High Altitude Free Balloons
Definition
The definition of an Unmanned Free Balloon (also known as a High Altitude Balloon) is a balloon that travels freely through the atmosphere through atmospheric buoyancy, and is unpowered.
Restrictions
For the following types of unmanned free balloons must follow the rules detailed below as outlined in Title 14 Chapter 1 Subchapter F Part 101:
Carries a payload package that weighs more than four pounds and has a weight/size ratio of more than three ounces per square inch on any surface of the package, determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface;
Carries a payload package that weighs more than six pounds;
Carries a payload, of two or more packages, that weighs more than 12 pounds; or
Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon
No Unmanned Free Balloon may
Operate below 2,000 feet within the surface area of Class B, Class C, Class D, or Class E airspace.
Operate at any altitude where there are clouds or obscuring phenomena of more than five-tenths coverage.
At any altitude below 60,000 feet, standard pressure altitude where the horizontal visibility is less than 5 miles.
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.
Operate in such a manner that the impact of a balloon, or any part of its payload, with the surface creates a hazard to persons or property not associated with the operation.
No person may operate an unmanned Free Balloon
Unless it is equipped with at least two payload cut-down systems or devices that operate independently of each other.
Unless at least 2 methods, systems, devices, or combinations thereof that function independently of each other are employed for terminating the flight of the balloon.
Unless the balloon is equipped with a radar reflective device or material that will present an echo to surface radar operating in the 200 MHz to 2700 MHz frequency range.
Below 60,000 feet standard pressure altitude between sunset and sunrise unless the balloon and its attachments/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.
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.
Between sunrise and sunset, that is equipped with a suspension device (other than a highly conspicuously colored open parachute) more than 50 feet long, 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.
Every Unmanned Free Balloon must notify the nearest FAA ATC facility of the following within 6 to 24 hours before beginning the operation.
The Balloon Identification.
The estimated date and time of launching, amended as necessary to remain within plus or minus 30 minutes.
The location of the launching site.
The cruising altitude.
The forecast trajectory and estimated time to cruising altitude or 60,000 feet standard pressure altitude, whichever is lower.
The length and diameter of the balloon, the length of the suspension device, the weight of the payload, and the length of the trailing antenna.
The duration of the flight.
The forecasted time and location of impact with the surface of the Earth.
For solar or cosmic disturbance investigations involving a critical time element, the above information shall be given within 30 minutes to 24 hours before beginning the operation.
If the operation is canceled, the person who intended to conduct the operation shall immediately notify the nearest FAA ATC facility.
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.
Each person operating an unmanned free balloon shall
Monitor the course of the balloon and record its position at least every 2 hours and forward this information to the nearest FAA ATC as requested.
One hour before descent, provide the following information to the nearest FAA ATC facility
The current geographical position
The Altitude.
The forecasted time of penetration of 60,000 feet standard pressure altitude (if applicable).
The forecasted trajectory for the balance of the flight.
The forecasted time and location of impact with the surface of the Earth.
If a balloon position report is not recorded for any 2-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 forecasted trajectory. The nearest FAA ATC facility shall be notified immediately when tracking of the balloon is re-established.
Each person operating an unmanned free balloon shall notify the nearest FAA ATC facility when the operation is ended.
Launching an Unmanned Free Balloon
Balloon Filling Instructions:
Once the team has arrived at the launch site, please ensure that there are a maximum of 4 people around the balloon to avoid overcrowding it, and everyone working with the balloon should be wearing gloves, hair nets, and safety glasses. Below is a list of steps to follow on how to fill and tie off the balloon, and a document with pictures. While this is ongoing, there should be another team preparing the payload for flight.
Lay a blanket, towel, or tarp on the ground to prevent the balloon from directly touching the ground. Especially when working on grass, the macroscopic sharpness of the grass can cause microtears in the balloon.
