Showing posts with label Science. Show all posts
Showing posts with label Science. Show all posts

Thursday, August 16, 2018

Inertial Measurement Unit (IMU)

We just learned about the Airspeed Indicator.

Some of the tools we've talked about are things called Inertial Measurement Units or just IMU for short.

Inertia is the change in the rockets speed or direction, so the tools that we talked about like the gyroscope, magnetometer and accelerometer are all used to tell how the rocket is moving, so they are all IMUs.

IMUs all help measure things called Roll, Pitch and Yaw.

Roll is like when an airplane is still going forward in the air, but does a spin so it is flipped upside down, but still going forward.
Pitch is like when the airplane moves its nose to go down toward the ground or up toward the sky.
Yaw is like when the airplane isn't flying along and then turns left or right.

Different types of rockets use different IMUs depending on what kind of sensors they need, but they all are used to measure roll, pitch and yaw.

(from: wikipedia - )

Kid Facts - Blast from the past: Tectonic plates.

Thursday, August 9, 2018

Airspeed Indicator

We just learned about the Spacecraft Magnetometer.

Another rocket guidance tool is an Airspeed Indicator.

When the rocket is blasting through the air, it can use this tool to figure out how fast it is going.
The Airspeed Indicator uses something called a pitot tube (pronounced PEE-toh) which is a tube that has some liquid in it.
As the rocket flies along the air flowing into the pitot tube puts pressure on the liquid, and the airspeed indicator uses that pressure to measure how fast the rocket is going.

If it is going very fast, there will be a lot of pressure.

(from: wikipedia - airspeed indicator)

Kid Facts - Blast from the past: Hypocenter

Thursday, August 2, 2018

Spacecraft Magnetometer

We just learned about the Gyroscope.

Another tool used for navigation and guidance is a Spacecraft Magnetometer.

This uses a magnet that is wrapped in metal coils, with electricity running through the metal coils.
If there are other magnetic forces around, these electric coils will give off fields that can tell the rocket which way to go.

(from: wikipedia - spacecraft magnetometer)

Kid Facts - Blast from the past: Cross Peen Hammer

Thursday, July 26, 2018


We just learned about the Star Tracker.

Another part of rocket navigation systems is the Gyroscope.

Gyroscopes are sort of like a spinning top, with a few other circles on them.
The top is a circle shaped disc spinning around sideways, with a post in the middle, like an anchor for it.

There are usually three circle shaped frames, called "gimbals" around the spinning top.
On the very inside there is a circle holding on to the post for the top. This is the "inner gimbal".
Another circle is hooked onto that inner gimbal, and that is called the "outer gimbal".
The one on the outside of the outer gimbal is called the "outer ring".

If the disc in the middle is spinning, and you move the outer ring around, the inner gimbal and outer gimbal will move up, down or sideways, and the disc will stay straight up and spinning.
This might seem like magic, but really it's the same kind of science that keeps a toy top spinning on the ground, or helps you ride a bike.
The fancy name for it is "angular momentum", but it really just means a spinning wheel doesn't like to fall over, so for a gyroscope it makes the inner and outer gimbal move instead of falling over when you move the outer ring.

Rocket scientists figured out that if you hook the outer ring up to sensors in the rocket, you can tell when the rocket is tilting, and they can hook up the nozzle to a gyroscope to use the gimbaled thrust we learned about and steer the rocket back on course!

The science behind gyroscopes was discovered hundreds of years ago, and used to help steer ships on the water.
These days gyroscopes are even used in video games and cell phones, to tell the phone when it is being tilted!
The ones inside phones aren't spinning wheels though, they are microscopic sensors that move around when you move your phone.

(from: wikipedia - gyroscope)

Kid Facts - Blast from the past: Earthquakes

Thursday, July 19, 2018

Star Tracker

We just learned about the Accelerometer.

Another guidance system that rockets can use is the Star Tracker.

When a rocket is way up in the sky, it might not be able to talk to any of the computers on the ground to find out where it is, especially if there are a lot of clouds or bad weather.

But if the rocket is up above the clouds and it is dark, the rocket can use cameras to look up into space and see the stars.
These stars can be compared to a star chart that says where each star is, and it can use this chart to keep itself on course, whether it's going to the moon, outer space, or even another planet!

(from: wikipedia - star tracker)

Kid Facts - Blast from the past: Numerical Control - CNC

Thursday, July 12, 2018


We just learned about the Altimeter.

Another part of rocket science is the Accelerometer.

This is something in the rocket that tells the rocket how fast it is accelerating.
This isn't the same as it's speed, which is just how fast it is going.
Acceleration is the difference in speed over time.

So think about it like if you are walking, and then you are jogging, and then you are running as fast as you can.
When you switch from walking to jogging, there is a difference in speed, and it however long it takes you to get from walking speed to jogging speed is the acceleration.

