Several days ago, Russia’s space probe the Phobos Grunt crashed to earth somewhere. The trouble is, as ABC News points out, we’re still not sure where exactly it landed. Billed as one of the heaviest pieces of space equipment to fall to Earth yet, the 170 million dollar craft was also the most toxic; it contained a large amount of rocket fuel that in theory would have burned off on reentry.
Calculations done by the Russian Defense Ministry showed that the debris would fall in the Pacific Ocean off Chile’s coast, and that it was assumed that the craft broke up in orbit somewhere over Brazil. No eye-witness reports have surfaced of the crash, nor did Brazil report any debris landings or sightings.
The bigger question that remains as yet another very expensive and very large piece of space real estate crashes to Earth in flames is, why can’t we predict better where these things are going to land? Various defense and space agencies have been able to guess a huge swath and latitude and longitude that generally covers the entire livable expanse of the planet. At best, inhabitants will have scant hours of warning before a swath of flaming debris hundreds of miles long (in some cases) peppers their yard.
The answer to the question is pretty simple; it’s all about our sun and upper-atmospheric winds. Solar activity like rays and solar wind can knock around a space object quite a bit; a satellite without the means to fine-tune its orbit can quickly find itself spiraling into Earth’s gravity and being pulled down.
Once the object has entered Earth’s atmosphere, its mass can create drag and the wind in the upper atmosphere can be volatile, slowing or accelerating the object’s descent considerably. A trajectory change of a scant few degrees can translate into hundreds of miles of variance, so a couple hours of warning is probably the best we’ll ever be able to get, unless technology can somehow tame the randomness of the Sun and wind here on Earth.
I’m not sure about you, but I didn’t take any chances. I brought an umbrella with me throughout the day; the forecast was clear and cold in my neck of the woods, without much chance of a falling space object. One can never be too sure, though.