Opinion | Seth Shostak: Why the Chinese space junk that crashed to Earth should worry scientists. - NBCNewsTHINK
. Sure, half of them are dead, but that distinction will be of little consolation if one punches through your roof. With so many objects above our heads, the rain of debris will continue.
However, there are cures for this growing threat. Imagine fitting every large satellite with an auxiliary thruster. When the satellite reaches its use-by date, the thruster fires and kicks the defunct satellite upstairs, to a roomier graveyard orbit where the atmosphere is far thinner. It could safely hang out there for millions of years, out of sight, out of mind and hopefully out of the way.
Of course, installing this kind of system in everything that rolls on to a launch pad costs money — both the direct expense of the necessary technology and the opportunity cost of sacrificing additional payload. But countries might agree to do this, considering it a tax for the common good.Other proposals don't require individual buy-in. For example, the space industry could buildfitted with giant nets or harpoons to collect debris.
In any case, doing nothing about space junk won't be an option much longer. That's because of a destructive chain reaction described by NASA scientist Donald Kessler in the late 1970s. As the density of space junk increases, the chance of collision also increases. And collisions produce more debris, which leads to yet more collisions.