Communication
Satellites: There are presently many different
types of satellites orbiting our planet. There are those that orbit close to the
planet's surface. These are called Low
Orbiting Satellites. They can be found anywhere from 200 to 1000 km above
the Earth's surface. They can take up to 1.5 hours to orbit the Earth. They are
primarily used for communication such as that that links radio waves from long
distances to ground stations and vice versa as well as for remote sensing
(making observations). These types of satellites are more common. It was the
third country in the world to launch a satellite in 1962. The Alouette 1 was
used primarily for scientific research. Observation
Satellites are primarily used to forecast weather and look for patterns in our
atmosphere study water resources and surface features on the land, crop
failures, etc. Others are used more for research purposes as well as to help
planes, boats, and other vehicles to determine their exact location on Earth.
These types of satellites also have the ability to take photographs, form images
through the use of infrared rays, and other types of invisible light waves from
the electromagnetic spectrum. They can conduct a spectroscopic analysis of gases
found on the Earth' s surface, as well as analyze their content, concentration,
and location, etc. Of course, these types of satellites have also been used for
military purposes such as the location of troops and other information. They are
referred to as spy satellites.
There are other satellites that contain
telescopes for the purpose of space exploration. This serves as an advantage
since Earth bound satellites are limited by the weather conditions as well as
atmospheric interference. The more famous space telescope is the Hubble
telescope. It has recently undergone some repairs and has a promising future of
providing us with images never before seen.
Global
Positioning System (GPS) Satellites are
primarily used for the purpose of navigation. These are gaining more popularity
now with the use of hand held devices as well as other devices that are being
put into cars and other vehicles. There are more than 24 satellites in high
orbit for the purpose of determining navigational ranges and tracking. These
devices send out a signal to the
satellites. The satellites in turn send radio signals tracking your location and
time. The device then receives the information, reads, measures, and computes
your location using triangulation. The unit can locate your position anywhere
from 10 to 30 m. from your actual position. Obviously, the more expensive your
system, the more accurate it pinpoints your location.
RADARSAT,
another Canadian invention, is a satellite mainly used for the purpose helping
in emergencies. Once such example happened in Manitoba's flood of 1997. This
satellite helped rescue workers determine the devastation and damage caused by
the flood and thus employ a more effective means of rescue and relief. RADARSAT
uses radar to look at features on land and on oceans using radio waves. RADARSAT
has also been used for other types of natural disasters such as mudslides,
earthquakes, ice storms, etc, as well as other non natural disasters such as oil
spills on the oceans.
Industries have also used this system to
locate resources such as oil, natural gas, minerals, water, etc, that are
normally found underground.
Geosynchronous
Satellites, on the other hand, are in synch with
the time that the Earth takes to turn on its axis (about 24 hours). These
satellites can be found at about 42 000 km above the Earth's surface, directly
above the Earth's Equator. Canada was one of the first counties to launch this
type of satellite for domestic purposes. These satellites have the advantage of
remaining in one location at all times which allows signals to be received
constantly without being lost due to a change in satellite location. It is
mainly used in telecommunication. Canada is one of the world leaders in the
development and use of these types of communication satellites. Its Domestic
communication satellite, Anik 1, was first launched on November 10, 1972. The
Canadian Broadcasting Corporation (CBC) started its first transmission to the
North, becoming the first country in the world to use satellites to transmit
television signals. More advanced models of the Anik have been launched since
then and are used in the transmission of other types of signals such as those
used for internet communications between distant communities.
The International Space Station (ISS) is
humankind's attempt at colonization beyond the surface of the Earth. Much
preliminary study has gone on beforehand, such as the ability of living things
to survive in space, the recycling of valuable resources, etc. This research has
given rise to the construction of the International Space Station. Several
countries including Canada, Brazil, United States, Japan, Russia, and Europe are
now active members in this new space alliance. There has been several trips made
on a more regular basis transporting payloads of materials necessary to conduct
further experimentation and research, the testing of human endurance over longer
periods of time in space, as well as the maintenance and upkeep of such a
station.
