Mechanical Engineering students, Mr Presley Sagadaven, Mr Jared Sabbagha, Mr Vulinhlanhla Mchunu and Mr Shuaib Badat formed a team to work on improvements to UKZN’s Phoenix-1B Hybrid Mk I Sounding Rocket that will make the rocket recoverable (making it reusable and therefore more cost effective to launch), robust, versatile, and able to carry a payload of up to 10 kg.
Sounding rockets carry payloads on sub-orbital flights, as opposed to rockets that are used to launch satellites into orbit. South Africa currently has no sounding rocket or launch vehicle capability and thus has to rely on expensive foreign launch services, making the development of a high-altitude sounding rocket capable of lifting payloads to various altitudes a significant contribution to several South African scientific and engineering institutions. UKZN’s Phoenix Hybrid Sounding Rocket Programme aims to produce an indigenous sounding rocket that has the capacity to meet the requirements of South African and African scientific communities, while also building capacity in the country to develop these technologies.
Intended as a “workhorse” vehicle for the Phoenix Programme, the Phoenix-1B Mk I has not yet been flown and is a tool for aerospace technology development and testing. The team worked on several developments, including a dual parachute recovery system, a new nosecone transparent to radio frequencies to house the payload and flight computers, and a new fuselage to house the parachutes, and parachute deployment mechanisms. They also developed and tested new fins to stabilise the rocket during flight.
‘Enhancements to the Mobile Hybrid Rocket Launch Platform were required to improve the existing launch gantry positioning system, in order to make it easier, more accurate and safer to use,’ said Mchunu.
The group replaced the inclination control mechanism with a hydraulic system. They also eliminated an electronic interface to increase the robustness and versatility of the inclination control system.
Mchunu explained that hybrid propellant rockets use a solid fuel and a liquid oxidiser, which in the Phoenix series are paraffin wax and nitrous oxide, respectively. The team set out to make a new paraffin fuel grain casting apparatus to improve the efficiency and ease of the grain casting process as well as the quality of the fuel grain produced, and optimise the fuel grain production technique.
The rocket will be flight tested next year (2020) and it is expected to reach an altitude in excess of 10 km.
During what Mchunu described as a highly iterative process, the team had to undergo a lengthy learning process to develop skills in using new software, and had to adapt to liaising with industry professionals to ensure that their design was compatible with industry manufacturing processes. They also had to be resourceful when it came to procuring materials, having to order recovery system components from overseas and organise their work schedule around delivery times.
On 16 October, visitors viewed the full Phoenix-1B Mk I vehicle, including the new fins, nose cone and fuselage section, and heard directly from the project team about the theory behind the design and the design process. The team demonstrated the inclination control of the mobile launch gantry as part of the vehicle launch preparation, as well as the structure, actuation mechanism and detailed manufacturing process of the fuel grain.
Words: Christine Cuénod