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For anyone wondering what the High-Altitude Ballooning (HAB) team has been up to over the last few months – don’t worry, we have not been slacking off! The team has been hard at work developing a payload capable of logging a multitude of different types of data as well as a platform which could deliver it into the stratosphere.

This blog will recount the highlights of the mission and an overview of the systems inside our payload, for the more technically-curious.

A recount of the mission

The trip began with some last-minute logistical issues with regards to site approval but nevertheless, we were able to leave on time, early on Saturday morning for our launch site at Muswellbrook. The 3.5hr drive was smooth and relaxing, and each member of the team was hyped up for the launch (especially Dr Chris Lu).

Upon arrival at Muswellbrook, the team began swiftly unloading the cars and preparing for launch. We divided into groups for assembly of the payload and balloon inflation. Each team worked together effectively and managed to complete each of their assigned tasks in a reasonable amount of time.

Launch location in Muswellbrook
Launch location in Muswellbrook
Assembly of the balloon payload
Assembly of the payload
Final stages of inflation of the balloon
Final stages of inflation of the balloon

Soon enough, the balloon was up, up and away and we started to prepare ourselves for the recovery effort. The team members tasked with telemetry immediately started to track the balloon’s predicted flight path whilst the rest us packed up the launch equipment. The balloon was initially predicted to land a kilometre off-shore of Nelson Bay, so the team had to carefully consider whether or not to remotely terminate the flight. After some serious discussion, it was decided to let the balloon burst itself due to vastly improved predictions following the initial ascent phase (the prediction turned out to be over 40km from the east coast).

Balloon shortly after the release
Balloon shortly after the release

We began chasing the balloon as the tracking equipment led us towards an area named Glen William– around a 2-hour drive from the launch site. Thankfully, the prediction turned out to be extremely accurate and the balloon landing location was less than a kilometre from the anticipated location.

Aerial view of the landing site
Aerial view of the landing site

Once we arrived in the area of Glen William we had to work out who’s property the balloon had landed on. We spent some time door-knocking on surrounding properties in an attempt to achieve this. A very kind farm owner named ­­Graham agreed to help the team out once we had a chat to him, and he even led the search for the balloon which had landed on the middle of an island situated on his property.

Team performing a river crossing
The team performing a river crossing

After crossing a river to reach the island and taking part in a picturesque walk through the forested area, we found the payload and balloon. Unluckily for the team, the parachute and balloon were tangled around some branches of a 15-20m tall tree and the payload was hanging beneath it from a 5m piece of rope. Some initial brainstorming from the team and drone photography from Dr Elias Aboutanios to catch a glimpse of just how the parachute and balloon were tangled in the tree resulted in no immediate solution.

Payload hanging from tree
Payload hanging from tree

This is where Graham, the land owner, kindly offered to assist. He offered to shoot the payload down from the tree! He called his daughter Kirstie and asked her to “bring over the 223”…. Once the gun arrived, both Graham and Kirstie began to take turns shooting, directly upwards in the direction of the balloon and parachute in an attempt to dislodge it from the tree by shooting branches off. After 16 shots and much suspense, the parachute and balloon were detached from the branch that they were tangled in and the payload fell into the bed of scrub below!

Team photo including farmers
Team photo including farmers
Image taken using Raspberry Pi Camera
Image taken using Raspberry Pi Camera

This mission was UNSW BLUEsat HAB’s most successful to date, the balloon was launched and recovered within a single day! This was thanks to the dynamic teamwork between team members as well as the much-appreciated help from the farmers.

Balloon Payload Description

The launched payload consisted of devices that fall under four main categories:

  • Tracking
  • Remote separation
  • Imaging
  • Sensing

Tracking

The tracking component of the payload was comprised of both an Automatic Packet Reporting System (APRS) and a Pi In The Sky (PITS) GPS receiver and a radio transmitter. Both devices were used for real-time communication of the location of the payload which enabled the team to track and chase the balloon and payload. A tracking website was used with both tracking devices (callsigns VK2UNS-11 and VK2LNA) in order to visualise live predictions of the flight envelope.

Once on the ground, a Spot GPS Tracker was used to transmit a more accurate location of the payload’s location. Additionally, for redundancy, a mobile phone with a GPS app was included within the payload.

Remote Separation

A remote separation mechanism is a CASA requirement for a High-Altitude Balloon and thus had to be included. The mechanism that we launched consisted of an Arduino board with a Hamshield – a powerful radio transceiver. The Arduino was set up in such a way that it could be used to trigger a circuit containing a nichrome wire, which heated up sufficiently to burn through the rope that attached the payload to the balloon.

Imaging

3 different cameras were installed on the payload. The main camera was a Samsung Gear 360 attached to the bottom of the payload. This camera opened up a realm of possibility for VR experiences of the launch itself. The second camera was a PiCamera, attached to the top of the payload to monitor the condition of the balloon during the flight enveloped as well as to witness the time when it burst. The final camera was purely for redundancy and was operated by the Pi In The Sky Telemetry board.

Sensing

Two sensor boards (one Arduino based board and one Raspberry Pi based board) were utilised to measure temperature (both internal and external), humidity, atmospheric pressure as well as the motion of the payload. A phone was included for redundancy, logging the motion of the payload.

Team Members

Adithya Rajendran

Emma Su

Hamish Clark

Jeffrey Wu

Timothy Guo

Anna Chan

Raghav Hariharan

Benjamin La

Shevaani Rams

Supervisors

Dr Elias Aboutanios

Dr Chris Lu

Acknowledgements

Graham Braithwaite – land owner

Kirstie Braithwaite – rifle owner and daughter of Graham

Sue Bartlett – neighbouring land owner