How Many Satellites are in Space?

Modern society depends heavily on satellites for a wide range of applications.

From military intelligence to how you plan your morning commute, satellites are constantly feeding us essential information. Without this stream of data from space, we would grind to a halt.

As needs expand, so too does the number of satellites required to work in tandem and provide the necessary networks to relay information to the ground.

Just how many satellites are in space? Do we need more, or could we do with fewer?

How many satellites are orbiting the Earth in 2022?

The Satellite Database, compiled and maintained by the Union of Concerned Scientists (UCS), keeps a constant record of how many satellites orbit Earth. It lists its latest figures at more than 4,850 satellites currently orbiting Earth. However, that is just the proportion of Earth’s satellites that are operational.

This places well over 2,000 inert satellites in orbit, a fraction of the high density of ‘space junk’ orbiting our planet. Many of these will be satellites that have either served their purpose, become obsolete, or are no longer functional. Satellites have a limited life span due to solar arrays no longer working or fuel supplies running dry.

The orbital locations of Earth’s operational satellites are:

Low Earth Orbit (LEO)

Satellites in LEO: 4,078

The vast majority of satellites currently in operation are in LEO. ‘Low’ is a relative term in this orbit, as a satellite in LEO could still be many hundreds of kilometres above the Earth’s surface. Definitions of what constitutes LEO vary, being between 160km and 1,000km/2,000km dependent upon source. Generally, an altitude below 2,000km will be considered low orbit.

This type of orbit is commonly chosen as the plane can be tilted, unlike geostationary orbit which follows the plane of the Earth’s equator. This allows for more simultaneous orbits to take place with less risk of collision.

However, this type of orbit also means satellites circle the Earth at high speed, often making them difficult to track. This is why individual LEO satellites are often more useful for imaging due to their relative proximity to the Earth, rather than for roles such as telecommunications. Constellations of satellites in LEO, however, can fulfil communications roles easily.

Perhaps the most recognisable object in LEO is the International Space Station, the 408km altitude of which makes the transport of astronauts to and from much easier. Many CubeSats are launched into LEO, some from the ISS, which helps to keep mission costs smaller because LEO requires the smallest amount of fuel and energy.

Medium Earth Orbit (MEO)

Satellites in MEO: 141

MEO comprises orbits that fall anywhere between LEO and GEO (geostationary orbit), covering a region of over 30,000km. Like LEO, satellites in MEO are free to take various paths around the Earth and can have tilted planes. MEO makes up a small percentage of operational satellite orbits; around only 3% as of 2022.

MEO is commonly used for communications and navigation satellites. Some of the largest and most heavily used global navigation systems are positioned in MEO, such as the US-owned Global Positioning System (GPS), Europe’s Galileo system, and Russia’s GLONASS. These satellites work in constellations to aid with global navigation, from tracking the positions of commercial aircraft to powering Google’s and Apple’s map applications.

Satellites in MEO vary in the speed at which they complete an orbit, falling typically around 12 hours. A particular kind of medium orbit called semi-synchronous orbit uses an altitude of roughly 20,200km for this half-day orbit. Because it passes any two given points on the equator twice a day, it is highly predictable and consistent.

Another form of MEO, invented by Russian scientists in the 1960s, is the Molniya orbit. This orbit is eccentric, forming an extreme ellipse that rounds the Earth closely at one end. The satellite passes the Earth quickly at this low, close angle, then slows down as it reaches the high top end of the ellipse where it will spend several hours. This makes the Molniya orbit useful for communications at the top and bottom of the planet’s hemispheres.

MEO orbits are used as a happy medium between the near-Earth proximity of LEO, and the planetwide perspective and reach afforded by GEO. This is what makes MEO constellations so useful for communications and navigation roles.

Geostationary Orbit (GEO)

Satellites in GEO: 574

GEO satellites are positioned at the farthest places from Earth while still being within its orbit. Geostationary and geosynchronous are terms used interchangeably.

While there are slight technical variations in their meaning – with geosynchronous orbits occupying any plane and geostationary orbits being roughly level with the equator – both types have the same basic advantages. They take a single day to complete one orbit, and the satellites do not move relative to the ground (unless some longitudinal movement has been planned and accounted for).

At roughly 36,000km above the Earth’s surface, satellites in GEO occupy a special area of space that means the speed of their orbit matches the planet’s rotation. GEO satellites travel at around 3km per second at these far distances.

