Space shuttle:
I want to show you how they launched the space shuttle. We'll look at all thepreparation beforehand, then the details of the launch pad, and then their 8 1/2-minute journey into space.Sadly, the space shuttle is retired. It no longer flies. However, I think it's stillreally important to learn about. After all, some of this technology is still being used for space programs. In preparation for this video, I read a few books. One of them was called "Riding Rockets," and it was written by three-time astronaut Mike Mullane. He does a good job of capturing what it was like to rideon the space shuttle. I reached out to Mike,and he was really helpful. He made a lot of good suggestions for what to include in this video. Though before we gettoo far, let's review. This is the Orbiter Vehicle, the part that looks like an airplane and carries the astronautsand payloads into space. I have a video all about the inside of the Orbiter Vehicle. It takes so much fuel to get into space that we need a really big gas tank. That's what the orangeexternal tank is for. It provides the fuel for the three Space Shuttle Main Engines. Even this isn't enoughto launch us into space. We need two extra rockets on each side. These are called the SolidRocket Boosters or SRBs. It takes a lot of work toget all of these pieces ready for the launch. There were two launch sitesfor the space shuttle, Kennedy Space Center in Florida and Vandenberg Air ForceBase in California. Shuttle launches from theVandenberg site ended up being canceled, and as a result, all 135 shuttle missions werelaunched out of Florida. So let's take a closer look at Kennedy Space Center in Florida. It has two launch pads, 39A and 39B. Shuttle missions were launchedfrom both of these pads. There's a few buildings way over here, about five kilometers away from the pads. The large one here is theVehicle Assembly Building or VAB.
It's as tall as a 38-story building. This is where they would assemble the space shuttle in preparation for a launch. Next to it is the Launch Control Centre. Notice how it's positioned with a good view of both launchpads. This building is called theOrbiter Processing Facility, or OPF, and actually there were three OPF buildings. It's where the orbiter was serviced in between missions. Over here is the Shuttle Landing Facility. This is where a mission end s for the space shuttle. But they didn't always land here. Sometimes due to weather or other circumstances, the shuttle would land in California at Edwards Air Force Base. When this happened, we need to get the Orbiter Vehicle all the way back to Florida, and the shuttle can't really take off again and fly like an airplane. It wasn't built for that. So here's what happened. The Orbiter Vehicle was taken to the Mate Demate Device, or MDD, which would lift up the shuttle and then load it on the back of a special airplane called the Shuttle Carrier Aircraft. It was then flown across the United States to get back to KennedySpace Centre in Florida. It was then taken to one of the OPFs. Once inside, the engineers would literally crawl all over it to fix or replace any of the shuttle components to make sure that it's safe to fly for the next shuttle mission. This process can take several months to complete. This is part of the reason why the space shuttle was so expensive. Meanwhile, work starts over here at the VAB. We start with the solid rocket boosters, which are assembled piece by piece. On the inside is the solid rocket fuel. Once ignition starts at lift off, it cannot be turned off. Now it's time to lift the externally tank into place. Inside, there are two smaller tanks. One for liquid hydrogen, and one for liquid oxygen. These tanks will remain empty until just a few hours before the launch. Now at room temperature, hydrogen and oxygen are both gases which take up an enormous amount of space. But if we put them at extremely cold temperatures, they will turn into liquids, and we can put a lot more fuel inside of the tanks. The liquids from each tank will flow through pipes down to where it will-connect to the orbiter. This side is for the liquid hydrogen. And this side is for the liquid oxygen. Once the orbiter was ready, it was then transferred from the OPF to the VAB. This was referred to as a Rollover. (bright orchestral music) The orbiter was then hooked up to a crane and then carefully lifted up, moved over to the high bay, and then mounted to the side of the external tank. The fuel and electrical connections are attached to the bottom of the orbiter. There is also another attachment point up towards the top. Once this is all ready to go, we need to move it to-one of the launch pads, which are more than five kilometres away. This is referred to as the Rollout. (gentle orchestral music) The weight of the entire shuttle stack is supported at the base by eight Hold-Down Posts, four on each of the SRBs.
It's then secured in placeby the Hold-Down Bolts. At the moment of liftoff,these will detonate to free the shuttle. The platform it's on is calledthe Mobile Launch Platform. Underneath is the Crawler-Transporter, which moves everything at just under 1 1/2 kilometers per hour. It takes many hours to get all the way to one of the two launch pads. (grandiose orchestral music) Then it's up the rampand slowly into position. The platform is put down on supports. And the crawler goes back down the ramp. (gentle orchestral music) The Mobile Launch Platform has large holes for the rocket flames. The three main engine flameswill go through this hole. And the flames from the two SRBs will go through these two holes. Below the pad is the Flame Trench. During the liftoff, the flames will be deflected to each side. The structure next to theshuttle stack has two main parts, the Fixed Service Structure,which doesn't move, and the Rotating Service Structure, which can pivot around to completely enclose the space shuttle. (bright orchestral music) Sometimes the payloads were loaded here in the vertical position, and other times theywere loaded before this, when the orbiter was onthe ground at the OPF. The Fixed Service Structurehas a Lightning Mast on top, and then three service arms. Two of them are ventarms, which will collect excess hydrogen and oxygenfrom the external tank. This is the Gaseous Hydrogen Vent Arm with the Ground UmbilicalCarrier Plate at the very end. At the top is the Gaseous Oxygen Vent Arm. Because the fuels are so cold, the Beanie Cap is really important to prevent ice buildup at the very top. The third arm is calledthe Orbiter Access Arm. At the end of it is the White Room. This is how the astronautsget on board the orbiter in preparation for a launch. Down here are the two Tail Service Masts. They have connections toeach side of the orbiter. On the day of the launch,this is where the fuel will come in to fill theorange external tank. If there is an emergency on the launchpad and the astronauts needto get away in a hurry, they will come over here tothe Emergency Egress System. It has several basketsthat can quickly carry them far away from the launch tower. Each basket can hold three people. One more feature of theMobile Launch Platform is the Sound Suppression System. Beginning at just a fewseconds before launch, water will start pouring outfrom a few different places. This will limit the sound shockwaves from bouncing back up and damaging parts of the space shuttle asit leaves the ground. The water is stored in thislarge tower on the launchpad. So let's see how this workson the day of the launch.
