From: Amara Graps (amara@amara.com)
Date: Wed Jul 17 2002 - 02:04:19 MDT
Amara Graps:
> This is kinda what it looks like (see map of orbiting debris)
>
> http://www.wstf.nasa.gov/Hazard/Hyper/debris.htm
>
> Good luck with the clean up! :-(
Adrian Tymes:
>It's not as bad as it looks yet. Remember that the scrap is actually
>far, far smaller than each one of the pixels. If they were to leave
>empty and pixel with less than 50% obstruction, they'd have an empty
>map.
>That said, the map certainly makes a good dramatization of what
>could be.
dramatization?
Well, truthfully, I don't know if that graphic is the result of debris
_measurements_ or debris _modeling_. I thought it was debris
measurements, but I could be wrong. Measurements are a tricky business
in the micrometeroid studies, you have to be careful about particle
sizes and techniques and lifetimes.
Measurements
http://www.orbitaldebris.jsc.nasa.gov/measure/measurement.html
Modeling
http://www.orbitaldebris.jsc.nasa.gov/model/modeling.html
Here are some larger resolution graphics of the animation that I pointed
to earlier:
Orbital Debris Graphics
http://orbitaldebris.jsc.nasa.gov/beehives.html
http://orbitaldebris.jsc.nasa.gov/graphics/beehive3.jpg
I would be alarmed if I were you, but maybe I'm an alarmist about our
Earth environment. The following is some data for you.
--------------------------------------------------
From this text
"Orbital Debris: A Technical Assessment"
available on line through the National Research Council.
http://pompeii.nap.edu/books/0309051258/html/index.html
Page 63
Debris Population Distribution
As discussed in Chapter 2, a variety of techniques have been developed
to characterize the orbital debris environment, but a high level of
uncertainty remains in our understanding of the debris population. While
extensive data have been acquired on the cataloged population, cataloged
objects represent only a small fraction of the debris in orbit;
estimates of the populations of uncataloged debris are based on a
limited number of sampling measurements tied together with models. Any
estimates of the overall debris population are thus uncertain; they are
likely to change as new data are acquired. Figure 3-1 presents one
estimate of the total number of objects of various sizes in LEO, based
on various measurements. Table 3-1 estimates the total orbital debris
population in each size range and the fraction of the total mass in
orbit contributed by objects in each size range.
Large Debris
The best-known segment of the debris population is the population of
cataloged large debris. Figure 3-2 is a "snapshot" depiction of the
location of all cataloged debris at a particular moment in time. Some
features of the distribution of the cataloged debris population can
already be seen in this figure, including the concentrations in the GEO
ring and in LEO. Figure 3-3 quantifies Figure 3-2 by portraying the
approximate spatial density of cataloged objects at various altitudes.
Clear concentrations can be seen at less than 2,000-km altitude (LEO),
around 20,000 km (semisynchronous orbit), and at 36,000 km (GEO).
The figure here might interest you. "FIGURE 3-1 Number of objects in LEO
as estimated from various measurements."
http://books.nap.edu/books/0309051258/html/64.html#pagetop
--------------------------------------------------
More Information
"Technical Report on Space Debris"
Text of the Report adopted by the Scientific and Technical Subcommittee
of the United Nations Committee on the Peaceful uses of Outer Space. (UN
Document: A/AC.105/720)
http://www.oosa.unvienna.org/Reports/AC105_720E.pdf
Frequently Asked Questions About Orbital Debris
http://orbitaldebris.jsc.nasa.gov/faq/faq.html
Modeling Orbital Debris Problems
Student Exercises
http://illuminations.nctm.org/lessonplans/9-12/debris/
-- ******************************************************************** Amara Graps, PhD email: amara@amara.com Computational Physics vita: ftp://ftp.amara.com/pub/resume.txt Multiplex Answers URL: http://www.amara.com/ ******************************************************************** enscarfment n. a food break at the edge of a cliff.
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