GEO satellites’ immobile position in the sky makes them excellently positioned for telecommunications, as their locations can be relied upon by ground stations and tracked easily. Their distance above Earth means that they cover long, wide areas too, which is why GEO satellites are also ideal for weather monitoring and environmental sciences. Most meteorological data is received from satellites.

For large sections of the Earth that need to be monitored from afar over long time periods, GEO satellites provide the kind of perspective that could only otherwise be achieved by aerial craft, without the need to constantly manoeuvre or refuel.

Satellites in GEO can also lend their advantages to non-GEO satellites, which is something that the European Space Agency does. The European Data Relay System (EDRS) relays information from GEO satellites to those in other orbits that aren’t always in the right windows to transmit data, meaning certain connections can remain unbroken.

There are other kinds of orbits that are used to achieve different goals, but the three listed above are the most common for the majority of operational satellites working around Earth.

How many satellites were launched in 2021?

According to the Satellite Database, around 1,697 satellites are thought to have been launched in 2021. Of those, 1,191 are owned by the USA, 94 by China, and 288 belong to the UK. Despite Russia’s historic space efforts and its modern involvement in joint ventures such as the International Space Station, Russia only put six of its satellites into orbit in 2021.

The US is not only the country to own the most satellites launched in 2021, but also the biggest contractor operator. US-based contractors aided the launch of 1,476 satellites, the vast majority overseen by Elon Musk’s SpaceX and joint venture Airbus OneWeb.

The popularity of low Earth orbit – due to its proximily and lower associated costs – stands out amongst the 2021 satellite launches. 1,664 of the satellites were put into LEO, 27 were put into GEO, and only three were put into the MEO range.

In terms of function, communication was the most in-demand purpose for 2021’s satellite launches.

A total of 1,389 satellites were launched for that reason, encompassing all GEO satellite launches.

Only 305 LEO satellites were launched for other objectives like technology development, Earth observation and science, and global positioning.

Though many of these satellites are intended for commercial use, some are reserved strictly for government and military use.

The individual missions of many satellites launched in 2021 are varied and range from observation to experiments conducted in the vacuum of space. CACTUS1 helped tackle the issue of space debris by utilising a substance called aerogel – which is roughly 99.8% oxygen – to capture and analyse microdebris in space.

PTD-1 was launched to demonstrate a new propulsion system. Carrying a pint of water, it is intended to split the water down into hydrogen and oxygen, which is then burned inside a small rocket to create thrust.

Some purposes are not known, and are left to interpretation by independent analysists. These might be satellites for gathering intelligence on other country’s military activities, providing early warning networks, or for undisclosed technological tests.

Which country has the most satellites in space?

To see how many satellites orbit Earth by the hand of single countries can be surprising. The USA, for instance, has easily the largest cache of operational satellites, with over 2,900 thought to be currently operational. This represents over half of the Earth’s operational manmade satellites currently in orbit.

The next largest amount for a single country is China, with around 500 satellites operating in orbit. Russia is thought to own approximately 170, with around 1,240 satellites making up the rest of the world including Europe, South America, Canada, and parts of Africa.

Historically, America and Russia have always been involved in space activity and are amongst the earliest adopters of satellite technology. The first satellite to be launched into space, Sputnik 1, was sent into orbit by the former Soviet Union at the end of 1957. It completed roughly 1,400 orbits of the planet, travelling around 70 million kilometres before its orbit decayed and the chemical batteries powering its transmitters failed.

By 1966, only a handful of countries owned satellites: the US and Russia, Canada, France, Italy, and the UK.

Even fewer of these countries were themselves space launching; only the US, Russia, and France had the capacity to put their own satellites into orbit at the time.

Today, well over half the world owns operational satellites. The number of countries capable of launching into space has also grown exponentially, with India, China, Japan, New Zealand and the majority of continental Europe now possessing indigenous space launching facilities.

The rapid advancement of technology has not only meant that more countries can develop and put their own satellites into orbit, but the accessibility of satellite technology has also opened up. CubeSat kits can be purchased privately and commercially, meaning that the barriers to entry for satellite missions are lower than ever. Traditionally, CubeSats have only used off-the-shelf hardware, but innovative solutions such as Software Development Kits for satellites bring the software into the ready-made domain.

As space becomes a more contested ground for business, intelligence, and international competitive interests, the USA’s position as most populous in terms of orbiting satellites may not be so secure.

With China reportedly developing its space technology at twice the speed of the US, and the UK’s space capital Scotland aiming to become a European leader in small satellite launches by the end of the decade, it could be that the number of operational satellites per country will shift dramatically in the near future.

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