The Pentagon is looking into the possibility of deploying weapons in space to defend the United States and its allies from missile attacks. The Defense Department is following congressional orders and looking at putting interceptor missiles in space, John Rood, undersecretary of defense for policy, said Tuesday at a conference organized by the Missile Defense Advocacy Alliance.

However, the department is not yet ready to proceed ahead with the program.

“Those are bridges yet to be crossed,” Rood said adding the decision to deploy defensive weapons in space is “some time away given the level of examination” that is required.

Space News reported that Congress has directed the Pentagon to develop a space-based missile shield. The department said the nation could find its dominance in space challenged by countries like China and Russia and for that, it needs to strengthen its capabilities to detect the attacks, and also be prepared to fight back.

The Defense Department is particularly worried about Chinese and Russian hypersonic weapons that are not detectable by current U.S. missile-defense radars.

“Hypersonic missiles are being developed by both China and Russia. We are concerned about both. When they have done dozens of tests we have not done that is a concern,” said Michael Griffin, undersecretary of defense for management and engineering, Sputnik News reported.

Griffin added that the U.S. is not worried about upsetting China or Russia.

“When you have President Putin on TV bragging about his multi-thousand kilometer hypersonic nuclear strike weapon, and you have China making several dozen successful hypersonic tests, that’s great power competition. Somewhere well down on that priority list is caring about what people think. We just cannot afford to do that,” he said.

Hypersonic weapons fly into outer space and back into the atmosphere in unpredictable trajectories, unlike ballistic missiles and only sensors in space could spot these threats early enough to shot them down, the Defense Department said.

“If the U.S. pursues a space sensor layer, it watches, it detects what others are doing. It’s not a provocative act. It’s no different than what we’ve done for decades,” Rood said, adding “If we’re attacked, we can deal with it, that’s what we want. I don’t think having a sensor capability is a sea change for the United States.”

Griffin also said the current defenses only work against ballistic missiles. “We can’t hit a target we cannot see coming. We would not see it coming until it’s too late.”

He also fired back at critics who estimated a space-based missile shield would cost $100 billion while a layer of 1,000 interceptors each weighing 1,000 kg would cost only $20 billion.

“I am very tired of people saying we cannot afford it. We’ve paid a lot more and gotten a lot less in the Defense Department,” Griffin said adding he is not advocating a system of 1,000 interceptors.

However, the details about the number of weapons and the orbits where they would be placed have not yet been investigated. “I do what engineers do, which is try to bound the problem. As we study the problem we will produce answers,” he said.

The Pentagon is looking at deploying weapons in space to defend U.S. and allies from missile attacks. In this image, the guided-missile cruiser USS Philippine Sea (CG 58) launches a Tomahawk cruise missile, as seen from the aircraft carrier USS George H.W. Bush (CVN 77), in the Gulf, Sept. 23, 2014. REUTERS/Mass Communication Specialist 1st Class Eric Garst/U.S. Navy/Handout/File Photo