Galaxy Is The Limit

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Near space near you

WHAT ARE HIGH ALTITUDE BALLONS?

High-altitude balloons are crewed or uncrewed balloons, usually filled with helium or hydrogen, that are released into the stratosphere, generally attaining between 18 and 37 km (11 and 23 mi; 59,000 and 121,000 ft) above sea level.

The most common type of high-altitude balloons is weather balloons. Other purposes include use as a platform for experiments in the upper atmosphere. Modern balloons generally contain electronic equipment such as radio transmitters, cameras, or satellite navigation systems, such as GPS receivers.

These balloons are launched into what is termed "near space", defined as the area of Earth's atmosphere between the Armstrong limit (18–19 km (11–12 mi) above sea level), where pressure falls to the point that a human being cannot survive without a pressurised suit, and the Kármán line (85 km (53 mi) above sea level), where astrodynamics must take over from aerodynamics in order to maintain flight.

WHAT ARE WEATHER BALLOONS ?

A weather balloon, also known as sounding balloon, is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems (such as the satellite-based Global Positioning System, GPS). Balloons meant to stay at a constant altitude for long periods of time are known as transosondes.

Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers. For such balloons, a theodolite or total station is used to track the balloon's azimuth and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable.

Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and computer models for weather forecasting. Between 900 and 1,300 locations around the globe do routine releases, two or four times daily.

How Weather Balloons Work – 

Aweather balloonfilled with helium will fly for the same reason oil floats on water. Oil has less density than water. As an experiment, pour a tablespoon of cooking oil into a glass of water. You should see the oil rise to the surface of the water. Just as the oil has less density than water and rises to the surface of the water, helium has less density than air and will rise to the surface of the earth’s atmosphere.

This is a good thing for us because the surface of our atmosphere is where space begins and where we want to fly our payload. By trapping the helium inside a balloon, we can attach a line to the balloon, called the flight train, with our payload suspended at the other end. The balloon will then lift our payload to the edge of space.

However, as the balloon climbs higher, the pressure in the atmosphere decreases. The reduced pressure causes the balloon to expand.

Weather balloons are specially designed to be able to expand to a very large diameter. Joseph is demonstrating this with a leaf blower we

hooked up to the same balloon he was holding in the previous image. A weather balloon that starts out at 2 m in diameter at launch can expand to a diameter of up to 10 m. As the balloon climbs to the edge of space it eventually expands to the point where it bursts. Our payload then falls back to earth under a parachute. As long as we can track our payload, we can recover it along with its recorded scientific data and flight video.

KEY POINTS:-

The smaller the balloon’s initial volume, the higher it will go before it reaches its burst volume

 

1. can be launched from locations worldwide to support scientific needs.

2. can be readied for flight in as little as six months.  

3. offer a low-cost method of conducting science investigations.

4. provide a stable platform for longer flight durations.

Types of Balloons:

Conventional Balloons: Conventional missions typically use direct line-of-sight electronics for command and data with flight durations ranging from a few hours to days.

 Long Duration Balloons: A Long Duration Balloon (LDB) mission normally traverses between continents or around the world for one circumnavigation. LDB flights may last up to three weeks and satellite-based electronic systems are utilized for command and data.

Ultra Long Duration Balloons (ULDB): The super pressure pumpkin balloon has been designed to increase flight durations up to one hundred days. This new balloon will significantly increase the amount of data that can be collected in one balloon mission.

Scientific Balloons:

Balloons have been used for decades to conduct scientific studies. While the basics of ballooning have not changed, balloon capabilities have increased and their dependability has improved greatly.

Scientific Balloons...

   1. can be launched from locations worldwide to suport scientific needs.

   2. can be readied for flight in as little as six months.

   3. offer a low-cost method of conducting science investigations.

   4. provide a stable platform for longer flight durations.

Scientists use scientific data collected during balloon flights to help answer important questions about the universe, atmosphere, the Sun and the space environment. Questions such as "How did the universe, galaxies, stars, and planets form and evolve?" and "Are there Earth-like planets beyond our solar system?" are being answered by NASA with the help of experiments flown on scientific balloons.

HOW NASA MAKES ITS BALLOON:

Standard NASA scientific balloons are constructed of polyethylene film; the same type material used for plastic bags. This material is only 0.002 centimetres (0.0008inches) thick, about the same as an ordinary sandwich wrap. The film is cut into banana-peel shaped sections called gores and heat sealed together to form the balloon. Up to 180 gores are used to make NASA’s largest balloons. These standard, zero-pressure, balloons are open to the atmosphere at the bottom to equalize the internal pressure with the surroundings. The balloon system includes the balloon, the parachute and a payload that holds instruments to conduct scientific measurements.

Helium, the same gas used to fill party balloons, is used in NASA balloons. These very large balloons can carry a payload weighing as much as 3,600 kilograms (8,000 pounds), about the weight of three small cars. They can fly up to 42kilometers (26 miles) high and stay there for up to two weeks.

How to launch your own high altitude weather balloon:

High altitude balloons (weather balloons) can be an incredibly fun and rewarding experience. It’s a great home project for students and adults, but there are some best practices and important safety regulations that you must follow if you’re going to operate your own flight.

