The flight test record of the Army’s Long-Range Hypersonic Weapon — now formally the Dark Eagle — spans nearly five years of failures, cancellations, delays, and, eventually, two successful end-to-end demonstrations in a single calendar year. That arc tells a story about the difficulty of developing hypersonic systems at operational scale, and about what it takes to bring one from prototype to fielding.

The Army originally intended three flight tests before fielding the first battery in FY2023. That schedule did not survive contact with the physics involved.