Friday, February 16, 2007

Ground Control To Major Tom

I meant to post about this over the weekend, because I was watching "Arsenal of Hypocrisy" FreeSpeech TV on DISH Network (channel 9415, and really, if you aren't a DISH Network subscriber, you're missing out on two of the best progressive media outlets in the nation).

"AOH" deals with how the public has been misled about the origins and true purpose of the Space Program. Not saying I agree with all the premises and/or conclusions of the producers, however some of the evidence is compelling and it is a must-see, because it was during this show I discovered something I had not know, something that affects me personally. And you.

I missed this story on Sunday, which would have nailed it down that I needed to post about this:
For decades, space experts have worried that a speeding bit of orbital debris might one day smash a large spacecraft into hundreds of pieces and start a chain reaction, a slow cascade of collisions that would expand for centuries, spreading chaos through the heavens.

In the last decade or so, as scientists came to agree that the number of objects in orbit had surpassed a critical mass -- or, in their terms, the critical spatial density, the point at which a chain reaction becomes inevitable -- they grew more anxious.

Early this year, after a half-century of growth, the federal list of detectable objects (4 inches wide or larger) reached 10,000, including dead satellites, spent rocket stages, a camera, a hand tool and junkyards of whirling debris left over from chance explosions and destructive tests.

Now, experts say, China's test Jan. 11 of an anti-satellite rocket that shattered an old satellite into hundreds of large fragments means the chain reaction will most likely start sooner. If their predictions are right, the cascade could put billions of dollars' worth of advanced satellites at risk and eventually threaten to limit humanity's reach for the stars.
OK, fair enough: near-earth space is full of debris, most of which would burn up upon re-entry anyway, and couldn't we simply move the working satellites to higher orbits?

Well, there are other concerns we have to address:
The United States has launched 22 missions with RTG (Radioisotopic Thermoelectric Generators) power sources. Three accidents have occurred, though only one has resulted in release of radioactive materials.
That release?
In the single instance of radiological release from a U.S. NPS, the RTG performed as designed. The SNAP 9-A RTG (Space Nuclear Auxiliary Power) was launched in 1964 aboard a Department of Defense weather satellite that failed to achieve polar orbit. The SNAP 9-A, designed to burn up and disperse its nuclear inventory in the upper atmosphere during re-entry, performed as planned. The release of radioactive materials was measured by scientists from the Atomic Energy Commission in air and soil sampling efforts.
Care to take a guess at what it's fuel was?

Plutonium, specifically, two pounds worth. The dispersal? Worldwide by the year 1970. No place on the planet was left untouched by this most deadly of radioactive materials:
[P]lutonium may be extremely dangerous when handled incorrectly. The alpha radiation it emits does not penetrate the skin, but can irradiate internal organs when plutonium is inhaled or ingested. Particularly at risk are the skeleton, where it is likely to be absorbed by the bone surface, and the liver, where it will likely collect and become concentrated. Approximately 0.008 microcuries absorbed in bone marrow is the maximum withstandable dose. Anything more is considered toxic. Extremely fine particles of plutonium (on the order of micrograms) can cause lung cancer if inhaled.
Not good. Not as bad as we were led to believe all along, but still, not something I want to walk around inhaling. Given that plutonium's half-life is either 88 years (Pu238) or 25,000 years (Pu 239), I think it's safe to say we're all walking cancer machines. It doesn't surprise me that 100% of men develop prostate cancers, if they live long enough. Goodness knows what else we've ingested.

So this is a pretty important issue (thanks, "Arsenal of Hypocrisy"!), since there are at least another 19 United States nuclear satellites orbiting the planet, and goodness knows how many former Soviet satellites. What to do about it? Call in "The Terminator" is one solution. Once the satellite's active life has passed, the Terminator will automatically extend a tether down to the atmosphere, which would then drag and slow down the satellite, bringing it into the atmosphere. Obvoiously, this is not something we want to do with nuclear-powered objects, but it will clear significant amounts of non-nuclear debris which might collide with nukes. One other use of tethers might be to fling satellites to higher orbits, and perhaps out of earth's gravity well and into the sun.

Stay tuned. This is one of those problems we don't think about that will come back to bite us in the ass.