Layoff everyone on the PR team and just do shit. When you are 95% of the way there and actually have some sort of prototype, announce a hard plan and details. No interviews, no artist renditions of shit that's never going to happen, no congratulating yourself for ideas and hopes, just get shit done--that's the best PR. James Webb and was a constant massive let down because of its continuously slipping deadlines. Years and years late and billions over budget....but then...it actually happened and it was amazing.
NASA, quit setting our expectations if you never meet them. Just do shit and let us be amazed when it happens.