Shreyas

3/22/11 - Entry 1: Electronics and Their Importance in a Mission to Mars
Electronics are used in almost everything we touch today. Most of them transmit information through two different kinds of signals: analog and digital. Analog signals are signals that move from one value to the next smoothly, like a wave. These are used in analog clocks, where the hands move smoothly around the clock. Digital signals advance in steps, like a digital clock that counts up in numbers. Semiconductors are a main component in almost all electronics. As the name suggests, they are less conductive than conductors, but they are more conductive than insulators. They can be used to make components that react differently to electrical current, causing it to be amplified, stopped, or controllable like a switch. Semiconductor material is usually doped with other atoms, meaning that the perfect sheet of semiconductor material is mixed with other elements, introducing extra electrons or extra protons. This dramatically improves the conductivity. Semiconductors doped with atoms that create extra electrons are called N type semiconductors, and those doped with atoms that create extra protons are called P type semiconductors. Some components that are made of semiconductors are diodes and transistors. Diodes, a layer of P type semiconductor and a layer of N type semiconductor sandwiched together, allow electricity to pass in one direction, but block it the other way. A type of diode, the Light Emitting Diode (LED), emits light when electricity passes through it. Transistors, which have three layers of semiconductor – PNP or NPN, function as switches and can also amplify current. But for many circuits that do lightning fast computations and process things quickly, normal transistors and diodes occupy too much space. Integrated circuits solve this problem; they are sheets of semiconductors that may have millions of components on them. This can dramatically reduce size of components.

Electronics are useful in the search for life on Mars in many ways. They include navigations systems to get to Mars, systems to actually pilot the spacecraft that goes to Mars, processors in rovers and other robots that are sent to Mars’ surface, effective radio transmissions, and many other functions. Without electronics, the voyage to Mars would be nearly impossible. The lack of an electronic navigation system would mean that humans would have to pilot the spacecraft all the way to Mars, which could take a very long time. This long time dramatically increases the chance of human error in the process. Humans would also have to manage every other function of the spaceship themselves, which compounds the risk with the thousands of configurations necessary to safely travel to Mars. Robots that are sent to the surface would also have no way of processing anything, and therefore everything would have to be done manually. The robot would also have no way of communication with people on Earth without the electronics necessary for radio communication or other forms.

With all these considerations and many more, going to Mars would be impractical and incredibly risky without electronics. //Ms. Mc: Excellent overview of electronics and ideas about how we would use electronic devices on our mission! 10/10 //

4/1/2011 - Entry 2: History of Rockets
Rockets started out in a very early age. In around 100 BC, a device called the aeolipile was built by Hero of Alexandria in Greece. It was a sphere on top of a bowl of water with tubes connecting itself to the water. When the water was heated, it turned into steam and went into the sphere and out L shaped holes, causing the sphere to spin. The aeolipile was one of the first times that rocket technology was employed. We are, however, not sure when the first rockets appeared on the scene. Rocket-like devices appeared in many cultures soon. The discovery could even have been an accident. In China, explosive devices designed for religious festivals were made from bamboo tubes filled with gunpowder. When these sticks were thrown into fire, they sometimes would fail to light and instead shoot off and fly around. After this discovery, the Chinese attached the tubes to bows and found out that the arrows could fly under their own power. These rockets were used in the battle of Kai-Keng against the Mongols. After this, the Mongols developed their own rockets and may have spread the technology to Europe. But so far, rockets had only been used for warfare or fireworks. This was soon to change.

