Three, two, one...Blast off! Written for the KidsKnowIt Network by:
Gemma Lavender, MPhys, FRAS
Have you ever wondered what it would be like to go up into space? What it would be like to see the Solar System without the need for a telescope? What do you think it would be like? Some have been able to answer these questions and these people are called astronauts. You might even want to be an astronaut yourself! After putting on their spacesuits and jumping into their rocket, the first thing that astronauts notice when they reach space is that they feel much lighter - so much lighter in fact that they start floating around their spacecrafts when they leave the Earth’s atmosphere! Do you know why this is? The answer is quite tricky so here’s a clue: it’s nothing to do with there being more gravity on Earth than in space!
You might have heard of the word gravity, but do you know what it is? We experience it everyday; from when you drop something on the floor to walking to school or to your friend’s house. Gravity makes sure that we are able to walk on the ground and that everything on Earth is how it should be. It is a force that gives us weight. But if the Earth has gravity, then surely the further we move from it, the less gravity there will be?
While this is true, it is not the right answer to why astronauts are lighter in space than on the Earth. So far, astronauts have not gotten too far away from our planet and so, the gravity is 11% less where they are compared to us walking around on the surface. Imagine if you had a ladder; one that reached high enough to reach a shuttle’s orbit. If you measured your weight at the first rung and you weighed yourself to be 100 pounds, then by the end of your climb to the very last step of the ladder, you would find that if you weighed yourself again, you would only weigh 89 pounds - all thanks to a very small change in gravity. However, it is not until you let go of the ladder at the very top, that you will notice that you are not too heavy at all. This effect won’t last for long if you are not inside your spacesuit and shuttle meaning that you will end up falling back down to the Earth!
Inside your spaceship, things are a little bit different. You probably know that the Earth is curved and thanks to this, that’s where the magic really begins! You, your spaceship and everything inside it might all be falling towards the Earth, but because it is curved and you’re moving in a quick sideways movement in orbit, such that our planet is continually curving away, you never really reach the surface so start floating around instead.
So while you are up in space for a long time, what do you think is the most important thing to have? Here’s a clue: it’s something to give your body fuel. That’s right – food! If you went up into space, what is on the menu might disappoint you - there’s no fast food delivery into outer space so there would be no freshly cooked pizzas or burgers! So instead, every few months, a spacecraft will deliver food to the hungry astronauts loaded with ready made meals, frozen vegetables and other foods that you’re likely to find in the refrigerator at home along with frozen desserts and dairy products. Astronauts are also given ketchup, mustard and mayonnaise as well as salt and pepper. Space condiments have to be in liquid form - and that includes salt and pepper! Their food is either canned or wrapped in aluminum foil and in some cases, they have to add hot water to it to cook. It’s not all boring though and luckily they don’t have to drink flavourless water all of the time - they are allowed to have coffee, tea and orange juice as well as fizzy drinks like root beer.
Image: NASA - Astronauts also enjoy treats while in orbit.
You might be wondering how they can run on a treadmill or cycle on a fitness bike when it is so easy for them to float away. The answer is that they have to be tied to their fitness machines so they do not end up drifting off when they should be exercising! Astronauts do not have to stay on their spacecraft though - they can go for a stroll; a little wander called a spacewalk! But first they need to make sure that their spacesuits are on. Do you know why? That’s right, there is no oxygen in space, so they need them to breathe as well as to protect them from the harmful radiation thrown out by the Sun.
Space is also very very cold, so an astronaut's spacesuit keeps them warm, while protecting them from deadly radiation. Astronauts often go on spacewalks to fix and build space stations - it’s amazing how a suit can allow them to go on a stroll through space!
All of that exercise can be quite tiring, but where do you go for a lay down without floating away? There are beds on the spacecraft, the only trouble is that an astronaut needs to be tied to their bed to get a proper night’s sleep - you could say that it is very much like when your parents tuck you in too tightly when you turn in for the night!
Watch astronauts on the International Space Station answer students' questions about what life is like in space.
Astronauts can get a sense of weightlessness before they travel into orbit. NASA uses a large plane equipped with padded inside walls to travel high into the atmosphere where it then flies upward at a 45 degree angle and then down at a 45 degree angle to create 25-30 second periods of weightlessness. Each flight performs about 40-60 of these maneuvers. These flights take place over the Gulf of Mexico.