HOUSTON • Travellers have problems not exceeding a 20kg checked-in baggage allowance when they fly economy.
But spare a thought for Mr Tim Peake, who was limited to 1.5kg for his six months at the International Space Station.
The British astronaut with the European Space Agency returned to Earth on June 18 last year. His book of photographs taken in space - Hello, Is This Planet Earth? My View From The International Space Station - was published recently.
"One of the interesting things about what astronauts pack is what we don't have to pack," Mr Peake said. "We don't have to pack any clothes or a wash kit. That's all provided for us on board the space station.
"Your clothing is chosen in advance so they've got the right sizes. Your wash kit is chosen as well, although you can tell them if you like a certain shaving gel or toothpaste."
Carry-on restrictions on board the Soyuz (the spacecraft that launches the astronauts into space) are even worse than a commercial airline's. "The Russians give you a 1.5kg allowance that you can take in the Soyuz with you and it literally sits inside the capsule as you launch into space."
Being British, I decided to take a T-shirt that had a tuxedo on the front because, I thought, there's going to be an occasion where I need to be properly dressed.
MR TIM PEAKE
Astronauts are also allowed to fill a small bag, just bigger than a shoe box, with personal items. It is delivered to the space station in advance.
Here is what he took to space: Mementos: "I've got two small boys who, at the time I left, were seven and four, and they each sleep with their own little blanket.
"My wife, unknown to me, cut a corner of their blankets out and snuck them in the bag.
"I brought photographs of family and friends for my crew quarters.
"I brought the watch that my wife gave me on our seventh anniversary and some coins commemorating the mission, which I gave as gifts when I returned." T-shirts: "I took up some T-shirts because, you know, that during the six months of your mission, there are some events you'll want to celebrate on board the space station.
"I've done a lot of educational outreach programmes for schoolkids. So I brought T-shirts for those programmes I wanted to support: Mission X, Astro Pi, Unlimited Space Agency and Raleigh International.
"A London Marathon vest because I ran the London Marathon.
"And, being British, I decided to take a T-shirt that had a tuxedo on the front because, I thought, there's going to be an occasion where I need to be properly dressed.
"I got to wear it twice: once when I was asked to present an award to Adele at the Brit Awards and I had a school competition running where schoolkids designed some of my space food and they got to cook it with British chef Heston Blumenthal.
"He did a television tie-up with me at one point, so I wore it for that too." Flags: "Being from the UK, I brought flags for St George's Day, St Patrick's Day, St Andrew's Day and St David's Day, for England, Ireland, Scotland and Wales.
"I hung them up in the European science laboratory and just did a small video message to each country when it was its national day." Compression garments: "On the way up, you don't have to wear a compression garment; you just wear your spacesuit.
"On the way back down, we wear it underneath our spacesuit. It goes around your calf muscles and you lace it up really tightly. And then there's another garment, like a long pair of running shorts, and you lace it up really tightly as well, like a corset.
"It's almost like an anti-gravity suit. It helps with the G-loading for re-entry and with the blood pooling in your legs and feet - it keeps the blood in your chest and head." iPod Nano: "I listen to it on the journey up while we're rendezvousing with the space station.
"There's a fun science podcast from the UK called The Infinite Monkey Cage with Professor Brian Cox. He's a particle physicist and he can make things really easy to understand in a funny way. I love listening to his podcast.