GAO,Vulcanロケット開発遅れでロシア製エンジン利用期限(2022年末)までの切り替えに間に合わない可能性を指摘

SpaceNews(6/8)
“A U.S. produced rocket engine under development for ULA’s Vulcan launch vehicle is experiencing technical challenges related to the igniter and booster capabilities required and may not be qualified in time to support first launches beginning in 2021,” said GAO.