Gravity is another way to think about acceleration.
If a rock is dropped off of a tall building, it starts falling slowly, but then gets faster and faster, and by the time it hits the ground could be going fast enough to really hurt if it crashed into something.

The difference in how fast it is falling every second is the acceleration.
That is what the accelerometer measures, so that the rocket knows how much faster it is getting every second.

(from: wikipedia - accelerometer)

Kid Facts - Blast from the past: Plasma Cutting

Thursday, July 5, 2018


We just learned about the GNC - Guidance Navigation and Control.

One type of tool used to help navigation is an Altimeter.

This measures the pressure in the air to figure out how high up off the ground a rocket is.
When a rocket is close to the ground it has higher air pressure, and when it goes further up off the ground, the air pressure gets less and less.

With an altimeter inside the rocket's controls, the rocket can tell how high up in the sky it is.

(from: wikipedia - altimeter)

Kid Facts - Blast from the past: Water Jet Cutting

Thursday, June 28, 2018

GNC - Guidance, navigation and control

We just learned about Gimbaled Thrust.

After a rocket is launched, it needs to be guided to make sure that it goes to the right place, whether that's outer space or just up into the atmosphere.

This is called Guidance, navigation and control, sometimes shortened to just GNC.

GNC is the science of how to control a rocket after it's been launched up into the air.

(from: wikipedia - guidance, navigation and control)

Kid Facts - Blast from the past: Electrical Discharge Machining

Thursday, June 21, 2018

Gimbaled Thrust

We just learned about how Rocket Thrust Vectoring is changing the direction the rocket is going using thrust in different dirctions.

Another part of rocket science is Gimbaled Thrust.

This is a way for a rocket to tilt its nozzle to change the direction of the thrust for rocket thrust vectoring.

When the nozzle is tilted, it sends the rocket in a different path.

(from: wikipedia - gimbaled thrust)

Kid Facts - Blast from the past: Stamping

Thursday, June 14, 2018

Rocket Thrust Vectoring

We just learned about the Fire Arrow.

Another part of rocket science is Thrust Vectoring.

When a rocket is flying up in the sky, there needs to be some way to steer it.

Sometimes rockets are built with a nozzle at the end that can be moved around to thrust in different directions, and sometimes they are built with extra rocket propellant tanks on the sides to give extra thrust to steer it.

Thrust vectoring really just means steering the rocket by changing where the thrust is going.

(from: wikipedia - thrust vectoring)

Kid Facts - Blast from the past: Bending

Thursday, June 7, 2018

Fire Arrow

We just learned about the Specific Impulse.

Some of the first rockets that were made came from China over a thousand years ago, after the invention of gunpowder.

These were known as Fire Arrows.

At first people just had the idea to tie an explosive ball of gunpowder to the arrow that would blow up after the arrow was shot with a bow.
Later on someone figured out how to use the gunpowder as a solid propellant for the rocket in a wooden tube as the propellant tank, and use the burning of the gunpowder to thrust the arrow up higher and farther.

(from: wikipedia - fire arrow)

Kid Facts - Blast from the past: Burr

Thursday, May 31, 2018

Specific Impulse

We just learned about Rocket Engine Thrust.

Another part of rocket science is called the Specific Impulse.

This is a way for scientists to measure how fast a rocket moves along, combined with how fast it uses up it's fuel as the rocket engine is blasting off.

The rocket can only burn up so much fuel before it runs out, so the more thrust the rocket for every little drop of its fuel really matters!

(from: wikipedia - specific impulse)

Kid Facts - Blast from the past: Grinding

Thursday, May 24, 2018

Rocket Engine Thrust

We just learned about the Rocket Engine.

Another part of rocket science is the Thrust.

We learned that a rocket has propellant in a tank, and an engine that burns up that propellant and pushes the burning fuel out the back of the rocket at the nozzle.

As the fuel is being burned and pushed out of the nozzle, the rocket is pushed along through the air.
That push is called THRUST.

Some rocket engines have a lot of thrust and make rockets go very fast, blasting off into outer space.
Others only have a little bit of thrust, but they are very careful about exactly how much thrust they make in the right direction, like for steering a rocket.

Scientists have to know exactly how much thrust a rocket will have, so they know how much propellant they need, and how big of a tank to use and the shape of the nozzle.

(from: wikipedia - rocket engine)

Kid Facts - Blast from the past: Hole Saw

Thursday, May 17, 2018

Rocket Engine

We just learned about the rocket's Combustion Chamber.

So we know about the rocket propellant, the propellant tank, the combustion chamber and the nozzle.

When these pieces are all put together it makes the Rocket Engine.

The engine is all of those pieces working together to push the rocket along up into the sky.

