### equipment:

Satellite
* Explain why a satellite stays in orbit and define orbit parameters.
* Many satellites are in orbit around the Earth.
* Many satellites are visible to the naked eye
  - with the naked eye or with the aid of binoculars
  - function as orbiting bulletin boards, relaying packet messages around the world
  - orbit each of the four giant planets
  - use so-called spotting scopes to aim at the stars and keep the satellite positioned
* Most satellites have more than one antenna on- board
  - surfaces
  - too little gravity to retain an atmosphere
  - operate in a geosynchronous orbit
  - spin while they are in orbit
  - stop functioning long before they fall to Earth
* Some satellites are low-powered and provide weak signals
  - natural, like the moon, which natural satellite of the earth
  - can divide their signal into many movable spot beams
* Some satellites carry detectors
  - equipment to receive signals
  - instruments
  - telescopes
  - ultraviolet telescopes
  - collect over a terabyte worth of data each day
* Some satellites have a digital signal processor, which is like a very powerful computer
  - dual modes that operate simultaneously
  - sensors
  - special cameras that can take pictures of the Earth
  - water vapour sensors
  - identify weather patterns and enhance weather predictions
  - look out into space and record information about the galaxy
  - revolve around the earth in elliptical orbits
* Some satellites send and receive telephone, fax, and computer communications
  - television signals
* Some satellites use cameras
  - film cameras
* actually remain in orbit about Earth because of gravity.
* allow fast transmission over immense distances with no loss of signal
  - for the transformation of information in many forms
  - measurements to be made over vast ocean areas on a daily basis
  - meteorologists to see what the earth and clouds look like from space
* also can see into space better than telescopes at Earth's surface
  - help correct errors due to the curvature of the Earth
  - move in orbits at a wide variety of altitudes
  - serve an important role as a redundant, or backup system, to fiber-optic cable
  - slow their planets' rotation
* appear as a starlike dot moving across the sky in a straight line
  - small, steady, extremely fast-moving points of light
* are a completely different breed of television services
  - key component of almost every communication system
* are able to take pictures of our planet at night, as well as in daylight
  - transmit information quickly from one part of the earth to another
  - accurate because they have atomic clocks on board
  - almost the only convenient way to monitor ice accumulations in the polar regions
* are also at risk during solar storms
  - wireless systems that use RF to communicate
  - an important component in true economy of scale
  - celestial bodies
  - devices that use sensors to observe Earth and our solar system
  - electronic devices
  - followers
  - heavenly bodies
  - laptop computers
* are located in orbits
  - solar systems
  - near planets
  - most visible in the hours after sunset or before sunrise
  - objects that orbit another object in space
  - propelled by rockets to their orbits
* are sensitive to bad weather and sun spots
  - the shock and vibration produced by rocket motors
  - spacecrafts
  - species
  - the only technology that have economics independent of density
* are used for a large number of purposes
  - spying
  - useful for weather observation because they are at an ideal vantage point
* broadcasting television typically provide many gigabytes of bandwidth.
* can also lock into synchronous orbits and produce important effects
  - be natural, like moons, or made by people
  - cover large areas of the Earth
  - detect volcanic eruptions and the motion of ash clouds
* can experience increased drag reducing the lifetime of their orbits
  - drag, which reduces the lifetime of their orbits
* can measure cloud fraction over the entire atmosphere and for all types of clouds
  - ocean surface temperatures shown in computer-generated colors
  - observe the Earth's atmosphere, surface and oceans
  - only view the upper few meters of the ocean's surface
  - operate in several types of Earth orbit
  - orbit the Earth several times in a day
  - oversee the entire earth's surface on a periodical basis covering large areas
* can provide an image of the weather day or night, when sunlight is no longer available
  - continuous communication coverage over most of the earth
  - sometimes be damaged by particles from the sun, so there are hazards
* circle our globe in several types of orbits.
* circling the Earth can survey an entire Ocean in less than an hour.
* come in all shapes and sizes and play a variety of roles
  - many shapes and sizes and have many uses
* do sometimes fall out of orbit due to space weather events.
* drift in a westerly direction
  - out of position because of solar wind or gravitational or magnetic forces
* dwells over polar regions which change in longitude as the earth rotates.
* efficiently form heterochromatin, and heterochromatin silences genes.
* go from one end of the sky to the other in one steady direction.
* have four atomic clocks on board
* have the ability to transmit information virtually in an instant
  - advantage of a bird's eye view of weather systems
  - possibility of looking both at the Earth and at the Universe
  - unique advantage of being able to cover large portions of the earth's surface
* having infrared channels, however, are capable of detecting hotspots, like fires.
* is equipment
* look at many different types of light emitted by an object.
* looking toward Earth provide information about clouds, oceans, land and ice.
* measure precipitation using visible, infrared and microwave channels.
* monitor weather patterns and human land use.
* move across the sky, and every year they multiply.
* now observe the sea surface temperature, winds, elevation and color
  - play a role in everything from television to pagers to car navigation systems
* observe Earth systems from orbit.
* often loop around Earth or other planets to increase their speed
  - operate in the space environment for many years
* operate above the atmosphere.
* orbit at several hundreds of miles above Earth
  - the same speed as the earth's rotation therefore remaining in the same position
  - the earth, making repeated visits to places
* orbiting the Earth provide more than a twinkle in the night sky
  - use solar power
  - earth can measure chlorophyll pigment and water temperature
* play a more and more important role in the development of the society.
* play an important role in providing atmospheric data over the oceans
  - transmitting all sorts of data today
* provide an extensive cover of an ocean's surface
  - continuous surveillance
  - detail information
  - images of the sea surface temperatures over the entire ocean
* provide more detail information
  - national trunk services
  - synchronous measurements of ocean temperature and vegetation conditions
* receive and retransmit electromagnetic signals.
* represent a platform for remote sensing.
* scan the earth, like huge orbiting eyes.
* seem to affect the structure of even tenuous rings like that found at Jupiter.
* send information as a microwave beam.
* sometimes experience increased drag, reducing their longevity.
* track across the Earth's surface, encompassed by their visibility circles.
* transmit a number of different types of images
  - information and images immediately to and from every part of the world
  - signals which are observed by ground based receivers
* travel faster along their orbital path when they are closest to the earth.
* travelling deep into space often carry additional nuclear power supplies.
* typically have some means of propulsion for orbit corrections.
* use a variety of light-sensitive sensors to determine their position
  - wide variety of orbits to fullfil their missions
  - cameras to produce a visible image
* use remote sensing instruments to track levels of ozone in the upper atmosphere
  - sensing, too
* usually start out in an orbit that is elliptical
  - take several images from frequency bands in the visual and non-visual range
* vary greatly in size.
* view the Earth and send communications.
* watch Earth's weather from space.