The Virginia-headquartered defense contractor first revealed the weapon, also referred to by the abbreviation VLWT, on May 21, 2020. The firm says this is the first industry-built torpedo of its kind and that it privately funded the development. However, it is based on design documentation for a Common Very Lightweight Torpedo (CVLWT) that Pennsylvania State University’s Applied Research Laboratory (PSU-ARL) had developed for the Office of Naval Research (ONR) and which the service had distributed to defense contractors in 2016. The War Zone had previously written a deep dive into the PSU-ARL design and its potential applications, which you can find here.
Visually, Northrop Grumman’s VLWT is very similar visually to ARL’s CVLWT design and also uses a Stored Chemical Energy Propulsion System (SCEPS) to propel the weapon. The SCEPS in the earlier CVLWT consists of a solid block of lithium that then gets bathed in sulfur hexafluoride gas, which triggers a very energetic chemical reaction. The resulting steam drives a turbine that powers the torpedo’s single screw. SCEPS, which already in use in more traditionally-sized torpedos, is known for being able to rapidly accelerate the weapon compared to other propulsion methods.