How to coordinate the flight of the probe into the stratosphere (what we will encounter in practice at launch)

    On April 12, we are going to launch a stratospheric probe with a small server, from where our page will be transferred to the CDN below . Incoming channel - low-orbit communication satellites, outgoing - radio stream at the frequencies of the amateur band (telemetry and control) and Wi-Fi (video and data).


    The problem with the launch is that it is an uncontrolled aircraft. I mean, it's just a ball of helium, to which several kilograms of iron are attached. And this is important because this iron can knock on someone else’s plane or fall on someone’s territory. Municipalities, for example, do not like it when it falls on the territory of its facilities. The nature reserves too. But Rosatom really does not like it at all.

    There will be a camera on board, that is, it will turn out aerial photography. Permission for it must be obtained from the Federal Security Service.

    This is the peak flight, that is, we rise to the working altitude, quickly complete the mission and go down to the landing. The probe usually carries 100-150 kilometers from the starting point in the direction of the wind blowing at an altitude of 30 kilometers from the ground. Above 20 km, turbulence usually disappears, and the air density there is 100 times less (the characteristic boundary of the atmosphere is visible in the survey), so the flight there becomes smoother. We can fly even to Vladivostok, but the larger the trajectory, the more difficult it is to obtain official approval of the flight, which makes us reduce the flight as much as possible.

    This is how this flight looks like, 99% of the entire Earth’s atmosphere is already below our stratospheric platform:


    The first thing we do is look for a place where 150 kilometers of flight in the “roughly that” direction in the wind will be easiest to coordinate. To do this, go to the site fpln.ru (by the way, it works on OpenStreetMap) and look for a place where you need a minimum of approvals:


    As a rule, this means that you need to get away from Moscow - go beyond the zones of airports, various military facilities and generally dense buildings. I would like to start not from the city (this will reduce coordination) and certainly land in the field or at least into the forest for the same reason. It would also be nice if there was nothing at the landing point that made us look for a probe with a payload of more than 5-6 hours.

    If these are your first approvals, then get ready for a very long quest with official documents. Some approvals can calmly take up to a couple of months. To reduce risks, we do the following:

    1. For the longest approvals (starting points, flights over large areas) we give a fairly large area and several starting points. If the wind suddenly changes from the expected, then it will be possible to change the starting point. For example, if it has changed by 20 degrees, it will be possible to move to another start and make the landing be in the same place as we originally planned. Starting points are the easiest to negotiate. In our history, we will start from a field outside the municipal territory, so we will simply agree with the owner.
    2. We are laying reserve start dates, of course.

    The flight plan of an unmanaged vehicle prior to direct departure is a sector. From the point of view of the logic of coordination, the device can be located anywhere in this sector at any time of the flight, therefore it is allocated exclusively for our flight for the whole stated time ...

    With all owners of forbidden zones on the map, you need to go through the coordination process. For example, if we fly over the reserve - get permission from them, if over the aforementioned Rosatom - from them and so on. Naturally, it is also necessary to coordinate with all surrounding airfields. All aviation dispatchers controlling flight routes of aircraft must also be warned.

    3-5 days before the start, a weather and wind forecast appears, which you can trust, and you need to start coordinating the flight in the form of a fork of trajectories. This is no longer a wide brushstroke area with different starting points, but one starting point and the angle of dispersion from the wind. Sometimes it’s z-shaped trajectories, sometimes circles or squares (depending on the specific weather and plan). But most often it is the starting point and angle.

    An example of drawing up an application for launching balloons and balloons - probes

    At this stage, you must submit an application to the center for air traffic management. This application permits or does not permit the use of airspace. Then they establish a particular use mode and insert it into the plan. This is if they are not confused by anything in the approvals. But the center may request additional coordination with neighboring areas, airfields, or with the General Staff.

    If everything is fine, then they give preliminary permission three days before the start. At this point, we are already starting to prepare our mini-MCC. This is what it looks like:


    An hour before the start, you need to call and clarify whether everything is fine. At this point, the flight plan for the center is compared with the actual weather (wind). Then there are three possible options:

    1. The weather was predicted well. Then we just fly.
    2. The weather is changeable, but it fits into the forecast. Then we must transmit the coordinates of the probe to the dispatchers every few minutes over the air as they fly.
    3. The weather is not predicted correctly. Flight is generally prohibited or transferred to another window (if any).