·     Weather Balloon Sizes

Balloon sizes are measured by the measured mass of the balloon in grams. The size of your balloon will depend on how heavy your payload is and how high you want to travel to. We recommend starting small. We started with a 600g balloon which can usually get you to 80,000+ ft. for stunning imagery while keeping the cost down. There are several online calculators to help you with selecting a size for your weather balloon. Most will ask you about your intended ascent rate. You should keep your ascent rate around 5 m/s as a starting point, but anything between 4 m/s and 6 m/s should be acceptable. Faster ascent rates will result in the flight being shorter, the balloon bursting lower and more wake turbulence on your payload. Slower ascent rates will result in longer flights, higher altitude and less wake turbulence. Too slow, and your balloon may never burst!

·     Weather Balloon Integrity:

Latex atmospheric weather balloons are very sensitive. You’ll need to take extra special care when handling the balloon. First, keep the balloon stored in a dark, cool and dry space until you’re ready to start filling it.

The temperature and particularly the UV rays from the sun can weaken or damage the balloon if left in the sunlight. When you’re ready to begin your inflation procedures, all members of your launch team should wear latex or vinyl gloves to keep the oils from your skin off of the balloon. The oils from your skin can weaken the latex and cause a premature burst.

Also, avoid pinching the balloon as that can create micro-tears in the material.

·     Inflating & Sealing the Weather Balloon:

You’ll need to fill your weather balloon with a lifting gas to ascend through the atmosphere and seal it before launch. It can take anywhere from 15 to 30 minutes to inflate and seal your balloon. 

If you’re timing out your launch schedule, plan on at least 25 minutes from the moment you turn on the gas valve to the moment you’ve sealed off the balloon.

·     Lifting Gas:

Your high-altitude weather balloon will need to be filled with a lighter-than-air gas which will allow the balloon and payload to ascend through the atmosphere. Typically, you’ll be using either helium or hydrogen. In the United States, most flights use helium due, because it’s easier to find commercial and it’s much safer to handle and transport. Hydrogen is cheaper and can give more lift due to its lower density, however, hydrogen is very flammable and must be handled with extreme care. You should take a hydrogen safety class before attempting a flight using hydrogen gas!

Helium can be bought by a number of local suppliers, such as Air Gas, Praxair, or Matheson Trigas. Depending on the quantity, you can get one of your own high-pressure containers filled or use one of theirs. Helium is typically stored in high pressure containers like K-cylinders. 

·     Inflating you weather balloon:

*Before you start the inflation process, be sure everyone on your launch team is wearing latex or vinyl gloves to keep the oils on your skin away from the balloon material.

Step #1: Prepare filler hose

You’ll need a way to transfer helium from the tank to your balloon. You can either purchase an inflation tube and regulator from a supplier or build your own using some pipe tubing and a gas regulator valve from a home supply store. 

Your inflation tube will have at least 3 parts: an opening/connection point to wrap the neck of the balloon around, a flexible tube for the gas and a regulator to restrict the gas flow and attach the tube to the tank. Regulators are important. Helium tanks are usually pressurized to 3,000 psi which can be dangerous. Use a regulator that brings that down to at least 80 psi.

Step #2: Attach balloon to filler hose

Gently unroll your weather balloon and lay it on a tarp or smooth surface to protect the material. Next, slide your payload lines over the filler hose (see pro tips, below). Finally, slide the neck of your balloon over the filler hose and secure it. We use duct tape for this to secure it to the filler and then add one zip-tie for extra security.

Pro Tips:

1. Include a safety line (or two) with a solid anchor with the zip tie and always have your balloon firmly attached to the safety line until you’re ready to launch.
2. Have your payload line looped around your filler hose (not zip-tied) so that when you’re done filling you can just slide the payload line up to the balloon before removing it from the filler.
3. Along with your safety line, you can attach a counter weight (see step #3).
4. Before we slide the balloon over the filler, we have 4 total lines loop over the filler: the payload, the counter weight and 2 safety lines/anchors.

Step #3: Begin inflating

Now, it’s time to open the valve of your gas tank. The air will flow FAST! Start slowly until the balloon starts to lift it’s own weight and rise. Once it begins to rise you can open the tank valve more. Be careful handling the balloon especially during the early stages before it begins rising. Try not to grab or pull the material and just gently guide it. Ideally, when you pick your launch day, try to shoot for a day with surface winds less than 10 mph to make it easier for yourselves – especially for your first flight.

Step #4: Measuring Lift

Days before you even plan to launch, you should already know the weight of your payload along with the target lift that you want to achieve. There are several online calculators to help you identify the lift amount. You should keep your ascent rate around 5 m/s as a starting point and read the online calculator data to determine the lift amount. On average, this is usually 1.5x the weight of your payload. So a 1000g payload, should shoot for 1500g lift from the balloon. There are two common methods to measure this: either via a fish scale or using a counter weight. We actually do both just to be sure. A fish scale is easy since you can directly measure the pull of the balloon to see if it matches your expected lift. A counter weight is also easy to use. Fill a water just so that the jug and water weighs exactly what you want your lift to be. Once the balloon can consistently lift the counter weight off the ground, then you’ve achieved the appropriate lift amount and can stop filling.  

