from Lucas, which Tupolev was not permitted to purchase for the Tu-144 as it could also be used on military aircraft. Concorde's designers used fuel as coolant for the cabin air conditioning and for the hydraulic system (see Concorde for details). Tupolev also used fuel/hydraulic heat exchangers, but used cooling turbines for the cabin air. The Tu-144 prototype was a full-scale demonstrator aircraft with the very different production aircraft being developed in parallel. While both Concorde and the Tu-144 prototype had ogival delta wings, the Tu-144's wing lacked Concorde's conical camber. Production Tu-144s replaced this wing with a double delta wing including spanwise and chordwise camber. They also added two small retractable surfaces called a moustache canard, with fixed double-slotted leading-edge slats and retractable double-slotted flaps. These were fitted just behind the cockpit and increased lift at low speeds. Moving the elevons downward in a delta-wing aircraft increases the lift, but also pitches its nose downward. The canards cancel out this nose-downwards moment, thus reducing the landing speed of the production Tu-144s to , still faster than that of Concorde. The NASA study lists final approach speeds during Tu-144LL test flights as . An FAA circular lists Tu-144S approach speed as , as opposed to Concorde's approach speed of , based on the characteristics declared by the manufacturers to Western regulatory bodies. It is open to argument how stable the Tu-144S was at the listed airspeed. In any event, when NASA subcontracted Tupolev bureau in the 1990s to convert one of the remaining Tu-144D to a Tu-144LL standard, the procedure set by Tupolev for landing defined the Tu-144LL "final approach speed... on the order of 360 km/h depending on fuel weight." Brian Calvert, Concorde's technical flight manager and its first commercial pilot in command for several inaugural flights, cites final approach speed of a typical Concorde landing to be . The lower landing speed compared to Tu-144 is due to Concorde's more refined design of the wing profile that provides higher lift at low speeds without degrading supersonic cruise performance – a feature often mentioned in Western publications on Concorde and acknowledged by Tupolev designers as well. Design Along with early Tu-134s, the Tu-144 was one of the last commercial aircraft with a braking parachute. The Tu-144 was not fitted with any reverse thrust capabilities, and so the parachute was used as the sole alternative. The prototypes were also the