\<COLOUR 1> CONSTRUCTION: \<COLOUR 0> Airframe constructed conventionally in aluminium alloys, with titanium in high-stressed areas; covered with insulation as protection against re-entry heating - silica tiles on nose, tail, wings and underneath, carbon ceramic on wing edges, insulating felt elsewhere; the airframe is made up of three main sections - the forward fuselage, housing the pressurized three-level crew cabin, the mid-fuselage, which houses the payload bay and to which the delta wings are attached, and the aft fuselage, which interfaces with the main and OMS engines and carries the tail and body flap
\<COLOUR 1> MAIN ENGINES: \<COLOUR 0> Three SSMEs (space shuttle main engines) in tail pod, each producing some 170,000 kg lift-off thrust, burning liquid hydrogen fuel and liquid oxygen carried in external tank
\<COLOUR 1> OMS ENGINES: \<COLOUR 0> Two OMS (orbital manoeuvring system) engines, each putting out 2,700 kg thrust in space, burning hydrazine fuel and nitrogen tetroxide oxidant
\<COLOUR 1> RCS ENGINES: \<COLOUR 0> The RCS (reaction control system) comprises 38 main thrusters set on either side of the tail pod and in the nose, fuelled with hydrazine and nitrogen tetroxide
\<COLOUR 1> POWER: \<COLOUR 0> Three sets of fuel cells provide electrical power, combining hydrogen and oxygen to form water, which also supplies astronauts' on-board requirements
\<COLOUR 1> COMMENTS: \<COLOUR 0> Reusable: The orbiter is the most important part of the space shuttle transportation system, being the vehicle that carries the crew and payload. It rides into space atop the external tank (ET), to which are attached the twin solid rocket boosters (SRBs), the whole comprising the shuttle stack.
