Page 54 - All About Space 68 - 2017 UK

SPACE EXPLORATION
When the Shuttle launched, it rose on twin towers
W
Why do rocket hy do rocket Soyuz and Falcon 9 had an orange to yellow
of bright white smoke issuing from its boosters.
flame, leaving little smoke; these differences are
caused by the propellants used by these vehicles.
Rocket propulsion falls into three categories, solid
exhausts look (the source of oxygen) are solid substances mixed
propellant motors, where both fuel and oxidiser
up together, bi-liquid engines, where two liquid
propellants are kept in tanks before being mixed
and burnt in a separate chamber, and hybrid
engines, with one liquid and one solid propellant.
different? characteristic temperature and exhaust mix. The
Each combination of propellant has a
Space Shuttle had a combination of systems with
solid propellant boosters and liquid hydrogen-
oxygen bi-liquid engines. The solid propellant is
Whilst all rockets follow the same basic a mix of 69.6 per cent ammonium perchlorate
oxidiser, 12 per cent rubber binder, and 16 per
principles, they use many different cent aluminium dust; even though the rubber
contributes too, the aluminium is considered
propellants, making launches look different the actual fuel. This produces bright yellow
flame and a lot of smoke, including aluminium

Solid propellant boosters Ethyl alcohol and oxygen Liquid hydrogen Kerosene and oxygen
Often a mixture of perchlorate The first propellant combination and oxygen The dominant launch vehicle
oxidisers, rubber, and metals, to reach space (German A4 missile The most powerful conventional propellants (usually used slightly
modern solids produce bright yellow 1942). It produces a yellow flame, but propellant combination, it produces fuel rich), the carbon in the exhaust
to white flame and a lot of smoke, as less pronounced and smoky than the 3,300ºC degree water vapour, but produces the yellow-orange flame
seen on the Space Shuttle. later kero-ox. needs large insulated tanks. and some smoke.

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