Why are Satellites so Important?-part 2 (4 of 9)

Satellites are also used to observe space, to find out the mysteries, laws and events of the cosmos. Space is ideal for this because most of the emissions from space, x-ray, gamma and such, are blocked out by the Earth’s atmosphere. This atmospheric shield is perfect to sustain life, but becomes rather annoying when you want to know what goes on beyond Earth and in space. Figure 3 shows clearly the percentage of each electromagnetic wavelength that goes through the Earth’s atmosphere, and some of the satellites utilized to observe space on their differing wavelength frequencies. The far left represents gamma rays, x-rays and ultraviolet light. The rainbow on the left side represents the visible light spectrum, which is partially blocked by the atmosphere but is monitored by the Hubble and land-based telescopes. The middle is the infrared range. The right shows the only range that is let fully though, the mid-range radio waves, which are monitored on Earth. The chart clearly shows that the range of full and even partial clarity of wavelength is small, showing the necessity of space-observing satellites. With all of the additional wavelengths to study, it increases that many more chances to learn about the universe.
So if these satellites are becoming so increasingly important, is there so much space trash? The space age is only 45 years old, but already the 680.4 tons of space debris make placing anything in space hazardous, especially the more fragile elements of satellites. But if the larger fragments, if objects the size of a softball are considered large, can demolish a satellite with one errant twist in an orbit, why are the smaller fragments, from the .4 and 3.9 inch range, are the ones that are classified as threats by the debris scientists. The smaller debris are almost untrackable and can do considerable damage, because they cannot be detected but can still mutilate spacecraft. But even the tiniest debris, the paint chips the size of a fingernail, are hazardous, for they can form clouds of speeding fragments that can strip an object with the destructive force of a sandblaster, corrupting the satellite elements.

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Figure 3 was created by NASA and the European Space Agency (ESA)

What are satellites so important?-part 1 (3 of 9)

There exists a recent surge in demand of continually available up-to-the-minute information; so satellite-based telecommunications businesses, including, radio, television and telephony, have a huge potential commercial profit, especially to places where traditional cable isn’t feasible, leading to an increase in satellite communications. For example, DirecTV, a major satellite television company that was started in 1994, has 14 satellites in geosynchronous orbit, each costing hundreds of millions of dollars to construct and But there also exists a much wider variety of use with these communication satellites, which are used for direct-to-home television channels and packages, broadcast feeds to and from television networks and local member stations, distance education by schools and universities, business television, videoconferencing, and to distribute national cable channels (such as ESPN, CNN, or HBO) to the cable TV receiver and satellite TV stations. Satellites are also used to distribute satellite radio, sending digital radio streams across the entire continental US, and satellite telephony, a necessity in extremely isolated areas, such as Mount Everest and the savannahs of Africa or other less exotic, but equally remote areas where cell phone towers do not reach or exist.
But satellites are also relied upon for GPS, a staple in modern American navigating, civil planning and scientific research. GPS, or Global Positioning System (the nickname of the U.S. NAVSTAR Global Navigation Satellite System (GNSS)), which is made of a network of 24 satellites in geosynchronous orbit, an orbit that allows a satellite to return to exactly the same place in the sky at exactly the same time each day, which allows continually transmitted time and position information that, used in a system of triangulation, allow one to find a receiver/transmitter’s precise location anywhere across the world. The recent and quite complete success and dependence upon the United States’ NAVSTAR GNSS also has inspired other countries to launch their own GNSS networks such as The European Union’s Galileo Positioning system, China’s COMPASS, Japan’s QZSS, India’s IRNSS and the restoration of Russia’s GLONASS. GNSS, along with aerial pictures from weather or other earth-observing satellites, is responsible for the recent jump in information about the world and the infamous Google Maps and similar programs, and allowing for a precise time reference (atomic time) used in earth sciences and telecommunication networks, enhanced 911, more efficient search and rescue, in addition to the more precise and more rapid creation of geospatial information systems, which are used in navigation programs that tell you how far you might be to a place such as a restaurant or museum, for instance, but are used in various occupations such as: environmental impact evaluations, urban planning, criminology, history, sales and marketing.

Artifical Satellites and Orbital debris( 2 of 9)

Artificial satellites are used in almost every business or even for personal use. From satellite communications, earth science, astronomy, urban planning, to tracking packages and monitoring weather patterns and natural disasters, satellites are becoming increasingly essential to the modern way of business and life. For example, enhanced 911, in which the emergency station finds the location of the caller, depends upon GPS satellites for most mobile phones. And weather tracking and imaging, vital to air and water traffic and a great help to everyone else, is greatly dependent upon the images that weather satellites provide. So, far from abandoning space after the final moon landing in 1972, space use has only been expanded. In 2007 alone, there were 68 orbital launches and 22 spacewalks worldwide, 19 of those to maintenance artificial satellites. The US and the world have come to depend upon these orbiting satellites, necessitating the tracking and use of thousands of them.
Space debris is considered a problem because of the collisions between spacecraft, especially satellites, and debris. Figure 1 shows the distribution of observable debris (>3.9 inches) in Earth’s orbit, while Figure 2 shows the distribution of satellites in Earth’s orbit. This comparison shows the correlation between the most commonly used orbits and the amount of debris they possess. While spacecraft are made out of extremely durable material, the main problem lies in the large velocities that objects have in orbiting the earth. In space, a .4 inch aluminum sphere in an average orbital velocity of about 16.1 miles/sec has the equivalent velocity of a bowling ball moving at 300 miles/hour. (NASA, n.d.) So while a great deal of the mass of the satellite may be due to the shielding, it usually is not enough to protect against larger debris. And that debris has an especially dehabilitating effect on artificial satellites with their more delicate elements such as memory chips, solar cells and observational lenses that are easily corrupted. So a collision between debris and a satellite is always disastrous to both the information payload on the satellite and the usefulness of the satellite afterwards.


