On the Matter of Space Junk

SpaceAdmiral writes "Nature reports that space is in need of cleaning. From the article: 'Space could soon become too risky to visit unless derelict satellites and rockets are removed from orbit. That's the stark warning from a new simulation of space junk drifting around the Earth, and scientists are calling for swift international action to solve the problem.'" According to another astronaut there is at least one more piece of space trash they haven't accounted for. Philip K Dickhead writes "Veteran astronaut Mike Mullane claimed that the NASA Space Shuttle is 'the most dangerous manned spacecraft ever flown [...] It has no powered-flight escape system." He also accused US space officials of suppressing safety concerns raised by crew-members of shuttle flights."

Comments

Re:If we can't clean up junk, forget other NEOs.

[Jerf]

Big number fallacy; a nuke is big, sure, but let's be amazingly optimistic and assume it can completely physically clear a 10-mile radius of space junk, while not adding anything itself.

The average radius of the Earth is 3,959 miles, call it 4000. The definition of LEO orbit is from 400 to 1600 miles above the Earth. Sphere volume (close enough) is defined as (4/3)*pi*r^3.

To cover LEO, we need to cover a volume of (4.0/3)*pi*((4000+1600)**3 - (4000+400)**3) miles, which is 378,000,000,000 cubic miles (378 American billion). Our incredible optimistic nuke can "clean" (4.0/3)*pi*(10 **3) cubic miles, or 4,200 cubic miles. Dividing the (unrounded) numbers reveals that we need to set off 90,449,062 (~90 million) miracle nukes to clean the orbit.

(If you start python and type as your first line "from math import pi", those expressions will slide right into Python so you can verify them. Insignificant figures have been trimmed for presentation.)

And it's even harder than that, since the objects are moving at different speeds, and it's quite easy for objects to slip between the cracks if we don't light up the entire orbit at once.

Clearly, this is absurd, because we don't even have that many pieces of space trash in orbit, by many orders of magnitude. Because of the difference, we don't even need to do any sort of statistics to safely conclude that there are no "concentrations" of space trash that could be nuked, and we are in fact going to have to address the situation one piece of trash at a time.

Re:Make the corporations responsible..

[DerekLyons]

What sounds like the bigger problem is all the tiny hard to track fragments, the sort of stuff created when stages of a rocket seperate explosively. Here, perhaps, more work could be done in developing rockets and satellites that don't shed this sort of garbage.

Well, welcome to 2006 - where not shedding debris has been the gold standard for a decade and more. Contrary to the TFA, the problem *is* being adressed. Among other things, every major rocket manufacturer has modified stages of theirs that will be left in orbit to depressurize themselves at the end of the burn - no pressure, no breakup. Every major rocket manufacturer has replaced their seperation systems with ones that don't shed parts.