Pro Tip: On very windy days (10+ mph) the wind can create aerodynamic lift on the balloon and create false measurements. Be careful measuring in these conditions and make sure the balloon is actually pulling the weight and not the wind

Step #5: Sealing the balloon

Once you’ve reached your lift amount, you’ll need to seal the balloon. There are many ways to do this, but here’s our method. Before we even detach the balloon from the filler, we first twist the neck of the balloon 2 or 3 times and use a zip-tie to seal the twisted neck. As part of that initial zip tie we plea, we ensure that the payload line and our two safety lines are included in that initial zip-tie. This ensures you’re always attached to the safety line. Be careful with the pointy end of the zip-tie to ensure it doesn’t poke your balloon!  

Once this is done, you can cut/detach your counter weight line, if you have one and completely detach the balloon from the filler – but you’re not done yet. Fold the neck in half (U-shape) and attach 2 more zip-ties for a firm seal. Cut the excess ends of the zip-ties and wrap the sharp ends in 2-inch wide electrical tape to protect the balloon from the sharp ends. As long as your balloon is attached to an anchored safety line, you may slow raise the balloon and let it float while you prepare the payload. 

On a windy day, you may want to have someone hold the balloon or use a bedsheet or packing blanket to hold the balloon down until you’re ready to launch.

Balloon Performance Calculator:

The Balloon Performance Calculator starts by collecting three pieces of information: the size of your weather balloon, your payload's weight, and how much positive lift you want to use. With these three values, the Balloon Performance Calculator determines exactly how much helium you need. To accomplish this the calculator adds the weight of the balloon, the weight of the payload, and the positive lift. It then divides this summation by 27.82 to get the amount of helium you need in cubic feet (1 cu.ft. helium can conservatively lift 27.82 grams). Next the Balloon Performance Calculator calculates the altitude at which the balloon will burst. It already knows what the initial volume of the balloon is at launch in cu.ft. and can therefore predict at what altitude the balloon will be when it reaches its maximum volume. The smaller the balloon's initial volume, the higher it will go before it reaches its burst volume.

Things to Keep in Mind:

1. Our Balloon Performance Calculator is conservative when calculating predicted burst altitude. We want our customers to be pleased with their achieved altitude and not be disappointed because they never reached a theoretical altitude generated by our calculator.
2. Two identical size balloons made by the same manufacturer will typically burst at the same diameter/volume. More expensive balloons have a greater burst diameter/volume than those made by a cheaper manufacturer.
3. Balloon sizes are measured by their weight in grams. 350 g weather balloon weighs ~ 350 grams. A 1200 g weather balloon weighs ~ 1200 grams.
4. The larger the balloon size (the more it weighs), the larger its diameter/volume will be before it bursts.
5. If you launch two payloads with the same size balloon, the balloon with the least amount of helium will burst at the higher altitude.

Steps to be followed:

·      Step 1 - Input your balloon size, payload weight, and positive lift of 100 g into the calculator. 

·      Step 2 - Calculate.

·      Step 3 - Increase / decrease positive lift* until you are satisfied with your ascent rate / time.

*What is Positive Lift?

Positive lift is the extra lift your weather balloon needs to rise upward in addition to the lift needed to carry the weight of your payload and the weight of the balloon itself. As an example, let's say you want to launch a payload that weighs 1200 grams (including the weight of the parachute, rigging, etc.). Let's also assume you are using our 1200 g weather balloon (which also weighs 1200 grams). You calculate how much helium you need to launch your payload with the knowledge that 1 cu.ft. of helium will lift 28 grams. You divide the weight of your balloon and payload (2400 g) by 28 g/cu.ft. to get the total number of cubic feet of helium required for your launch (2400 g ÷ 28 g/cu.ft = 86 cu.ft.). You inflate your balloon with 86 cu.ft. of helium and release your payload. To your surprise it doesn't climb. It just floats right in front of you, neither climbing nor descending. This is because your balloon has only enough helium to lift its own weight and the weight of the payload. It's at perfect equilibrium. You need a force that will make the balloon and payload rise upward. The easiest solution is to add more helium to the balloon. This additional helium will provide the extra lift you need to make your balloon climb. The lift force created by this additional helium is called positive lift. The more helium you add to your balloon in addition to the helium used to lift the weight of the payload and the balloon itself, the more positive lift you will have. The more positive lift you have, the faster your payload will climb.

·     High Altitude Balloon Parachutes

In most high altitude weather balloon projects, your balloon will rise, then burst and parachute back to the ground. Your payload parachute is what will slow the payload down for a soft and safe landing so it’s important to think about how the parachute will be attached to your payload (securely!) and what size parachute you’ll use. In most cases, you’ll want to use what’s called an inline parachute where the payload is attached to the bottom and the weather balloon is attached to a special loop in the top of the canopy. 

