Hi Folks,

Climbing out of the mire of Brexit, I want to raise my sights a little higher to look at Space Junk.   Years ago, I used to watch a dark, but quite amusing TV program called “Dead Like Me“.   Starring Mandy Patinkin and Ellen Muth, it had an interesting story line. It seems  certain people when they die are invited to become “Grim Reapers”.  They get to stay on the earth in virtually indestructible bodies but with a different appearance to their old mortal body. Once they collect a requisite number of souls, their job passes on to the last soul on their list and they, presumably, pass on to heaven.

Georgie, or George as she prefers to be known, played by Ellen Muth,  is the latest member of the Grim Reaper team in Seattle. She joins their ranks after being hit on the head and killed by a flaming toilet seat that had  fallen to earth from Space.  Sounds very far fetched I know. No, not the Grim Reaper bit, the falling toilet seat bit.  But is it?  I ask because it seems the space around the earth is rapidly becoming a celestial rubbish dump.  It’s full of space junk. So where is all this space junk coming from and what happens to it?

Space Junk

At this very moment, there are some 5,000 artificial satellites whizzing around the earth.  In 2009, around 500 miles over Siberia, two satellites collided at a speed of nearly 22,300 mph.  As you might expect, there wasn’t much left of them after the crash. What was left is a cloud of thousands off pieces of high energy debris.

NASA reckon there are more than 23,000 known bits of man made junk with a diameter larger than 4″  whizzing around the planet.  These are just the bits we know about. They also estimate there are probably more than 500,000 bits, smaller than 4″ joining those larger fragments.

4″ is about the width of 2 golf balls, which doesn’t sound that big. The problem is the incredible speed they are travelling at. A bullet travels at less than 2,000 mph. So with a velocity of more than 20,000 mph, even the tiniest piece of junk can inflict damage if it hits something.  Most satellites and orbiting telescopes have pits and dents from these tiny particles smacking into them. In 2006, a tiny piece of debris hit the International Space Station (ISS) and took a large chip out of the heavily reinforced window.   But what is all this space junk? Is it all bits of dead satellite?

What is Space Junk

Since man first started to explore space, we have been leaving rubbish behind.  This included the stages from rockets. Everyone will have seen footage of the old Saturn 5 rockets, jettisoning spent fuel stages as they took off and broke away from earth. This still happens with rockets launching satellites, today.  Last year nearly 400 new satellites were launched. 2017 was a record year with well over 400.  This year there will another 400 or more.   That’s a lot of rocket stages being left behind.  These satellites will eventually die, but still carry on orbiting around the earth.

The rocket stages and satellites are pretty big and easy to track. The real problem is the smaller bits. In 2007 China destroyed an old, dead satellite in an anti satellite missile test. India did the same in March this year.  Debris from these tests is up there, orbiting around the earth and is estimated to have increased the risk of collision with the ISS by 44% over a 10 day period.  At least the ISS can manoeuvre out of the way if it has warning.

Other space junk is believed to include paint flakes, ( yes even a flake of paint can cause damage), nuts and bolts, garbage bags, a lens cap, a screw driver  and also a spatula.  Honestly, you can’t trust people to be tidy anywhere these days.  And on the subject of people in space, there is some very unsavoury flotsam flying around up there thanks to them.

People and Space Junk

In the early days of space exploration, the US and the Russians had the likes of Uri Gagarin and Alan Shepherd, popping into space for just a few hours. Later, astronauts would stay for a few days, orbiting the earth.  Nowadays, with the ISS, there is a more or less permanent presence.   People, even astronauts in the ISS generate waste and I am not just thinking about empty food wrappers. They all have to go to the loo.

Space Conveniences

I have never tried it, not many people have, but I bet pee’ing and pooping in zero gravity is a bit of a challenge. Hence the space station loos are a bit more complicated than those on earth. They still flush. Sort of. But with air, not water.  It’s not a pleasant topic to dwell on, so lets press on quickly. No. 1’s tend to be recycled up there these days.  The astronauts eventually drink their recycled urine once it’s been processed into potable water.  No. 2’s are bagged and kept in a solid waste recepticle that is emptied every 10 days or so.  This solid waste ends up getting ejected and, hopefully burns up in the earths atmosphere on reentry. Thats not a shooting star you want to wish on, or be underneath.

