The aim of the Comet Project is to develop a small sounding rocket system that will be launched from a helium balloon at around 30km altitude. The rocket will have a maximum apogee of around 150km, taking it past the official boundary boundary of space that is set at 100km. Launching at this altitude is much more efficient as air density is only around 1% of its value at ground level, so much less energy is wasted by the rocket in drag. The reduced pressure of the environment also allows further expansion through the nozzle of the rocket motor, increasing the thrust from a given motor. For small rockets, the increased difficulty of launching from a balloon is outweighed by these benefits and provides great potential for payload carrying at minimum fuel cost.
Comet modelling in Matlab
Advanced computer modelling and prototyping has begun and our current concept is two-stage, powered by two commercially available L-class motors. The casing will be constructed by the team with carbon-fibre prepreg by using an industrial standard autoclave and precision moulds.
Prototype Mould Created
A prototype mould of the nosecone and frontal body section has already been manufactured by Cambridge Precision, one of our Platinum Sponsors. A video of the mould’s manufacture was created by them which can be seen below. The mould was hand finished and polished to an almost mirror sheen before being chemically coated in a layer of teflon using Freekote 44. Prototype rocket body sections will now be constructed and tested with different composite laminations before a full carbon-fibre rocket will be built for a ground launch.
To test launch high-power rockets from UKRA (united Kingdom Rocketry Association) rocketry sites certification exams must be passed for the appropriate motor power of the rocket. We have embarked on achieving UKRA certification with a small test rocket, “Racing Blue”. The inset video shows its maiden flight at Big EARS 2008, when it passed the Level 1 Certification exam. It reached an altitude of roughly 960m and accelerated to around 380 mph in 1.8 seconds. On its next flight, it should pass Level 2 certification and allow us to fly rockets up to L-Class motors. However, this second launch has been delayed by bad weather several times.