*You’ll need to ensure your parachute allows your payload to land at a safe speed, preferably around 11 mph or 5 m/s. This speed ensures the payload lands softly enough to not cause damage, but also quickly enough that it doesn’t drift downwind forever.

·     Attaching & Deploying the Parachute:

When it comes to your parachute, you’ll want a fail-safe deployment method.

There are 3 common methods for attaching your parachute to your payload and balloon:

1. Inline Parachute (most common)
2. This is recommended for almost all flights. The payload string will attach to the bottom of the parachute and the balloon string will attach to a special loop on the top of the canopy. During ascent, the tension from the weather balloon will pull the parachute closed so reduce drag. Once the weather balloon breaks, the tension will be released and the parachute will be free to open.
3.  
4. Mid-Point Parachute
5. This is the second most common method and a good method if your parachute does not have a loop at the top of the canopy. In this method, you’ll attach both the payload and balloon strings to the bottom of the parachute. During ascent the parachute will hang and drag beside the payload line. This causes a bit of extra drag, but not much. The parachute remains open the entire time.
6.  
7. Low-Point Parachute
8. This is the least common method, but still an acceptable option when your parachute does not have a loop on the canopy. In this method, your payload will be connected directly to your balloon and the parachute will be connected to the bottom of the payload. Like the mid-point option, this also causes the payload to drag, but this time below the payload. This method usually causes the payload to descend upside down.

Pro Tip: Consider the payload and balloon weights! When your balloon bursts, much of the weather balloon remnants will remain attached to your payload line. This can be upwards of 75% of the original balloon weight or more! If your payload is very lightweight, this can cause your system to descend balloon-first if your balloon remnants weigh a lot more than the payload. For super-ultra-light payloads, you may want to consider mounting options #2 or #3 to ensure the balloon remnants don’t render your parachute useless. This really only applies to extremely light payloads. If your payload weighs more than 50% the weight of your balloon, then mounting option is the recommended method.

·     Weather Balloon Radar Reflectors

To ensure aviation safety, the rules and safety regulations in place by the Federal Aviation Administration (FAA) generally require the use of an in-flight radar reflector in the United States for larger high altitude balloon flights. This helps avoid collisions even in conditions of poor visibility, although, we recommend that you don’t fly at all in poor visibility. Smaller high altitude balloon flights are that exempt from FAR Part 101 Subpart D are not technically required to utilize an on-board radar reflector, but it’s still a good idea to include one anyways.

Radar reflectors can be bought commercially or built yourself. Commercially available radar reflectors are frequently found as a sailboat supply item, but we recommend building your own because it is so easy!

All you need is some cardboard as a support surface and aluminum foil or (even better) some aluminum foil tape. Simply use some thin and rigid cardboard to create surfaces that face in all three directions: up/down, front/back and left/right. They can be completely rectangular or rounded surfaces. We use rounded surfaces to conserve weight. Cover the surfaces with the aluminum foil and try to keep them as smooth as possible. You can use a credit card to squeegee the surface and smooth out any wrinkles.

When building your own, the biggest requirement is that the radar reflector is visible from all angles. It must be three dimensional so that a radar signal will have a reflective surface to bounce off of no matter where it comes from. Any shape (cubular, spherical) will work. You can attach it to your payload train by cutting a hole through the center and slipping it onto the rope. You can use tape (or other knotting techniques) to keep it in place. The diameter of your reflector should be between 8 and 12 inches across.

·     

Tracking & Recovering Your Weather Balloon Payload:

Most amateur high altitude balloon flights aim to recover their entire payloads. Usually, this is to obtain onboard data, photos, videos or just to reuse the package again on another flight. In order to do this, you’ll need to have some sort of onboard tracking system so you can follow your flight and find the landing location when your mission is completed.

Most of the time, you’ll lose visual contact with your weather balloon payload after just a few minutes so you’ll need to rely on something that can record and relay the weather balloon’s position throughout the flight. 

There are three typical methods that are used for this: amateur radio system, GPS messaging systems, cellular data systems. For reliability, you should implement at least two of these methods so you have a primary tracking system and a backup in case something goes wrong. 

Amateur Radio Tracking

Using amateur radio (ham radio) signals to track your high altitude balloon flight is by far the best option and we strongly recommend utilizing this method. Not only is it the most reliable method, but it is also very rewarding to develop and/or configure a computer tracking system yourself! Using a radio tracking method will allow you to receive positioning reports throughout the entire flight in roughly one minute increments. 

This allows you to follow the entire flight all the way up to burst altitude and even predict the landing location in realtime while the weather balloon payload is still in the air! In the United States (and many other countries), you’ll need to obtain an amateur radio license first, which is not that hard to get. You’ll need to do some minimal studying and take an amateur radio test to obtain a license.

The best tracking method to start with is using the Automatic Packet Reporting System (APRS) which only requires a Technician license. This is the first stage of FCC licensing and the easiest to obtain. Once you’re licensed, you can either purchase a pre-built radio tracking system or build your own radio tracking system with a small computer like an Arduino or a Raspberry Pi.

