What Goes Up Must Come Down

Here’s the problem. When you’ve got an object as big as this 10-ton satellite, some of it will survive the plunge to Earth. That’s especially true when there are hardened pieces.

mir_atmosphere.jpgIt looks like a US spy satellite is out-of-control and will soon plunge back into the Earth’s atmosphere. It’s happened before.

I remember when Mir plunged to Earth. The photo on the left shows what was left as the debris passed over Fiji.

Back in 1979 pieces of Skylab fell on Australia. No one was injured.

The question is, is this dangerous? Uh… yeah. Though there is some conflict in that opinion.

I just checked Google’s news site and found “Falling US satellite is not dangerous – NASA” from Russia’s Interfax news agency. That’s a relief.

Oops. Hold on. Here’s what the Times of London says: “Threat as 10-ton satellite set to crash back to Earth”

So, it’s either not dangerous or a threat. Got it?

Here’s the problem. When you’ve got an object as big as this 10-ton satellite, some of it will survive the plunge to Earth. That’s especially true when there are hardened pieces.

From the New York Times:

John E. Pike, the director of Globalsecurity.org in Alexandria, Va., said that if the satellite in question was a spy satellite, it was unlikely to have any kind of nuclear fuel, but that it could contain toxins, including beryllium, which is often used as a rigid frame for optical components.

The speculation is this is a spy satellite, launched in 2006 and quickly lost. It probably went up with hydrazine for thrusters. That’s really nasty stuff.

When properly used in space:

The catalyst chamber can reach 800° C&#185 in a matter of milliseconds, and they produce large volumes of hot gas from a small volume of liquid hydrazine, making it an efficient thruster propellant.” – Wikipedia

When improperly encountered on the ground:

Hydrazine is highly toxic and dangerously unstable, especially in the anhydrous form. Symptoms of acute exposure to high levels of hydrazine in humans may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, coma, and it can also damage the liver, kidneys, and central nervous system. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals. Effects to the lungs, liver, spleen, and thyroid have been reported in animals chronically exposed to hydrazine via inhalation. Increased incidences of lung, nasal cavity, and liver tumors have been observed in rodents exposed to hydrazine. – Wikipedia

The Earth is mainly covered by water. Even the land portion of Earth is sparsely populated in most spots. The odds of anyone getting hurt is small.

However, the more stuff that falls down, the worse those odds get.

&#185 – Here in the US, we use Fahrenheit. 800&#176 C is about 1,500&#176 F.

For perspective, aluminum melts at 1218&#176 F. Most other ‘substantial’ metals have significantly higher melt points.