Sending a Weather Balloon to 95,000 Feet




About: I like anything to do with RC, Model Rocketry, and Crafts! Follow me for fun things to do in your free time!

On April 30, 2016 I launched Project BAHAB, a two year project, into Space. The Berwick Academy High Altitude Balloon, it was originally designed to carry 1 camera facing down to recreate the famous Powers of Ten Documentary (link). It ended up merging into sending the Berwick Academy mascot up to space. So, why did I do this? Well, I love anything that is related to flying or space. I design and build balsa DLGs (Discuss Launch Gliders) and I love flying Rc planes. I thought that this way of sending cameras through the air was non conventional compared to the thousands of quadcopters (or Drones) that you see flying around. I also thought that this would be a bit harder to do, and I love challenges.

I hope that this guide will provide enough information for you to go off and build your own without doing too much research outside of this guide.

So, without further or do, lets design and make your own weather balloon.

Please, if you like what I do and want to see more, please vote for me in the contests above!

Step 1: FAA Rules Relating to Payload

If you are in the United States these are the rules you have to follow in order to legally launch your weather balloon. These are just the rules for the payload/balloon. Don't worry there are more :).

§101.35 Equipment and marking requirements.

(a) No person may operate an unmanned free balloon unless— (1) It is equipped with at least two payload cut-down systems or devices that operate independently of each other; (2) At least two methods, systems, devices, or combinations thereof, that function independently of each other, are employed for terminating the flight of the balloon envelope; and (3) The balloon envelope is equipped with a radar reflective device(s) or material that will present an echo to surface radar operating in the 200 MHz to 2700 MHz frequency range. The operator shall activate the appropriate devices required by paragraphs (a) (1) and (2) of this section when weather conditions are less than those prescribed for operation under this subpart, or if a malfunction or any other reason makes the further operation hazardous to other air traffic or to persons and property on the surface.

(b) No person may operate an unmanned free balloon below 60,000 feet standard pressure altitude between sunset and sunrise (as corrected to the altitude of operation) unless the balloon and its attachments and payload, whether or not they become separated during the operation, are equipped with lights that are visible for at least 5 miles and have a flash frequency of at least 40, and not more than 100, cycles per minute.

(c) No person may operate an unmanned free balloon that is equipped with a trailing antenna that requires an impact force of more than 50 pounds to break it at any point, unless the antenna has colored pennants or streamers that are attached at not more than 50 foot intervals and that are visible for at least one mile.

(d) No person may operate between sunrise and sunset an unmanned free balloon that is equipped with a suspension device (other than a highly conspicuously colored open parachute) more than 50 feet along, unless the suspension device is colored in alternate bands of high conspicuity colors or has colored pennants or streamers attached which are visible for at least one mile.

Now that we are past this point lets start designing our payload while paying attention to these rules.

Step 2: Design

The first step in our process to send stuff up to space is to design the capsule that will carry up all our objects. When I went through this stage I drew 3 different designs. Some people send things up that look like R2-D2 or "rockets". Here are things that I considered to determine whether a design would work or not;

1. Durability. It should be able to withstand a harsh landing and the force of the balloon popping.

2. Simplicity. It should be simple to put together and take apart so you can put stuff in and take stuff out.

3. Size. This one is important, because if there is unused space and if something goes wrong in the air it could be catastrophic. Though later I found out that if it is too big, you can still put a filler inside to keep everything safe (that's what I did).

The material that the payload is made out of is also important. In picture number 2 The medium that I ended up choosing was foam. Look at picture 1 for a chart I made on this. I really wanted my payload to be simple to build and be easy to work with so I could move on to the next part. Take a look at picture 3 for a good box design that I almost based mine off of.

I went through multiple designs of what I wanted. My first design was just a box but then I felt like I wasn't getting enough space for the electronics. My next design was a tower style. This design was meant to be aerodynamic to produce the least amount of drag and be made out of cardboard. I then thought that if it landed in the water the SPOT Tracker wouldn't be facing up so what I used was two foam half spheres. I found this to be the best, because in all landing scenarios the SPOT would face up due to the weight on the bottom of the payload.

If you are going to do it my way and have 2 half spheres I suggest the following to prevent them from splitting open in mid-flight.

Use an eye hook at the top of one of the spheres (see pic 4). Do this by drilling a hole through the top. After that attach a big washer to the bottom and use epoxy/ hot glue. This will prevent the eye hook from ripping out when the balloon pops.

Next thing I would suggest is to use Duct Tape, and lots of it. Don't just go around horizontally to water proof it but go parallel and wrap it around to insure it not separating.