(from: wikipedia - rocket engine)

Kid Facts - Blast from the past: Twist Drill Bits

Thursday, May 10, 2018

Combustion Chamber

We just learned about the Rocket Propellant Tank.

Another part of a rocket is the Combustion Chamber.

We've learned about the propellant tank that holds the propellant, which is the fuel to make the rocket blast off.
Usually with solid propellants, the propellant tank is the same place where the fuel burns up and pushes the rocket along.
With liquid or gas propellants, the tank is usually separate, and there are tubes and pipes that bring the propellant into another area where the fuel burns up and pushes the rocket along.

This tank where things are burning up is called the Combustion Chamber.
Combustion basically just means burning up or even exploding.

(from: wikipedia - combustion chamber)

Kid Facts - Blast from the past: Drill Bits

Thursday, May 3, 2018

Rocket Propellant Tank

We just learned about the Rocket Engine Nozzle.

Another part of a rocket is the Propellant Tank.

This is where the rocket fuel goes, and is usually a very large.
The tank used for the space shuttle rocket was over 150 feet tall, and weighed over 58,000 pounds empty, but over 1,680,000 pounds when filled up.

(from: wikipedia - space shuttle external tank)

Kid Facts - Blast from the past: Drilling

Thursday, April 26, 2018

Rocket Engine Nozzle

We just learned about the Gas Rocket Propellants.

Another part of rocket science is the Rocket Engine Nozzle.

When the rocket propellant is burning up coming out of the rocket, the nozzle makes it so that it pushes out very fast and very strong, by putting some pressure right at the end of the rocket.

This is kind of like putting your finger over the end of a water hose, to make the water spray farther.

The shape and size of the nozzle is very important.
It has to be just the right size to get the most thrust and use up just the right amount of fuel.

(from: wikipedia - rocket engine nozzle)

Kid Facts - Blast from the past: Boring

Thursday, April 19, 2018

Gas Rocket Propellants

We just learned about the Solid and Liquid Rocket Propellants.

Another type of propellant is Gas Rocket Propellant.

This type of propellant is the easiest to control the exact amount of fuel burned and the exact amount of thrust created.
To keep the gas stored safely and under pressure, the fuel tank in the rocket has to be very heavy, so gas is not usually used for the bigger rockets.
Gas has been used the most for little rockets that just change the direction of a rocket to the left or right.
Small rocket thrusters called Vernier Thrusters were on the sides of rockets like the SM-65 Atlas, to help it go in the right direction.

(from: wikipedia - vernier thruster)

Kid Facts - Blast from the past: Swarf

Thursday, April 12, 2018

Liquid Rocket Propellants

We just learned about the Solid Rocket Propellants.

Another type of propellant is Liquid Rocket Propellants.

These can be made up of liquids like gasoline, kerosene or alcohol that are liquids at regular temperatures.
They can also be things that are liquids at really cold temperatures like liquid oxygen, or liquid hydrogen.

The good thing about liquid propellants is that they are lighter than solid ones, so a rocket doesn't have to try as hard to push itself along.
The bad thing is that sometimes they have to be stored very cold in a very high pressure container, and sometimes the liquids can cause problems and eat away at the metals and rubbers that they are stored in.

The first person to make a liquid fueled rocket was Robert H. Goddard, who used gasoline and liquid oxygen to launch a rocket in 1926 in Massachusetts.

(from: wikipedia - robert h. goddard)

Kid Facts - Blast from the past: Threading

Thursday, April 5, 2018

Solid Rocket Propellants

We just learned that Rocket Propellant is the fuel that pushes a rocket along, and they can be solid, liquid or gas.

Solid Rocket Propellants are made up of a few different types of chemicals all mixed together.
Some parts of the mixture are to make a big explosion that will push the rocket along.
Other parts are soft and sticky almost like dough that help hold all the explosive stuff together.
Different chemicals will make bigger explosions or burn longer or hotter, so the rocket scientists have to pick the right kind of propellant for the right job.

Solid propellants are easier to store than liquid or gas, because they don't leak out much.
Also some liquid or gas propellants can eat away at the rocket tanks or rubber seals holding it in.

Solid propellants are heavier than liquid or gas, and a rocket with the same amount of liquid or gas would get more power and weigh less.
Sometimes the solid propellants can even get cracks or bubbles in the mix.
If you think about it like a big ball of playdough, any of the parts that aren't smooth, or any folds in the middle that have air pockets would cause problems.

The NASA space shuttle used two rockets with solid propellant, called the "Space Shuttle Solid Rocket Boosters (SRBs)"
At the time they were the most powerful solid rocket motors ever flown, and the two of them together weighed 2.6 million pounds.

(from: wikipedia - space shuttle solid rocket booster)

Kid Facts - Blast from the past: Skivving Machine