There are many things thathave to happen in order. I can't cover them all in this video, but let me show you some of the main ones. At T-5 hours and 35minutes before the launch, fuel begins loadinginto the external tank. The fuel comes from thewhite spherical tanks on the edges of the launchpad. Remember that the SRBs already have their solid fuel inside of them. At T-3 hours, the astronautsleave for the launchpad and begin to enter the Orbiter Vehicle. Since the shuttle isvertical on the launchpad, all of the seats are inthe laid back position. Most missions had seven astronauts, three in the mid deck, andfour in the flight deck. There are no windows on the mid deck, so some of the astronauts won't be able to enjoy the view on the way up. (bright orchestral music) There's a lot of excitement coming up to the moment of liftoff. However, if there are any problems such as mechanical failures or even bad weather, than the launch will be delayed or even canceled until another day. This is called a LaunchScrub, and it can happen all the way up until just afew seconds before liftoff. At T-7 minutes and 30 seconds, the Orbiter Access Armis slowly retracted. If there is an emergency, they can quickly bring it back into place. A T-3 minutes and 45 seconds, the main engine gimbal test to make sure that it's working correctly. T-2 minutes and 55 seconds,the Beanie Cap is lifted and the Gaseous OxygenVent Arm is retracted. At T-10 seconds, activatethe Hydrogen Burn Off System, and no, this does notactually start the engines. That happens up here insideof the combustion chamber. What these sparks do isignite any excess hydrogen. This hydrogen can causean unexpected explosion at launch if it isn't taken care of. At T-6.6 seconds, thethree main engines ignite. All three of them must work correctly, or they will shut downand abort the launch. At the moment of liftoff, manythings happen simultaneously. The Gaseous Hydrogen Vent Arm is retracted from the external tank. The two connections at theTail Surface Mass will retract. The eight Hold-Down Bolts will detonate, which frees the shuttle, and then both SRBs ignite. (grandiose orchestral music) For their journey into space, the shuttle is mostlyflown by the autopilot. Of course, the astronautscan still take over if they need to. Shortly after clearing the tower, they do what's called the Roll Program to get the shuttle so that it's heads down for most of the ascent into space. This reduces the aerodynamicstress on the wings. It will also allow theastronauts to see the curve of the Earth as they ascended to space. Now, as we keep gainingmore and more speed, the air in the atmospherewill create pressure on the front of the spacecraft. Then as we get higher, theair starts to thin out.
They use the term Max-Qto refer to the time when the aerodynamic pressurewill be at its highest. During Max-Q, the mainengines will be throttled down so we don't accelerate too quickly. But then shortly after, we canthrottle them back up again. A little more than twominutes after liftoff, the two SRBs have done their job. They are detached, andthen small rocket motors on the bottom and on thetop fire on each booster to ensure that they areseparated from the vehicle. The SRBs fall back down to the Earth where they will parachute in for a soft landing in the ocean. They will be recovered by boat, and then refurbished fora future shuttle mission. Now the three mainengines are on their own. As we get higher, more and more fuel will be used up from the external tank. This means that the shuttlewill keep getting lighter. We have to keep throttlingdown the engines or we'll accelerate too quickly. The maximum amount of accelerationwe want the astronauts to feel is 3 Gs, or threetimes the force of gravity pushing them into their seats. At about eight minutes and 30 seconds, we have Main Engine Cutoff, or MECO. This must happen before the tanks run dry so that the engines aren't damaged. The external tank is now detached. We're not an orbit yet, sothe tank will head back down to Earth and burn up in the atmosphere. (gentle music) The two doors on the bottomside of the shuttle will close now that the external tank is gone. If they didn't close, we wouldhave gaps in the heat shield at the end of a mission,which would not be so good. At this point, the orbiter vehicle is on the same path as the external tank. We're not quite going fast enough to stay in orbit around the Earth. Remember that theexternal tank had the fuel for the three Space Shuttle Main Engines, so we can't really use these anymore. Instead, we'll use thetwo OMS Rocket Motors.
These each carry their ownfuel inside of the pod here. (gentle music) This gives us that last pushinto orbit around the Earth. Now it's traveling at28,000 kilometers per hour, many times faster thanthe speed of a bullet. Now it's time to do some science, release a satellite, or dock to theInternational Space Station. It takes a lot of timeto make these videos. I think I've spent most of my summer learning about the space shuttle. I do this for a living.
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