The newer Kuznetsov NK-321 turbofan engines, rated at more than 55,000 pounds thrust in full afterburner, give the aircraft a maximum cruising speed above Mach 2.3 (about 1,550 mph). These engines also give the Tu-144LL a greatly improved range of about 3,500 nautical miles (4,040 statute miles/6,500 km).
Why wouldn't you want to fly in a NASA TU-144LL??? They could do the most epic vomit comet ever just put quiet spike on the nose so FAA clears it over land. Screw six flags. Call it Vodka Vomiter. Give every passenger a little astronaut suit and this would be one helluva amusement ride. It's not practical for an airliner, but its a lot cheaper per seat than renting a MiG or Flanker for edge of space or zoom climb flights.
How many tens of thousands of feet does this do in minute in vertical climb rate with upgraded engines? Oh certainly the national governmental agencies would get rather pissed about a expensive lab turned into entertainment rides. But what if NASA actually made money for once???