Keith’s note: Sources report that NASA is looking at using the EM-2 SLS launch vehicle for the EM-1 mission due to hydrogen tank issues on the EM-1 vehicle. NASA is also looking at using the EM-3 SLS launch vehicle to fly the EM-2 mission. In addition, NASA is considering a delay in issuing the SLS block buy procurement notice (EM-3 and beyond) originally due out in June into Oct 2017 […]