The UK’s sovereign nuclear warhead, dubbed “Project Astraea,” is making progress, Defence Minister Luke Pollard confirmed in a written parliamentary response this month.
“Funding for the Astraea programme is included within the £15 billion investment in the sovereign nuclear warhead programme this Parliament,” he wrote, without specifying the exact cost for the program, citing national security reasons.
Pollard added that the investment also covers the sustainment of the existing Holbrook/Mk4A nuclear warhead, which is fitted on the Trident II D5 missile deployed by the Royal Navy’s Vanguard-class submarines and the future Dreadnought-class submarines, as well as associated infrastructure upgrades.
In a recent and separate publication explaining the country’s nuclear deterrent strategy, the government noted that Astraea’s research and development projected expense will reach around 1 billion pounds ($1.3 billion) over the next 10 years.
Project Astraea
In March 2024, the Defence Nuclear Enterprise Command Paper revealed the upcoming next-generation sovereign warhead’s designation as Astraea or A21/Mk7.
It is meant to replace the aging Holbrook/Mk4A warhead while retaining compatibility with the Lockheed Martin-developed Trident II D5 submarine-launched ballistic missiles, and is expected to enter service by the 2030s.
The defense ministry’s research facility, the Atomic Weapons Establishment, is responsible for the design, development, and manufacturing of the Astraea.
The policy paper further noted that Astraea’s development will be “in parallel” with the US’ W93/Mk7 warhead program.
While Astraea is not the first British sovereign nuclear warhead, it will be the first to be developed without live nuclear testing, complying with the country’s “voluntary moratorium on nuclear weapon test explosions.”
London will instead rely on advanced technology for testing, such as supercomputer simulations or experiments at the EPURE hydrodynamic facility located in France.
