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<center> https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstage.html </center>
The study of rockets is an excellent way for students to learn the basics of forces and the response of an object to external forces. All rockets use the thrust generated by a propulsion system to overcome the weight of the rocket. For full scale satellite launchers, the weight of the payload is only a small portion of the lift-off weight. Most of the weight of the rocket is the weight of the propellants. As the propellants are burned off during powered ascent, a larger proportion of the weight of the vehicle becomes the near-empty tankage and structure that was required when the vehicle was fully loaded. In order to lighten the weight of the vehicle to achieve orbital velocity, most launchers discard a portion of the vehicle in a process called staging. There are two types of rocket staging, serial and parallel.
## <center> Timing is everything! </center>
In picking a time to launch, space engineers and scientists have to consider quite a number of things. Most of them have to do with getting the biggest boost possible from the big launch pad called planet Earth!
Earth goes around the sun at a brisk 107,000 kilometers per hour (66,000 miles per hour)! If our interplanetary spacecraft is aimed in the same direction Earth is already going, it will get a big head start
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Also, Earth rotates eastward on its axis, one complete turn each day. At the equator, Earth's surface is rotating at 1675 kilometers per hour (1041 miles per hour)!So if we launch the rocket toward the east, it will get another big boost from Earth's rotational motion.
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Now, we launch eastward. We pick the time of launch (in Deep Space 1's case, early morning) to give the rocket time to accelerate as it goes partway around Earth. Then, when the spacecraft is headed in the same direction as Earth's orbital motion around the sun, the rocket gives it a final boost out of Earth orbit and on its way.
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## <center> Space Shuttle Basics </center>
### Launch
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<center> https://thepoetryofscience.scienceblog.com/541/an-interstellar-climate/ </center>
The space shuttle is launched in a vertical position, with thrust provided by two solid rocket boosters, called the first stage, and three space shuttle main engines, called the second stage. At liftoff, both the boosters and the main engines are operating. The three main engines together provide almost 1.2 million pounds of thrust and the two solid rocket boosters provide a total of 6,600,000 pounds of thrust. The total thrust at launch is about 7.8 million pounds. To achieve orbit, the shuttle must accelerate from zero to a speed of almost 28,968 kilometers per hour (18,000 miles per hour), a speed nine times as fast as the average rifle bullet.
### First Stage Ascent
After about two minutes, when the shuttle is about 45 kilometers (28 miles) high and traveling more than 4,828 kilometers per hour (3,000 mph), the propellant in the two boosters is exhausted and the booster casings are jettisoned. They parachute into the Atlantic Ocean, splashing down about 225 kilometers (140 miles) off the Florida coast.
The empty boosters -- the largest solid rockets ever built -- are recovered by special NASA ships to be eventually refilled with fuel and launched again. The solid fuel used by the boosters is actually powdered aluminum -- a form of the same metal you find in foil wraps in your kitchen -- with oxygen provided by a chemical called ammonium perchlorate.
# <center> How is this object still spinning? </center>
https://youtu.be/1n-HMSCDYtM
If ever there was a symbol for what astronauts put themselves through in the name of science, it would be this crazy spinning T-handle. Up there in the zero-gravity environment of the International Space Station (ISS), everything happens according to a completely different set of rules, and the things you take for granted on Earth suddenly no longer apply. For example, in zero gravity, your sweat doesn't evaporate, there's a constant concern that your eyeballs might be going flat, and carbonated beverages hurt because it's physically impossible to burp out all that extra gas. But as that T-handle so elegantly demonstrates, we can learn so much from what's going on.
Found recently by Digg, the video above shows an astronaut spinning a T-handle in the SpaceDRUMS (Space Dynamically Responding Ultrasonic Matrix System) facility aboard the ISS, and as they so delicately point out, "You thought things in space pretty much follow the rule 'go in one direction forever' right? Well it turns out you are wrong and not a physicist."
For those of us who aren't physicists, what's going on here? Our friend Henry Reich from MinutePhysics actually discusses it in the video below, when he was lucky enough to ask astronaut Scott Kelly to demonstrate it using a Leatherman tool. He calls it the "instability of rotation around the intermediate axis of an object," and explains that if you rotate an object around its largest and smallest axes, it will spin in a stable, consistent manner.
# Well that has been all for this post I hope you will like to remember to leave your vote and comment!
## sources
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstage.html
https://spaceplace.nasa.gov/launch-windows/en/
https://spaceflight.nasa.gov/shuttle/reference/basics/launch.html
http://www.sciencealert.com/watch-wtf-is-going-on-with-this-object-spinning-in-zero-gravity
