Space exploration would have been impossible without satellites. These “Earth observers” were, are, and will be essential to opening new opportunities space data holds. Thanks to such long way satellites have passed backed up by different technological innovations, people now have easy access to historical satellite images that can be used by a variety of businesses and governments for different purposes. In this article, we will guide you through the milestones of satellites’ history from the first launch till now, ramping up with the possibilities the future holds for this spacecraft.
Brief History of Satellites
The history of satellites commenced with the first artificial satellite launch back in 1957 by the Soviet Union. This exact event has got the famous space race between the Soviet Union and the United States underway. The latter orbited their own artificial satellite just 4 months after.
Three years after the first satellite saw space, NASA successfully launched its first weather satellite Tiros-1 that transmitted infrared images of Earth’s cloud cover to identify and track hurricanes. And in 1962, the first low orbit communications satellite Telstar-1 was launched.
One of the main events in satellite history took place in 1972 when the Landsat program was implemented. It marked the beginning of the longest-running program of satellite Earth imagery, later renamed Landsat. Landsat satellites obtain millions of images that are a source of invaluable data for almost any on-Earth changes detection and monitoring.
Only 22 years after the Landsat program launch, in 1994, the first GPS constellation consisting of 24 geosynchronous satellites became operational. GPS-based satellite navigation system enabled location and time information tracking in all weather near or on the Earth. And in 2012, the number of satellites orbiting the Earth exceeded 1000 objects.
Currently, the more space technology develops, the bigger role satellites play in on-Earth processes observation and analysis, which leads to the constant increase in the number of satellite constellations for different purposes. But before we move on to the future of satellite games, let’s see what exactly these space objects are.
A satellite refers to an unmanned spacecraft that is launched by the carrier rocket into the Earth’s orbit. The orbits of the Earth are different and are classified mainly by altitude. There are low-Earth orbits, near-Earth orbits (altitude from 200 to 2000 km), and medium near-earth orbits (altitude over 2000 km). The most widely known is the geostationary orbit (35 km). This is where communication or telecommunication satellites are located exactly above the equator of the Earth. And since these satellites revolve around the Earth in exactly one day, they remain stationary for ground-based observers. Therefore, all communications based on satellites located in geostationary orbit do not need rotary devices on base station antennas.
Satellites can be utilized for different purposes. These are research satellites, navigation satellites (GPS), telecommunications satellites, Earth remote sensing satellites, meteorological satellites, military (reconnaissance) satellites. And they differ not only in what orbit they are in, but also with what speed they move, what mass they are, and what kind of structure they have.
Although, there are some parts every satellite has. Each artificial satellite consists of a power system, attitude control system, an antenna to transmit and receive information, and a payload for data collection.
Depending on its purpose, a satellite can be solar, nuclear, or battery-based. If the spacecraft is required to function for as long as years or even decades, it will have either a nuclear or solar power system.
An antenna system transmits radio waves and enables satellite communications with the Earth. Thanks to the antenna system, ground administrators control spacecraft’s movements and functions and retrieve the data it has gathered.
Altitude control implies the use of magnetic, gyroscopic or gas propulsion systems to enable minor satellite movements and self-reorientation.
The payload could be represented by cameras, sensors, telescopes, particle detectors, gauges, and other electrical equipment that is mounted on the satellite with the purpose of capturing the information and measurements a spacecraft is aimed to obtain.
One of the most interesting questions when it comes to artificial satellites concerns their ability to orbit the Earth without falling to it. How is that possible?
The satellite remains in orbit, despite the Earth’s gravity, due to the high speed of movement (in fact, the satellite constantly “falls” to the Earth, but because of the high speed it manages to shift in the horizontal direction, and since the Earth is round, the spacecraft appears to be at the same altitude as it was. In order not to fall, the low orbit satellite must move at a speed of 7.9 km / s, or about 28,400 km / h. The higher the orbit, the lower the speed required for the satellite to remain at the same altitude.
Knowing all that, let’s now move on to see what the future holds for satellites and their abilities.
What’s Ahead for Satellites?
The satellite industry is currently under the influence of a new space race where private companies are now able to join the game by launching their own satellites. Some of these companies strive to build or launch satellites, some want to provide Internet service, and some aim to do all of it. Here are the most famous examples.
SpaceX is Elon Musk’s rocket company that has two major projects: Starlink and Starship. Starlink is a project aimed at creating a satellite constellation, and Starship is a project dedicated to the mission of Mars exploration.
By the end of 2021, SpaceX plans to deploy satellite communications in 25 countries. To do this, the company is planning to build a Starlink kit manufacturing plant in Austin, Texas. The company also recently filed an application to provide access to satellite Internet for moving objects: ground vehicles, ships, and aircraft.
Iridium Communications is considered a veteran of the low Earth orbit telecom satellite cluster. The first generation of the cluster consisted of 77 satellites launched in 1997-2002, with an approximate project cost of $ 5 billion.
SpaceX has been awarded a contract to launch all of the next-generation Iridium NEXT satellites. The launches were carried out using a Falcon 9 rocket, and in 2017-2019 the number of modernized satellites in orbit reached 75 objects.
In January 2020, the Iridium Communications satellite cluster was certified for use in the Global Maritime Distress and Safety System (GMDSS). The certification ended the monopoly of the American company Inmarsat that lasted since 1999.
The Canadian company Telesat, in partnership with the Canadian government (which has invested $ 462 million in the program), has so far launched only one satellite in 2018. In February 2021, Telesat selected Thales Alenia Space as the general contractor for the production of satellites. The first batch will consist of 298 objects weighing from 700 to 750 kg and will go into orbit in 2023. Full coverage is promised in the second half of 2024. Earlier, the company announced its intention to increase the number of satellites to 500. Rockets from Blue Origin and other companies will be used for launch.
In the long run, the real winners in the space race are always people as the ones who enjoy the new benefits modern satellites have to offer now and will continue to offer in the future.