Taking a step back from the German program,
The DPP's description of the program states that it is for the:
'Development and acquisition of an innovative and sustainable weapon system, intended to arm naval ships and aircraft, including those unmanned. This new torpedo responds to the growing needs of the [Min. of] Defense in relation to the modern submarine threat, filling the capability gaps of the MU90 system. The integration of the new torpedo will ensure a more effective and versatile response against underwater threats, improving the security and operational effectiveness of the armed forces.'
WRT to the Black Arrow hypothesis - I do find it interesting that there are some overlaps in requirements, but I think it is definitely something else.
For those unfamiliar, Black Arrow is the A244/S Mod 4, which was a major improvement on the earlier Mod 3 (a late 1990s development) derived from technology in both the Mod 3, the A290 program and subsequent MU90, and the Black Shark torpedo. On top of performance enhancements, it is also advertising as being use from USVs and UAVs - which is likewise a requirement of this new torpedo.
With that said, Black Arrow itself is 'old news' at this point, being a 2010s development that entered service with an unspecified launch customer in the early 2020s. This program is for the development of a new torpedo system, and I think it is also important to highlight that this is meant for the Marina Militare, and that it has a need to fill capability gaps with the MU90.
The A244 series was not used by the Marina Militare, even though it was extensively exported as a lower-cost competitor to the Mk.46 series (if I'm not mistaken, it was the most successful non-American or Soviet lightweight torpedo of the Cold War?). The intended replacement for the Mk.44 and Mk.46 lightweight torpedoes in Italian service was the A290, which was ultimately merged with the MU90. This aimed for a specifically higher performance that even the more modern incarnations of A244 have not really tried for in terms of speed and certain other characteristics.
My read of the program description is that they are looking for a newer and better development in that A290 -> MU90 legacy, rather than a cheaper export torpedo like A244 - which already has a very recent offering. Given MU90's age I am sure there are good reasons to want to replace it.
Cynically, I also cannot help but wonder if they also feel they can pursue a fully national LWT program because they have the capability to do so in house, and without MU90 the number of competitors within Europe are limited to American (Mk.54) or British (Stingray) models. A290's merging with Murène in the 1990s in part reflected a shrinking market domestically and abroad, with the end of the Cold War. The situation at present is distinctly the opposite, and if LWT procurement numbers are anything like the Cold War then there is not really a need to worry about bringing in additional partners to produce an economical number of torpedoes. Especially given the export potential.
