NASA has issued a draft request for proposals for development of its Quiet Supersonic Transport (QueSST) low-boom flight demonstrator. The draft request comes as Lockheed Martin completes work on the preliminary design of a low-boom demonstrator concept under a $20 million contract. NASA's initial plan was to have the contenders build on Lockheed's preliminary design, however it is now completely optional, providing the contenders more flexibility in their studies. 

NASA expects to issue the full request for proposals in August and will award the contract in the first quarter of 2018. QueSST's critical design review is scheduled in the third quarter of 2019 and the first flight in 2021.