Nasa has sent a four-year-old British boy a heartbreakingly lovely video response, after he sent in his own video letter for a school project.
Lucas Whiteley from Sunny Hill School in Wrenthorpe, Yorkshire, sent Nasa the video asking questions including "how many stars are there?".
Three weeks went by without a response - but then NASA's Ames Research Centre did the honourable thing and sent a reply.
But this was no ordinary reply. In fact it was a full 10-minute video recorded by engineer Ted Garbeff in his spare time, containing long and funny responses to Lucas's questions.
It's now proven to be a hit on YouTube, with more than 60,000 views and rising.
Lucas promptly sent a thank you note - and received back emails from NASA Administrator Charles Bolden and Ames Director S. Peter Worden.
"It was a really nice note saying thanks for taking the time to do that," said Garbeff. "I know he’s our administrator, but he’s also an astronaut, so he’s a total hero to me."