|Early Artificial Satellites - the beginning
of the space race…
With the launch of the Sputnik I - the FIRST artificial satellite to orbit
the Earth, the Soviet Union shocked the world. In particular the United
States, at the height of the Cold War, was taken by surprise by this
aluminum sphere which remained aloft for 92 days before it burnt up in the
atmosphere. What's more? The satellite was launched using an
Intercontinental Ballistic Missile, SS-6, implying that American might one
day see Soviet nuclear warheads and satellites above their heads. This
surely spurred the Americans, there began the space race. The founding of
the renowned National Aeronautics and Space Administration (NASA) in October
1958 was part of the result.
Named from the Russian phrase for "travelling companion of the world"
(Sputnik Zemli), it was a small satellite measuring only 58 cm (23 in)
across. The sphere contained instruments which, for 21 days, radioed data
concerning cosmic rays, meteoroids, and the density and temperature of the
upper atmosphere. At the end of 57 days the satellite re-entered the
atmosphere of the Earth and was destroyed by aerodynamic frictional heat.
|To see Info about Sputnik I
and Sputnik II
Union soon repeated their glorious achievement by sending the Sputnik II
looping the Earth in 1957. With it went the first living being ever sent to
the space- a dog named Laika, and the first biomedical measurement was made
in Sputnik II.
Meanwhile, the United States set their record after the successful launching
of Explorer I from Cape Canaveral (a.k.a. Cape Kennedy), Florida. The 14-kg
(31-lb) cylindrical spacecraft, 15 cm (6 in) in diameter and 203 cm (80 in)
long, transmitted measurements of cosmic rays and micrometeoroids for 112
days and gave the first satellite-derived data leading to the discovery of
the Van Allen radiation belts.
The Earth is pear-shaped… This might be general knowledge to you, but it was
not proven until a precise measurement was taken by Vanguard 2 - the second
artificial satellite launched on March 17, 1958 by the United States. The
solar-powered spacecraft stayed in its orbit for over six years. Vanguard 2
was followed by the American satellite Explorer 3, launched on March 26,
1958, and by the Soviet satellite Sputnik 3, launched on May 15.
|Scientific Satellites- Close observations…
As scientific measuring devices and rocket boosters became more reliable,
satellites were developed for the purpose of scientific studies of the Sun,
other planets, the Earth and the space itself. With the aid of scientific
satellites, close observations of the planets from outside the atmosphere
were first made possible.
Since 1962, the Orbiting Solar Observatories (OSO) have studied the Sun's
ultraviolet, X-ray, and gamma radiation. Pioneer satellites have studied
cosmic radiation, the solar wind, and the electromagnetic characteristics of
space. The Orbiting Astronomical Observatories (OAO) have observed stellar
radiation, and Orbiting Geophysical Observatories (OGO) have studied the
relationships between the Sun, the Earth, and their space environment. The
Infrared Astronomy Satellite (IRAS), an Anglo-American project launched in
1983, has probed the hidden reaches of our galaxy. The Hubble Space
Telescope was launched by the space shuttle Discovery in 1990. Although
scientists discovered soon after the space telescope began operating that
the telescope's main mirror was flawed, astronauts aboard the space shuttle
Endeavour repaired the Hubble Space Telescope (HST) in December 1993. Even
before the repair, however, the telescope was able to transmit valuable
images-some of never-before-observed phenomena-back to astronomers on Earth.
Problems with faulty gyroscopes were resolved by their replacement in
another space shuttle mission in December 1999. This mission also added
further new equipment to the HST, making it a more sophisticated observatory
ten years on from its original configuration at launch.
A major new scientific satellite, the Chandra X-ray Observatory, was
launched by NASA in July 1999. It has already provided large amounts of data
on the X-ray sky, including images of active galactic nuclei and nebulae
bathed in X-rays, as well as pinpointing many more X-ray sources at the
outer reaches of the universe.
The Hubble Space Telescope is seen from the cargo bay of the space shuttle
Discovery as a robot arm, left, places it in orbit on April 25, 1990. Free
of the distorting effects of the Earth's atmosphere, the telescope has an
unrivalled view of distant galaxies.
|Applications Satellites - this is where the weather reports
Applications Satellites can be classified into three main categories, namely
communications, environmental and navigation satellites.
The navigation satellites work as landmarks. They provide some known
observation points orbiting the Earth, so when they are spotted by ships and
submarines, the vessels can figure out their position quickly and
The United States has developed a Global Positioning System (On the left)
employing 24 satellites, capable of providing information to even drivers
Environmental satellites observe the Earth and atmosphere, and transmit
images for a variety of purposes. Weather satellites provide daily
transmissions of temperatures and cloud patterns. One example is the
Synchronous Meteorological Satellite (SMS). From stationary orbit, it sends
pictures of a large area of the Earth's surface at 30-minute intervals.
Information on soil characteristics, water and ice quantities, coastal-water
pollution, salinity, and insect blights of crops and forests are obtained.
Even forest fires can be detected from Earth orbit. Study of folds and
fractures in the Earth's crust helps geologists to identify deposits of oil
Earth observation satellites are used by the United States and other
countries to obtain images of military value, as of nuclear explosions in
the atmosphere and in space, ballistic-missile launch sites, and ship and
troop movements. In the 1980s, controversy was aroused by the American
proposal to develop a satellite antiballistic missile defense system making
use of laser technology.
see various satellites charts here-- Scientific |