Topic 6 Space Exploration Above the Atmosphere and Under Control Topic 6 Space Exploration

Rockets – Getting Up There A tube that contains combustible material in one end and a payload in the other end and moves by the action, reaction principle   Payload: The device or material that a rocket carries

Rockets – Getting Up There As the fuel in the rocket combusts it produces exhaust from the rocket The exhaust pushes the rocket in the opposite direction This is called the action / reaction principle  

Rocket Fuel Exhaust Velocity: The speed at which exhaust leaves a rocket   All rockets require a type of fuel in order to operate Rocket fuel used to be solid (ex. Gun powder), however this type of fuel has very low exhaust velocity

Rocket Fuel Robert Goddard: American Physics professor First scientist to successfully launch a liquid fuel rocket in 1926 He also knew that if a rocket had more than one stage it would fly faster and higher  

Rocket Fuel Staged Rocket: A rocket with more than one stage A stage is a section of a rocket that drops of once its fuel is used up

The V-2 Rocket Werner von Braun: German Scientist During World War 2 he created the world’s first ballistic missile called the V-2 rocket and launched it in 1942 The V-2 rocket was a liquid fuel rocket The V-2 Rocket successfully hit a target about 200 km away Now, almost every rocket is a variation on this design Dr. Wernher von Braun

The V-2 Rocket Ballistic Missile: A rocket with a bomb as a payload, launched in a trajectory that sends it up into space and down onto its target Ballistic Missile Test  

The V-2 Rocket Near the end of WWII the Americans and Russians both wanted to capture von Braun and his team The Americans were successful and his team helped create the U.S. Space Program  

The V-2 Rocket Von Braun’s team built the rockets that took the first U.S. astronauts into space in the 1960’s After WWII the Russians were able to design the Vostok, Voshkod and Soyuz rockets that sent their Russian Cosmonauts into orbit Cosmonaut: The Russian term for astronaut  

Computers – Making Adjustments Computers were invented in WWII and were the size of entire rooms These first computers were used to decipher enemy code 

Computers – Making Adjustments In the 1960’s, computers were required to keep rockets in orbit around the earth but had to be used on the ground as they were too big Now, computers are small enough to fit on the spacecraft and are used to calculate orbits, keep track of other satellites, collect, store, and analyze data, and execute orbital manoeuvres of the satellites.

Using Gravity Gravitational Assist: A method of acceleration which enables spacecraft to change speed by using the gravity of a planet This technique is used because spacecraft are too heavy to send on long journeys throughout the solar system

Using Gravity Steps of Gravitational Assist As the spacecraft comes near to a planet it is attracted to it by its gravitational pull As the spacecraft begins to orbit the planet it speeds up The spacecraft will then leave the orbit moving faster than it was before it entered This gives the spacecraft enough speed to travel to more distant celestial objects

Clarifying Images Charge Coupled Devices (CCD’s): Devices that convert light signals into electric signals in digital format The images are then sent to a computer This allows images of distant objects to be altered in order to become more clear and detailed

Aiming the Hubble Telescope The Hubble telescope (named after the famous astronomer Edwin Hubble) is the size of a bus with a main mirror diameter of 2.4 m In April of 1990 it was sent into Earth’s orbit using a rocket

Aiming the Hubble Telescope It is controlled by an on- board computer system The Hubble telescope is a fantastic viewing tool as it contains spectrometers and cameras that are able to see distant objects without interference from Earth’s atmosphere

Looking at Earth An example of a naturally occurring satellite is the Moon (or the Earth if you really think about it!) However, humans have sent many artificial satellites into the Earth’s orbit.

Looking at Earth Artificial Satellite: A satellite made by humans, such as a spacecraft or telescope. These artificial satellites carry instrumentation (including computers) and their own power source (usually solar panels) Sputnik

Looking at Earth Artificial Satellite cont’d: Artificial satellites are required for the following Earthly reasons: Communications Observation Monitoring Navigation Mapping Real World: Mission to Mercury

Communication Satellites The world is now a “Global Village” because of instant communications These communications are made possible by orbiting satellites There are two types of communications satellites: Low Earth Orbit satellites Geosynchronous Orbit satellites.

Communication Satellites Low Earth Orbit Satellites: Placed 200-800 km high above the Earth They complete one orbit of Earth in roughly 1.5 h. These satellites circle Earth faster than Earth rotates

Communication Satellites Low Earth Orbit Satellites cont’d: When seen from the ground, these satellites move across the sky in a matter of minutes Moving antennae track their signals These types of satellites are often used for telephone signals as they are close enough to the Earth to eliminate lag time in phone conversation

Communication Satellites Geosynchronous Orbit Satellites: Placed 36000 km above Earth directly above the equator Move in the same direction as Earth rotates Take 24 h to orbit the Earth once (ie. they are synchronized with Earth’s rotation)

Communication Satellites Geosynchronous Orbit Satellites cont’d: When seen from the ground, these satellites appear stationary in the night’s sky Stationary antennae track their signals These types of satellites are often used for television as they allow for a continuous signal

Observation and Monitoring Satellites Observation and Monitoring Satellites are used for forecasting weather, carrying our research and helping ships, aircraft, and other vehicles determine their exact location on Earth Ex. The satellites used to create the images for “Google Earth”

Remote Sensing Remote Sensing: Taking measurements of Earth (and other planets) from space Remote sensing is used for the following: Can show healthy vs. unhealthy regions of vegetation on the Earth Clear-cut and burned forests can be mapped to show the rates of their degradation Water pollution can be imaged Erosion can be tracked Land use in cities can be observed Weather can be tracked

Global Positioning System (GPS) Using a fleet of GPs satellites above Earth and small hand-held GPS units on Earth, you can calculate your position on Earth to within 30 m (military units can be accurate to within a few centimetres!!!!!)

Global Positioning System (GPS) GPS Satellites: NAVSTAR (Navigation Satellite Tracking and Ranging) is a group of satellites that were placed 20000 km above the Earth’s surface by the U.S. military These satellites take about 12 h to complete one orbit There are enough GPS satellites in orbit so that there are always at least three above the horizon, wherever you are in the world, whatever time of the day!!!!

Global Positioning System (GPS) GPS Satellites cont’d: The satellites send out radio signals that are detected by the hand-held GPS units The distance is calculated based on the time that it took for the signal to be detected (like sonar or ultrasound) The hand-held unit then calculate your location on Earth using triangulation

Global Positioning System (GPS) GPS Satellites cont’d: GPS was originally designed for military use but is now used for: Fishing Airplanes Palaeontology Golf Etc.