On Wednesday 29th February 2012, the Apex team set off to Churchill College, Cambridge to launch Apex III for the first time. Unlike previous launches we aimed to launch during the afternoon at approximately 16:00 GMT.
Preparation began swiftly after arriving at the launch site at 14:00 GMT. The layered structure of the payload enabled the various modules to be held together during assembly.
Together with the Core board, this launch also included the RGB Light Sensor board, the Gas Sensor board, the Camera Tilt system and the Cutdown and Siren system. A GoPro was also included on board.
The Camera Tilt board was connected to the GoPro HD camcorder which could tilt between various angles after receiving a command from the Core board. In a similar manner the Core board could activate the siren upon descent to make recovery easier and quicker. Battery Station were kind enough to sponsor the batteries which powered this payload.
Once the payload assembly had been completed the balloon filling process began. For this launch we chose to use a Totex 1500g balloon filled with Helium. BOC kindly sponsored the gas for this launch.
Unfortunately after filling had began the GPS started experiencing issues and lost lock. The team spent the next hour or so debugging this issue by changing the GPS antenna and creating a new ground-plane only to discover that it was caused by a newly developed HF transmitter which was being tested by the Apex team for a third party. The HF transmitter was removed but in doing so the GPS patch cable was damaged and a replacement had to be found in time for the launch. Luckily enough Cambridge University Spaceflight had a spare available and after rushing back to the Engineering Department and back the payload was ready to fly.
By the time we were ready to launch it was getting late and approaching sunset. We had to rush the launch but did so successfully at 17:52.
We returned to the chase vehicles and shortly began tracking the payload as it ascended. The team quickly realised that the ascent rate was much lower than expected which could potentially mean losing the payload, especially as the launch was delayed and predictions for a later launch had not been made. In addition to the delay, the payload’s mass had changed and was no longer as accurate as necessary which was a likely reason for the incorrect ascent rate.
For tracking, the minibus headed North-East out of Cambridge and began tracking from a location outside of the city centre. The chase car headed towards Thetford. The minibus headed back to Sutton as the payload did not seem recoverable. Unexpectedly at 21:30 the payload began to float for a duration of approximately 45 minutes. This was eventually put down to the balloon which was delivered directly from the warehouse in Japan after manufacture.
The unexpected float confirmed the non-recovery and so the chase car also headed back towards London. At 22:23 the balloon burst over the North Sea and signal was lost at an altitude of 2889m at 22:56.
We would like to thank Cambridge University Spaceflight for the use of their launch facilities at Churchill College, Cambridge.
Rescue from the North Sea
After weeks drifting in the North Sea, Apex III was found by Fred Koppers and Max on a beach between Noordwijk and Katwijk in the province of South Holland, Netherlands. We received an email notifying us of the rescue on 4th April and received the parcel back on the 27th April.
A large portion of the payload was rescued. This included the Core board and the sideways facing camera. Unfortunately the downwards facing camera, the lid and the GoPro was lost due to the payload being opened on the beach. Data was recovered from the Core board (which is available on GitHub) and photos from the camera (which are on the gallery). We are very grateful to Fred Koppers, Evert Waal and Max for the kind recovery of Apex III.
Upon landing in the North Sea the Core board continued to run for an amazing 210 minutes. The GPS managed to keep lock for the first 90 minutes after landing. We suspect that the drain in the batteries (accelerated by the water) were the ultimate reason for the board turning off in the sea. The Core board also managed to successfully booted up after recovery!