Falcon 9, SpaceX's rocket, is about 70 meters long, and its warhead is about 10 meters long. And it was in this warhead that 90 satellites from around the world flew into orbit on Saturday, November 11. One of them contains a research module, which was built by graduates and students of Wroclaw University of Science and Technology, working for Saule Technologies.
Design: only an engineer knows how much you can fit in one cub
One cube is 10 × 10 × 10 centimeters. And that's how much, no more, no less, a research module could have. And inside are 28 photovoltaic panels based on perovskite cells, as well as the electronics needed to take measurements and transmit them via satellite to earth.
- We started the work with a sketch made on a piece of paper, and we know a piece of paper doesn't limit the imagination in any way," says Kuba Sieczka, head of the engineering team that built the module, a fourth-year student of electrical engineering at Wroclaw University of Science and Technology.
He adds: - Based on the parameters given to us by the scientific team led by Dr. Vivka Babu of Saule Technologies, we created from scratch a design for a module that conforms to space industry standards.
Standards: hundreds of pages on space materials
To ensure that the module wouldn't fall apart in space, engineers built it with special NASA-recommended materials that meet stringent standards for space conditions.
- We spent a huge amount of time analyzing several hundred pages of standards for materials suitable for use in such a demanding environment as vacuum and rapid temperature changes, says Kuba Sieczka.
The problem is that using these most robust and recommended materials would exceed the budget of many a company. To give an idea of what these costs are, one product is enough: glue. NASA's recommended adhesive costs, a bagatelle, 600 zlotys... for 6 milliliters.
So the engineering team had to work out a balance between budget and durability. Therefore, endurance tests were conducted: overload and vibration tests (in Warsaw) and vacuum tests in Wroclaw (at Saule Technologies).
- We call the vacuum tanks "vacuum chambers." Saule Technologies is equipped with one of the most advanced laboratories in Europe, so we were able to conduct this part of the tests at our place," explains Kuba Sieczka.
Construction: Thousands of components and only 157 grams? No problem
- The module itself was built very quickly, it took us only four months," explains Kuba Sieczka. - The experience we gained from creating advanced electric motorcycles in the LEM Wroclaw Motorsport Scientific Circle came in handy. High technology and precision, that's what we like best.
And this is necessary because the satellite - recall: with dimensions of 10 × 10 × 10 centimeters and a maximum weight of 157 grams - consists of more than 1,000 electronic and several hundred mechanical components.
Most of the electronic parts on the module's main board were less than one millimeter in size, and the team's chief electronics engineer, Adam Mizerkiwiecz, was responsible for its design and operation. Other members of the engineering team included Szymon Wierzowiecki - execution technologist, Andrzej Tatarczuk - who handled documentation and calculations, Piotr Wyszynski - project engineer and Albert Iwanicki - module designer. Each of them was irreplaceable.
Polish research module in space - all OK, but what for?
The Falcon 9 rocket was sent into low earth orbit (so-called Low Earth Orbit), that is, about 550 kilometers from the Earth's surface. There the procedure of separating the satellites from the rocket began, and now they fly over our heads, circling the globe every 90 minutes or so. Why go.
There are 28 small perovskite-based photovoltaic panels in the module, as well as electronics that continuously transmit the collected data on the parameters of the panels under space conditions (because how it works on Earth is already known). It is these two elements that make this mission unique.
First: a lightweight and flexible photovoltaic panel
Until now, in space, the effectiveness of panels has been studied in technologies where the module itself is usually very massive rigid and, above all, very heavy. The material from which Saule Technologies' cells are made - perovskite - is their opposite. Photovoltaics made by Saule are ultralight, very flexible and thin.
Here it should be emphasized that perovskite is not a new material. It's a mineral that was discovered in 1839 by Gustav Rosy (as cited in Wikipedia) and named after Lev Perovskite. Not much was seen of what it could be used for, until in the early 2000s Japanese Tsutomu Miyasaja discovered and proved that it could be used for photovoltaics.
To prove it is one thing, but to do it is another. And this has been done by Olga Malinkiewicz, who manufactures printed perovskite solar cells in Wroclaw, Poland. This is the world's first photovoltaic production line using this technology.
The perovskite panel has been sent into orbit to see what efficiency it will have in space conditions. It is already known that its lightness and flexibility are invaluable in the conditions there. First of all, their lightness makes it much cheaper to take them into space than panels created with other technologies. Secondly, perovskite-based photovoltaics can be rolled and later, in space, rolled out to make the active photovoltaic area larger.
Second: ongoing efficiency measurements
The second innovation of this mission is the ongoing readings of each panel's parameters. Until now, a batch of photovoltaic samples was inserted into the satellite and possibly controlled flight. No ongoing measurements were taken.
- In practice, it looks like we are waiting for the so-called communication window, that is, the moment when we can connect to the satellite and retrieve measurements," explains Kuba Sieczka.
The acquired data will be analyzed for the efficiency of perovskite cells in space, and the results may allow further tests and a future revolution of space photovoltaic technology.