Project Horus High altitude balloon project

Horus 29

Technical information:

Launch date 7/10/12, 1:26:21 UTC
Landing date 7/10/12, 2:43:16 UTC
Flight duration 1 hour, 16 minutes
Launch site -35.127, 138.8475
Landing site -34.7235, 140.1770
Flight path
Distance traveled
Average speed
Maximum speed
Maximum altitude 11,010 m
Average ascent rate
Impact speed
Flight computer MicroNut Flight Computer
Additional payloads Osiris Cutdown Payload, GoPro HD Hero
Primary radio TX
Radiometrix NTX2 25mW (RTTY)
Telemetry 300 baud RTTY, CRC16 checksum
Tracking Ground stations (distributed listener), 3 chase cars, web based tracker

As we hadn't launched for a while (due to various team members being busy, or overseas), it was decided that a systems check was in order. The launch was set-up on relatively short notice, with the idea being that the payload would be cut down early (using Mark's Osiris payload), to land near VK5CP's holiday shack in the Riverland - a nice place for a BBQ lunch! Since we were to be cutting down so early, a GoPro was added to the balloon train, as weight wasn't a big issue.

Preparing to launch

All three of the main chase teams were along for this launch:

  • Terry VK5VZI with Alan and Emma.
  • Matt VK5ZM with Grant VK5GR, Scott VK5TST and Josh VK5FMJP
  • Adrian VK5ZSN with Tina and Mark VK5QI.

Impromptu group photo taken by the GoPro.

After the balloon drain was setup and the balloon filled, Terry's team headed off to get a head start on the balloon. Predictions showed the balloon speeding up quite considerably at 10km altitude, so we wanted to be sure at least one team was in the landing area. After about half an hour's wait (during which we discovered the taut balloon line could be played like a single-string bass), the balloon was launched, and the remaining chase teams headed off.


True to the predictions, the balloon headed east, and started to speed up. At around 10km altitude the speed peaked around 300kph - a sure sign it was time to cutdown! After a quick discussion with the other teams, Mark VK5QI commanded the Osiris payload to cut away the balloon, and at 11.01km altitude, the payloads started their descent.

View of the Riverlands from 11km altitude.

By this point Matt and Terry had gained a significant lead on Adrian's truck, so Adrian decided to head straight to VK5CP's shack to get the BBQ started, while Terry and Matt's teams went to recover the payload. The payload eventually landed approximately 10km north of a small locality called Mindarie, much further away than intended. After checking with the landowner, Terry and Matt's teams were able to enter the landing field and recover the payloads.