Near Space Balloon

Project Summary

The idea is to create a high altitude balloon that will reach at least 80,000 feet. The balloon should meet the following requirements:
  1. Be designed to reach at least 80,000 foot altitude.
  2. Have a primary payload that is less than 6lbs.
  3. Primary payload and secondary payloads may not weight more than 12lbs combined.
  4. Take photographs on the way up and down.
  5. Transmit GPS coordinates so we can track it from the ground.

Project Members

Name Contact Callsign
Rick O rick (at) KE7SAL
Kassie K kassandra_kaplan (at)  
Cord S cord42 (at)  
Weston T wstnturner (at) KI7ECP
Jeffrey G wholepair (at)  
Ben H ben.hallert (at)  
Kevin F kevin.forsythe (at) KI7HDG
Dean W dpwalton (at) AF7VN
Dileep R dileepvr (at) KI7HDF
Clif C clif (at) KB7ABA
Joe W joe.wisecaver (at) KG7YPB
Dave C dave (at) NK7Z


  1. Acquire GPS unit for payload. This needs a serial interface to talk to the TinyTrak3.
  2. Come up with a power supply for the GPS and TinyTrak.
  3. Get all of the electronics together and test them together.
  4. Figure out how much room we need in the chassis.
  5. Design and build the chassis.
  6. Find an easy way to mount everything inside the chassis so it is accessible but secured nicely (Velcro?).
  7. Acquire the balloon.
  8. Build the balloon filling apparatus.
  9. Build and test the tracking station(s).
  10. Acquire everything else.
  11. Write and triple check launch procedures.
  12. Document Build Process
  13. GO GO GO!

Tasks and Procedures

Name Description Assigned to
Launch Planning Coordinates the selection of launch dates and assigning tasks to the subset of the group that can make it. Same for the practice runs. Rick
Launch Control Follows the checklist and coordinates the launch crew.  
Document Control Manages the checklist and other document update process Jeffrey
Site Selection / Path Prediction Suggests possible launch sites and runs flight path predictions. Cord

Task Status

Testing and Q&A

There probably are two main areas of pre-launch testing; the balloon equipment, the payload, and the ground tracking / telemetry equipment. We need to come up with some QA testing checklists.

Balloon Testing

Inventory and test the usability of the filling station components. Run though a mock filling and launch.

Payload Testing

Power on self test to run some simple sanity checks, like are we getting sensor data. is the GPS locked? Do we draw more current when we beacon? etc...

We should probably do some testing before the big launch eh? The first idea would be to get a mostly empty chest freezer, turn it down all the way, and put the capsule in it and run it all night with a laptop sitting on top of the lid with its RTL antenna dangling just inside the lid, (because the freezer is a Faraday cage smile and look at the number of packets sent and received. Also look at the free memory on the capsule SBC to see if there are any memory leaks. Add more tests as we think of them.

Then the next level of testing would be to do some fox / hound RDF finding on the capsule, this tests our APRS and RDF equipment, (and motivates people to get that part set up) It's also a fun activity for the crew. We have one fox with the capsule in a car with antennas on the roof and they can drive around to some somewhat high points while the "Hounds" chase it using the receivers. This makes a game out of testing and could even get others involved like girlfriends for example, since there would be lunch or dinner as part of the outing. We get way more fun group activities for each iteration of a capsule this way. smile

Ground Tracker Testing

There should probably be more than one tracking setup, and it's fun to be part of a driver / navigator pair in a chase vehicle! smile By the way, lets try not to have anyone driving alone. In addition to the fox hound games above, there could be some hangout time at the space or someones house with snacks to help everyone get their laptops setup for tracking.

Launch Procedure

Launch procedure goes here once we have everything else designed and built. We need a good launch checklist to follow. Perhaps like these:

Balloon Components

Component Description Supplier Price Assigned to
Chassis Lightweight but strong chassis big enough to contain all electronics. Need to access internals for adjustments and need to be able to attach parachute/balloon. Need identifying information and make it VISIBLE. Jeffrey ? Jeffrey
Balloon Needs to be big enough to lift the full weight of the payload and then some. Kassie $0 Kassie
Parachute Needs to be able to safely return the full payload weight to the ground, but quickly so it doesn't drift too far. Also must be VISIBLE eg. Brightly colored. Ben $0 Ben
Laminated ID Tag Should include EMS and team contact info, emails, cell numbers, and callsign. On all payloads.      
Power Supply Needs to power the GPS and TNC at least. Maybe also the radio and camera.      
Power Bus USB friendly power bus with remote control of each device. Current sensing is good too. Clif   Clif
MCU Arduino, or RPi based control system. Best if CPU can sleep with timer or ext int wakeup for power conservation.      
Data Logging Try to log all sensor data along with altitude, location, and timestamp. Including all photos, and videos.      
Telemetry Possibly more than one transmitter for position and sensor data. Weston   Weston
GPS Radio 5 watts should be enough. 2 meters is preferable. Rick $0  
Radio Antenna Can make a simple J-pole out of ladder line from Radio Shack. Rick $0  
RDF Xmitter A simple low duty cycle transmitter for RDF tracking after the capsule lands. Should last for a week or more.      
Connectors Use Standardized connectors and voltages      
Sensor Modules
GPS Must work over 65,000ft. Many GPS units do not work at those altitudes. Weston $0 Weston
Camera Needs to be able to take time lapse photos, and or High rate photos. Kevin ? Kevin
Helios Camera Camera with gimbal setup that tracks the Sun Ben?    
TNC Using the TinyTrak 3. TEST to make sure it reaches digipeaters and transmits altitude before launch. Rick $0  
Video Camera Power Figure out how to power video camera with external power Kevin $0 Kevin
RF measure? The Sun emits 2.4GHz but if it's not attenuated by the atmosphere then why host it in a balloon?      
Audible Beacon? Some loud noise maker so we can find it easily once it lands ? ? ?