GPS Messaging Systems

Using a GPS Messaging System to track your high-altitude balloon flight is the second-best method available. These systems are fast and easy to get up and running and don’t require a license to use, however, they are usually much more expensive and require an annual subscription to use the GPS Messaging service. 

The most popular GPS Messaging System used for weather balloon flights is the Spot 3 Satellite Messenger. This system will work anywhere in the world and just needs a clear view of the sky, but there are some downsides and things to consider. 

First, the system will only operate to approximately 60,000 ft (18,300 m) in altitude. These systems aren’t designed to be airborne so the system will lose it’s GPS fix above the maximum altitude, however, it should regain a GPS fix during descent.

This limitation means that you won’t be able to obtain a definitive maximum altitude reading unless you have some other onboard system recording altitude. Secondly, the GPS System requires a clear view of the sky and should be pointed upwards for the best signal.

Payloads have been lost simply by landing upside down or on it’s side causing the GPS System to lose signal. To help mitigate this risk, you can use something like an onboard weighted hamster ball or another similar method to create a gimbal system that will force the GPS device to always point upwards no matter how your payload lands.

Cellular Data Systems

These systems are the worst and we strongly recommend avoiding them in most circumstances. If you must use one, it should be only as a backup method and you’ll need to take special care to comply with FCC airborne cellular device rules.

To start with, your landing location will require a good cellular data signal in order to have any chance of reporting it’s position. This is hard to predict and rely on. Secondly, per FCC rules, you cannot use a cellular device while it is in-flight. This means that you cannot obtain Realtime positioning during the flight and can only use the device to report it’s final landing location. Even without considering the FCC rules, cellular towers are pointed towards the ground so you couldn’t even obtain a signal once you get a few thousand feet above the ground.

Additionally, to comply with FCC rules, you would need to implement a custom application that turns on Airplane Mode (disables the radio) once you launch your weather balloon and then automatically disables Airplane Mode (enables the radio) upon landing.

The radio must be off while the high altitude balloon is airborne. This can be done, but it is a lot of work. The only benefit is that if you do all the work to comply with FCC rules, it can be an inexpensive backup method. You could potentially use a cheap pre-paid Android device and write a custom Android application to enable/disable Airplane Mode.

·     Sending a Camera to Space

Well, it’s not really space, but rather “near-space” – an area between that Armstrong Limit and the Kármán Line. It looks a whole lot like space, but you’re not technically there yet. If you’re going to send a camera up on a weather balloon to the edge of space and back there are a lot of different ways you can do so. 

Most high altitude weather balloon flights that are performed by amateurs will feature onboard cameras to capture the breath-taking views from a place that most humans can never get to themselves. If you’re trying to set an altitude record, you may want to do without the camera to keep your flight weight down, but the first time around, you’ve got to get some photos!

What type of camera to use

One of the first things you’ll need to decide is what type of camera to use. Do you want to capture photos? videos? What’s your budget? How will you power it?

These are all the questions you’ll need to consider. Most flights will use a small action camera, like the GoPro. These small action cameras are great, because they’re small, lightweight, weather resistant and can withstand the cold temperatures of the upper atmosphere. They’re also easy to use and you can simply start recording on the ground and let it run for the remainder of your flight. The actual GoPro brand cameras are great, but they are pricey.

 If it’s your first flight, you may want to consider something less expensive, in case you lose it. So the best camera to use is Lightdow LD4000 Action Cameras. These cameras take fantastic footage and are very inexpensive. 

Another popular option, especially for technology fanatics, is using a Canon camera with custom firmware via the Canon Hack Development Kit (CHDK). The CHDK allows you to load custom firmware onto your Canon camera to control the camera programmatically. 

The three most common operations with the CHDK are:

1. Write a script to record video on a loop
2. Write a script to take a picture on an interval
3. Connect a CHDK powered camera to an Arduino or Raspberry Pi to have a computer control when to take photos and/or videos through the camera’s USB port.

Finally, another popular camera option is to use a camera built specifically for the Arduino or Raspberry Pi platforms such as the ArduCam for Arduino or the Raspberry Pi Camera Module. These cameras are fun to use and play with and are often extremely small and compact which saves a lot on weight and space.

Camera Battery Life

Your high altitude weather balloon flight is generally going to last somewhere between 90 to 180 minutes so you’ll need to consider battery life for your cameras.

Most action cameras like the GoPro or the Lightdow LD4000 cameras are able to capture continuous video for only 45 minutes with their stock battery so you’ll need to consider adding an external battery pack to your camera to keep it powered on for the entire flight. Using an external battery pack can be tricky, though. It’s very difficult to add an external battery to a small Canon PowerShot Camera. It’s a little easy to add to small action cameras and very easy to add to the ArduCam or Raspberry Pi Camera since you can just ensure to provide extra capacity to your Arduino or Raspberry Pi’s battery supply.

If you’re adding an extended battery pack to an action camera, you’ll want to make sure that you camera can record at the same time that it is charging. Also, be sure that once the camera is fully charged that it doesn’t cause your battery pack to turn off. 

