Overview
- The CBO modeled a notional layered homeland defense that includes space‑based interceptors, surface sites, and regional layers and estimated roughly $1.2 trillion in lifetime costs with about $8.3 billion a year to operate, a figure the Pentagon disputes.
- The Department of Defense and Space Force push back on the CBO numbers, with the Pentagon citing a much lower internal 10‑year estimate of about $185 billion and program leaders arguing the CBO did not model the architecture they plan to build.
- Space Force has moved quickly on procurement, awarding early other‑transaction contracts worth about $3.2 billion to multiple firms and aiming to demonstrate an initial capability in 2028 under accelerated prototyping authorities.
- Technical and sustainment challenges drive much of the cost risk: the CBO’s notional design calls for roughly 7,800 low‑Earth‑orbit interceptors that would likely last about five years, requiring replacement of roughly one‑fifth of the fleet each year.
- Analysts warn the system would not be an impenetrable shield and could prompt adversaries to expand missile stocks or countermeasures, while Congress and investors weigh large and widely varying cost estimates before committing long‑term funding.