The Department of Energy (DOE) has released details about an incoming supercomputer, set to be installed at Los Alamos National Laboratory, New Mexico, in 2027.

The system, dubbed ATS-5, will replace the 30 petaflops ATS-3 Crossroads machine which the DOE said is “nearing the end of its useful lifetime.”

Los Alamos National Laboratory Tycho.jpg
Los Alamos National Laboratory – Los Alamos National Laboratory

According to the DOE, the primary purpose of ATS-5 is to support the National Nuclear Security Administration’s (NNSA) efforts to maintain nuclear stockpiles by tackling “some of the largest-scale 3D simulation workloads.”

The NNSA and the Department of Energy have previously collaborated on the construction of the world’s most powerful supercomputer, the 1.742 exaflops El Capitan. Housed at the Lawrence Livermore National Laboratory in California, the system was officially dedicated on January 9, 2025.

Documents released by the DOE claim the ATS-5 will be able to reduce the time-to-completion of these simulations – known as hero-class simulations – from months to days, whilst providing the ability to run multiple of these hero-class simulations simultaneously.

The department also said “numerous architectural advancements” will be baked into the design of the ATS-5 system to help meet the project’s goals. These include improvements to memory bandwidth performance, increased efficiency, and architectural diversity.

“Achieving these goals will enable weapons designers, analysts, and computational scientists to make more routine use of today’s hero-class simulations in support of the stockpile stewardship certification and assessments to ensure that the Nation’s nuclear stockpile is safe, secure, and reliable,” said a statement on the Los Alamos National Lab’s website.

The DOE is hoping to award the build contract in May of 2025, with the lab expected to take delivery of the system in late 2026 or early 2027. The ATS-5 system has a target deployment date of August – September 2027.

While no information about the compute power of the ATS-5 has been released, the DOE has described the system as the “first post-exascale NNSA system.”

Documents released by the department say that the supercomputer will only draw 20MW or less of power, making it more efficient than the US' other exascale systems.

To date, both El Capitan and Frontier, the only two exascale systems currently listed in the Top500, use more than 20MW of power.