    In addition to surprises with the weather on the day of the flight, unpredictable events like the exercises at some military airfield can happen. There is priority in the use of airspace. Our probe is launched from an individual, and an individual has the lowest priority in comparison with state tasks, military tasks, passenger flights and so on. If the military has exercises, then the center may say: “Well, I'm sorry, three planes flew into your square, there's nothing to be done.” Periodically, at launches of weather balloons, intersections with the flying laboratory of cosmonauts IL-76 occur, where they train to work in zero gravity. Their priority is also predictably higher. We must wait for the completion of their flight. 

    We ourselves can unhook the load from the ball. Air traffic controllers can also request this at any time. This means that we give a command to the device, there a special device disengages the carbine, and the ball soars upward (where it bursts quickly from pressure), and the load goes down under a parachute. This is necessary in case of a sharp change in wind and other incidents, when the danger of a ball moving in an off-design zone is much higher than the danger of landing in an off-design location. We really hope that the result of the flight will not be something like "killed the cow by the router."


    The ball itself is almost no danger, it is filled with inert non-combustible helium. But the load is heavier than a bird and flies higher than a bird, so it can be an unpleasant obstacle for airplanes, although so far we do not know a single case of accidents involving balloons of probes. Naturally, we try to draw a trajectory over sparsely populated areas in order to minimize possible troubles during landing.

    Our start will most likely be in the area of ​​Pereslavl-Zalessky, where we have coordination with the FSB, the military, the airport, the zonal center and the owner of the launch field.

    Will we launch exactly on the day of cosmonautics? Not.


    Here's what can prevent:

    - Dense cloud cover
    There will be no problems starting up, but there will be interference on video broadcasting, since the clouds will dampen the signal (and we are limited in power and in the properties of the transmitters). The cloud cover probability is estimated at about 30%.

    - Strong wind near the ground.
    This complicates the launch. 2 out of 100 launches fail because of this, or you need to have spare probes in case the main one breaks with gusts of wind. Casual rating - 20%.

    - Precipitation (rain or snow)
    Starting during rain or snow can lead to a change in flight path. Rain on the electronics or camera lenses can damage equipment or the image. Score 20%.

    -Sudden exercises or special flights
    Depending on the work schedule of the nearest airdromes, it may be more difficult to get permission for one day than for another. Because of this, sometimes you have to postpone the start. The probability is below 20% by experience.

    What can happen during flight and landing?


    - Landing in a difficult place The
    chance is less than 10% in the current sector. But it is still possible to land in an inaccessible place, requiring more than 1 day to select equipment. You need to get to the landing site, pick up equipment and download video materials from the board. Therefore, do not wait for the results immediately)

    - “Buy-out” of the probe
    1 time had to pay the finder to return the equipment. 2 times gave away for free. This happens if strangers land in the line of sight when they pick up the probe before us. That is why we are hunting for a probe with a prize in cars - so that they can be caught directly on the descent by telemetry. The probability of 3% according to statistics of 100 flights.

    - Loss of equipment when landing in an inaccessible place
    Of the 100 launched stratostats, 3 were lost due to splashdown or landing in a place from where the equipment could not establish communication with the satellite and transmit its coordinates.
    To reduce this probability, we try to ensure positive buoyancy of the payload and duplicate communication systems.

    - Problems with the capacity of communication channels
    On the launch day in the approved place, the speed of the available Internet access channels may not be sufficient. This applies to the transponder capacity and broadcast video from the mini-MCC to you. On our stratosphere balloon we use two different communication channels. On earth - all available operators with a bridge. Risk assessment - less than 10%.

    - Disappearance of the communication channel from the stratostat to the ground
    Due to bad weather conditions or technical problems associated with the harsh operating conditions of equipment in the stratosphere (temperature up to -70 ° C), the broadcast from the stratosphere to the ground may stop. In this case, we will all be bored, but such is life. Risk assessment - less than 10%.


    So we do not promise 100% of the show, but we do everything to make it work. The main thing is to have the weather. And with it, it seems (pah-pah) so far everything is in order according to the forecast, but you know how forecasts are sometimes mistaken :).

    We invite the Habrazhitel to take part in our experiment and compete for the main prize - a trip to Baikonur.


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