HIGH ALTITUDE BALLOON LAUNCHES
High Altitude Balloons (HAB) are a passion of mine because of my fascination with aerospace engineering. I lead a local team of fellow HAB enthusiasts with a shared appreciation for designing and executing HAB launches.
Spring 2025 Launch
In Spring 2025 the HAB team will launch an improved version of the previous launch in 2023. Several features have been added to enhance the safety and reliability from previous launches. These features have been carefully implemented as of March 2025.
The following video shows one of the upgrades which is a touchscreen ground station monitor enabling independent control of ground stations tests with two quick taps of the monitor.
In this video, the added debugging console outputs for the antenna pointing calculations are displayed in the popup terminal.
The payload and ground station for the Spring 2025 launch have several enhancements:
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Both units now leverage a 3D printed mounting fixture to secure boards and components with standoffs
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The ground station - inside the Cantex box on right - can now be operated independently using a touch screen Raspberry Pi monitor
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Automated tests can be run with a double tap of desktop shortcuts on the Raspberry Pi monitor
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The payload - the fixture on the left - now has a killswitch that can be enabled to terminate flights at will
Communications Link Pointing Test
The image to the right shows the LoRA payload with the drone that will be used to test PTU pointing for the Spring 2025 launch. You might notice that the payload is in a different fixture than in the image above.
To allow us to test pointing with a small commercial drone, we needed to develop a smaller and lighter version of the payload fixture just for testing the PTU pointing. This consists of just the LoRa radio, the GPS module and LiPo battery.
After this testing phase, the payload will be assembled back into the complete version shown above.
FALL 2023 LAUNCH
In fall 2023 our local HAB club team launched the third HAB from Western Massachusetts. The updated payload design used a LoRa radio - ground based pointing to which was the focus of the launch. The team demonstrated point-to-point communications between the HAB transmitter and the ground station. The overall communications architecture consisted of the following components.
Trackuino
The trackuino combines the and Arduino with uBlox GPS receiver and FM transmitter to create APRS (Automatic Packet Reporting System) functionality
The Arduino uses GPS location from the uBlox GPS receiver to develop APRS packets which are modulated with a Radiometrix FM transmitter
These packets are transmitted in the Ham Radio VHF band at 143.9 MHz and distributed to APRS.fi through IP
LoRa Radio
A LoRA radio is also configured on the HAB Payload to send and LoRa packets to a ground control receiver containing GPS location of the HAB
NOTE: The upcoming Spring 2023 launch design will be updated to include a significantly lighter electronics payload mass by consolidating the Raspberry Pi and Arduino based radio functions smaller, lighter Adafruit featherboards.
Ground Station
The ground station contains a LoRa radio to receive GPS coordinates from the HAB
The ground station also contains an external GPS receiver and IMU to point a Yagi antenna toward the payload during its ascent
The PTU is implement using the Yaesu 5600 rotator
NOTE: The ground station maintained a receive only link with the LoRa payload until balloon reached the radio horizon.
LAUNCH DAY
Teamwork makes this possible
The Fall 2023 HAB launch day team is shown to the right. All members played critical roles in successful flight.
FALL 2023 LAUNCH OUTCOMES
The images below show the recovery site and the final APRS track location, which was within 100 yards of the recovery site in Merrimack, NH.
The image above shows a still image from the video recorded on the Payload from the GoPro.
RECOVERY SITE
Merrimack, NH
The payload was found the day after launch day within 100 yards of the last measured flight location in Merrimack, NH. The search included drone flight and on foot inspection of the search radius.
APRS TRACKING
APRS was used to track the flight through aprs.fi and the final flight location data is shown to the right.
HAB COMMUNICATION SYSTEMS
PAYLOAD
The payload communication system is shown to the left. The bottom left is the Raspberry Pi with Waveshare Sx1262 LoRa Hat. The top left is the Trackuino. Bottom center is the uBlox GPS receiver.
GROUND STATION
The ground station uses a Raspberry Pi as the host computer for Python source code that receives GPS coordinates and bearing from the uBlox GPS receiver and the IMU, respectively. The Raspberry Pi also hosts a Waveshare Sx1262 LoRa hat, which receives GPS coordinates from the HAB payload. Using its own position and heading and the coordinates of the balloon received over LoRa the ground station will point a Yagi antenna toward the balloon.
PAN-TILT UNIT (PTU) POINTING
The command prompt shown to the left shows the pan-tilt unit outputting the azimuth and elevation to point the ground station Yagi antenna toward the HAB.
Trajectory Planning
Estimates of HAB trajectories are generated using the Sondehub.org web-based predictor. This predictor determines the projected trajectory based on ascent rate, descent rate, current weather measurements and short term predicitions fed into atmospheric models.
HELIUM BUDGET
The required helium quantity is a function of the desired ascent rate (5 m/s), balloon mass (600 g), and payload mass (750 g). The ascent rate determines approximately what altitude the balloon will burst at, since higher ascent rates are associated with higher delta-P and lower altitude bursts.
PREVIOUS LAUNCHES!
JANUARY 2022 LAUNCH
In January of 2022 we launched a high altitude balloon from Valatie, New York. The payload was recovered in Leominster, MA in May 2022 by a hunter - indicating that the balloon burst close to approximately 90kft. However, we weren't able to see any location updates on APRS.fi. After an autopsy, we found the transmitter had faulted. Based on this lesson learned, we plan to comprehensively test communication prior to the next launch, which will also contain an additional LoRa radio for added communications resiliency.
FIRST LAUNCH WITH REDUNDANT TRACKUINOS
In fall of 2021 myself and a team of engineers launched a balloon containing a payload with redundant APRS transmitters. We tracked the balloon until the transmitter lost power. Unfortunately, we were unable to get the balloon to the required altitude for the balloon to burst prior to the transmitter battery running out.