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Figure 1 is from the NASA Orbital Debris Program Office Education Package (2005)
Figure 2 is from NASA’s J-Track 3-D (November 16, 2008.) (please click to enlarge)

Why Should I Care About This Space Trash Problem, Anyway (1 of 9)

The Effect of the Uncontrolled Growth of Space Debris on the Current and
Future Space Use of Artificial Satellites


The space around Earth is empty, isn’t it? Just occupied by the moon, a few comets and satellites, right? But the earth’s orbit has over 680.4 tons (3 million kilograms) of space debris, unusable man-made material speeding in Earth’s orbits; space “junk” made up of not only items accidentally lost during space missions, such as a glove lost on the first American spacewalk, a camera lost near the spacecraft Gemini 10 and so forth, but also discarded rocket stages, dead satellites and other abandoned spacecraft that are beyond their usefulness but cannot be sent back to earth (Tufte, 1990). But much of the debris is made up of the shattered fragments of such deserted spacecraft, due to collisions with other debris or normal wear and tear of use. For example, all 31 of the nuclear-powered Radar Ocean Reconnaissance satellites (RORSATs), launched from 1967 to 1988 by the Soviet Union, still orbit the Earth unused, but, due to a construction error they create a much bigger problem. 16 of the satellites leak liquid sodium-potassium reactor coolant, making tens of thousands of coolant droplets speeding around after the abandoned satellites, making the orbit extremely hazardous to any human use. But while the RORSAT problem is unique, the fact of debris has become commonplace. After 45 years of space use, there are known to be 17,000 objects larger than 3.9 inches in orbit, which is confirmed by debris monitoring by the US and other countries. But the projected amount of objects between .4 and 3.9 inches in diameter is greater than 200,000, and the numbers of particles smaller than .4 inches, such as paint flakes and metal splinters, probably exceed 10,000,000. (Stansbury, 2005) This is in addition to thousands of orbital satellites that currently have considerable use.

Space Trash-an introduction

The next few posts will cover a research paper about orbital debris. Orbital debris or space trash is a problem that most people are not aware of and probably can not get good information about (I know I had difficulty at first), but this is assuming that they care about such problems. This paper is intended to produce well-researched information that will educate about the effects of orbital debris on communication satellites and countries' reaction to this growing problem. It is intended to convince that orbital debris is a relevant problem to our everyday lives, and we should have an opinion on it.

Bibliography:

Broad, W. (2007, February 6). Orbiting Junk, Once a Nuisance, Is Now a Threat. Retrieved April 11, 2008,
Crowther, R. (2002) "Space Junk-Protecting Space for Future Generations (Policy Forum: Space Science). (Statistical Data Included)."[Electronic version] Science 296.
David, L. (2004) . Havoc in the Heavens: Soviet-Era Satellite's Leaky Reactor's Lethal Legacy Retrieved April 11, 2008, from Space News Website.
David, L. (2003)"Tossed in Space (Between the Lines). (Debris in Outer Space)." [Electronic Version] Foreign Policy
De Selding, P. (2004) FCC Enters Orbital Debris Debate. Retrieved April 12, 2008, from the Space News Website
Grinberg, M. (2007) "Risk: the Final Frontier. (FOREFRONT) (Dealing with Orbital Debris)." [Electronic version] Risk Management4.
Inter-Agency Space Debris Coordination Committee. (2007) IADC Space Debris Mitigation Guidelines. Retrieved March, 21 2008.
Japan. (2003) Hyper Velocity Impact Test of Kibo's Shield. Japan Aerospace Exploration Agency. Retrieved on March 15, 2008.
NASA. (2008)"Monthly Number of Catalogued Objects in Earth Orbit by Object Type." Chart. Orbital Debris Quarterly News. Retrieved March 15, 2008, from The NASA Orbital Debris Program Office Website
NASA "Chinese Anti-Satellite Test Creates Most Severe Orbital Debris Cloud in History." (2007) Orbital Debris Quarterly News. Retrieved March 15, 2008.
NASA. (2008) "Two Minor Fragmentations End Worst Debris Year Ever." Orbital Debris Quarterly News Retrieved March 15, 2008.
NASA Johnson Space Center Orbital Debris Program Office. Orbital Debris Education Package. (2005). Retrieved March 25, 2008, from .
NASA. (2007)"United States Adopts Space Debris Mitigation Guidelines." Orbital Debris Quarterly News. Retrieved March 15, 2008.
Primack, J. (2002)"Pelted by Paint, Downed by Debris: Missile Defenses Will Put Valuable Satellites At Even Greater Risk (Opinion)."[Electronic version] Bulletin of Atomic Scientists 58
Space law. (2008). In Encyclopædia Britannica Online. Retrieved March 16, 2008.
"Space Law: Frequently Asked Questions." (2006) Retrieved March 15, 2008 from the United Nations Office for Outer Space Affairs Website.
Stansbery, E."Orbital Debris Frequently Asked Questions."(2005) NASA Orbital Debris Program Office. Retrieved March 15, 2008.
Taggart, S. (2001) Australians Take Mir Deorbit Risks in Stride. Retrieved April 12, 2008, from the Space News Website.
Taku Otsuka (Director).Fact Meets Fiction: a Discussion with NASA's Orbital Debris Program Office Part One. (2005) [Motion Picture]. Japan/United States: Bandai Entertainment INC.
Walls, B. (2007) NASA’s J-Track 3-D [Computer software]. NASA.
"What is Orbital Debris?" (2005) Center for Orbital and Reentry Debris Studies. From Retrieved March 15, 2008, from The Aerospace Corporation Website.