Later use
thumb|The Tu-144LL used by [[NASA to carry out research for the High Speed Civil Transport in 1997.]]
thumb|Tu-144LL in flight in 1998.
thumb|Tu-144 with distinctive [[Droop nose (aeronautics)|droop nose on display at the MAKS Airshow in 2007.]]
The Tu-144 programme was cancelled by a Soviet government decree on 1 July 1983 that also provided for future use of the remaining Tu-144 aircraft as airborne laboratories. In 1985, Tu-144D were used to train pilots for the Soviet Buran space shuttle. In 1986–1988 Tu-144D No. 77114, built in 1981, was used for medical and biological research of high-altitude atmosphere radiological conditions. Further research was planned but not completed, due to lack of funding. In 1995, Tu-144D No. 77114 (with only 82.5 hours of flight time) was taken out of storage and after extensive modification at a cost of US$350million, designated the Tu-144LL (where LL is a Russian abbreviation for Flying Laboratory, , Letayushchaya Laboratoriya). The aircraft made 27 flights in Russia during 1996 and 1997.
In 2003, after the retirement of Concorde, there was renewed interest from several wealthy individuals who wanted to use the Tu-144LL for a transatlantic record attempt, despite the high cost of a flight readiness overhaul even if military authorities would authorize the use of NK-321 engines outside Russian Federation airspace.
Reasons for failure and cancellation
Limited routes
Only one commercial route was ever used, an approximately route from Moscow to Alma-Ata (now Almaty), and flights were limited to one a week, despite there being eight Tu-144S certified aircraft available and a number of other routes suitable for supersonic flights, suggesting that the Aeroflot decision-makers had little confidence in the Tu-144 commercial viability when passenger service began in 1977.
Compressor disc and other failures
On 31 August 1980, Tu-144D (77113) suffered an uncontained compressor disc failure in supersonic flight which damaged part of the airframe structure and systems. The crew was able to perform an emergency landing at Engels-2 strategic bomber base.
On 12 November 1981, a Tu-144D's RD-36-51 engine was destroyed during bench tests, leading to a temporary suspension of all Tu-144D flights.
Economic inefficiency
Global trends facilitated the transition of jet transportation from a luxury available only to the elite, to a widespread form of mass transportation. Although the 1973 oil crisis did not directly impact decision-making processes within the Soviet Union, the expansion of Soviet air travel in the late 1970s made the supply of aviation fuel a growth constraint, and it was obvious that potential Western buyers were heavily dissuaded by high fuel prices. By the late 1970s, Soviet promotional efforts shifted to the Ilyushin Il-86, a more economically efficient jumbo jet that went on to become the country's flagship airliner. Moon notes that in 1976, Aeroflot was promoting the Il-86 over the Tu-144, despite the latter's incipient and long-awaited entry into service.
G.A. Cheryomukhin, an aerodynamics engineer who took part in the design and certification of Tu-144,
The rushed introduction to service of poorly tested aircraft happened previously with another Tupolev project that had high political visibility and prestige: the Tu-104 passenger jet-liner was the first successful Soviet passenger jet in service. In a decision-making similar to the Tu-144-story, the Soviet government introduced the Tu-104 into passenger service before satisfactory stability and controllability had been achieved. During high-altitude and high-speed flight the aircraft was prone to longitudinal instability, and also at high altitudes, it had a narrow range of angle of attack separating the aircraft from stalls known as coffin corner. These problems created the preconditions for spin dives, that happened twice before the Tu-104 was eventually properly tested and the problem was resolved.
Personal factors
, a notable Soviet aircraft designer,
These records established an altitude of with a range of loads up to 30 tonnes, and a sustained speed of over a closed circuit of up to with similar loads.
To put the numbers in perspective, Concorde's service ceiling under a typical Transatlantic flight payload of 10 tonnes was ,