On that day, the White Hall of the capital's House of Scientists of the National Academy of Sciences of Ukraine was crowded. The lecture "Stratospheric balloons. Typology and possibilities" brought together those interested in the design and use of lighter-than-air vehicles. The speaker from the Scientific Meetings lecture series, Mykola Mironov, a leading engineer at the Igor Sikorsky Kyiv Polytechnic Institute's Information Systems Design Bureau, was able to interest the audience by telling them about stratospheres, their behavior in flight at high altitudes, the prospects for stratospheric airships, and more. Mykola Ihorovych's practical experience in operating balloons over the past 15 years allowed him to answer, in particular, the question: what allows some stratospheres to stay in the air for several months and reach the areas specified by the operator? After the lecture, the correspondent of Kyiv Polytechnic took the opportunity to talk to Mykola Myronov.

- Mykola Ihorovych, this lecture proved that you have been in the field for a long time. Is the history of ballooning your hobby, so to speak?

- Let me start with a quote. The outstanding aircraft designer, scientist, inventor, creator of the helicopter, philosopher Igor Sikorsky once said about the beginning of the aviation era that "aeronautics was neither a science nor an industry. It was a miracle". These are the words that come to mind when I recall how, when I was a student, a decade and a half ago, at the Ukrainian Ballooning Championships (thermal balloons), I, along with my colleagues, as part of a meteorological team, conducted a study of the use of a balloon. Imagine, researchers are monitoring the flight of a small balloon using a ground-based optical theodolite. Thanks to the angular data and other indicators, the directions of wind flows were determined depending on the height of the balloon, as well as the height of the lower edge of the clouds. Of course, this data was useful for balloon pilots. In practice, I got to know meteorology and the basics of unmanned aerial vehicle operation. It was very interesting.

Soon I was invited to work with standard radiosondes at an aerological observatory. I decided that the experience gained would be enough to create the first stratospheric platform. At the time, it was the first project in Ukraine to use a container with meteorological equipment and a soft landing after the flight. By the way, the data on the location of the gondola (the container with the equipment) was transmitted via mobile communication.

- So, a stratospheric balloon is a balloon with a tightly closed gondola attached to it. What difficulties can be encountered during the observation?

- The difficulty is that the container with the equipment is not hermetically sealed. Therefore, the electronics and batteries have to withstand temperature fluctuations. And most importantly, overheating, because at an altitude of more than 17 km in the stratosphere, heat is poorly dissipated due to the rarefied atmosphere. Thus, the temperature around the gondola can reach 70 degrees Celsius. Under such conditions, electronic parts can melt. It was attention to this fact that allowed us to avoid the loss of stratospheres due to electronics failure, unlike similar devices used in the near abroad. After all, we conducted our research in baroque chambers and thermostats.

- How did you prepare for the first and subsequent launches? I wonder how the balloons' operational cycle went?

- Let me remind you that the experience and scientific component of future research arose during the development of student projects. At the same time, we were interested in the results of experiments with cosmic radiation and demonstration observations of the Earth's atmosphere. The first launch took place from the Aerological Observatory in Kyiv. It took five years to prepare for it. The stratospheric balloon was powered by hydrogen. Later, due to the increase in the volume of the shells and the weight of the vehicle, as well as the requirements of the airspace control authorities, we moved the launches of the stratospheres away from Kyiv. Later, with the improvement of the relevant equipment, it became possible to study the composition of the ozone layer and conduct biological experiments. Studies of cosmic and ionizing radiation in the atmosphere, analysis of the biosphere in the upper layers of the "celestial ocean," study of the ozone layer, aerosols in the upper atmosphere - this is not a complete list of our interests. We also found customers for flights.

The operational cycle looked like this. According to the customer's task, his equipment was integrated into the balloon. Everything is important here: weight, size, power supply of the instruments, placement of sensor antennas. Based on these results, the stratospheric shell parameters were calculated: gas volume, basic flight characteristics.

Once these parameters were agreed upon, an approximate launch date was set. Approximately a week before the launch, the balloon complex assessed the direction of wind flows and, accordingly, possible flight areas. The range of the air traveler sometimes reached 300 km. Thus, we took into account the distance to the state border, large cities, water bodies, etc. After all, each flight was approved by the controlling state organizations.

- You mentioned the balloon complex. What are you talking about?

- The balloon complex consists of four teams that are placed in cars. It is clear that there is a lack of personnel during flights, so the actions of specialists are combined. The first team deals with control and pilot calculations. It processes the necessary data, corrects weather forecasts in accordance with the flight trajectory, maintains communication with the crews, etc.

