Video shows Musk's reaction as Trump promises to put US flag on Mars

SpaceX Founder Elon Musk was seen cheering, applauding and doing the thumbs up gesture as US President Donald Trump talked about space exploration in his inaugural address. Trump said, "We'll pursue our manifest destiny into the stars, launching American astronauts to plant the Stars and Stripes (American flag) on...Mars." Donald Trump's son Barron was seen standing next to Musk.