Yes, the sky is falling. Recently, there have been several instances of large satellites and other objects that have been deliberately put into orbit coming down.
On September 24, 2011 a bus-sized US satellite plunged to earth, scattering its debris “harmlessly” near Calgary in Canada. On October 23, 2011, a car-sized German spacecraft fell uncontrollably to earth, hitting Asia “somewhere”. . In March, 2011, a hiker in Northwestern Colorado encountered some space junk and a crater, and reported it – first to military aerospace officials, who told him to call the local sheriff. He eventually got through to NASA after getting quite a run-around. It turned out to be part of a Russian Zenit-3 rocket launched about 2 months earlier.
This seems to be becoming a regular event.
The latest event is that a Russian spacecraft headed for Mars did not go off properly. It is orbiting the wrong planet. Instead of orbiting Mars and its moons, as planned, it’s orbiting earth, in a decaying orbit. As if having this large object coming crashing to earth “in a couple of weeks” is not enough, there is concern over its fuel – whether it will remain liquid or if it will freeze. If it remains liquid, it will probably explode high in the atmosphere. “Harmlessly”, but then again what will it leave in the atmosphere, and how will that effect such things as the ozone layer? If it freezes, this fuel which is extremely toxic, could hit the ground.
Yes, it is most likely to hit the oceans, simply because 4/5th of the earth is covered in oceans. But, oceans are not “desolate” or “vacant”. There are islands in oceans, there are ships on oceans, and there is marine life. If something large enough hits an ocean at a high enough velocity, it can lead to tidal waves, and if large enough at a high enough velocity, could stir up enough debris into the atmosphere to cause an extinction event, such as what happened to the dinosaurs 65 million years ago when a meteorite hit near the Yucatan or , although this theory is not without its detractors, including a different asteroid or comet strike off the coast of India that may have caused the same sort of problem.
This is not the first time, nor is it expected to be the last time that manmade objects have hit earth. Some of them just hit the earth, and some left such things as toxic or radioactive debris or dust. For five of these events over the past few decades, see
Objects directly hitting earth are only part of this risk. In 2008, the Russian Mars-96 spacecraft crashed in the Andes Mountains and sprinkled some nuclear material. The risk could be nuclear, could be toxic, and could be reduced to dust and spread anywhere on earth through weather patterns.
The articles proudly state that no one has ever been injured by a piece of falling space debris. A few erroneously claim that no one has been hit by such a piece of falling space debris. Lottie Williams of Oklahoma was indeed hit by such a piece of debris from a Delta II rocket in 1997.
There are many many such objects, which will eventually come plunging to earth. It’s a matter of probability about whether they fall over sea, land, in remote, or in a populated area. Even hitting in the ocean or in a remote area simply means that fewer people are at risk from that piece of debris: People exist in remote areas. In a populated area, it’s just that more people are going to be hit. There was fear while the German spacecraft was flying over Asia – and radar lost track of it for awhile – on whether it might hit Hong Kong, or any of several other cities in China near the Pacific coast. Or, possibly a city on the Pacific coast of the United States. This one didn’t. It’s a matter of time. We’re playing a sort of planetary-wide game of “Russian Roulette” with these large pieces of “space junk”, or derelict spacecraft. There are international treaties to make future objects launched into space less durable for a re-entry, but that only applies to future launches, and only to countries which have signed the treaty.
Is it possible to clean this junk up, and to ensure that no further “junk” goes up into orbit with potentially cataclysmic consequences, without a complete ban on putting objects into orbit, which may be impractical with today’s dependence on technology?