The second team is responsible for preparing the balloon for launch. They fill the shell with gas (helium is used in the field) and put the equipment into operation. The colleagues have a launcher, gas cylinder equipment, etc. at their disposal. It is the second team that must release the vehicle into a specific "launch window". Members of the second team must be able to work even in adverse weather conditions.

Radio-technical surveillance. This is the responsibility of the third team. By the way, our first stratospheres were only able to communicate after landing. Later, we received online telemetry during the flight of the sky traveler. This is important, for example, for rapid response in terms of determining the landing area. For this purpose, the members of the third team, in addition to experience and relevant knowledge, need a directional antenna system and a signal receiver.

The next is the selection team. The name itself contains the task for the fourth team. It is to get to the stratospheric landing area as quickly as possible and find the parachute container. This task is usually not very easy. After all, with an uncontrolled parachute, the gondola can land on the tops of trees, in a swamp, or in a body of water, etc. This is where climbing skills with the appropriate equipment come in handy. Endurance, physical strength and determination are a big plus.

- I listened to your lecture and realized that at the end of 2021, you and your colleagues skillfully operated a vehicle capable of reaching a 30-kilometer altitude. And its takeoff weight was three and a half kilograms. Of course, the large-scale war on the part of the Russian invaders prevented further research. However, we believe that you will return to your experiments. Did the technical base of the aircraft allow you to increase the operating altitude, say, to 35 km?

- Yes, we can do it. To launch at a greater distance from the ground, we need to study the properties of latex shells. After all, we have to take into account the low gradient of atmospheric pressure and overpressure in the shell at high altitudes, as well as the influence of ambient temperature and solar irradiation. I think that if the scientists and engineers of our university worked together to develop the field of stratospheric flight further, we could serve the Ukrainian military-industrial complex. Do you remember how at the end of February, the media made public the fact that enemy balloons had appeared that could detect specific locations of anti-aircraft missile systems? On February 15 this year, 12 balloons were spotted, of which six were shot down. Why are we lagging behind?

- A rhetorical question. However, it is appropriate. World practice proves that the capabilities of the stratospheric platform are vast. What should be mentioned in terms of student balloon research programs?

- Global experience shows that such initiatives are feasible. Here are some examples.

The HASP (High-Altitude Student Platform) program was implemented by NASA together with American universities in Virginia, Montana, Florida, North Dakota, and in collaboration with the Universidad Nacional de Ingenieria in Peru. In the course of many operational cycles, prototypes of small satellites, various payloads for studying the atmosphere, and cosmic rays were lifted. This is all in the context of STEM education.

The UMaine High Altitude Ballooning program is a stratospheric program of the University of Maine (USA). In addition to their own research, they provide space for other educational institutions to fly balloons, which fits perfectly into federal educational programs.

High Altitude Balloon Workshop (Fort Hays State University, USA, Kansas) is a regular set of events that can be compared to our Spring School in format: students get acquainted with the stratospheric carrier (and the relevant sections of atmospheric and space physics), use university laboratories to design payloads and participate in the operational cycle as participants in launch, control, and search calculations.

High-Altitude Balloon Near-Space Experiment (NSE) Launch is being implemented at the University of Nebraska (USA). Together with students, scientists create and test microsatellite elements in stratospheric flights.

PILOT Experiment - operation of a stratospheric telescope. The program is aimed at scientific rather than educational tasks. It is carried out by France, Australia, New Zealand, Canada, Mexico, and the United States.

HABDM. This project is implemented in cooperation with educational institutions and the Zimbabwe Meteorological Service (Africa).

By the way, the most active American company in this field, Raven (which created balloons for Google - ed.), has brought the operational cycle of its own balloons to one year. Astronomical stratospheric observatories are launched from US balloon bases every year.

This list can be significantly extended. The complex of qualities of stratospheric aircraft, combined with safety, makes their use, for example, in the university environment very convenient. And high flight performance allows for professional development. After all, specialists who have a background in working with such devices can use their skills in any field.

I am convinced that Igor Sikorsky Kyiv Polytechnic Institute, as a scientific and educational institution with a long tradition, is an ideal environment for implementing such projects. This is especially facilitated by the significant number and concentration of specialists and scientific schools of various fields. Experience shows that the regular operation of the stratospheric balloon complex takes place in an interdisciplinary field. This activity arouses interest and helps to attract specialists at the intersection of various scientific and technical fields.

The interview was conducted by Viktor Zadvornov