Space Pollution: A Growing Threat Around Earth

When you are gazing up in the night sky, space appears empty. The earth orbit is however becoming congested with what is indeed very unromantic JUNK.

Scientists call this junk by the names: space debris, orbital debris, space junk, and occasionally MMOD (Micrometeoroid and Orbital Debris). They all lead to the same conclusion made objects in the orbit that no longer work but move at high speed to cause great damage.

And now here is the important point which makes this a practical difficulty, that the universe is great, and the orbits we use are not. Most of the satellites are in a thin shell around the earth and more specifically Low Earth Orbit (LEO) and that shell is this shell is beginning to resemble a busy highway where everyone has thrown in their glass bottles.

What is space junk?

Space junk refers to any manmade object abandoned in orbit no longer of use. It comprises the dead satellites which have ceased functioning, yet they remain orbiting the earth, the discarded phases of rockets following launches, and debris which forms as a result of explosions or breakages or collisions like fuel tanks, batteries, etc. It contains little scraps as well such as paint flakes, screw, and metal scraps. The most worrying thing about this issue is not only what space junk is, but the quantity of it that is currently in the orbit of the Earth.

As stated in Orbital Debris Program Office of NASA, there are over 25,000 tracked objects bigger than 10 cm. They also approximate 500,000 between 1 and 10 cm, and more than 100 million bigger than 1 mm.

Most of those smaller fragments cannot be traced separately, yet they can harm space vehicles.

Why satellite collisions are dangerous

A space collision is not comparable to a car crash.

Objects travel at a speed of 7-8 kilometres per second in LEO (tens of thousands of km per hour). Even a small part of metal contains tremendous kinetic energy at such speed. This is why debris can punch holes, shred solar panels, damage sensors and even destroy a satellite entirely.

It is not the initial collision but rather what comes thereafter that is dangerous.

In collision between two objects at the orbital speed, the objects break into thousands of new pieces. Those pieces were dispersed into numerous surrounding orbits forming a broader minefield. This may cause a vicious circle: the bigger is the number of debris, the greater the chances of collision, which produces more debris.

Such a chain-reaction concept is commonly referred to as the Kessler Syndrome: a situation in which the growth of debris becomes self-perpetuating to the extent that some orbits have become unsafe to operate in.

Won’t the debris just scatter away because space is huge?

This notion initially makes sense, but the near-Earth orbit is not an empty room. Rather, it is more of a series of racetracks in which objects continue to move. Majority of the debris does not fall into deep space as the gravitational pull of the Earth holds it in its orbit. It is only able to leave orbit when it falls back into the atmosphere under the drag or when a powerful occurrence moves it onto an alternate orbit, which is uncommon. Nevertheless, only in low orbits the atmospheric drag is strong. The debris at the greater altitudes of the Low Earth orbit can stay in the space for decades and even centuries. This is why the notion of just letting it clear itself is impractical, it could be true on the geologic scale, but it is of no use on human ones.

Famous real-world examples: when things went wrong

Space debris isn’t a theoretical risk. Several major incidents permanently worsened the orbital environment.

1) China’s Fengyun-1C destruction (2007): the biggest debris event

The Chinese used an anti-satellite (ASAT) weapon to destroy one of their own weather satellites Fengyun-1C in January 2007. This formed the worst artificial debris cloud since the onset of the space age as described by NASA researchers.

It created thousands of tractable pieces and numerous smaller ones. It was important since the satellite was struck at such an altitude (approximately the upper LEO region), where debris may be long lived, that is, subsequent missions continue to bear the cost.

2) Iridium 33 and Cosmos 2251 collision (2009): a real accidental crash

In February 2009, a functioning commercial satellite (Iridium 33) collided with a defunct Russian satellite (Cosmos 2251). More than 1,800 pieces of debris measuring 10 cm and more were created, according to NASA, which called this the most severe accidental fragmentation on record. This incident marked a turning point because it demonstrated that unintentional satellite-to-satellite collisions can occur even in the absence of weapons testing, and that these collisions can produce persistent debris fields.

3) Russia’s Kosmos-1408 destruction (2021): when astronauts had to shelter

The International Space Station's orbit was impacted by the debris cloud created when Russia destroyed its outdated satellite Kosmos-1408 in an ASAT test in November 2021. According to an incident report posted by NASA’s Space Mission Assurance site, the seven people aboard the ISS were instructed to shelter in their Crew Dragon and Soyuz vehicles due to the debris cloud. That goes beyond "risk." That’s work disruption in real time: experiments paused, station operations shifted to safety mode, crew time consumed by emergency procedures.

