BAe 146-100 wrote
Is the TU-144 still operated by Nasa?
From
NASA DFRC
Six flight and two ground experiments were conducted during the program's first flight phase, which began in June 1996 and concluded in February 1998 after 19 research flights. A shorter follow-on program involving about seven flights began in September 1998 and concluded in April 1999. All flights were conducted in Russia from Tupolev's facility at the Zhukovsky Air Development Center near Moscow.