Konstantin Tsiolkovsky was a Russian teacher. He suggested that rockets could be made to go to space. He said that the range of a rocket was only limited by the velocity of the exhaust gases. He also suggested a liquid fuel instead of a solid fuel. Robert H. Goddard, an American scientist, was the first to actually build a liquid fuel rocket. Liquid fuel rockets were much more complicated than solid fuel rockets. They had many more parts. Goddard finally got his liquid fuel rocket, powered by gasoline and liquid oxygen, to fly on March 16, 1926; it reached an altitude of 12.5 meters. Goddard continued to research liquid fuel rockets and contributed greatly to the field; he is now considered the “Father of Modern Rocketry”. Soon, many different rockets came up. The V-2 was one of them. It was used against Britain in the end of World War II and could obliterate large areas. However, it was too late to change the outcome of the war. The United States and Russia now realized the power of rockets and many projects were started.

Sputnik I, a Russian satellite, was launched on October 4, 1957. It was the one event that started the space race between the US and Russia. The US answered by launching Explorer I a few months later. Then, the US created its organization, NASA to organize its space agency. The space race led to many huge successes. We have landed men on the moon, know far more than before, and continue to explore the vast area of space. Figure 2 - The Apollo lander on the Moon.

Rockets are getting more powerful and advanced all the time, and we have only studied a fraction of the expanse of the universe. We might never know everything about the vast expanse of space in the cosmic world around us.

Ms. //Mc. Excellent summary of the history of rocketry and great drawings! My only suggestion would be to refer to your drawings/photos in your text (i.e., "as seen in Figure 1 . . ."). 15/15//

4/4/11 - Entry 3: Rocket Stages Scratch Program
media type="custom" key="8957958"

Instructions:

1. Press the red stop button. 2. Turn on sound if possible. 3. Click the green button to watch the animation. 4. After the animation is done, click the green button to replay.

4/13/11 - Entry 4: Parts of a Rocket


There are many different parts of a rocket that make it fly. The nose cone cuts the air so that there is minimal air resistance. The body tube houses all the internal parts of the rocket and creates the main shape of the rocket. The recovery system is housed inside of the body tube, and consists of a parachute and shock cord. When the rocket motor deploys its ejection charge, it blows out the nose cone and deploys the parachute and recovery system. The recovery system ensures that the rocket returns safely. The recovery wadding separates the rocket motor from the recovery system so that when the ejection charge is deployed, it does not burn or damage the recovery system. The launch lug helps guide the rocket off of the launch pad vertically. The motor mount holds the rocket motor stiffly so that the rocket motor doesn't move. The fins guide the rocket in the air so that it doesn't stray from its vertical position. The rocket motor propels the rocket with gunpowder and ejects the recovery system.

//Ms. Mc: Excellent explanation of the function of the rocket parts and good labels! 20/20//

INTRODUCTION
The purpose of this experiment was to determine a relation between the mass of the rocket and its height of flight. The rocket has many forces acting on it at various parts of the flight. At ignition, there is no acceleration. The forces acting on the rocket are gravity and the force of the launch pad, which balance each other out. At liftoff, the rocket is slowly accelerating upward, so the forces are not balanced. The force of thrust from the engine is greater than the combined force of gravity and the slight air resistance from the movement. The rocket quickly accelerates. As soon as the rocket runs out of fuel, coasting begins. The force of thrust is now absent, so the rocket starts accelerating downward because of gravity. However, inertia keeps the rocket moving upward. At apogee, the rocket completely stops for a split second. The only force acting on the rocket at apogee is gravity. Gravity quickly starts pulling the rocket to the ground. After apogee, the rocket ejects the recovery system, which dramatically increases the air resistance on the rocket. This slows the descent down to a safe speed so that the rocket does not break on touchdown. It was hypothesized that the less the mass of the rocket, the greater the height it would fly. This is because the force of gravity will be less on the rocket the less mass there is. This is because of Newton’s Second Law, F=ma. The less the force of gravity, the more the rocket will accelerate during the liftoff phase. Therefore, it will be moving faster during the coasting phase, and gravity will have to act on the rocket for longer to decelerate it to a stop.

