It seems as though whenever I use the word, BELIEVE, in an article, I’m inundated with critical email from the unwavering religious. I deserve it, of course, because I’m highly critical of “blind believers” and “seeing deniers.”
But, this isn’t about religion; so, relax. If your driving force is a need to “believe,” join a church. But, if it’s a will to discover, join a science group.
This past Thursday, two local high school seniors were discussing a research assignment (The Dangers of Space Junk: real or imagined) that their physics teacher had given them as a means of receiving a few extra credit points. It’s due by mid-March.
The two of them had thoroughly researched the subject through newspaper and magazine articles, as well as several legitimate scientific sources via the Internet.
While their well-researched conclusion that debris floating around in space close to Earth poses a major problem for space travelers, from the United States or otherwise, it lacked some needed perspective—as much high school research usually does.
I introduced myself and told them that I would update a previous article I had written on the subject and post it this Sunday (today) if they were interested in some additional research.
So, here it is. Eric and Jason, feel free to include it in your final draft. You have my full name, home address and telephone number if your teacher wants to verify your sources. I hope it helps.
We’re no longer launching space shuttles; but, we’re still sending our own astronauts to the International Space Station via Russian–built Soyuz space craft.
So, relative to the human component, the danger from floating space junk has not changed a bit since I wrote my original piece. In fact, in absolute terms, it’s become worse! But, what about context?
Our best estimate is that between 4.5- and 6-MILLION pounds of human-made space garbage, including over 3,200 burned out booster rockets, is floating around up there within 1,200 miles of Earth’s surface.
The United States Air Force currently tracks about 9,000 sizable pieces of space junk. But, there are other pieces too small for radar detection.
However, it’s all floating around out there in different orbits, at varying altitudes—although at the same speed but often in opposing directions—as an orbiting shuttle or space station: about 17,500 miles per hour.
So, if even a small piece hits an orbiting space vehicle—think of a space shuttle or the International Space Station—the combined speed of the collision’s going to be around 35,000 miles per hour.
Imagine yourself driving along I-95 at 60 MPH and a piece of debris the size of a standard baseball hits the grill of your car at the same speed. The combined impact velocity would be 120 MPH. Get the picture?
So, even a small piece of junk could ruin an astronaut’s day. We don’t even want to discuss what a large piece could do! But, even still, we have to put it in perspective.
Space is mostly empty; it’s why we call it space. Plus, all the junk we’re tracing is whizzing around in different orbits at different levels up to about 1,200 miles above the Earth.
Our space shuttles used to orbit at altitudes between 180- and 200-miles above Earth. The International Space Station orbits between altitudes of 205- and 250 miles. But, for this piece, we’ll just arbitrarily pick an altitude of 200-miles.
We can’t consider ONLY the absolute amount of space junk whipping around at different altitudes. We must ALSO consider the average DISTRIBUTION of the debris, which requires analyzing the surface area of a sphere as calculated by 4 times TT times R2. TT is pi and R is radius.
We can sloppily round TT (pi) to 3.14. The radius (R) is equal to the radius of the Earth (3,950 miles) plus 200 miles (the altitude we’re considering). The total comes to 4,150 miles.
Simply apply the above formula to arrive at the area of an imaginary surface at 200-miles above the Earth: 216,314,600 square miles.
If we divide this by those estimated 10,000 pieces of debris (assuming they’re ALL in the same orbit as our space vehicle—they’re NOT!), we should expect to encounter one—not necessarily collide with it—about once every 21,632 square miles.
Want more perspective? Delaware is the 49th largest state in the nation with a land mass of 1,954 square miles. One could drive the state’s entire length 11 times without even seeing another vehicle on the road.
Or, looking at it another way, the contiguous land mass of the United States is 3,537,441 square miles. One could drive from New Jersey to Los Angeles while encountering only about 164 other vehicles. And, even at this, a collision is not inevitable.
In fact, relative to a low Earth orbital collision with space debris, one is not likely given our country’s ability to detect such things with time to maneuver our space craft out of harm’s way—including the International Space Station.
Mind you, I’m not trying to make light of the potential problems from space debris. It’s a cumulative problem that virtually guarantees a catastrophe if we don’t clean the place up every now and then.
The point is that EVERYTHING has context. We can’t realistically evaluate our problems to arrive at practical solutions without considering the context. And, this applies to ALL of humanity’s problems, not just to ours here in America.
Joe Walther is a freelance writer and publisher of The True Facts. Email comments here.