A bipartisan group of senators wants the government to explore how to expand United States missile defense systems to a new realm: space.

"We're in unique times, and we need to explore all means of protecting ourselves," Sen. Brian Schatz, D-Hawaii, told the Washington Examiner.

Schatz is one of the most liberal members of the Senate, but the looming threat of North Korean dictator Kim Jong Un's nuclear weapons program has prompted him to collaborate with Alaska Republican Dan Sullivan and six other senators across the ideological spectrum on a broad missile defense bill.

Their proposal calls for "the development and deployment of a space-based sensor layer" to aid 28 new ground-based interceptors in detecting and downing incoming ballistic missile attacks.

"Our nation's missile defense is a critical insurance policy that protects Americans and our allies from a nuclear catastrophe," said Sullivan, whose home state — along with Hawaii — is much more vulnerable to ballistic missile attacks than the continental United States. "Top military leaders have been sounding the alarm, saying it is only a matter of ‘when, not if,' Kim Jong Un will get the capability to range cities in the continental United States with a nuclear inter-continental ballistic missile."

Sen. Ted Cruz, R-Texas, another co-sponsor, likened the proposals to the missile defense research that former President Ronald Reagan authorized in the 1980s. "This bill is a statement of rededication to Reagan's vision, particularly its attention to space-based sensors, and I hope all my colleagues will come together to invest in the security of the American people," he said.

Reagan's proposals drew mockery from liberal critics. The late Sen. Ted Kennedy, D-Mass., dismissed the space-based missile defenses as "reckless Star Wars schemes." That backdrop makes the involvement of Schatz and two other Democratic senators — Gary Peters of Michigan and West Virginia's Joe Manchin — more notable. "There are organizations with whom I normally work who would have great heartburn about that issue," Schatz acknowledged.

The senators focused with near-uniformity on the threat of North Korea in their formal statements explaining the need for an expanded missile defense system. But the legislation was unveiled the same week that Russian President Vladimir Putin called for his nation's scientists "enhance the Earth's remote sensing system" at a forum on the space sector.

"As you know, the most advanced countries make broad use of this technology," Putin said on Monday. "Russia, too, should make more active use of the possibilities it offers for bolstering our national defense and security and for developing the economy and social sector and raising the quality of governance."