Humans have always dreamed of launching into space, and it took many generations to create the technology that allowed us to get there. The word “launch” means to propel with force or to embark on a mission. Long ago, humans realized the scientific value of putting satellites in orbit and people into space. We wanted to land on the Moon, study the Earth, and explore the solar system. The only way to do it was to launch into space.
Often, the reason we launch things is to deliver a “payload”. A payload means a valuable spacecraft, cargo, or people that need to be delivered into space. An example is a NASA satellite to be put into orbit around the Earth. The payload is contained within the launch vehicle.
The most common launch vehicle into space is, of course, a rocket! In the past, the Space Shuttle was also used to deploy satellites and other payloads. But for now, let’s talk about rockets.
A rocket is a special type of vehicle that is designed to launch into the atmosphere and space to deliver a payload. A rocket uses an engine to burn rocket fuel and thrust the rocket upward at incredible speeds.
How are rockets put together? In this example, the rocket combines liquid hydrogen and liquid oxygen in a combustion chamber. The burning of this fuel then pushes the rocket up at extreme speeds. These are boosters that help the main rocket. There is a control system to help with guidance of the rocket. Also, the cargo area is for the payload that must get into space, and that payload is protected by “fairings”.
Many rockets are actually “multi-stage” rockets. These rockets are actually multiple smaller rockets stacked on top of each other within the same big rocket! Each part comes off when it is no longer needed, and then the smaller rocket ignites its boosters and proceeds to the next stage until the payload is finally delivered!
Rocket fuel, or propellant, is essential to pushing the rocket into the atmosphere and space. The rocket fuel is either solid, similar to gunpowder but with different chemicals, or the fuel is liquid, like liquid oxygen and liquid hydrogen mixed together.
The gravity of the Earth is constantly trying to pull things down to the ground. Rockets are very heavy and need to be able to generate incredible speed to escape the Earth’s strong gravity.This speed is called the “escape velocity”. A rocket needs to be going about 25,000 miles per hour or 40,000 kph to escape the Earth and get to space!
NASA’s Space Shuttle was a reusable delivery vehicle which flew from 1981 to 2012. It played a crucial role in delivering many satellites into orbit around Earth, spacecraft to other planets, and putting people and cargo on the International Space Station.
Rockets have been around for a long time actually. Centuries ago, the Chinese were one of the first cultures to create simple rockets that were used to make fireworks. But it wasn’t until Robert Goddard in the 1920’s demonstrated the first liquid fuel, multi-stage rockets designed to launch into the Earth’s atmosphere. Tsiolkovsky and Von Braun were two more brilliant scientists, along with Goddard, that would be called the “fathers of rocket science”.
Not all rockets are the same, there have been many types of rockets over time. Some examples are: the Saturn, Antares, Atlas, Delta, Falcon, Ariane , Titan, Soyuz, IUS, SLS, sounding rockets and many more. Some of these are bigger, some are smaller, they all have different designs and all are used for different types of missions.
The IUS is a rocket attached to a payload and launched from another rocket or the Space Shuttle. IUS is designed to boost its payload further into space after achieving an initial orbit. An example is NASA’s TDRS-K that used IUS to get into a geo-synchronous orbit. TDRSS is a series of data relay satellites at much higher orbits that enable lower satellites to talk to each other all around the Earth. Missions like Magellan and Galileo in the 1980’s and 90’s successfully explored Venus and Jupiter thanks to IUS rockets.
Sometimes we don’t want to launch from land, we need to launch from the ocean, called a Sea Launch. Sometimes to get a rocket where you want it in space, you have to launch it from specific coordinates on the ocean. The rockets are launched from a large mobile platform that is similar to a big barge.
SpaceX
Besides NASA and other government space agencies around the world, there is growing interest in private industry launches into space. SpaceX is a good example of a new private company successfully launching vehicles into space. In 2012, SpaceX was the world’s first company to launch a rocket, called the Dragon, to the International Space Station.
Where does a rocket launch from anyway? Well, a rocket needs a facility for the rocket to lift off from, called a launch platform. A great example of this is the Kennedy Space Center (or Cape Canaveral) which was used for every NASA human space flight since 1968.
Many launches are not successful.In 2011 the launch of the Glory mission failed about 3 minutes after liftoff, when the clamshell nose cone fairings did not jettison properly. In 2013 the launch of Intelsat 27 communication satellite failed due to a hydraulic system malfunction which prevented the booster from being controlled properly.
So what are some of the safety measures implemented to protect the people in the surrounding areas near the launch site? One method is called “command destruct” where an entire launch vehicle can be destroyed remotely if there is an immediate danger. Another method is to move the launch site to the middle of an ocean as we have already discussed with Sea Launch.
Another crucial part of a successful mission is a launch window. What is a “launch window”? A launch window is a short span of time during which the launch must take place in order for its payload to achieve mission orbit, or the correct trajectory.
The payload now needs to be “deployed” into space. Deployment, in this context, means moving the spacecraft out of the launch vehicle and into the right orbit or trajectory.
In our example, the payload is contained within our example rocket. First, the rocket is launched into orbit and the rocket burns through its stages. Next, the fairings are jettisoned. Finally, the spacecraft activates its own thrusters to push itself into the right orbit or trajectory. Often, the entire rocket is expendable and only used once to deploy the payload into space. The people on the ground monitor every stage of the launch and deployment of the spacecraft.
Historically, the Space Shuttle would also be used to transport and deploy payloads contained within the shuttle. A robotic arm would then grab and move the spacecraft into orbit. Also worth mentioning is the deployment of Curiosity, an amazing accomplishment to deploy a rover to a precise location on Mars.
Many things can potentially go wrong during a deployment. One mechanical problem that could occur is if the payload fairings are not jettisoned properly as was the case of Glory. Or, if the deployment of the antenna system or solar panels does not happen properly, the entire mission could be in jeopardy.
After the deployment success, then the mission phase really begins. Every stage of a launch and the deployment of a payload must be carried out properly. Launching rockets and deploying spacecraft has enabled the human race to achieve amazing feats. These accomplishments include putting men on the moon, studying the universe and our own planet for the benefit of mankind.