This astronaut just called out Donald Trump on Twitter. Twice

When he's not performing complex tasks and research in space, astronaut Mark Kelly devotes some of his time to calling out the President of the United States. And he's had a busy start to the year so far.

Donald Trump was slammed on social media yesterday after bragging about the size of his nuclear button, following Kim Jong Un's claims that his own nuclear button is 'always on his desk'.

Kelly joined in, pointing out the obvious seriousness of threatening nuclear war. He even kindly offered to chat with the President if he wanted to learn more.

While on Tuesday, Trump took to Twitter claiming credit for the absence of fatal commercial airline crashes in the US last year.

Kelly, who spent nearly a year aboard the International Space Station, was quick to bring Trump back down to Earth by arguing that the stat was nothing to do with Trump but a result of a campaign to improve passenger safety by federal agencies.

The astronaut, who became a gun-control activist after his wife was seriously wounded in a 2011 shooting, went on to suggest that the President should follow his own logic and take responsibility for gun deaths.

Kelly is not alone in dismissing Trump's boasts. Rather than praising the President for the safety streak after only a year in office, experts instead thank a long-term worldwide push for airline safety.

In fact, commercial airline deaths in the US have been non-existent for longer than just 2017.