Since the inauguration of the Space Age with the launch of Sputnik 1 by the Soviet Union in 1957, the human presence in space has intensified and diversified. Today, the constellation of artificial satellites circling Earth is a tangible representation of human ingenuity and technical prowess, as well as our inherent desire to explore, understand and connect.
Today we will take a detailed look at the field of artificial satellites, ranging from their historical conception to the latest developments in satellite technology. We’ll discuss its invaluable importance to a variety of sectors such as science, defence, meteorology and telecommunications, and explore the future challenges facing the global community as we continue to expand our presence beyond Earth’s atmosphere.
What are artificial satellites?
An artificial satellite is a man-made object launched into space that orbits around larger celestial bodies, such as planets or the Moon. These satellites are built and programmed to fulfill a variety of scientific, technological or communication functions. Artificial satellites are distinct from natural satellites, such as the Moon, which orbit the Earth in a natural way.
Artificial satellites have a variety of applications, including:
- Communication : Many satellites are used to facilitate long distance communication, transmit television signals, radio and provide internet services.
- Navigation : The Global Positioning System (GPS) system, for example, relies on a constellation of satellites to provide accurate location and time information to users on Earth.
- Scientific Research : Some satellites are launched to study the cosmos, Earth’s climate, Earth’s magnetic field, and many other phenomena.
- Observation and Reconnaissance : Satellites are used to monitor weather conditions, climate changes, wartime troop movements, and even for the detection of nuclear tests.
While artificial satellites are extremely useful tools, they also present challenges, such as the growing concern about space pollution, also known as “space junk”.
What are the main artificial satellites?
Over the course of humanity there have been many technological advances, including in the space area. This opened space for the creation of several satellites.
Here are some of the major satellites that have been launched:
- Sputnik 1
- Explorer 1
- Telstar 1
- Hubble Space Telescope
- GPS Satellites
- International Space Station (ISS)
Sputnik 1
Sputnik 1, launched by the Soviet Union on October 4, 1957, is famously credited with being the first artificial satellite to orbit the Earth. This historic event marked the beginning of the space age and triggered the intense Space Race between the Soviet Union and the United States during the Cold War period.
The main objective of the Sputnik 1 mission was to collect data on the density of the upper layers of the Earth’s atmosphere and the propagation of radio waves in ionospheric space. It didn’t carry a camera or other advanced scientific instruments, but its successful launch marked a milestone in space exploration.
The launch of Sputnik 1 not only demonstrated the Soviet ability to launch satellites, but also to launch intercontinental ballistic missiles, generating anxiety and concern in the United States and ushering in an era of accelerated space advancement.
Explorer 1
Explorer 1 was the first satellite launched by the United States and represented the beginning of American participation in space exploration. The launch took place on January 31, 1958, a few months after the launch of the world’s first artificial satellite, Sputnik 1, by the Soviet Union.
This satellite was developed as part of the US Army Explorer program under the leadership of the Jet Propulsion Laboratory (JPL). An important figure behind the Explorer 1 mission was renowned rocket scientist Dr. Wernher von Braun.
Explorer 1 continued to transmit data until May 1958, when its batteries died. It remained in orbit for over a decade, finally re-entering Earth’s atmosphere and burning up in March 1970. The successful launch of Explorer 1 was a milestone for the US space program. The satellite not only regained American prestige after the Sputnik crash, but also paved the way for future scientific and space missions, including the eventual creation of NASA, the US space agency.
Telstar 1
Telstar 1 was a landmark in the history of artificial satellites, having been the first to transmit transatlantic television broadcasts and telephone calls. Launched on July 10, 1962 by AT&T, this satellite paved the way for the modern era of satellite telecommunications. Telstar 1 was relatively small, about 34.5 centimeters in diameter, and weighed approximately 77 kilograms. Low Earth Orbit (LEO) aboard a NASA Thor-Delta rocket.
One of the most notable moments of Telstar 1’s mission occurred on July 11, 1962, when it successfully transmitted the first live transatlantic television broadcast. This transmission was a milestone in the history of television and an important step towards the globalization of communication.