RESULTS


The results of the experiment showed that there was no relationship between the mass of the rocket and its apogee height. As seen in Graph 1, the lightest rocket, weighing 42.8 grams, flew 135 feet; the middle rocket, weighing 44.1 grams, flew 81 feet, and the heaviest rocket, weighing 48.7 grams, flew 84 feet. These data points do not create a trend. The hypothesis was determined to be wrong because the hypothesis stated that there would be an inverse relationship between the rocket’s mass and its apogee height. There were many possible errors that could have entered the experiment. A main error was wind. On the first launch day, there was strong gusty wind, but on the second launch day, there was very little wind. This could have affected the height, as the rocket would have to fly a longer path if it wasn’t flying straight up, and it would have affected the accuracy of the trigonometry calculation. Another error that could have been introduced was the accuracy of the angle measurements. Many different people were measuring, so there was a high chance of error in the measurements. Also, only two measurements were taken per launch. The other big error is the independent variable. The independent variable only varied 5.7 grams, so this could have led to inaccurate measurements. If this experiment were to be repeated, the independent variable would have a greater range.

What is a quark? What types of quarks are there?
A quark is a subatomic particle that makes up protons and neutrons. There are six types, or flavors, of quarks – up, down, charm, strange, top, and bottom. Quarks have fractional charges. Protons and neutrons have 3 quarks each. A proton has two up quarks and one down quark (as seen in Figure 1), while a neutron has two down quarks and one up quark. The up quarks have a +2/3 charge, and the down quarks have a -1/3 charge. A proton has a +1 charge, +2/3+2/3-1/3 = +1. A neutron has a zero charge, so +2/3-1/3-1/3 =0. Quarks are not stable. The up and down quarks are the lightest and the most stable of all the quarks. They are the most common. The other quarks are created in high energy collisions, such as collisions between cosmic rays, and quickly decay into up and down quarks shortly after being created. All six types of quarks have been created and observed in particle accelerators.



How did our moon come to revolve around the Earth?
The Moon came to revolve around the Earth when a planetesimal the size of Mars collided into Earth (as seen in Figure 2). This caused the Earth to tilt onto its axis and also caused it to get smaller. The debris from the collision collected together because of gravity. This started orbiting the Earth. This theory is supported by the fact that the Moon has very little iron and at the time, the iron in the Earth had settled into the core. When the planetesimal hit Earth, it blew out iron-depleted sections of the Earth, which explains why the moon has no iron. Another reason is the composition of the Earth is the same as the composition of the moon, whereas other worlds, such as Mars, have different compositions. This supports the idea that the moon came from the Earth.The Moon was much closer to the Earth and slowly moved away from the Earth. Even now, it is moving about an inch and a half farther from the Earth every year. Eventually, the Earth’s gravitational pull won't be strong enough to hold the Moon anymore, and the Moon will not remain within the Earth's gravitational field and will escape.



//Ms. Mc: Excellent answers, pictures, and captions! 10/10//

5/5/2011 - Entry 8: "On the Edge" Program Explanation
Overview - When the robot hears someone say "go", it moves to the end of table and stops, then says "Watch Out!". At end of table, there is a strip of blue tape. This program resembles the way that rovers on Mars have to avoid the craters and holes that they could fall into. This has happened to //Spirit// multiple times, and it would be helpful to avoid it in the future.



Block 1 - Wait Block. This block waits until the sound sensor (port 2) detects a sound greater than 60 decibels. Basically, it tells the robot to wait until someone says "go." Block 2 - Move Block. This block causes the robot to move forward at 50% power forever by activating the C and B port servo motors. Basically, it tells the robot to move for infinity. Block 3 - Wait Block. This block waits until the light sensor (port 3) detects a light level less than 30. Basically, it tells the robot to wait until it detects the blue line. Block 4 - Move Block. This block causes the robot to stop by activating C and B port servo motors and braking. Basically, it tells the robot to stop when it detects the blue line. Block 5 - Sound Block. This block causes the robot to play the "Watch Out!" sound at 75% volume. Basically, it plays the sound "Watch Out" at the edge of the table.