Some battery packs will continue to trickle power to the camera once fully charged, some battery packs will completely shut off once it’s fully charged. That means, if you launch a fully charged camera, it may never use the battery pack and die mid-flight. 

Ideally, use a battery pack that doesn’t shut off once fully charged. If you can’t find one, a trick would be to start your flight with a drained camera battery. The first half of your flight will record video while your camera is charged, then if the battery pack shuts off once charged, you should hopefully be able to finish out the flight with just the camera’s native battery.

Camera Lens Choice

One thing you’ll want to consider is what type of camera lens you’ll want to use during your flight. Most action cameras like the GoPro or the Lightdow cameras will have an ultra wide-angle lens, otherwise known as a Fisheye lens. 

There is a lot of controversy about the use of Fisheye lenses on high altitude weather balloons simply because a fisheye lens will indeed cause strong distortion on the image you’re capturing. The benefit of a fisheye lens is that you can capture a wide angle of the Earth and you’ll see more of the ground features over a wider distance. However, if you’re trying to see the actual curvature of the Earth and/or prove the the Earth is round (or flat if that’s your theory), then a fisheye lens isn’t going to help you in this goal since it will inevitably distort the curvature of the Earth in the distance.

There are software products that will remove and correct the fisheye lens distortion afterwards, if needed. Both Adobe Photoshop and GoPro Studio have built in tools to remove and correct fisheye distortion.

If you hate the look of a fisheye lens, then you’ll either need to find an aftermarket replacement lens for your actions camera or use a different type of camera. Aftermarket replacement lenses do exists, mostly for just the GoPro brand items, but they are hard to find. Your best bet would be to use a Canon camera with the Canon Hack Development Kit (CHDK) instead so you can full control what camera lens you use for your footage. Usually this is a more expensive route to go, but the best method if you’re trying to see the actual curvature of the Earth.

Don’t forget, though, that the Earth is very large! Your balloon will only reach about 20 miles in altitude. This is only 8% of the altitude of the International Space Station and means that you’re only going to see 5% of the Earth’s diameter. Although you can certainly measure curvature from this altitude, you’ll need a clear cloudless day for hundreds of miles and a high quality camera to measure the (minimal) curvature at that altitude. See this curvature simulator which shows what you can expect to see for curvature at 30,000 m (98,425 ft). Note that the simulator input uses altitude in meters not feet.

Earth Curvature Simulation at our maximum altitude of 34,291 meters (112,506 ft):

Camera Capture Mode

One final thing to consider is the capture mode you want to use to obtain your imagery. You can choose to take photos on at certain intervals or record video of the entire flight and the suggested software in VLC PLAYER. 

One thing highly recommend is to set your video recording to be captured on a loop. This means that instead of creating one giant video file, you should instruct the camera to stop and save your recording every few minutes and start a new video file.

The benefit of this is that if anything happens to your camera during the flight, you can at least recover some video from a portion of the flight that had no issues. 

Another tip we have is to use dashcam mode, if possible. This is an optional method, but one we use on every flight. The Lightdow LD4000 cameras are capable of running in dashcam mode which means as soon as they receive power, they will turn on and begin recording without any extra button presses.

One caution, though, is that if you’re going to use dashcam mode once the SD card is full, it will loop around and start overwriting your oldest video files. Make sure your SD card has enough storage space to outlast your camera batteries.

Lastly, check and test your cameras for electromagnetic interference with your GPS tracking systems. Particularly, this is a common issue on action cameras when they are in close proximity to your GPS electronics.

The circuits that write the video data to the onboard SD cards can be noisy (electronically speaking). Even the cameras can be wrapped completely in copper tape to create a faraday cage around the camera and reduce the interference the camera causes. 

Additionally, we use an active GPS antenna which also helps weed out interference and performs better than cheaper ceramic passive antennas.

·     Pre-Flight Predictions

Before launching your flight, you should always run pre-flight predictions to get an idea on where your flight will be travelling to. There are many online calculators to help you with this. Most will allow you to run your flight predictions beginning 7 days prior to your launch date. 

This will help you decide whether or not it is safe to launch and/or whether or not your need to move your launch site to a different location or adjust your balloon’s size or ascent rate to avoid hazards. 

For example, if the flight path passes over an airport or large body of water, you should consider changing your launch location, your balloon size/fill, or waiting a few days for a different wind profile. Ideally you want to land in open farm land. This allows for a safe and easy recovery.

The most popular online flight prediction tool is the Cambridge University Spaceflight (CUSF) Landing Predictor. In our experience, this prediction tool has been very accurate and will usually give you a landing estimate that is within about 5 miles from the actual landing site. Although it is rare, it’s not unusual for the prediction to be off by upwards of 20 miles so when planning your flight, you should ensure that you have at least 15 miles or more between the predicted landing site and any major hazards like big cities, airports or large bodies of water. 

We recommend running multiple predictions with various parameters so you can identify a trend. This will give you insight as to where the payload could land if the flight ends sooner or later than you expected. 

One of our favourite secondary prediction tools we use to help with this is the University of Southampton ASTRA High Altitude Balloon Planner. This tool allows you to run multiple prediction variations (we run 250 each time) at once and will give you a heatmap of your landing zone so you can see and plan for the possible margin of error.

