Sleeping Space Debris

Sleeping Space Debris 

There is nothing cooler than space. It’s the next frontier for human civilization and the progress we’re making should get everyone excited. I’ve been watching the new Netflix series on Inspiration 4 and needless to say, I’m inspired. Yet there are still so many challenges that remain if we want to continue to develop our space infrastructure and eventually colonize the great beyond. Perhaps no bigger than cleaning up space debris. There are currently 34,000 objects orbiting in space, only 29,000 of which are trackable with reasonable accuracy. 96% is a pretty good accuracy but things continue to get crowded up there. In 2011 there were ~965 satellites in space. In 2021 there are 4,500. This is a number that will continue to grow as cheap satellites are a booming business, a la Planet Labs. 

The worst possible situation we could experience in space is something referred to as a Kessler effect. This is a theoretical scenario in which the number of objects in low Earth orbit (LEO) due to space debris is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. One potential outcome is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbits difficult for many generations. That would be most unfortunate. If it happened in LEO it would wipe out the entirety of SpaceX’s Starlink satellite network, new Earth observation companies, and advanced monitoring systems. It would also make it virtually impossible to get objects or people to get to orbit. I’ll need to explore the idea of redundancy for space systems in the future.

It’s a good thing we’ve invested in monitoring capabilities. Radars operated by the US DoD and private enterprises are what we predominantly rely on. A big advancement on the military side has been the “Space Fence” which is a radar system based on the Marshall Islands that can make close to 2 million observations every day. Many of which are objects just 5cm across, which is about the length of a AA battery. Being able to detect those objects via radar from the ground is amazing in-itself - however, we still have to try and predict where these objects will actually go next. In order to predict an object's future orbit, the position must be recorded several times, to observe how its path is being altered by the gravitational pull of the Earth, Moon, and sun, along with the pressure from solar radiation and if you’re looking at LEO, the drag of occasional wisps of air from the upper atmosphere. All those data points are computed to give a predicted path which we hope is accurate. This is essentially Iron Dome, but applied to Space. This data is already used to reposition satellites and prevent collisions.

Orbital tracking and debris clean up are two areas to keep an eye on if you’re interested in space. There are proposals for satellites that can go up and act as a space sweeper of sorts, deploying a collector pod to grab the debris then reconvene with the main unit. There are companies attempting to use lasers to eliminate rogue pieces. There are private companies that do observation both on earth and via satellites already up in space are selling data to make it easier for operators to alter flight paths away from debris. Orbital tracking has a very interesting national security consideration which I have to mention. By projecting an object's orbit, you can also detect when it deviates, potentially revealing the potential for an attack. Scott Norr, an expert at Lockheed Martin who works with Space Fence, gives the example of an object that appeared to be debris from a Russian military launch. In 2014, the debris started moving suddenly, triggering fears that it could be an anti-satellite weapon. These types of sleeper cell debris may exist already - and who knows how many of them at that.