Get small bungee cords. Attach one end to the Eye hook and one end to a spur out of the side of the bottom sphere without the eye hook (see pic 5). For the spur I cut off a piece of carbon fibre rod found in a kite to about 4" and then fed it through at a downward angle to hold the other bungee. I then hot glued it with a washer to prevent it from ripping out. I did this to both sides.

Misc Suggestions:

If you are sending up a school mascot I suggest that you print it out to a small size (mine was 1 inch by 1 1/2 inches) and cover it with clear packing tape/ laminate it. Then attach it to a black popsicle stick about 6" out from the edge of the container (might want to cut it to 7 so you can stab it in an inch and then hot glue so it is more stable). This worked well for the GOPRO.

Have taped to outside your contact info, and what it is. Be sure to say it isn't dangerous. Maybe offer cash reward if found. Also have another copy inside payload inside plastic bag so it doesn't get wet.

Step 3: Inside the Payload/Materials

Here is a list of everything I got for this project including ground items. It has links and most have cost:


Inside the Payload Inside my payload I had a SPOT Tracker, Altimeter, and two GoPros. This is a great beginner HAB (High Altitude Balloon) for your first time. Here is a list of what I think will provide you with enough information on what to put inside. If you want to do something different please do.

Beginner: SPOT Tracker, Altimeter, GoPro (or any other camera)

Intermediate: SPOT Tracker, Back up tracker*, Telemetry, Possibly more GoPros

Advanced: APRS**, Back up tracker, Telemetry, Cameras

I also highly suggest a buzzer or a small beacon of some sort. This is if you can't find your payload you can listen for it or you can wait until dusk and see it. Also reflective tape.

*For a backup tracker I suggest pocket finder. Really cool and I almost used it for my main one.

**APRS is a way of tracking with something called a HAM Radio. HAM Radio requires a license to use and can be hard. I was going to go this route since I already have mine but I found it too difficult for my first launch.

Step 4: Placement of Objects Inside the Payload

Here are some tips that I have. This is really how you want it.

One important thing that I tried to do and mostly succeed was balance the payload. The reason why one would do this, is if you have a camera facing the horizon (side) you want to put the tracker and other stuff on the opposite side of the payload to balance it out. This helps a lot.

Waterproof everything with plastic sandwich bags. I wasn't going to do this originally but I am glad I did as I had an unexpected water landing.

If you can try to have the SPOT in the middle on a gimbal. I didn't do it because I thought balance was more important at the time but I had much more of a risk of losing my whole payload.

Make camera bumpers. This is so your lense/case of the camera won't get scratched.

Tape everything in when you are done even if you hot glued it. Don't risk it coming loose.

Step 5: Payload Train

The Payload Train is what we call the rope that Attaches the balloon to the Payload. What it consists of is the Parachute and the Radar reflector. The parachute I got was 3 feet in diameter and did a great job. I bought mine from Rocketman but you can easily make your own using a trash bag and string. It doesn't have to look pretty, it just has to do its job to slow it down. As a bonus, make it a bright color so it will be easier to find.

The Radar Reflector is really just tin foil. I made a separate one, but you can also cover your payload with tin foil. Just be sure not to cover the top of the payload because it will disrupt the GPS signal being sent to you by the SPOT. If you want to make yours like I did (not on the payload) then use this ible' (link). I found it very helpful.

Payload Train Rope.

Use paracord! It is lightweight but very strong. Also because it is braided, it won't twist as easily. Try to get atleast 50 feet. More is better, though I wouldn't go above 75' because you want to get the maximum height!

Step 6: Ground Items

This part was not my favorite part... But fear not! I have put together all the ground items I have used for you to easily put together. Ground items include:

Helium (we will talk more about this later on), Tarp, Latex Gloves (try to get latex as that is what the balloon is made of so your oils in your hands won't pop it), Bucket with weights (a little heavier than your payload), and hose with regulator.

Don't forget tools! Scissors, Phillips head, Alan wrenches, and knives also helped me with various things from unscrewing the altimeter to put the battery in to making last minute cuts with my knife.

Be sure to look at the list of ground items here: Ground Items

Step 7: Balloon

We have worked our way up the Payload Train to the Balloon. This is probably the biggest part of the project. Depending on the weight of your payload (my setup is 1060 grams) you will need a different size balloon. My balloon I got from High Altitude Science and they are great! I got their 1200 gram balloon for $95 with is really good! Depending on where you are launching from, the time in which you want your balloon to be in the air, and where you want it to land, you will want your ascent rate to be either faster or slower.