Most flight predictions tools use the Global Forecast System (GFS) weather models to supply their predictions. These tools are updated every six hours with new weather data so you can run multiple updated predictions as your launch time approaches. 

New weather models are published at 04:00 UTC, 10:00 UTC, 16:00 UTC and 22:00 UTC. The predictions tools are usually ready to provide a prediction with the updated forecast about 45 minutes after the new weather model has been published so you can run new predictions starting at 04:45 UTC, 10:45 UTC, 16:45 UTC and 22:45 UTC.

FAQs (Frequently Asked Questions):

1.    Is it safe?

Yes, but only if you take the necessary precautions. Never launch a weather balloon in an area with congested air space and always coordinate your launch with the appropriate authorities. In the US that may include filing a NOTAM (Notice to Airmen). For our Canadian customers, it includes contacting Transport Canada and Navigation Canada. This important process informs air traffic controllers and pilots to be on the lookout for a weather balloon when flying in the same airspace as your weather balloon. It also gives them a way of contacting you if they need you to delay your launch or get an update on your weather balloon’s position. Filing a NOTAM is easy and only takes a few minutes. Our comprehensive flight manual that comes with every Eagle Kit will guide you through the entire process. Every week over 10,000 weather balloons are launched by meteorological organizations around the world. There are also an additional 10-20 amateur launches performed each week. To date there has never been a report of an airplane striking a weather balloon. 

2.    How long does a flight typically last?

Flights typically last two to three hours. Flight time depends on how much helium you put in your balloon and the size of your parachute. The more helium you use, the faster your balloon will climb. It also means your balloon will burst at a lower altitude. Typical ascent times are one to two hours. A larger parachute will also increase your flight time by reducing your descent rate. Typical descent times are 30 minutes to one hour. To calculate your ascent time for a given size balloon and payload, use our balloon performance calculator.

3.    How far from your launch site does your payload typically land?

The biggest factor on how far your payload will travel is the jet stream. There are four of them that constantly circle our globe from West to East at an altitude of roughly 18,000 m ~ 60,000 ft. Jet streams can typically reach speeds of over 120 km/h ~ 75 mph. If one of these jet streams happens to be directly over your launch site, your payload could travel up to 120 km ~ 75 miles. If the jet stream isn’t above your launch site, then your payload could land as little as 30 km ~ 20 miles from your launch site.

4.    Is launching a weather balloon environmentally friendly?

The helium gas used to launch weather balloons is an inert gas naturally found in our atmosphere and has no impact on our environment. Another concern is the balloon. Our weather balloons are manufactured from latex, a natural material which is made from tree sap and collected in a manner similar to maple syrup. Although your chance of not being able to recover one of our kits is small, just to be safe we use predominantly natural materials as the main structural members of our kit. High Altitude Science is serious about being a steward of our environment. We use natural materials whenever possible.

5.    How do you know where your payload will land?

Twenty-four hours before you launch, look up the weather forecast on ground winds and the jet stream on your favorite weather website. Then, using a simple formula in our Eagle Flight Manual, you should be able to predict your landing site within 15 km ~ 10 miles. Some people like to use online weather balloon flight prediction software. We have found some of these sites to be unreliable and prefer our simple pencil and paper approach. If your payload is predicted to land near a lake, mountain, populated area, etc. just move your launch site.

6.    How do you find your payload after it lands?

The SPOT Trace is our fail-proof go-to tracking solution. It doesn’t require a license to operate and performs flawlessly with no need for a heat pack. The only drawback to the SPOT is that it doesn’t work above roughly 18,000 m ~ 60,000 ft. Above this altitude your payload enters what we call “blackout.” When using the SPOT Trace, it is important to remember that it must be facing the sky to uplink its coordinates to the satellite network. This is why our Eagle has a flat profile. If you use a cooler box to house your gear, it could flip on its side when it lands preventing the SPOT from connecting with the satellite network.

7.    Why not use a Styrofoam box as my weather balloon payload?

Styrofoam boxes are cheap but they have a major flaw. When we first started developing our weather balloon kits, we experimented with the “box” approach as a cheaper alternative to our Delta Flight Frame design. Unfortunately, our test flight payloads were disappearing without cause. It wasn’t until a farmer found one of our lost payloads and we were able to look at the flight video that we realized what was going wrong. Our Styrofoam boxes would bounce and land on their side when they hit the ground. This would prevent the GPS tracker from being able to reliably receive and transmit signals to the satellite network overhead. Sometimes you get lucky and your “box” gets suspended upright in a tree or does not roll onto its side (or upside down) when it lands, but we cannot justify taking this risk. Our goal is to make our kits 100% reliable regardless of where they fly and what terrain they land on.

8.    I'm a student who wants to launch one of your kits, but I don't have the necessary funds. Any suggestions?

Get your community involved. Talk to friends, family, teachers, co-workers, people at church, clubs, and businesses. If everyone contributes a few dollars, you will be able to afford one of our Eagle Kits in no time. Be creative in your advertising campaign and do not get discouraged if contributions start out small. The more excited you are about starting your own space program and the more your campaign grows, the more people will be willing to contribute.

