From 4:42pm to 4:50pm on 24 December, the International Space Station will be visible over the UK – bearing a strong resemblance to Santa’s flying sleigh, weighed down with presents.
The ISS orbits at a height of around 250 miles, and measures around 110 metres in length – it’ll be hard to spot, but it won’t be impossible.
Stargazers looking to get a glimpse of the space station should keep their eyes peeled for a fast-moving object with no flashing lights – it’s easy to mistake for a bright star or a distant plane, but its speed and unusual light should make it recognisable.
The ISS makes a full orbit of Earth every 92 minutes, so it’s possible to see it from the UK fairly regularly.
However, thanks to a bit of good timing, the ISS will appear fairly bright and high in the sky in the run-up to Christmas, making it easier to spot than it is at the moment.
On Christmas Eve, it’ll start rising in the West before setting on the South East – amateur astronomers can find the exact position where the ISS will emerge by using Nasa’s ‘Spot the Station’ tool.
Even if you don’t believe in Santa, it’s worth sparing a thought for the astronauts orbiting in the space station – on Christmas Eve, Russian cosmonaut Mikhail Kornienko and American astronaut Scott Kelly will be marking their 271st day in space, with another couple of months to go before their year-long ISS mission comes to an end.
Although there’s still important work to be done on the ISS on Christmas, crew members are usually given time off from their normal duties to celebrate by opening presents and having a meal together – and despite weight considerations severely limiting what can be sent up to space, ISS astronauts get to mark the holiday with a small artificial Christmas tree.