WASHINGTON — The U.S. Air Force has issued, and quietly revoked, a solicitation to industry seeking technologies that would support a hypersonic glide vehicle capable of traversing intercontinental ranges, potentially signaling the military’s interest in a hypersonic nuclear weapon.

According to an Aug. 12 request for information first reported by Aviation Week, the Air Force Nuclear Weapons Center sought ideas for potential upgrades to intercontinental ballistic missiles, including a “thermal protection system that can support [a] hypersonic glide to ICBM ranges.”

The items listed as potential ICBM upgrades were all marked “unclassified/for official use only,” which notes information that — while not secret — is not normally released to the public. The RFI was then withdrawn after Aviation Week began inquiring about it, the report noted.

Asked about the RFI on Wednesday, Lt. Gen. Richard Clark, the Air Force’s deputy chief of staff for strategic deterrence and nuclear integration, said the service’s next-generation ICBMs — known as the Ground Based Strategic Deterrent — will not be available as a hypersonic variant when it is fielded in the late 2020s.

“With a weapon system that’s going to be fielded until the 2070 time frame, it’s hard to know exactly where we may go with that down the road,” he during an event hosted by the Mitchell Institute for Aerospace Studies. “Right now, though, the threshold warhead does not include hypersonic glide vehicles. I think I can say that safely without talking too much about what the warheads will look like.”

However, he noted that GBSD’s open-architecture backbone makes it able to adopt emerging technologies. He did not comment specifically on whether a hypersonic glide vehicle was under consideration.

As we bring the system online, we will ensure that we have the ability to roll different technologies in and to incorporate that into GBSD,” he said. “And that’s one of the, I think, best features … of GBSD, is that it’s going to give us that flexibility. So that if we decide down the road that there’s a particular technology that needs to be incorporated, we’ll be able to do that.”

As the sole bidder in the GBSD competition, Northrop Grumman is expected to win an estimated $85 billion over the life of the program. A contract award is slated to occur by September, although Northrop CEO Kathy Warden said in April that she expected a decision this month.