Satellites come in two types, either natural or artificial satellites. Natural satellites are Moon, stars, or planets that orbit either the Earth or the Sun. Meanwhile, artificial satellites are machine or spacecraft that moves around Earth or another body in space.
Man-made or artificial satellites were created to orbit the Earth to gather data like images of the planet to help meteorologists’ study and predict weather conditions and other phenomena like storms and hurricanes. Satellites also capture images of various celestial objects like black holes, planets, the Sun, stars, nebula, and dark matter of galaxies to better understand the solar system and universe.
Other satellites are designed to beam T.V. signals and provide navigation systems like the Global Positioning System or GPS. If you have GPS, a satellite can determine where exactly you are located. There are about 20 20 satellites that make up this system.
When Was the First Satellite Launched?
On October 4, 1957, the Soviet Union launched the first artificial satellite they named Sputnik 1. It orbits into a low elliptical Earth for three weeks before its batteries die and then orbited silently for over two months before it fell back into the atmosphere. The capsule weighed 83.6-kg (184-pound).
It had reached an apogee or the farthest point from Earth, of 940 km, and a perigee (nearest point) of 230 km (143 miles). It only remained in orbit on January 4, 1958, and it fell back to the Earth and burned in the atmosphere on its landing.
America was surprised by the Soviet Union with the launching of Sputnik because they assumed that they had the most advanced technology. The event triggered a “space race” between these two countries. Since the launching of Sputnik 1, about 8,900 satellites from more than 40 countries have been launched.
In a survey in 2018, about 5 000 satellites remain in orbit, and about 1 900 of them are operational while the rest have lived out their useful lives and become space debris.
Of the operational satellites, about 63% are in low Earth orbit, 6% are in medium-Earth orbit at about 20 000 km, 29% are in geostationary orbit or 36,000 km. The remaining 2% are in various elliptical orbits.
Although the Soviet Union was the first to launch a satellite, the USA is still the leading country regarding the most significant number of satellites; the USA has 859 satellites, China has 250, and Russia comes third with 146 satellites. Other countries that sent off satellites in space are India with 118 satellites, Japan with 72, and the U.K. with 52.
Many space probes, including large space stations like the International Space Station, were launched and assembled in orbit and become artificial satellites of Mercury, Venus, Mars, Jupiter, Saturn, Moon, and a few asteroids, a comet, and the Sun.
Launch and Mission
The Sputnik rocket’s control system was altered to a 223 by 1,450 km (139 by 901 mi) orbit with a 101.5-minute orbital period. Georgi Grechko has already calculated the trajectory on the mainframe computer of the USSR Academy of Sciences.
The Sputnik rocket was launched from Site No. 1 at NIIP-5 at 19:28:34 UTC (October 5 at the launch site) on October 4, 1957. According to telemetry, the strap-ons parted 116 seconds into the flight, and the core stage engine shut down 295.4 seconds later.
The 7.5-tonne core stage had reached a height of 223 kilometers (139 miles) above sea level, a velocity of 7,780 meters per second (25,500 feet per second), and a 0-degree 24-minute velocity vector inclination to the local horizon at the time of shutdown. This ended in an initial orbit of 223 kilometers (139 miles) by 950 kilometers (590 miles), with an apogee 500 kilometers (310 miles) lower than intended, a period of 96.20 minutes, and an inclination of 65.10 degrees.
Around 16 seconds after launch, a fuel regulator in the booster failed, resulting in excessive consumption of RP-1 for most of the powered flight and engine thrust 4% above normal. The core stage was supposed to cut off at T+296 seconds; however, due to premature propellant depletion, the thrust was turned off one second sooner when a sensor identified the Overspeed of the blank RP-1 turbopump. At cutoff, there were 375 kilograms (827 lb) of LOX left.
PS-1 separated from the second stage at 19.9 seconds following engine cutoff, and the satellite’s transmitter was turned on. Junior Engineer-Lieutenant V.G. Borisov noticed these signals at the IP-1 station, where transmission of Sputnik 1’s “beep-beep-beep” tones verified the satellite’s successful deployment.
PS-1 remained in the air for two minutes until it dropped below the horizon. In its second orbit, the Tral telemetry device on the R-7 core stage continued to communicate and was discovered.
The launch was witnessed from the range by the designers, engineers, and technicians who worked on the rocket and satellite. They headed to the mobile radio station after the launch to listen for satellite signals. Before calling Soviet Premier Nikita Khrushchev, they waited around 90 minutes to ensure the satellite had completed one orbit and was communicating.
“As a consequence of huge, intense effort of scientific institutes and design bureaus, the first artificial satellite has been developed,” the Soviet Union’s Telegraph Agency (TASS) said on the maiden orbit. The R-7 core stage was also launched into orbit, weighing 7.5 tonnes and measuring 26 meters in length. It was a first-magnitude object visible at night, trailing behind the satellite.
The booster was fitted with deployable reflective panels to improve its visibility for tracking. The small, highly polished spherical satellite was scarcely visible at 6th magnitude and thus more difficult to track optically. After 326 orbits, the satellite’s batteries ran out on October 26, 1957.
The R-7’s core stage stayed in orbit for two months until December 2, 1957, while Sputnik 1 remained in orbit for 12 weeks, until January 4, 1958, after completing 1,440 Earth orbits.
The Sputnik 1 rocket booster also managed to reach Earth orbit. It was visible as a first magnitude object from the ground at night, whereas the small but highly polished spherical, barely visible at 6th magnitude, was more difficult to track visually. Sputnik 1 satellite replicas can be exhibited in Russian museums, and another is on display in Washington, D.C., at the Smithsonian National Air and Space Museum.