Thats now, but it wasn’t always like that and its probable that some of the space junk hurling around the earth is the frozen waste from  relieved astronauts.  Traveling at 10 times the speed of a bullet, you definitely wouldn’t want to be hit by that. Doesn’t bear thinking about.

What to do?

Can we do anything about all this space junk?  Not a lot. There have been various ideas put forward over the years. One such idea is snag big pieces with a harpoon like device. This was actually tested in February this year by the imaginatively entitled satellite, RemoveDEBRIS.    It worked, so it is possible. But only for big bits.

Another idea was to use a magnet type device or a big net. Yet another to zap the debris with a powerful laser to vaporise it.  All of these ideas are expensive and subject to being misused, which could be a problem. If a reliable method could be found for capturing or zapping debris, theoretically, it could also be used to capture or destroy rival satellites. That would be considered bad and lead to all sorts of issues we could do without , thank you very much.  We may have to mature as a race a little more and learn to trust each other before we go too far down that road.

Space Convention

Other more practical problems are the velocities involved and a lack of convention.  We have already established this space junk is travelling at stupid speeds. Hold a net out to catch a piece as it flies past and it is going to destroy the net, harpoon, magnet, whatever. Matching speed is the answer. If you are travelling at the same speed as the debris, then relatively speaking it isn’t moving so would be easy to capture.  However, there is no convention on which direction you can orbit around the earth. Not everything travels in the same direction.  The junk could be coming at you from every which way.  That might be a problem and one we haven’t really gotten to the bottom of yet. Space junk looks set to be whizzing around us for some time to come.

The Impact of Space Junk

Of course,  over time big bits of space junk break down into smaller bits. As the orbits of the space junk decays, it will eventually fall back to earth and the vast majority will burn up.  Bigger bits may make it through the atmosphere and hit  the earth. Just like Georgie’s toilet seat from “Dead Like Me. ”

We believe around 80% of the  debris that hits the atmosphere is destroyed.  That means 20% gets through and could potentially be lethal.  It’s a testament to how much of the earths surface is water and how sparsely populated the rest of it is that so far, no one has been killed by falling space junk.  In 1969 five sailers aboard a Japanese vessel were injured by falling junk and in 1997 a woman in Oklahoma was grazed by a piece of falling rocket.  But as the population increases and more and more debris is left behind, the odds must be shortening.  It might all get much worse very quickly if Donald Kessler’s scenario comes to pass.

The Kessler Syndrome

Have you seen the rather good film, “Gravity” starring the wonderful Sandra Bullock?  If you did, you will remember that Bullocks character is on a space walk when her shuttle is destroyed by space junk.  Things get progressively worse as the debris from her shuttle starts to impact and destroy other shuttles, satellites and structures.  Fortunately the lovely Miss Bullock makes it back to earth safely. Phew.  However, that in a nutshell, is the Kessler Syndrome.

In 1978 Donald Kessler proposed a scenario in which there is so much junk in orbit, collisions start to occur regularly. These collisions create more debris which in turn cause more collisions and the whole thing cascades.  It eventually reaches the stage where the area of space around the earth where these collisions are occurring becomes unusable.  This is likely to be the area 800 to 1500 kms above the earth where the majority of satellites are located.  We could place new satellites higher, but then the transport vehicle has to negotiate its way through this hostile debris field.  Going lower is a possibility but things would get cramped very quickly. At least there is a greater chance of the debris falling out of orbit and burning up.  Or hitting you in the head.

The Future

With our growing reliance on the internet and requirement for global communications, we are going to see more and more satellites in space. All kinds of countries are putting up their own satellites and not only countries. Corporations and even individuals are joining in. Elon Musk, he of Tesla fame also operates the Starlink satellite network with over 60 satellites in space.

This means there is going to be more space junk rather than less for the foreseeable future.  As usual we have started to think about the problem after the event rather than before it became an issue. I am sure in time we will come up with a workable solution, but in the meantime, watch out for falling toilet seats.

 

Graham Wannabe, September 27th 2019