Project Horus High altitude balloon project

Horus 7

Technical information:

Launch date 29/8/2010, 12:07pm
Landing date 29/8/2010, 15:09pm
Flight duration ~ 3 hours
Launch site -35.1018, 138.8248
Landing site -34.8044, 140.8756
Flight path Web, KMZ
Distance travelled
190.2 km
Maximum altitude 35,354 m
Average ascent rate 4.5 m/s
Impact speed 5 m/s (18 km/h)
Payload weight 500g
Flight computer Nut 1.1 flight computer
GPS module Falcom FSA03
Radio transmitter Radiometrix NTX2 25mw
Still Camera Canon a560, CHDK
Video Camera eBay spy video camera (provided by VK5ZBR - thanks!)
Telemetry 300 baud RTTY, CRC16 checksum
Tracking Ground stations (distributed listener), 3 chase cars, web based tracke


Horus 7 was the first payload I had flown with a camera (asides from Horus 5/SARP) since my first launch. The goal was to address the issues we'd encountered in the first launch - namely the condensation which formed on the inside of our lenses.

I'd also moved away from having my camera controlled by the onboard flight computer - instead I used a Canon camera running CHDK, an open source firmware modification supporting scripts. The camera was configured to take a photo every 7 seconds for the duration of the flight.


Much like the day before, launch conditions were good. The wind had picked up slightly which meant we did most of our filling in Graham VK5GH's shed to keep out of the wind, but no issues were encountered.

Graham VK5GH ready to launch

Asides from the launch team (Mark & I), we had 2 other chase cars, which were starting the day at Younghusband. Once inflation was done, the balloon was tied up to the fence until we'd notified everybody we were launching, and then Graham VK5GH did the honours.

Were off!


Horus 7 maintained a good ascent rate of approx 4.5m/s throughout the flight. The jetstream was slightly stronger than the previous day, the payload travelled in excess of 150km/h at times.

Our telemetry systems worked well, though we were concerned to see the internal temperature fall below -20 degrees Celcius. This did not seem to affect too much, asides from slightly affecting our telemetry's carrier shift - this did not cause any issues though.

After burst it looked almost certain that the payload would land east of the Victorian border in a large national park, making recovery quite difficult. Fortunately the gods were smiling upon us and the payload ended up coming down about 5km west of the border - Mark and I were racing to get into position, but ended up on the wrong side of a paddock - the payload came down about 1km away from us, though still in view.

Our other chase cars however had managed to get into position to catch the balloon coming down, and Grant VK5GR captured this excellent footage:


As we'd hoped, the onboard camera was still running despite the cold, and was full of amazing shots - over 2000!В  Some of the highlights are below: