By Ivan Noble
BBC News Online science staff
Designing and building Concorde was an incredible achievement.
Two Concorde prototypes were built, one in France and one in the UK
The airliner cruises at twice the speed of sound, just about as fast
as a rifle bullet leaves the muzzle.
Even today, as Concorde's decades of service draw to a close,
aircraft only sustain such speeds for brief bursts.
Putting together a plane which could carry 100 passengers at such speeds, safely and reliably, for hours at a time, involved a huge investment in research and years upon years of testing.
Elegant wing shape
Concorde's designers faced the classic aerodynamic problem that a wing which performs well at very high speeds tends not to do so well at the low speeds involved in take-off and landing.
At high speeds it is crucial that a wing offer as little resistance or drag as possible to the air flowing over the speeding plane.
During take-off and landing, however, the crucial thing is that the wing offer as much lift as possible, to get the plane up into the air in the first place and to allow it to manoeuvre safely as it comes back down again.
The engineering compromise eventually reached was Concorde's distinctive delta-shaped wing, reminiscent of 1950s military aircraft.
Slowing the pace
Concorde's engine design also posed an engineering dilemma.
Its four powerful jet engines are mounted in pairs below each wing and use afterburners, a technology also known as reheat and otherwise confined to military aircraft.
This technique involves injecting raw fuel into the exhaust of the engines, providing a huge boost in thrust and creating a distinctive glow.
The reheat is used as Concorde takes off.
The challenge for Concorde's designers was to come up with engine intakes which could stand the stresses of supersonic flight and at the same time slow down the air rushing into the engines, to cope with the fact that jet engines do not perform well in a supersonic airflow.
Concorde's flight automation systems were also novel for its time.
Autopilots themselves were nothing new but Concorde's flight deck offered greater sophistication.
Its two autopilots were integrated with flight director systems which calculated the ideal flight path following take-off.
And the aircraft also offered automatic stabilisation and automatic landing facilities.
The 001 Concorde prototype made its own contribution to science during the total solar eclipse of 30 June 1973.
It took off from Las Palmas in the Canary Islands and chased the eclipse at Mach 2 for 74 minutes, allowing a team of seven scientists from the US, Britain and France to make unprecedented observations.
The record observation may not be bettered before the year 2150, when a similarly long eclipse might permit another sun-chasing flight.
With acknowledgements to FG Clarke and Arthur Gibson, authors of Concorde: The story of the world's most advanced passenger aircraft.