The first Briton in space in 24 years blasted off from Kazakhstan to join the International Space Station on Tuesday.
Tim Peake has been training as an astronaut for years before his seven-month trip into space.
The former army pilot will spend seven months aboard the ISS conducting a series of experiments researching asthma, the immune system and the ageing process. But many people glancing at the headlines today managed to see the acronym 'ISS' and replace it with another one that's been in the news a lot recently:
At first there was mild confusion.
(Some of them were better than others.)
We are left wondering whether a few people really are clear on the distinction between ISS and Isis.