Space exploration is important for humanity: it enables scientific discoveries and improves our day-to-day lives on Earth, allows cooperation between countries. Space exploration is risky, of course. What happens if spaceships run out of fuel in space? It turns out, spaceships don't stop even if the engines are turned off. Why does it happen?
#brightside
Credit: NASA Image and Video Library Animation is created by Bright Side.
00:00Picture this. You're an astronaut hurtling through the cosmos in your state-of-the-art spaceship.
00:05But suddenly, you notice that you're running out of fuel.
00:08What are you going to do? Trapped in the middle of space?
00:12It's hardly like there's a floating gas station.
00:15The good news is that you're not going to get completely stuck.
00:18A spaceship will never actually stop after running out of fuel.
00:22All because there's basically no atmosphere in space.
00:25That's where the popular phrase, in space, no one can hear you scream.
00:30Comes from.
00:31Sound travels through the vibration of teeny tiny atoms and molecules.
00:35In space, where there is no air, there's simply no way for sound to travel.
00:40It's the same for our spaceship.
00:42Because there's no air, there's also a complete lack of air resistance.
00:46Those tiny particles that do exist in space are way too small to reduce the spacecraft's momentum or drag it back.
00:53Because of this, most spacecraft actually turn their engines off for the biggest part of their journey.
00:58So, don't believe those movies that show spaceships with their engines on all the time.
01:03That's completely inaccurate.
01:06Unlike vessels in the water, a ship in space doesn't need constant thrust to keep moving forward.
01:11Usually, its engine is only fired up for short periods of time.
01:15This is not only practical, but also saves money.
01:18Fuel is really expensive to transport into space, as it's heavy.
01:22That's why space probes try to use as little fuel as possible.
01:26They need it when they set off from Earth, and then again when they re-enter the atmosphere.
01:31It happens when they need to slow down upon their return.
01:34While cars and trains have brakes, it's not that simple to bring a spaceship to a screeching halt.
01:39The engines are needed to slow the ship down or bring it to a complete stop.
01:43This involves strategically firing up impressive thrusters at the front.
01:48It creates the needed drag and reduces the spaceship's speed, but this process also requires super high levels of precision.
01:56One wrong move, and you're toast.
01:59Literally.
02:00Hit the thrusters too fast, and the spacecraft will set on fire as you re-enter Earth's atmosphere at thousands of miles per hour.
02:06Traveling too slowly can also cause problems, because in this case, you might miss our planet's orbit completely and move way past Earth.
02:15And most spacecraft don't have enough fuel to try for a second re-entry, so traveling too slowly needs to be avoided at all costs.
02:24But back to the issue at hand.
02:26This basically means that any vehicle with an empty tank will continue traveling at the same speed across space until it eventually runs into something.
02:34There's just no other way for it to stop.
02:38Wait.
02:39Actually, maybe that's not good news.
02:41If you get stranded, it's pretty unlikely that your buddies over there at NASA are going to organize a rescue mission.
02:47This sounds kind of sad, but it does make sense.
02:51By the time they set up a new team and find a ship to come and rescue you, you'll have already traveled so far into space it would take them years to reach you.
02:59This would also cost a ridiculous amount of money.
03:01NASA spends on average a whopping $152 million to launch a ship into space.
03:07That's as much as buying six brand-new top-of-the-range Lamborghinis.
03:12Even crazier, it costs NASA about $49 billion to develop and launch the first space shuttle.
03:18Unfortunately, once you've left Earth's orbit, it's near impossible that you'll make it back without fuel.
03:24That's what actually happened to NASA's Dawn spacecraft back in 2018.
03:28On a random day, the spaceship ran out of fuel.
03:31This left it completely stranded in the middle of space.
03:34It stopped transmitting signals to Earth, bringing an end to an 11-year-long mission that set loads of space records.
03:42The spacecraft could no longer generate electricity, as it had no fuel to move its solar panels to point them toward the Sun.
03:48And to this day, the spaceship is still floating somewhere in space in a derelict state.
