Rocketry 101

Rocketry was originally invented by the Chinese, over 3000 years ago. Early rockets were designed to explode in the air to create a display for the rich and powerful monarchs; these were the very first fireworks. Rocketry techniques were very unsophisticated however, and it was nearly impossible to control where the rocket would land and how far it would travel. Some early inventors came up with designs for better rockets, but without the technology to build them, there was no way for their designs to be tested. It wasn't until Robert Goddard, the Father of Modern Rocketry, began redesigning the rockets that people really started to see a use and purpose for these rockets. 

Earlier inventors had designed rockets with a solid rocket fuel. A mix of Potassium Chlorate and Sulfar was a popular solid rocket fuel. What the solid rocket fuel did was, after the fuse was lit, the flame would reach the combustion chamber, that is, where the fuel was held, and it would ignite the fuel. The fuel would burn, creating a controlled flow of hot gases which would propel the rocket upward. The problem with the design was that there was no way to control the rockets ascent and trajectory. This was because the solid fuel would simply release propellant, but there was no way to maneuver the rocket to adjust trajectory. Robert Goddard was the first engineer to opt to use a liquid fuel, rather than the traditional solid. The liquid fuels were standardly a mixture of liquid hydrogen and oxygen. The hydrogen and oxygen would be ignited, and would also burn, creating a flow of propellant. But what made this design unique was that it made it possible to maneuver the rocket easily. With a push of a button, the angle of the rocket could be adjusted in order to change the trajectory of the rocket, a major improvement over previous designs. 

The Goddard rocket had an engine at the top of the rocket and a fuel combustion chamber near the bottom. The purpose for this was to stabilize the rocket and prevent it from shaking while in flight. The design was good, the only drawback was that the fuse was also near the top. To light the fuse, a person would have to climb up near the rocket, light the fuse, jump down and run away as fast as possible. So it really wasn't the safest design ever, though it still was an improvement over previous designs.

Wernher von Braun was a brilliant German scientist who was brought to the US after the end of WW2. He was the one who had designed the "Buzz Bomb" for the Germans. The Buzz Bomb was actually not the greatest bomb ever built because it had a slight hitch. It was loud. REALLY loud. The people of London could hear it coming from across the ocean, and as long as they could hear the noise, they knew they were safe. It was when the noise had stopped that they knew it was time to prepare. To overcome this, Wernher von Braun designed the rocket to travel at supersonic speed, that is, faster than the speed of sound. This made it impossible for Londoners to predict the time of the bombs impact.The US, although obviously unhappy about this turn of events for our allies, decided after the war that anyone with a mind like that would be very very valuable to have designing our missiles and rockets. After the war, America and the Soviet Union were entering the Cold War. After the Soviets launched Sputnik, the first artificial satellite in space, Wernher von Braun and his scientists began to design the Atlas rocket, with the intention of launching a human into space. The Soviets were able to launch a human into space before us, however, we were able to launch a human into orbit before them, and of course we also launched the first human on the Moon in 1969, using the Saturn 5 rocket.

Something all rocket engineers must keep in mind is the weight of the entire launch vehicle. If there is not enough volume for the propellant in the rocket, it will be too heavy, and it won't launch. The ratio between the weight of the rocket and the amount of propellant has to be exact, otherwise the rocket will launch about three feet and collapse in on itself, like what happened to Wernher von Braun's first Vanderbilt Rocket.

Now the equation for the rocket propellant system is actually quite simple. In English, it is Fuel and Oxygen are combined with heat to create Exhaust, which launches the rocket, and also heat, which can be funneled back the the combustion chamber to to combine more Fuel and Oxygen.

Now the Space Shuttle (see previous post) is unique because it uses a combination of both liquid and solid fuels. I'm not going to go into to many details because hopefully you've already read that post, but the reason for this is basically because although solid fuel is easier to store, is cheaper and is lighter, the liquid fuel is about 600% safer. It's safer because the main fuel line can be shut down in case of an emergency, but solid fuel can't be. So the engineers decided to combine solid and liquid fuel at a ratio that will give them all the cheap, easy benefits of solid fuel, but will have the safety of liquid fuel. Very ingenious.