Remember if you get two 1200 gram balloons and fill one more than the other then the one with less helium will go higher but will be slower to pop. This is bad if you need to get your payload down before it reaches an ocean. I filled my 1200 gram balloon with 184 cu ft of helium to achieve an altitude of approximately 95,000 feet. This leads us to our next topic; helium.

Step 8: Helium

Helium is a fun subject though it is really hard to get! Don't go to a party supply store to get the disposable tanks as those aren't the helium that we are looking for. In those it has a little oil and nitrogen mixed in to bring down the cost. What we want are those big tanks that are 99% helium or Industrial grade. I Party might have what we are looking for. Ask them for Industrial grade helium. You want about 200 cu. ft. of helium for a 1200 gram balloon lifting 1060 grams of weight. I used a K-Type helium canister. If I Party doesn't have it which they probably won't look online for retailers. Try to get the helium a couple days before launch so you can test everything but won't have to pay for keeping too long.

Use this calculator to see how much helium you need to lift your payload: for target burst altitude type in 30480. This is 100,000 feet and since the predictor is a little forgiving you will probably go higher! When seeing how much helium to put in you want a ascent speed of atleast 5 meters per second (mine was 8) because of ocean).

The less you fill your balloon the higher it will go but the more time it will be in the air. If you fill your balloon up more it will go less high but will be in the air for shorter amount of time. Just be aware of that when you are filling your balloon up. It is better if you play it safe by filling more of it up and having it pop a little premature than staying up in the air and landing somewhere inaccessible.

Step 9: Landing Predictor and Calculators

Landing Predictor:

The landing predictor is basically the thing that will tell you where the balloon will land before you launch it. Not only does this one tell you where it will land based off of location, but it also will tell you how much helium you need based on balloon size. You need to do this because you need to let the FAA know where it will land and launch from. The landing predictor that I used is called the CUSF Landing Predictor 2.5 (link). This one is extremely easy to use and is very helpful. Refer to pictures on how to use it.

Descent Calculator:

This is also something that you need to know. Descent is when the payload starts falling back to earth. I used a rocketry calculator (link) to tell me how fast the payload would come down. My payload was 1060 grams so I used a 3 foot parachute to slow it down to a speed of 20 mph. This is fast but where my payload was landing it didn't matter since it would touch down in the ocean. If you wanted a slower descent rate then use a bigger parachute. Once you have figured out how big the parachute is going to be write down the number that the calculator showed. Refer to pictures for more information.

Step 10: FAA Regulations and Alerting the FAA

What you are about to read from is straight from part 101 subpart D (Unmanned Free Balloons) of the FAA Regulations. I will help explain what I interpreted each section to focus on the most. Here is a link if you want to open it on another page: Remember it is subpart D.

This part of the regulations is mainly so you can pick out a safe launch zone that does not interfere with any air traffic and that your payload will land in a safe area. What you can use to determine this is a VFR map. Here is a link: It is a little confusing, but read this article on how to read the map so you can find a location that is safe to launch from How do we find a safe landing zone you may ask? Well, what you do is play around in the simulator until you get a spot that will be a safe launch and an area that will land in a rural area. See picture 2-3 for more info. Here is the code.

No person may operate an unmanned free balloon—
(a) Unless otherwise authorized by ATC, below 2,000 feet above the surface within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport;

(b) At any altitude where there are clouds or obscuring phenomena of more than five-tenths coverage;

(c) At any altitude below 60,000 feet standard pressure altitude where the horizontal visibility is less than five miles;

(d) During the first 1,000 feet of ascent, over a congested area of a city, town, or settlement or an open-air assembly of persons not associated with the operation; or

(e) In such a manner that impact of the balloon, or part thereof including its payload, with the surface creates a hazard to persons or property not associated with the operation.

In this next one you have to call the nearest Air Traffic Control Within 6 to 24 Hours before beginning the launch. Even if the nearest one is 200 miles away still call. When I put an * and bold it, that means I'm commenting. It is not code.

§101.37 Notice requirements. (a) Prelaunch notice: Except as provided in paragraph (b) of this section, no person may operate an unmanned free balloon unless, within 6 to 24 hours before beginning the operation, he gives the following information to the FAA ATC facility that is nearest to the place of intended operation:

(1) The balloon identification. *Name your balloon something (mine was BAHAB)

(2) The estimated date and time of launching, amended as necessary to remain within plus or minus 30 minutes.

(3) The location of the launching site. *Make sure you are not interfering with any airports!

