That technology remains in development and it may not be feasible for years for a counter-missile launched from space to cut through Earth’s atmosphere with enough force to eliminate a ballistic missile, the people said.
The defense department already struggles with ground-based interceptors, which have been in development since the 1980s to take out missiles in their so-called “glide phase”, but still have only a roughly 20% success rate.
A White House spokesperson did not respond to a request for comment. Pentagon spokesperson Sean Parnell said in a statement that the defense department “will not publicly disclose specific technical details regarding the capabilities or acquisition strategies of certain advanced systems”.
The Trump administration has said Golden Dome could cost in the region of $175bn, a figure derived from what the Pentagon allocated for the project, according to two people familiar with the matter: $17.6bn for 2026, roughly $50bn for 2027 and approximately $100bn for 2028.
The final cost could be higher but Pentagon officials have said privately it depends on how ambitious Trump orders Golden Dome to be.
If Trump wants the ability to protect against 100 ballistic missiles, for instance, it could necessitate Golden Dome having several thousands of satellites that will naturally de-orbit every few years and need to be replaced, one of the people said.
Trump said in a Truth Social post on Tuesday that Canada could participate in Golden Dome, but that it would have to pay $61bn or become the 51st US state to get it for free. It was not clear how Trump reached that figure.
The idea of having Canada be a part of the program was discussed at the Pentagon when Trump first ordered Golden Dome months ago, one of the people said, but it was more about Canada contributing its satellite and radar data into Golden Dome.
Initially, the White House’s national security council called the program “Moonshot”, the people said. The defense secretary, Pete Hegseth, thought it was a terrible name and came up with three tiers for a possible missile shield system: silver, gold and platinum. The only tier costed out was gold.