Telstar 1 operated until February 1963, when it failed due to the effects of high-energy radiation released by high-altitude nuclear tests. Despite its short lifespan, Telstar 1’s legacy is enduring, having played a key role in shaping the interconnected modern world we live in today.
Hubble Space Telescope
The Hubble Space Telescope (HST) is one of the most famous artificial satellites in operation and one of the most productive astronomical observatories of all time. Launched on April 24, 1990 by NASA’s Space Shuttle Discovery, Hubble is named after astronomer Edwin Hubble, who made several fundamental discoveries in the field of cosmology in the 20th century.
The Hubble Space Telescope (HST) is one of the most famous artificial satellites in operation and one of the most productive astronomical observatories of all time. Launched on April 24, 1990 by NASA’s Space Shuttle Discovery, Hubble is named after astronomer Edwin Hubble, who made several fundamental discoveries in the field of cosmology in the 20th century.
However, Hubble did not have an easy start. A flaw in the shape of the telescope’s primary mirror caused blurred images, an issue that was corrected by a maintenance mission in 1993. Since then, Hubble has made a series of stunning discoveries and produced some of the most iconic images of the cosmos.
Hubble has made a number of significant contributions to science, including accurately measuring the universe’s expansion rate, discovering the acceleration of the universe’s expansion, detailed observations of planets in our solar system, and deep field views, which are images of small regions of space that reveal thousands of distant galaxies.
Hubble’s mission, which was initially planned to last 15 years, has been extended several times, and the telescope continues to operate and make important discoveries more than three decades after its launch. Despite its age, Hubble is still a valuable tool for astronomers and continues to contribute to our understanding of the universe.
GPS Satellites
The Global Positioning System, or GPS, is a constellation of satellites that was originally developed by the United States Department of Defense. Today, this system is essential for a wide variety of civil and military applications around the world. GPS consists of a network of about 24 to 32 satellites orbiting approximately 20,000 kilometers above the Earth. These satellites orbit the planet twice a day in six different orbital planes to ensure that at least four satellites are visible from any point on Earth at any given time.
Each GPS satellite continuously transmits information about its own location and exact time, based on highly accurate atomic clocks on board. GPS receivers on Earth (such as those found in smartphones, watches, car navigation systems, etc.) pick up signals from these satellites. By receiving signals from at least four GPS satellites, the receiver can calculate its own three-dimensional location (latitude, longitude, and altitude) and time, based on the time it takes the signals to reach the receiver.
The first GPS satellite was launched in 1978, and the system became fully operational in 1995. Since then, GPS has revolutionized navigation and accurate time, enabling everything from personal navigation and transportation logistics to research. science, precision agriculture, search and rescue operations, and much more.
It is important to note that there are also other GPS-like navigation satellite constellations operated by other countries, such as Russia’s GLONASS, European Union’s Galileo, and China’s Beidou. Each of these systems has its own characteristics, but all operate on similar principles to GPS.
International Space Station (ISS)
The International Space Station (ISS) is a permanent human habitat in space and an outstanding example of international cooperation in science and engineering. Its development and operation involve the space agencies of five main entities: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan) and CSA (Canada).
Construction of the ISS began in 1998 and the first permanent crew arrived in November 2000. Since then, the ISS has been continuously inhabited. Astronauts aboard the ISS typically spend around six months there, performing a variety of jobs including station maintenance, science experiments, and participating in educational and outreach activities.
The station is made up of a series of connected modules that provide living and working areas. These modules include laboratories where astronauts conduct experiments in many fields such as biology, physics, astronomy and meteorology. The ISS’s microgravity environment allows researchers to conduct experiments that would be impossible on Earth.
The ISS is powered by solar panels and is equipped with a range of systems to support life, including equipment to recycle water and air. It also has a robotic arm that can be used to perform maintenance, capture unmanned spacecraft and assist with spacewalks. The International Space Station has been an important springboard for human space exploration, providing a laboratory to study the long-term effects of living in space on the human body, as well as a testbed for technologies that might be used on future missions to the Moon. , Mars and beyond.