Originally posted 5/19/09
I predict that in the next ten years, much of the space around Earth will be inaccessible to us. With more and more debris in space, the risk of impacts due to space debris increases geometrically. There will be a cascade of collisions which will make low Earth orbit too dangerous to put expensive satellites (or people) into. It will remain inaccessible for hundreds of years or until it is cleaned up.
Today, depending on your definition, there are as few as ten-thousand or as many as one-million things in orbit around the Earth.
In low Earth orbit (LEO) everything must traveling at least 14,000 miles per hour. Impacts can happen at relative speeds of up to 35,000 mph. Visualize two cars hitting each other at a closing speed of 35,000 mph; pieces will fly off in all directions. Most of the new objects created from the collision will not be in sustainable orbits but enough of it will hang around to be a hazard to other objects in space.
If there are 10,000 objects in space, and two of them collide at high speed, there might immediately be 10,500 objects in space. That increases the chance of additional collisions and the number of objects will continue to increase.
This won't be a problem in all orbits. Because of atmospheric drag, nothing lasts for long in very low Earth orbit; so there won't be too much debris there. Of course because of the atmospheric drag it's difficult to keep a useful satellite there for long. Distant orbits and specifically geosynchronous orbits may be available too. There is a whole lot of extra room out that way and objects are generally traveling in similar directions making them less likely to collide.
Space is a tough place to get anything done. We need to do what we can to keep it from getting more difficult. Solutions are hugely expensive, but we need to study them. If cost benefit analysis is being done to examine this issue, I haven't heard it discussed.
2009/05/25
Life in Earth Orbit
2009/03/05
An Invitation to Join the Natural System
Originally posted 2008/06/29 in my old blog
Last summer I was visiting family in West Virginia and we had been canoeing. While waiting for others to catch up, I was lying on my back watching the large birds circling in a thermal on the side of a nearby mountain. There were dozens of them about a half mile away and at various altitudes, probably 400 - 800 feet. It appeared that they never moved a feather while circling in place. Beautiful to watch, especially when tired after canoeing.
Gradually, they changed positions. It appeared that they moved out of the thermal and were having to flap their wings occasionally to maintain altitude even as they descended. I wondered if the wind had shifted or if they saw some carrion which had attracted them to the new location. It seemed they were circling almost right over me.
They got lower and lower, and these birds are big. I could see them quite clearly when they were over a half mile away, and seeing them closer now, I realized that they had wing spans of three to five feet. Still thinking about why they had changed their orbits, I realized that they were looking down at me and wondering if I were available to eat yet.
After that epiphany, I got up and walked around to show just how alive I was.
The beautiful birds returned to their thermals in the mountains and I felt the closeness we have to nature deeper in my bones than I ever had before.
Long Term Thinking
There was a letter to the editor in our local paper explaining why bicycles were children's toys. It explained further that growth and consumption are the only ways forward. After thinking about it for a long while, the words I wrote were a poem of sorts.
If I had only been alive one day, I would celebrate the rising sun, but I would not know that I should prepare for night.
If I only lived one year, I would gorge at the harvest, but I would not know that winter comes.
If I only knew one life, I would gain in vigor, intelligence and wisdom, but I would not know that these gifts pass.
If I only knew my own country, I would witness its greatness climb until it was alone, but I would not know that every country of the past had gone into decline.
If there were only one planet . . . would I use it until there was no more?
If I believed God loved me, would I believe that for me there could be no fall. History, Death, Winter, Nightfall.
Can we learn that there are limits?
Can we learn to live within limits?
