We’re considered the most intelligent beings on this planet, discovering new things, inventing new things, and exploring our nature. We have built magnificent buildings, wonderful monuments, a great transport system to explore and many more. Even though we use our brains to the fullest, we have a very bad habit, we throw waste anywhere. Be it land, water or space, humans have deposited waste almost everywhere. And this bad habit is now coming back to haunt us. Be it land, water or space, mother nature is now giving back everything been we were disposing of her, space debris.
What’s Space Debris?
Space waste left by humans to roam around aimlessly. It can range from a small nail to huge satellites. There is about 100 million debris about the size of 1mm and some are even smaller (micro-debris) about 0.0009 mm. About 22,000 debris are the size of a football. Some are even bigger than Burj-Khalifa (the tallest building on planet Earth).
Space Debris comprises both natural and artificial waste. Natural means meteoroid which revolves around the sun, and artificial means human-made waste which revolves around Earth. This is also called Orbital Debris, as the human-made waste revolves around the Earth, only. Orbital debris is human-made objects which are now are of no use in exploring space. These are as nonworking satellites, fragmentation debris, non-functional space stations and many more. We will discuss more on the human-made waste.
Types of Space Debris
In the previous paragraph, it was clear that we have mainly 2 types-
Based on how that reached in the first place, artificial debris can be further broken down into:
- Nonfunctional satellites– Generally a satellite’s lifespan is nearly 10-12 years depending on the job it’s assigned, but after that point, satellites lose their connection from the earth, and now will be pulled towards Earth as satellites don’t have any power on its own.
Most satellite parts get detached by the force of experience and enter the atmosphere before reaching us, but some parts are made fireproof and thus reaching the surface of Earth. As Earth is 70% water, so maximum time the debris are reaching the water bodies.
- Fragmentation debris– As the spacecraft passes over the atmosphere, it disassembles, flying free of its fuel tanks through the atmosphere and landing in water bodies. Sometimes, detached fuel tanks enter into an orbit. Thus they also roam around the orbit increasing the concentration of debris.
Concentration Of Debris
There are mainly 2 types of concentration, one around LEO and GEO and the other in between them.
LEO (Low Earth Orbit) is about 400-500km from the surface of Earth, and in this range space stations and clicking photos of Earth, satellites are there. In this range, the concentration level of debris is highest as most of the spacecraft crosses the atmosphere and detach everything. Debris is mainly small paint chips, nails, nonfunctional satellites.
GEO (Geostationary orbit) as the name suggests objects in this range match the orbital speed of Earth and appears to be stationary. It’s 35,787km from the Earth, the main use of GEO is that we use satellites for telecommunication, as they appear to be stationary, we can establish an antenna for communication. In GEO, the concentration level is low as compared to LEO as LEO is the most common use range. Debris is mainly of nonfunctional satellites.
And in between these 2 ranges, debris concentration is comparatively low. As Earth’s gravity attracts them, their orbit is shifted from GEO and they slow down in entering Earth’s atmosphere.
Let’s check the numbers
More than 12,000 satellites have been launched into orbit since the start of sending spacecraft in space. But the rate of launching is growing exponentially and therefore space is about to get much busier. The Department of Defence’s sensors (Global Space Surveillance Network (SSN) sensors) have discovered more than 27000 debris. Many more are too small to followed. Thus they are more harmful especially for human spaceflight. Both the spacecraft and debris are travelling at around 25000kph and thus even a tiny piece can be very harmful to the spacecraft.
Damages caused by Debris
It’s now clear that the most harmful debris in space is the smallest one. Large numbers of spacecraft’s windows were replaced as the damage analysed was found to be of paint wrecks.
- In 1986, a French rocket has explored and its waste was roaming around Earth, and a decade later, a French satellite was hit and damaged by debris.
- Year 2007, China launched an anti-satellite test that aims to destroy the nonfunctional satellites. A missile was launched, destroying an old weather satellite. Yet, due to this concentration increased even more as more than 3,000 trackable large debris were formed.
- Feb 2009, a proper collision happened. It was between a defunct Russian satellite and a functional USA commercial satellite. This collision added more than 2,500 trackable large waste and much small debris which was not trackable.
How Spacecrafts will survive in Space Debris?
Department Of Defence’s Space Surveillance Network tracks ones as small as 5cm in diameter in LEO and about 1m in GEO. There are about 27,000 officially catalogue objects in orbit and many of them are 10 cm or larger. For ones less than 10cm, they use special ground-based sensors to inspect the returned satellite and predict the extent of the population of this small debris.
Collision risks are categorised into 3 parts depending on their size-
- For size 10cm or greater, we use collision avoidance and conjunction assessments maneuvers to take our shipcraft safety in between them. DoD’s Space Surveillance Network tracked these .
- SSN can’t track for size less than 10cm. Thus it can’t be comprised.
- For size less than 1cm, spacecraft use Debris Shields for withstanding the damage caused by these debris’.
Solution to Space Debris
All the solutions which are listed below are still in the training phases. Space waste will be reduced at a magnificent rate, after the successful testing of these methods,
- Use of robots is a technology which will be launched in the near future. These robots will self replicate themself and destroy these debris. This technology is still under progress and all the nations must fund this technology so that we can explore more in the space without much hindrance.
- Net capture– Net will be thrown to catch all the debris in the target area. Debris will then to reduced to smaller ones. After that the net will guide these debris towards the Earth’s atmosphere where they will be burned before reaching the surface.
- Harpoon capture – Same method as net capture then, but in this with the help of harpoon(spear) will be thrown to catch the big ones and repeat the same as with the net capture.
- Vision-based Navigation– All the debris after being captured by net or harpoon will be guided towards Earth’s atmosphere using vision based navigation. This navigation will directly send data to Earth by using cameras and light detection. Spacecraft will send an object which will use this navigation and guide the it towards atmosphere to destroy them.
We still have a long way to go in cleaning this space , but we are starting now. We have realized the importance of cleaning our space so that we can explore more in outer space. It’s not the work of one organization like NASA, ISRO, etc. We have to complement each other because in the end it will a human who will explore further in space, no one will say ISRO’s astronaut has stepped foot on Mars, we will say we humans have stepped down on Mars.