9.    Is the Eagle Flight Computer easy to use?

Just insert the micro SD card and add batteries. Once you recover your payload, remove the micro SD card and slide it into your SD card adapter. Download the file into Microsoft Excel and you’re ready to plot temperature, pressure, altitude, wind speed, flight path, etc. The Eagle Flight Computer comes with a manual that will guide you through the steps if you’re not familiar with using Microsoft Excel.

10. Where do I get Helium?

Most party supply stores such as Party City or iParty carry helium bottles.

11. I want to launch my own weather balloon. Where do I start?

Our tutorials are a great place to start. If you decide to purchase our Eagle Kit, it will come with our full-color flight manual that will turn you into a near-space pro.

12. What if my payload lands in a tree?

The safest thing to do in this situation is to have a certified tree climber retrieve your payload. Their fee is typically $50. Once on site, they can have your payload on the ground in less than 20 minutes. To find the local tree climber, call the nearest fire department. They work with tree climbers on a regular basis. Sometimes tree climbers offer to get your payload down for free. If they do, be sure to give them a good tip and thank them.

13. Do I need to insulate my payload from the cold temperatures of the upper atmosphere?

In most cases insulation is not necessary. Our Eagle Pro Weather Balloon Kit has no insulation and has never experienced negative effects from low temperatures. It is important to understand that low temperatures do not damage well designed electronics. However, cold temperatures do reduce the effectiveness of most batteries. A battery is simply a chemical reaction that produces electricity. As with most chemical reactions, the reaction rate slows as temperatures drop. A battery that has the capacity to power your electronics at room temperature could be inadequate at below freezing temperatures. The best solution to this problem is to only use batteries that are rated for cold temperatures. For this reason, High Altitude Science only recommends using Energizer Ultimate Lithium batteries to power your flight computer and satellite tracker.

14. What are the recommended lengths of flight line used to tie the payload to the parachute and the parachute to the balloon?

We recommend using two identical 5 m / 15 ft lengths of stratospheric flight line. One length is tied between the balloon and the apex of the parachute. The other length is tied between the parachute risers and ball bearing swivel on the payload harness. The total distance between the balloon and payload is therefore 10 m / 30 ft with the parachute suspended in tension halfway between the balloon and payload. Once the balloon bursts, the tension on the parachute apex is released allowing the parachute to flare open. This is a fail-proof setup for eliminating parachute tangles which will allow your payload to return safely to earth.

15. What is the shelf life of your weather balloons?

We recommend that our weather balloons are used within one year of your purchase. However, our customers have used our weather balloons after three years of storage with no noticeable degradation in performance. It is very important that you store your weather balloon in its original packaging at room temperature in a dry, dark place. Our weather balloons are made from latex which will slowly degrade in light, especially direct sunlight.

16. What balloon size is right for me?

For your first launch we recommend starting with a smaller balloon size such as our 350 g or 600 g weather balloons as they are easier to inflate and tie off. They also require less helium to inflate which reduces the cost of your first mission. For more experienced flyers, our larger size balloons such as our 1200 g or 1500 g weather balloons are a great option. Given the same size payload, our 1500 g weather balloon will burst at a higher altitude than our 350 g weather balloon. To estimate how high our balloons will fly with a given size payload, take a look at our Weather Balloon Performance Calculator tutorial. It will also help you calculate how much helium you need.

A common misconception is that a larger balloon will carry your payload further from the launch site as it will fly higher and thus longer and further. This is rarely the case since there is typically very little wind in the Stratosphere. Once the balloon climbs past the jet stream, it travels at a much slower speed. In some cases, there may even be a light wind above the jet stream that blows in the opposite direction, which may bring your payload closer to the launch site.

17. Do you need to wear gloves when handling a weather balloon?

There's a popular theory that natural oils on your hands will contaminate the balloon. We've launched missions with and without gloves. We have never noticed a difference in balloon performance in either case. Working with gloves is awkward and uncomfortable, but it also looks more professional. If you're launching a balloon for a client or in front of a lot of spectators, wear the gloves. If it's just you and a small research team and you don't believe the "oily hands" theory, keep them off.

BOM (Bill of Materials):

·      BALLON ($100)

UV resistant for balloon ($2)

Weather Balloon Radar Reflector ($1)

·      FISHING LINE ($3)

·      BATTERY WITH BMS ($10)

·      PARACHUTE ($15)

·      GROUND EQUIPMENTS:

Inflation system with Helium ($170)

Radio Tracking ($10)

Antenna Tracker ($13)

·      PAYLOAD

Camera 1 ($73)

Camera 2 ($130)

Camera 3 ($25)

Telemetry, GPS communication ($10)

Sensors ($60)

Flight Controller ($10)

Memory Card ($7)

We have used information from NASA'S provided resources along with some from real-life examples...

The hackathon journey has been an amazing one...we did learn so many things from it...

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#Highaltitudeballons #flying

This project has been submitted for consideration during the Judging process.