Readers write about the DIscovery space shuttle, use of force majeure, the Vietnam War, humans on Mars, sharkskin riblets and naming military aircraft and ships.
Stratolaunch is shifting its focus to its 747 launch platform after successful repeat flights of the first autonomous, fully reusable hypersonic test aircraft.
Western militaries confront the reality that Russian electromagnetic spectrum warfare puts everything in the crosshairs, from GPS-guided weapons to satellites.