The reason for all this is because of Newton's laws of physics and motion. (Of course. What else?)  These laws can be broken down into:

• Objects generate forces
• Forces cause motion
• Forces produce acceleration
• An object's mass resists acceleration
• Forces come in pairs

There are three types of payloads that can be placed in a rocket. These three are:

• People
• Artificial satellites
• Warheads

And that's about it for Rocketry 101. If you want to see a movie with lot's of rocket launches, I recommend both Apollo 13 and October Sky. And I also encourage you to design your own rockets, and to hopefully launch them. You can find many model rockets kits in store, but please don't get those cheater model kits where all you do is put it on the launch pad and push the button. You never learn anything doing that. Try to really build the rocket, and you don;t even need a kit after a while. You can just get materials, build the rocket, and watch her fly. :)

Next Focus: The ISS (International Space Station)

The Space Shuttle

NASA's Space Shuttle program was one of the greatest achievements of the Space Age. From 1981 to 2011, the Space Shuttles, Columbia, Discovery, Challenger, Endeavor, and Atlantis, flew astronauts to and from Space on various missions.

The history of the Space Shuttle goes all the way back to the Mercury Program, from 1962-1963. Mercury launched six people into Space, and laid the foundation for people to eventually live in Space.

After Mercury comes Gemini, 1965-1966. There were ten launches with the Gemini Program, and the basis here was for people to learn to work in Space.

After the Gemini Program came the famous Apollo Program, 1969-1972. The purpose of the Apollo Program was to explore Space. It was with Apollo that America made the historic milestone of landing a human on the moon, with the Apollo 11 spacecraft in 1969.

After Apollo, NASA wanted humans to go to Mars. To do this, we needed to build a moon base first, and for the moon base, we needed a low Earth orbiting space station. This leads us to the Space Shuttle. In 1972, Congress approved the budget for the Space Shuttle Program. When the Apollo 16 astronauts were informed of this approval, while still on the moon, they jumped up three feet in excitement!

Now that the funding was secured, NASA turned to Max Faget for assistance in designing the Shuttle. Max Faget designed both the Mercury and Gemini spacecraft, and assisted in the design of the Apollo spacecraft, so he was a logical choice for the design of the Space Shuttle. His early designs were conical, like the Apollo, with extra boosters and engines for returning to Earth. The design that NASA wanted to use had a plane like structure, much like today's Space Shuttle, but what was unique about it was the booster rockets. The rockets were also designed like a plane, with wings, a cockpit and jet engines; this was so that a pilot could sit in the cockpit and fly the rockets back to Kennedy Space Center for reuse. NASA was all set to go with this design, but than the early plans showed that the approximate weight at launch would be 4,600,000 lbs! So they redesigned the rockets to be expendable, and fall off at a certain point to decrease the launch weight.

Once they had this part of the plans down, NASA turned to Boeing, Grummen and Thiokel to design the actual shuttle part. The main specification was that the payload had to be 60 ft. long and 15 ft. wide to allow for military cargo.
Grummen opted to put extra rockets on the Shuttle and launch that as it was.
Boeing came up with putting wings and a cockpit on the Saturn 5 rocket, and their design was closest to what we have today.
Thiokel decided to put rocket boosters along the sides and under the main shuttle.
NASA eventually decided to use the Saturn 5 rocket, with boosters along the sides of the Shuttle.

Now they needed fuel. There are two types of rocket fuel, solid and liquid. The benefits to solid rocket fuel are that it is cheaper, easier to use, and less complex than liquid fuel. But liquid fuel, although more expensive, harder to use because it needs better containers, and more complex, is actually safer. This is because, while liquid fuel can be shut off in the case of an emergency, solid fuel can not.

So NASA's final design was the Shuttle, with an external fuel tank below, and boosters along the sides, just like we have today. :)

Enterprise was the first Space Shuttle. Originally called 'Constellation'; so many Trekkies wrote to NASA that they finally gave in and named it 'Enterprise'. Enterprise was designed to go into Space, but all it was ever used for was testing launch and landing sites.

Next came Columbia. Columbia was the first Space Shuttle to launch all the way into space and come back down in 1981. It exploded during a launch in 2003.

Challenger made very few flights before it exploded in the atmosphere after launch in 1989.

Discovery made more flights than any other shuttle. It launched the Hubble Space Telescope in 1991, and was the 'Back to Orbit' vehicle after both the Challenger and Columbia Tragedies.

Endeavor made more flights than any other shuttle except Discovery, and still has one more flight to go before retirement.

Atlantis will be the last shuttle to be launched in Summer 2011.

And Discovery, Atlantis and Endeavor all helped to build the International Space Station, the first permanent space station and first step towards the moon base and Mars.

The Space Shuttle was originally to be replaced by the Constellation Program, but sadly, Congress cut funding for it. However, NASA will continue flying to the Space Station using the new Orion spacecraft, and hopes to build a permanent moon base using Orion.

Next Focus: Rocketry 101