How space junk hampers real work

There is no reason why collisions and debris should crash into a satellite to destroy the space economy. They generate continuing operation expenses.

A) Evasion operations use fuel and decrease missions.

A satellite operator can do a collision-avoidance manoeuvre in case they receive a warning that a piece of debris is going to fly too near them. That uses fuel.

Most spacecrafts depend on fuel to survive. All dodges may decrease the lifetime of the satellite. That is to say that a satellite may fail sooner than intended, a costly silent failure.

B) There are safety protocols that interfere with crewed missions.

The most obvious case is that of the ISS shelter in 2021: a debris caused an immediate transition between the standard working mode and the survival mode.

C) The more debris the more people are at risk.

Following major events in the making of large debris (such as 2007 and 2009) the overall hazard background increases. It also implies the increased tracking, planning, evasion and the increased expenditure of new missions.

That is why space debris is commonly referred to as a tragedy of commons: the actions of one party (or just one accident) increase the risks to everyone involved with using orbit.

How do we clean up space junk?

There isn’t a single “cleanup truck” for orbit. There are two strategies:

1) Stop making the problem worse (mitigation)

This is the best section of space debris dealing since it is much cheaper and easier to prevent new junk than to eliminate it afterwards. The Inter-Agency Space Debris Coordination Committee (IADC) and the United Nations provide global leadership on this matter. The IADC guidelines are aimed at avoiding breakups in orbit, reducing the amount of debris discharged during normal operations, proper disposal of spacecrafts after completion of their mission and reducing the chances of collision. The most famous policy is the 25-year guideline, which promotes the fall of satellite operators to pull down their spacecrafts in the orbit within 25 years of the completion of mission, thus not leaving them to linger on in the space generations. This is also the case with the Orbital Debris Mitigation Standard Practices by the U.S. Government. Practically, such mitigation tools as designing satellites to allow them to safely deorbit, passivating rocket stages through draining residual fuel to eliminate explosions, enhancing tracking and collision warnings, and employing design for demise techniques in order to have satellites burn up more completely on re-entering the atmosphere have been implemented.

2) Remove existing debris (active debris removal)

It is the difficult, costly section, but probably required with the worst things.

Active removal concepts consist of:

• Robotic capture (arms/claws)

• Nets or tether systems

• Increase atmospheric drag with drag sails.

• Techniques of nudging (experimental)

One of the largest practical attempts belongs to European Space Agency. ESA contracted (announced as EUR86 million) to buy a debris removal service (only the first in the history of the world) by Clear Space, with the goal of getting a particular debris out of orbit.

ESA is also driving towards an expanded "Zero Debris" course, an endeavour to avert fresh long-lived debris in valuable orbits by 2030 through corrected standards and innovation of technology.

Active removal is not fast, as all objects of debris are different: different orbit, different speed, different spin. Trapping garbage is as much as attempting to catch a rolling piece of debris when both of you are running just as fast as a rifle bullet, and you do not leave any more debris in its wake. So, it can be cleaned up, but not fast.

Is this a long-term problem or a short-term one?

This is a long-term issue, simply because it has three reasons:

• It is debris: At most useful altitudes, debris can remain in orbit decades to centuries.

• Crash multiplies debris: Thousands of new dangers can be formed as a result of one collision.

• Recovery is complicated: It is technically difficult and expensive to clean up old stuff; prevention is better than cure.

  
  

Even the universe is vast concept does not save us since the debris is not aiming at filling the universe. It is caught up with the orbits we move in, the low lanes our satellites and astronauts are on.

The initial and most significant example of human environmental pollution outside of earth is space debris, and it has a recognizable trend:

• It is deposited quicker than we are cleaning it.

• It distributes the expenses among all.

•    It gives rewards to short-term behaviour unless they change.

  
  

We already know some instances of debris compelling the crews to seek refuge and altered the way missions are planned. There are also very significant historic events that left debris clouds of debris that remain in orbit to this day. And we are in earnest cleanup and prevention taking, but it will not "clean it up in a night. The orbit of the earth is not infinity. It is a resource held in common, it is not a blank space as much as it is a fragile ecosystem.

And physics, as ever is in expiatory.