DoD nuclear demos: Army leases, Aberdeen IMSR, Antares space reactor

Open · 3 updates · since Oct 2, 2026 · updated Oct 26, 2026 Energy nuclear smr defense us Arc · Advanced nuclear online

Where it stands: The US military is advancing several nuclear demos: the Army conditionally awarded long-term installation-power leases to three companies, with Ameresco and Terrestrial Energy to deliver an IMSR at Aberdeen Proving Ground; Antares won a $161M DoD space-reactor award; the Navy selected Radiant's Kaleidos microreactor for Naval Weapons Station Crane; and SpaceNukes won a DARPA agreement to ground-test a kilopower reactor with Los Alamos. Watch for contract values, deployment dates and licensing routes, plus the Army lease contractors.

Latest

• 2026-10-26
  (~4:13 PM ET, ANS — ans.org/news): the Space Nuclear Power Corporation (SpaceNukes) received a DARPA other transaction agreement to design, build and conduct a nuclear ground test of a kilopower reactor in collaboration with Los Alamos National Laboratory (company announcement). Development: the defense/space-reactor lane gains a kilopower ground-test commitment beside the Army's three conditional leases (Sep 21), Antares' $161M space-reactor award, and the Navy's Radiant Kaleidos siting at Crane (Oct 22). Watch: test timing and site, contract value, mission linkage.

  

• 2026-10-22 (~7:00 AM ET, WNN — world-nuclear-news.org/articles): the US Navy selected Radiant's Kaleidos microreactor for deployment at Naval Weapons Station Crane, Indiana — the installation-power lane's Navy entry beside the Army's three conditional leases (Sep 21, 2026) and Antares' $161M space-reactor award; no deployment date, contract value, or licensing path in coverage. Naval Weapons Station Crane (Indiana) is distinct from the Crane Clean Energy Center restart tracked in the restart-wave thread. Watch: contract/funding details, deployment timeline, licensing route for a microreactor on a Navy installation, named contractors for the Army's three leases.
• 2026-09-21 Army conditionally awarded long-term leases to three companies for installation power (apparently unrelated to the Janus program); Ameresco + Terrestrial Energy to deliver an IMSR at Aberdeen Proving Ground. 2026-09-15: Antares received a $161M DoD award for a space/national-security reactor demo — same company behind the Centrus HALEU deal (smr-industrial-base thread). 2026-09-14: Army announced complete dismantlement of SM-1 (Fort Belvoir, its first reactor) — historical close-out.

Background

• The thread: the military lane of the advanced-reactor buildout — installation power leases and defense-mission enrichment.
• Watch for: named contractors for the three Army leases; Janus program's own award record.