Payload Primary Radio

I suppose we will probably use a cheep-o Baufeng radio.

Old radios:

An old HTX-202 2 meter HT originally made by Radio Shack. This one has a strange glitch where you get an on screen error when power is applied. To bypass this, you have to hold the function key and the D1 key and then turn the power on. I'm not sure how to fix this permanently. The radio has a BNC connector for the antenna. This radio is capable of outputting 5 Watts and requires a 12 volt power supply. The radio has a small battery compartment that can hold 8 AA batteries. We have used 8 Lithium AA batteries in a previous balloon with success.

Payload Primary Antenna

We can make a simple J-Pole antenna from strong ladder line available at Radio Shack. We will need the proper BNC connector in order to hook the antenna up to the HTX-202 radio. Here is a guide on how a proper antenna can be made from ladder line. We will probably also need a small piece of coax cable to connect the antenna to the radio.

Payload Secondary Antenna

The secondary antenna could have a dual purpose. During most of the flight it could transmit live telemetry data, and later after landing it would go into long life low power beacon mode, which would just transmit in short bursts every few seconds to allow the batteries to last for a week or more and for RDF teams to home in on it.

TNC Configuration

We are using the TinyTrak3. The TinyTrak requires a 7 to 30 volt power supply. It is also currently configured to distribute power to the GPS through the DB-9 connector. We may or may not be able to use this depending on how much power the GPS requires. I believe this feature can be disabled by moving (or removing) a resistor on the TinyTrak3 PCB. We've been using Weston's callsign for the balloon - KI7ECP -3.

Primary GPS

James has lent his Garmin eTrex GPS unit to the project. He has also donated his serial/power cable to the project. We need to figure out how much power the eTrex requires and is capable of accepting. Initial tests show that it may be expecting around 3 Volts but perhaps it can accept 5 Volts, which would make our power supply simpler. There is some useful information about Garmin eTrex connectors on this site.

Sensor Modules

Various sensor modules that we would like to collect information with. Here are some ideas:
  1. Environmental Sensors:
    • Internal / External Temperature, Pressure, Humidity, Light, UV. GPS location, and altitude.
    • Measure these all together with GPS timestamps. Simple environmental maps can be extracted from the data.


Jeffrey would like to know what type of cameras they used on the first link under "Other Near Space Balloon flight videos" below. Either have the cameras time set correctly or have the OS store the pictures and have it's time set from the GPS. Possibly have some cameras turn on for a short period of time, or turn off after landing. More video could be taken during the eclipse.
  • Video Camera just under balloon, and parachute, viewing capsule and earth.
    • Observe Umbral shadows from above
  • Video Camera pointing up at balloon.


  • Small party balloons to indicate higher altitudes by popping.


Our parachute is bright orange which makes it easy to see, but what if we could make it even bigger without affecting the decent rate? Here is a page that talks about calculating that: Apparently you can measure it's drag coefficient. Perhaps by driving in a car with a pull scale on the cord.


Perhaps include the EMS URL in the telemetry data.

Launch Station Components

Component Description Supplier Price Assigned to
Large Tarp This protects the balloon from the dirt, rockets, etc on the ground.      
Folding Table To help us setup and configure various equipment.      
Folding Chairs Same.      
Helium Need enough to fill the balloon to proper buoyancy. Twice that if we want a second chance.      
Water Jug & measuring cup We attach this to the balloon during filling to ensure that it doesn't float away and also that we have reached proper buoyancy. Water is measured into the jug to get the correct weight.      
Helium tank regulator This allows us to control the speed at which we fill the balloon with helium.      
Hose To connect the Helium regulator to the balloon fill apparatus.      
Balloon fill apparatus Need something to insert into the neck of the balloon to pump the helium into. Small piece of PVC pipe could work.      
Pipe clamps/tape To clamp the balloon neck to the fill apparatus.      
Attachment Rigging Method to attach balloon to payload.      
Cotton gloves Anyone who handles the balloon wears these to protect the balloon from dirt and oil from hands.      
Extra Cables Extra Cables and adapters.      
Extra Batteries Batteries for everything. Just in case...      

