There were plans for a new cruise missile a few years ago which should make better use of the big weapons bays of the Tu-160.
The estimated range was between 8.000 and 10.000km.
That is a two stage 11 metre long missile that will be massively hypersonic... called Gzur 2. Gzur 1 being a 6 metre long mach 6 missile that weighs 1.5 tons and has a range of 1,500m, while the 6 ton 11 metre long Gzur 2 will have a range of 12,000km or so and intended to be carried internally in the Tu-160 and PAK DA.
Is this the nuclear cruise missile? When I look up the code it mentions burevestnik...
No, that is a nuclear propelled missile of essentially unlimited range... they don't need a bomber to carry that... it could be ground launched in the opposite direction to the target and hit the target by going around the world to get there.
These new cruise missiles needs to be Hypersonic, with AI capabilities, and more importantly with high degree of precision
In WWIII when they arrive the target area will already have been hammered by ICBMs and SLBMs hours before hand so they shouldn't have much trouble getting through.
These are probably new regular cruise missiles with Zircon fuel (plus air launch gives you a whole lot of extra range)
The two weapon bays on a Tu-160 are 11 metres long and the weapon bays of the PAK DA are not likely to be shorter.
The 3,000km range Kh-55SM is 6m long... which is just too long to fit two in tandem on the launcher, the Kh-101/102 are 7.4m long and can reach 5,000km, so these missiles might be 10m long to reach 6,500km.
No breakthrough in physics is needed for this.