Now that we have decided on the building materials for the GTP (Guidance Test Payload), we can start assembling it. The Gen 2 GTP will be made up of two segments; the parachute segment and below it, the electronics segment. Each segment has two parts; the outer shell and inside it, the module. The outer shell is a 14 cm (5.5 in) rocket tube that will have the fins, cameras and antenna attached to it. Inside this shell, internal components such as parachute tubes, batteries and flight computers are mounted to wooden bulkheads.
This week we have been working on the parachute segment, starting with the internal module. This module will contain the parachute system and drop system. During test 11, we identified a problem with the way the drop system attached to the payload. Essentially, we were at risk of the parachute becoming tangled. We corrected this with a rigid attachment. However, this solution was a temporary fix for testing purposes and it needed to be corrected for the GTP.
By moving the drop system to the GTP we could fix this problem. The original drop kit was 17 cm (6.6 in), far to large to mount on the GTP. Scaling the drop system down, proved to be a more complex task than it first appeared, as the drop system’s mechanism had a minimum size it could be reduced to before it lost functionality. Eventually, after much testing, we were able to reduce it to 8.5 cm (3.3 in) and fit it into the GTP.
With the drop system complete, we move to the parachute system which was much easier to fit in the module, as it was already designed to be compact. We were able to reuse many of the parts from the parachute test payload to reduce build time.
In the coming weeks, we plan to set up the 2 servos that will control the fins. They will be mounted below the parachute module. Before attaching the servos, we built a prototype of the fin system and tested it (see below).