Based on Lockheed's quarterly filing with the U.S. Securities and Exchange Commission, that places the total Lockheed losses associated with this single shadow program up to some $335 million since 2022.

Between February 2018, when the SR-72 went dark and September 2023, Lockheed Martin increased the size of the advanced development programs unit by 75 percent. They hired more than 2,300 new employees over five years.

Lockheed Martin began development on a hypersonic successor to the SR-71 Blackbird in 2006. The program continued in secret for seven years, before being formally announced to the public in 2013.

The SR-71 Blackbird spy plane had a reported top speed of mach 3.2 but there was unofficial speeds of Mach 3.5. The veteran SR-71 pilots indicated that the SR-71 could regularly fly at mach 3.3.

Lockheed has been working ob the turbine-based combined cycle, or TBCC, engine. Lockheed Martin was leading the design effort on the aircraft and Aerojet Rocketdyne was tasked with engine development.

Th SR72 is believed to be a Mach 6+ aircraft, this new platform was slated from the start as an intelligence, surveillance, and reconnaissance (ISR) asset with strike capabilities. This meant the aircraft would be capable of carrying a variety of payloads, including munitions to engage ground targets.

A startup, Hermeus, has over $100 million in funding and is rapidly developing a hypersonic drone.