03:53Luckily, Dawn had no astronauts on board.
03:57The spacecraft began to orbit the dwarf planet Ceres, which was the object it was originally investigating.
04:03For context, in orbit is a curved path around a star, planet, or moon that an object gets stuck in.
04:09But wait!
04:10NASA are experts in all things relating to spacecraft.
04:13So how did they allow a ship to run out of fuel in the first place?
04:16It's actually super difficult to accurately measure the amount of fuel you'll need in space.
04:22On Earth, gravity keeps all the fuel at the bottom of the tank.
04:26And you can use a float sensor to measure how full the tank is.
04:29But this is impossible in space due to a lack of gravity that normally weighs the fuel down.
04:34Instead, a common approach is to add an air bladder into the fuel tank that's pressurized before a launch to push the fuel into lines.
04:42The more fuel is used, the more this bladder expands.
04:45It takes up more space and keeps the fuel under the right amount of pressure.
04:49This pressure is monitored.
04:50That's how they can tell how much fuel is left.
04:53As you see, it's a lot more complicated than here on Earth.
04:57But say there were astronauts aboard a spacecraft that had run out of fuel.
05:01How long could they survive?
05:02Well, this depends on how much food and water is on board.
05:05NASA usually calculates the extra amount of food astronauts need for their trip to avoid adding extra weight to the spacecraft.
05:13But the good news is that this food can technically be rationed and its consumption can be spread out.
05:18That's because astronaut food comes in special packaging to stop it from going bad.
05:23There are no refrigerators aboard spacecraft.
05:26The food comes in clear, flexible pouches that can be snipped open with scissors.
05:30All the food is pre-cooked and processed, so it doesn't need to be stored in a fridge.
05:35The only exceptions are fresh fruit and vegetables.
05:38These are the only things that need to be eaten quickly as they will spoil.
05:42Today, astronauts also work with nutritionists so they can pick out the foods that they like and will enjoy eating.
05:48They can choose from a whole bunch of products, including mushroom soup, macaroni and cheese, chicken, beef, ham, nuts, and even yummy cookies.
05:58Shrimp cocktail is apparently a new favorite among astronauts because of how spicy it tastes.
06:03Flavored drinks also come in powdered form, just like the Kool-Aid or instant coffee packets you have sitting in your kitchen cupboard.
06:10Interestingly, astronauts often report not feeling hungry in space, so it may be easier than you'd think to ration the food.
06:17But even if you can make your food last, what about water?
06:21Transporting anything into space costs a lot, and water is quite heavy, so it costs even more to transport.
06:28For this reason, tanks of water can't be constantly shipped up to space.
06:32Instead, astronauts have a really complex water system.
06:35It squeezes every last drop of safe and available liquid out of the environment.
06:40This involves recycling used water.
06:42It means that our buddies in space drink water that's been filtered from old shower water.
06:47Their breath, the spaceship's fuel cells, sweat, and so on.
06:51But don't worry, such water is safe to drink, and it's actually even better than most drinking water that comes out of taps in the U.S.
06:58The water on a spacecraft first goes through a bunch of filters, starting with one that removes particles and debris.
07:05Then it passes through multi-filtration beds.
07:08Containing clever substances that remove impurities, the final stage gets rid of harmful compounds and destroys nasty bacteria and viruses.
07:16There are also water reserves, in case of emergency.
07:20For example, the International Space Station keeps around 530 gallons of water in its reserves, just in case.
07:27But what about the air supply?
07:29The primary source of oxygen on spacecraft comes from something called water electrolysis.
07:34This is an amazing system that uses electricity from the craft's solar panels to split water into hydrogen and oxygen gas.
07:42But as we saw with NASA's Dawn, without electricity, it's pretty difficult to aim the solar panels at the sun, which means that the oxygen system would likely shut down.
07:52There is some oxygen stored in a pressurized storage tank, though.
07:56This is a backup supply designed for emergencies.
Be the first to comment