The US Air Force has released a classified request for proposals (RfP) to industry for the replacement of the nuclear air-launched cruise missile, known as the Long-Range Standoff (LRSO) weapon.

The Pentagon approved Milestone A - or entry into the technology maturation and risk-reduction phase - on 29 July, USAF spokeswoman Leah Bryant tells Flight International, meaning that the decision was made just before the projected August date. The USAF had expected to reach that milestone by the end of June, but the Pentagon’s top acquisition chief Frank Kendall delayed the decision after he asked the service to re-examine the cost of the missile body.

The classified RfP claims that a maximum of two contracts will be awarded in the fourth quarter of Fiscal Year 2017, the USAF states. This will be followed by a 54-month preliminary design review period, and then a downselect to one contractor.

“After receipt of industry proposals, the air force will conduct a source selection and award contracts to up to two prime contractors,” the USAF states. “The prime contractors will execute a 54-month effort to complete a preliminary design with demonstrated reliability and manufacturability, which will be followed by a competitive down-select to a single contractor.”

Production is then expected to begin by 2026, and it could be fielded by 2030, Gen Robin Rand, chief of Air Force Global Strike Command, told the US Senate earlier this year. The air force has plans to purchase 1,000 LRSOs to replace the legacy Boeing AGM-86B air-launched cruise missile, and employ them on the Boeing B-52, Northrop Grumman B-2, and next-generation B-21 bombers.

Although the LRSO has faced some political headwinds from Democrats in the US Congress, efforts to thwart Fiscal 2017 funding for the weapon and the life-extension program of the W-80 warhead, which will be fielded on the new missile, have proved futile.