Unscrew the safety lid from the gas tank. From this point on, everyone within 20 feet of the balloon should be wearing safety glasses.
Attach the regulator to the gas tank. For Helium, this should be a CGA-580 regulator. A single-stage regulator is fine, but a dual-stage regulator is preferred due to safety reasons. A dual-stage regulator will allow users to regulate the rate at which the gas leaves the tank and has a separate valve to cut off the gas from leaving the regulator; however, dual-stage regulators are much more pricey.
Spread the balloon out on the blanket, and be careful not to step on the latex. The neck of the balloon is much thicker and can stand a little bit of roughness, but the skin on the rest of the balloon is very easy to tear. Using gloves and hairnets prevents the oil produced from the human body from getting onto the balloon and degrading it, as well as preventing the hair on our heads from poking microscopic tears in the balloon.
Insert the balloon fill-line into the neck of the balloon and zip tie it around the outside of the neck of the balloon. Before tightening the zip tie, please attach a small string with a loop to the zip tie and tie another length of string to attach to the gas tank cart or another weight to prevent the balloon from flying away if someone lets go of it.
If using a single-stage regulator, open the valve at the top of the tank, then slowly open the valve to stream gas into the balloon. Slowly open the regulator until the valve is entirely open. If using a dual-stage regulator, open the valve at the top of the tank, set the flow limit of the gas into the regulator, then slowly open the other valve at the end of the regulator. Slowly open the regulator until the valve is entirely open.
It is good practice that once a valve is opened entirely, the valve be closed a hair of a turn, so if someone else tries to test the state of the valve that they don't break it.
During this process, someone should be holding onto the tank and monitoring the pressure left in the tank while a separate person monitors the balloon by holding onto the neck.
Additional people may be required if the balloon is large or if it is windy; these additional people can put their hands up to stop the balloon from blowing in a certain direction.
Once the balloon lifts itself off the ground, attach the force scale to the string with the loop and either stake the other end into the ground or securely hold the force scale in place, like by gripping the handrail of the gas cart, so the lifting weight can be measured properly. Continue filling the balloon until the desired lift weight is achieved.
If the predetermined lift weight is too much for the force spring scale, a digital fish scale is not recommended. It is recommended that gym weights or calibration weights be used to hang from the same loop and to continue to fill the balloon until the balloon naturally lifts these weights off the ground without sinking.
Once the balloon has achieved its desired lift weight, close the valve to the regulator and the tank. Hold the neck of the balloon and twist the rest of it to cut off the flow through the neck. Place a zip tie around the twist so it doesn't undo itself. While maintaining a tight grip on the balloon, twist the inflator hose out of the neck and try not to let the zip ties that are holding the tether string fall. Push these zipties further up the neck of the balloon, and tighten them down around the twist. Very carefully, with the points pointed away from the balloon, snip the tails of the zip ties off.
Feed the neck of the balloon through an o-ring and fold the neck over the o-ring so it sits next to the twist. Use additional zip ties to hold the end of the neck up so the o-ring stays in place. Carefully cut the tails of the zip ties off and use electrical tape to cover the sharp ends so they do not swing up and puncture the balloon.
Attach a string for the payload to attach to, and attach the string tether to the o-ring.
Assign someone from the balloon filling team to hold the balloon via the o-ring until it is launch time.
Balloon Filling Video WIP
Launching with a Single Payload Configuration
The weight capacity of a single payload is 6 pounds.
Be sure that the payload is turned on and is broadcasting its telemetry, and *most importantly* that you’re receiving that telemetry BEFORE you tie up the payload.
Use the following video to help tie up the payload box. Instead of finishing with a bow, finish with a knot.
Additionally, knots similar to Alpine Butterfly Loops will be needed on the four sides of the payload, so make sure you leave enough rope for you to complete this. We recommend tying these loops as you tie up the payload. For assistance with the Alpine Butterfly Loops, follow this video:
On each of the Alpine Butterfly Loops, attach key rings on the top payload (or for Single Payloads, the payload)
Tie the end of the string to another key ring, then loop the string through one of the key rings on the payload.
