How Space Debris is Currently Handled-part 2 (6 of 9)

The mitigation or the slowing of growth, of debris consists of limiting the debris released during normal operations, minimizing in-orbit break-ups and collisions and to seeking to dispose of the spacecraft after its useful lifetime, either by placing in an unused (graveyard) orbit or to de-orbit it, sending it back to Earth. (IADC, 2007) In 2004, The FCC required that to receive a FCC license and continue transmitting, all U.S.-licensed satellites launched after March 18, 2002, will have to be retired in a graveyard orbit after their useful lives (de Selding, 2004). While this is a commendable effort, it is a problem for most of the commercial satellite companies, because the amount of fuel to send the spacecraft into an unused orbit equals 3 months of normal use. And this also quite is difficult to enforce, because much of the time satellites malfunction of are stopped in some way from changing orbits. So while the current method for dealing with the space debris problem by mitigation and shielding seems to work, it cannot be maintained at current levels and keep space usable at current or increased loads in the future. For one of the major problems of space debris is that even if no more spacecraft are deployed and no more potential debris introduced, the amount of space debris would still increase, as proposed by the Kessler syndrome.
The Kessler syndrome, as discovered by Donald J Kessler, formerly head of the NASA orbital debris program office, posits that when the number of debris in orbit reach a critical mass, than it reaches a domino effect of destruction and debris called collisional cascading.
his is when the debris created from one collision or explosion spreads out and causes another collision which then creates more debris and so on, creating a steady growth of damaging space debris that greatly decreases the potential for orbital space use. This decrease of use would be due to the sheer amount of speeding, colliding debris that would destroy a spacecraft in a matter of months or days, or would require so much shielding that, except for the wealthiest of organizations, it would be economically impossible to launch spacecraft that size. Despite this worrying predicament, the required critical mass has been reached in most of the commonly used low earth orbits because of the almost unchecked growth of space debris, due to a lack of concern. The future of space use is too important to risk. The world has become so heavily dependent and benefited so much from artificial satellites in only 45 years, that allowing Earth’s orbit to become a debris cage for the Earth is a step backwards, away from the technological and space age. But it sometimes seems that the countries of the world are taking that step backwards by arranging to weaponize space.

How Space Debris is Currently Handled-part 1 (5 of 9)

The current policy of the US (and all other countries) is to not seek ways to get rid of debris, just to diminish the growth of it. The most recent statement, from the United States’ National Space Policy says,
"Orbital debris poses a risk to continued reliable use of space-based services and operations and to the safety of persons and property in space and on Earth. The United States shall seek to minimize the creation of orbital debris by government and non-government operations in space in order to preserve the space environment for future generations."(USNSP, 2006)

The existing management of the problem of space debris is a combination of monitoring the larger debris and shielding orbital spacecraft from the smaller debris. The monitoring is done by The US Space Surveillance Network with a combination of satellites and ground-based radars, tracking debris larger than 3.9 inches in low earth orbit (124 vertical miles to 1240 vertical miles), where the majority of the satellites are, and larger than 3 feet in geosynchronous orbit (22,236 vertical miles), where there are approximately 300 satellites. The debris is tracked every day to predict and prevent collisions with spacecraft. Satellites and The International Space Station can be maneuvered out of the way of larger pieces of debris if given sufficient time to plan and implement beforehand and shielding can protect the spacecraft from the smallest debris (<.4 inches), even though it cannot be tracked. But even the smallest debris can ruin some satellites. For example, a single-tether satellite was rendered useless by a small particle severing the tether, losing its most recent information payload and requiring immediate action to stabilize it. But the middle range from .4 inches to 3.9 inches is classified as the debris “threat”, since debris that size can smash a satellite into more useless and dangerous debris, but technology to shield against that size of debris isn’t practically or economically feasible for most spacecraft, and it is too small to allow radars and other observational equipment to track it.

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.