Tracking Station Components


Component Description Supplier Price Assigned to
Laptop Laptop that can run tracking software and possibly hook up to a GPS for simplified tracking.      
Power Inverter Power DC/DC converter, or inverter so we can power the laptop indefinitely from a vehicle. Rick $0 Rick
TNC Can be software or hardware. Must be able to decode APRS packets for plotting on a map. Its a plus if it can also transmit it's location over the same antenna.      
Tracking Software For tracking the balloon's position in real time on a map.      
Data Logging Each tracking station should log all received data with timestamps. Using GPS time if possible.      
Digital Maps Need maps for the tracking software. These are not always free, but should include USFS roads.      
Situational Display Additionally, there should be a display of the telemetry data, capsule health, other vehicles in group, etc...      
Ham Radio Dedicated ham radio for receiving APRS packets directly from the balloon. Essential for tracking. Also used for broadcasting the chase vehicle's position. Rick $0 Rick
Digipeaters Some of the track vehicles eg. aircraft, could have Digipeater capability, so the group can be in touch if separated in a remote area.      
External 2m Antenna Like a mag-mount on top of the vehicle for signal reception. Including GPS, and 2m Rick $0 Rick
RDF 900Mhz antenna There should be several 900Mhz or whatever the secondary band is, RDF trackers in the group.      
Handy Talkies For vehicle to vehicle communication during the chase.      
GPS To keep track of vehicle location in comparison to balloon. Also for plotting optimal route to balloon.      
Handy Docs A Short manual or flip book of key locations, cell numbers, callsigns, and frequencies.      

Tracking Station Configuration

See the APRSTrackingStation page for more details.

RDF trackers

This is a necessary backup to the APRS beacon because it can be done at very low power, allowing the batteries to last for a week or more.


If you use a wifi link for any kind of local setup, it might be best to make the remote end the AP, and the local (your) end to be the client. typically there are more opportunities to manually debug the local end which gives you a better chance of establishing a connection.

Launch Sites

Potential launch sites go here. Good to have alternates in case weather conditions don't play well with our plans. Need to ensure the balloon will not land anywhere near large bodies of water, Forrest, or mountains. We want to recover the payload after all. Launching at airports gives our pilot friends the option to join us with a chase plane or two. smile
Name Code Lat Lon Ele ft Ele m Length OK? Camp?
Beaver Marsh State Airport 2S2 43.1275278 -121.8087222 4638 1414 4500 Yes Yes
Crescent Lake State Airport 5S2 43.5326242 -121.9500294 4810 1466 3900 Yes Yes
Sisters Eagle Airport 6K5 44.3044583 -121.5390972 3168 966 3500 Yes Yes
Lake Billy Chinook Airport 5S5 44.5192847 -121.3206003 2695 821 2500    
Redmond Airport KRDM 44.2540556 -121.1499722 3080.2 938.8 7000 Maybe  
Bend Municipal Airport KBDN 44.0945556 -121.2002222 3459.5 1054.5 5200 Yes Yes BLM
Madras Airport   44.6701667 -121.1551389 2436.6 742.7 5000   Yes
Gopher Gulch OR29 44.1112283 -121.3339225 3480 1061 3400    
Goering Ranches Airport 50OR 44.0973447 -120.9472411 3450 1051.6 5500    
  • Need to check back with Redmond for the Manager's email address.
  • Bend Airport: Have done balloon launches before, some folks rented a hanger to Google
    • No camping per se but surrounded by BLM land.
  • Sisters Airport: Steven Peterson does Balloon launches with high school students. They have a campground with a fire pit!

Legal Stuff

Hardware Needed

Radio Gear

Weather or not they're hams, some folks may be looking for licensed or unlicensed radio gear. We've tried to gather some helpful notes together on our RadioGear page.


Previous Launch Data

Up Coming Launches


Additional Ideas

  1. Logging all telemetry data to SD card, and record all data received by ground crew.
  2. Wrap the capsules in space blanket material for another layer of insulation. Looks very NASA like. smile They also reflect radar signals, though a corner reflector would be a better shape for that.
  3. Explore constant altitude balloon with cut down.
    • Gas relief valve
    • Cut down mechanism
  4. Record all voice radio traffic with timecodes from multiple channels.

-- RickO - 2011-10-12

-- ClifCox - 14 Jan 2017
Topic attachments
I Attachment Action Size Date Who Comment
B-1-battle-station.jpgjpg B-1-battle-station.jpg manage 340.1 K 12 Jan 2017 - 03:01 ClifCox EMS Tracking Station
Launch_1_APRS_data.loglog Launch_1_APRS_data.log manage 643.5 K 15 Oct 2016 - 23:32 ClifCox First Launch APRS packet data log, includes timestamps and some sensor data
Launch_1_Velocity_calc.loglog Launch_1_Velocity_calc.log manage 1055.7 K 15 Oct 2016 - 23:33 ClifCox  
Launch_2_900_Data.loglog Launch_2_900_Data.log manage 20.4 K 15 Oct 2016 - 23:20 ClifCox Second Launch 900Mhz telemetry data log, includes timestamps and other sensor data.
Launch_2_APRS_data.loglog Launch_2_APRS_data.log manage 8.8 K 15 Oct 2016 - 23:19 ClifCox Second Launch APRS packet data log, includes timestamps and some sensor data
Topic revision: r27 - 07 Jun 2017, ClifCox

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