Bloodhound
the und
A rocket is basically an engine which carries both a fuel and oxidiser (it does not require any oxygen from the air). In the early stages of the project we looked at the three main types of rocket: solid, liquid and hybrid propellant
Mk 1.5 HTP Pump 15
is water). HTP is a strong oxidising agent and has a high specific gravity (a desirable property in a rocket oxidiser). HTP is very sensitive to contamination and can be easily decomposed by many common substances.
HTP requires great care in handling and must only be allowed to come into contact with compatible materials, even then storage tanks, pipe work and valves must be specially cleaned and prepared. Personnel handling HTP must wear protective clothing. In the 1950s, 60s and 70s HTP was used in the UK space programme in vehicles such as Black Knight and Black Arrow, with an exceptional safety record. Unlike liquid oxygen, which is a cryogenic liquid (with a boiling point of -183°C) and has to be stored in insulated tanks, HTP can be stored at room temperature. This also simplifies the design of the oxidant feed systems. Inhibited Red Fuming Nitric Acid (IRFNA) is another good, high density oxidiser, however it is toxic, corrosive and gives off choking fumes. HTP is non-toxic and has another advantage – it can be decomposed by a catalyst pack into steam and oxygen generating heat.
In the liquid propellant rocket engines used in Black Knight and Black Arrow, atomised kerosene was injected into the hot oxygen and spontaneously ignited. This simplifies the engine by removing the need for a separate ignition system and the same principle can be used in a hybrid chamber.
At the top of the hybrid combustion chamber is a catalyst pack, The pack contains 80 silver plated nickel mesh disks, these decompose the HTP into steam and oxygen and the reaction is given as 2H2O2 > 2H2O and O2 plus Heat. The decomposition generates a temperature of around 600°C. The Mk 1 catalyst material had a smooth silver plating. The catalyst pack was only about 65% efficient and on the first attempt to fire the 6-inch chamber in early February 2008, the catalyst pack did not provide enough heat to ignite the fuel grain. While modifications to the fuel grain to achieve ignition proved successful in the next
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