(4) The cruising altitude. *They didn't ask me this one so I said the time it takes to cruising altitude

(5) The forecast trajectory and estimated time to cruising altitude or 60,000 feet standard pressure altitude, whichever is lower.

(6) The length and diameter of the balloon, length of the suspension device, weight of the payload, and length of the trailing antenna. *Basically asking how big is the balloon, and how long is the rope attaching the balloon for the first two. I didn't have a trailing antenna so I said I didn't have one.

(7) The duration of flight. *you can find this out in the simulator in the top right corner.

(8) The forecast time and location of impact with the surface of the earth. (b) For solar or cosmic disturbance investigations involving a critical time element, the information in paragraph (a) of this section shall be given within 30 minutes to 24 hours before beginning the operation. (c) Cancellation notice: If the operation is canceled, the person who intended to conduct the operation shall immediately notify the nearest FAA ATC facility. (d) Launch notice: Each person operating an unmanned free balloon shall notify the nearest FAA or military ATC facility of the launch time immediately after the balloon is launched. *really just the time and location of impact of the payload. I don't think you want to investigate any time critical phenomenons.

This next part I only had to do once since my flight time was only two hours. Just make a list so you can write down what you will say to them easily.

§101.39 Balloon position reports.

(a) Each person operating an unmanned free balloon shall: (1) Unless ATC requires otherwise, monitor the course of the balloon and record its position at least every two hours; and (2) Forward any balloon position reports requested by ATC. *I did mine in the first hour when the balloon reached it's popping height.

(b) One hour before beginning descent, each person operating an unmanned free balloon shall forward to the nearest FAA ATC facility the following information regarding the balloon: (1) The current geographical position. (2) The altitude. (3) The forecast time of penetration of 60,000 feet standard pressure altitude (if applicable). (4) The forecast trajectory for the balance of the flight. (5) The forecast time and location of impact with the surface of the earth.

(c) If a balloon position report is not recorded for any two-hour period of flight, the person operating an unmanned free balloon shall immediately notify the nearest FAA ATC facility. The notice shall include the last recorded position and any revision of the forecast trajectory. The nearest FAA ATC facility shall be notified immediately when tracking of the balloon is re-established.

(d) Each person operating an unmanned free balloon shall notify the nearest FAA ATC facility when the operation is ended.

Please make sure you follow these rules as I am not responsible for whatever you get yourself into.

Step 11: Final Note and Pre Flight Checklist

Thank you for viewing my Instructable. It means a lot to me. I hope you find this informative and I also hope that you will share pictures of your balloon projects too! Now I know this guide didn't cover everything you need to know as I found out that it will take me years to write everything so here are some helpful links to pages that show you how to properly fill and tie a balloon, attach it to the payload, and launch it, as well as helpful pages. Here are the links:

I hope this guide has also led you to a new hobby as most of these materials can be reused. As a final thing I would like to share my checklist with you so you know you have everything for your launch day. Make your own for the week leading up to it as well as the day of the launch. These are based of my own and other peoples checklists so you know that they are working. Here are the checklists:

Day of:

At launch site:

Thank you for viewing and please vote for me in the contests!

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    16 Discussions


    1 year ago

    was the school logo bibich


    2 years ago

    Awesome tutorial!! BTW how much helium would I need for a 600g PAWAN balloon with 1000g payload? Also I might consider Hydrogen to cut costs can you give me an approximate volume requirement?

    2 replies

    Reply 2 years ago

    Here is what it would look like for 20,000 m

    Burst Altitude:20000 m Ascent Rate:8.06 m/s

    Time to Burst:41 min Neck Lift:6016 g

    Volume:6.45 m36446 L 227.6 ft3

    there ya go


    Reply 2 years ago


    I'm glad you found it helpful! Use this link to find out how much you need:

    Remember: with a smaller balloon and more helium your payload won't go as high because it pops sooner. Also, do you have a target altitude? For the calculator you need to specify one or you need to have a target ascent rate. I believe if I remember correctly that mine was 5.2 m/s or something like that.


    2 years ago

    yup, awesome, do you have the footage that was recorded?

    2 replies

    Reply 2 years ago

    hi thanks, please also post it on my orangeboard thing or PM or whatever it is thats on you profile page.


    2 years ago

    Whoa! Cool project! I voted!


    2 years ago

    Amazing work! Hope you inspire other kids to try it!


    2 years ago

    where do you get the weather balloons from?

    1 reply

    Reply 2 years ago

    High Altitude Science. Their prices are great for the quality!