Assistant Secretary of Defense John Plumb testifies before the House Armed Services Committee in 2023.

Assistant Secretary of Defense John Plumb testifies before the House Armed Services Committee in 2023. Defense Department / EJ Hersom

Russian space nuke could render low-Earth orbit unusable for a year, US official says

Pentagon’s space-policy leader noted with concern Moscow’s recent veto of a UN resolution against putting nuclear weapons in space.

The detonation of a Russian nuclear space weapon could render low-Earth orbit unusable for a year, according to a top Pentagon space official.

“Several analysts do believe that detonation in space at the right magnitude in the right location could render low-Earth orbit, for example, unusable for some period of time,” John Plumb, assistant defense secretary for space policy, told a House hearing on Wednesday.

Plumb’s assessment follows the confirmation last week by National Security Advisor Jake Sullivan that “the United States assesses that Russia is developing a new satellite carrying a nuclear device.” 

At the hearing, Rep. Mike Turner, R-Ohio, wanted to know how long the weapon would leave low-Earth orbit unusable.

“Could it be a year?” asked Turner, who in February tweeted about a "destabilizing foreign military capability," which led to reports about Russia fielding a space-based anti-satellite nuclear weapon. 

“I believe it could be,” Plumb said. 

Plumb had confirmed in written testimony that the weapon is intended to be a satellite in orbit, but wouldn’t say which orbit when questioned by Turner. 

Russia is developing a “concerning anti-satellite capability related to a new satellite carrying a nuclear device that Russia is developing. This capability could pose a threat to all satellites operated by countries and companies around the globe, as well as to the vital communications, scientific, meteorological, agricultural, commercial, and national security services we all depend upon,” he wrote. 

The threat is not “imminent,” Plumb said at the hearing, but the department is concerned because Russia recently vetoed a United Nations resolution that would have reaffirmed a ban on placing nuclear weapons in space.   

“We just had that United Nations Security Council resolution that Russia vetoed which may in fact tip their hand on this. [The resolution] really just reaffirmed not placing nuclear weapons in outer space, which Russia and the United States and all spacefaring nations have already signed up not to do, so this is a concern for us,” Plumb said.

Plumb called Russia “hypocritical” and “unbelievable” for claiming it won’t deploy weapons in space while refusing to sign the U.N. resolution.

He was echoing sentiments expressed by Sullivan last week. “We have heard President Putin say publicly that Russia has no intention of deploying nuclear weapons in space. If that were the case, Russia would not have vetoed this resolution,” according to a statement the national security adviser released after the U.N. vote.