wouldn’t be a thing, but that doesn’t suddenly make it very easy. We do have the advantage that we have almost no obstacles, as opposed to a situation in a densely populated city.
Techniques such as LoRa already achieve this kind of distances, so they should be relatively easy to implement. However, we want more bandwidth, so we need to explore other possibilities as well.
Another challenge facing us is that of power supply. We use equipment that must not fall out. We can use wind energy for this, but the wind power is very low at that altitude. An advantage we do have is that the balloon is above the clouds, and therefore has all day sun power. Looking at project Loon, this should be enough.
However, we still need to test and investigate this properly before we can use it. We use more energy than Google’s project, because we will probably have to use a compressor.
We should also be able to steer the balloon. A normal hot air balloon can’t be steered just like that, but this balloon has information about the air currents and can descend and ascend for miles and use those currents in that way.
This means that the balloon always has to have accurate information and that it has to start the rise and descend on time. The steering can then be used to change the location, or to maintain a fixed location.
The balloon must be as light as possible in order to reach great heights. However, it must be equipped with equipment. This means that a lot of profit can be made based on the choice of materials.
With an area of about four thousand square meters, enormous savings can be made. If we made this balloon out of paper, it would weigh 320 kilograms.
Another problem is that there is hardly any protection against UV in the atmosphere and that there are enormous temperature fluctuations there. It can be as low as -90 degrees there.
The choice of material must take into account the conditions in the atmosphere and the intended weight targets.
How we are going to get there
This project will be carried out in full with students from the Rotterdam University of Applied Sciences. We will plan the balloon ourselves, execute it ourselves and manage it ourselves. We will do this with multidisciplinary teams, consisting of students from all study programmes. These are students who are looking for extra challenges.
In order to obtain funding, we are going to look for companies and institutions involved in research in the fields of aeronautics, telecommunications and robots.