Then loop it back through the “tied key ring,” then down to the key ring on the payload opposite of the side you just looped through.
Go back up to the “tied key ring”, then down to the payload again.
Return to the “tied key ring”, then down to the last key ring on the payload.
Return to the “tied key ring” and pull up on the “tied key ring” to stabilize the four points. Cut the rope from step 4 and tie it to the “tied key ring. This will be the point at which the payload attaches to the balloon train.
For the rest of the balloon train, we will start at the top with the balloon.
Using the O-ring that the balloon neck was zip-tied around, run a length of at least 6 feet of string to the top of the parachute. The parachute should have a loop at its apex.
Gently lay the parachute out so that it doesn’t tangle as the balloon rises when liftoff comes.
Attach the 4 loops of the parachute to a carabiner and attach that to one side of the swivel eye bolt.
Tie another length of string, at least 6 feet long to the side of the swivel eye bolt that is not shared with the parachute. Tie the other end of this string to the “tied key ring” from the steps above.
When it is time to launch, slowly raise the balloon train into the sky and hold on to the payload.
Count down and release.
Launching with a 2 Payload Configuration
Launching with a 2 payload configuration doesn’t deviate too much from a single payload, but there are a few more considerations.
Firstly, the total payload capacity now is 12 pounds, with each payload being a maximum of 6 pounds.
Because of the addition of a second payload, stability between the 2 payloads is important, and they should not be positioned right next to each other. According to physics, a longer pendulum swings at a longer frequency, so we recommend a separation distance of at least 6 feet between the payloads with a stabilizer in between. In the past, half of a 3D print filament has been used. See the picture below (stabilizer between the 2 white boxes):
We recommend tying the payloads up separately, then attaching them to the balloon train. Use the following YouTube video to help tie up the payload. Instead of finishing with a bow, finish with a knot. (This is the same sequence as the single payload.)
Additionally, knots similar to Alpine Butterfly Loops will be needed on the four sides of the payload, so make sure you leave enough rope for you to complete this. We recommend tying these loops as you tie up the payload. For assistance with the Alpine Butterfly Loops, follow this video:
On each of the Alpine Butterfly Loops, attach key rings on the top payload (or for Single Payloads, the payload)
Tie the end of the string to another key ring, then loop the string through one of the key rings on the payload.
Then loop it back through the “tied key ring,” then down to the key ring on the payload opposite of the side you just looped through.
Go back up to the “tied key ring”, then down to the payload again.
Return to the “tied key ring”, then down to the last key ring on the payload.
Return to the “tied key ring” and pull up on the “tied key ring” to stabilize the four points. Cut the rope from step 4 and tie it to the “tied key ring. This will be the point at which the payload attaches to the balloon train.
On the payload stabilizer, add 4 key rings to it and attach 2 pieces of string that are at least 3 feet long each to each key ring. Tie the other end of 4 pieces of string (one from each key ring) to the key rings on the Alpine Butterfly Loops. Attach key rings to the 4 Alpine Butterfly Loops to the bottom payload, and tie the other ends of the remaining 4 pieces of string.
For the rest of the balloon train, we will start at the top with the balloon.
Using the O-ring that the balloon neck was zip-tied around, run a length of at least 6 feet of string to the top of the parachute. The parachute should have a loop at its apex.
Gently lay the parachute out so that it doesn’t tangle as the balloon rises when liftoff comes.
Attach the 4 loops of the parachute to a carabiner and attach that to one side of the swivel eye bolt.
Tie another length of string, at least 6 feet long to the side of the swivel eye bolt that is not shared with the parachute. Tie the other end of this string to the “tied key ring” from the steps above.
When it is time to launch, slowly raise the balloon train into the sky and hold on to the payload.
Count down and release.
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