Space is vast, but it is not empty. It is filled with countless objects, both natural and artificial, that orbit the Earth or the Sun. Some of these objects are useful, such as satellites that provide communication, navigation, weather, and scientific services. But some of these objects are useless, such as defunct spacecraft, rocket stages, fragments, and even paint flakes. These are called space debris, or space junk, and they pose a serious threat to the safety and sustainability of space activities.
In this blog post, I will explain what space debris is, how it is created, why it is dangerous, and what can be done to mitigate or remove it. I will also share some examples of space debris incidents and initiatives. As a space enthusiast and a student of aerospace engineering, I am passionate about raising awareness and finding solutions to this global challenge.
What is Space Debris?
According to NASA, space debris is “any human-made object in orbit about the Earth that no longer serves a useful function”1 This includes nonfunctional spacecraft, abandoned launch vehicle stages, mission-related debris (such as bolts, nuts, tools, etc.), and fragmentation debris from the breakup of derelict rocket bodies and spacecraft. Space debris can range in size from micrometers to meters, and in mass from grams to tons.
Space debris is not a new phenomenon. It has been accumulating since the dawn of the space age in 1957, when the Soviet Union launched Sputnik 1, the first artificial satellite. Since then, more than 5,000 launches have placed over 10,000 satellites into orbit, of which only about 5,500 are still operational2 The rest have become space junk, along with thousands of other objects generated by various sources.
Some of the main sources of space debris are:
Explosions and collisions. These are the most catastrophic events that create large amounts of debris. For example, in 2007, China intentionally destroyed one of its own satellites with a missile test, creating over 3,000 pieces of trackable debris and many more smaller ones. In 2009, a defunct Russian satellite collided with an operational US satellite, creating over 2,000 pieces of trackable debris and many more smaller ones3
Malfunctions and accidents. These are unplanned events that cause spacecraft to lose control or functionality. For example, in 1978, a Soviet nuclear-powered satellite called Kosmos 954 reentered the atmosphere and scattered radioactive debris over Canada. In 1996, a French satellite was hit and damaged by debris from a French rocket that had exploded a decade earlier3
Normal operations. These are intentional or inevitable events that occur during the launch or operation of spacecraft. For example, during launch, rocket stages separate and are left in orbit. During operation, spacecraft release bolts, nuts, springs