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Space Junk: The Growing Trash Depot in the Sky
Space Junk: The Growing Trash Depot in the Sky

By Anne Shaw
Writing 105, Highline Community College



Coryell, Damrow, Skubis, and Stuckey
2

Abstract
Mankind has had increasing activity in space exploration in the last forty years. The amount of
garbagespace junkhas been steadily increasing since then. Space junk is estimated to total in the
tens of millions with only a microscopic percentage being functional. Safety is an issue for satellites
and Shuttles because of these objects. Over the years, the United Nations has tried to incorporate
treaties to establish responsibility to nations who regularly launch objects into orbit, like the United
States and Russia. But without growing research and technology, the problem will only continue.











Earth Rising; NASA 1969


In 1980, Star Wars fans were mesmerized when the evil Empire dumped their Starfleets
garbage into space before heading off to the far reaches of the galaxy, finally allowing Han Solo and
Princess Leias long and somewhat undetected, escape in The Empire Strikes Back. Admittedly, this
is complete fantasy. In accordance with our present knowledge of our Milky Way galaxy and the
known universe, there are no technologically advanced empires of destruction flying around in star
destroyers the size of Texas, in distant galaxies, shooting laser beams at one another.
Little do people know, dumping garbage in space has become a standard procedure for
most space faring nations. In the last forty plus years, we have dumped 4,500 tons of junk and
garbage into orbit around the Earth; the remnants of high-speed rockets, shuttles, exploratory probes,
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human waste, and ancient satellites (Grace & Johnson, 1998). We have polluted the space around
our planet with what is now referred to as something called space junk or orbital debris. According
to Wikipedia, The Free [Online] Encyclopedia (2005), orbital debris is defined as: objects in orbit
around Earth created by man that no longer serve any useful purpose (para. 1). It seems the old
motto of if in doubt, throw it out works great for space travel, regardless of the galaxy.

Breaking Down the Garbage
According to the National Aeronautics and Space Administration (NASA), there are four
main categories of space junk nowadays. The biggest, consisting of about 42% of all orbital debris is
fragmentation debris. Fragmentation debris consists of break-ups of satellites and [products] of
deterioration. This can be anything from large objects like dead batteries and thermal blankets
1
, to
smaller and (sometimes) miniscule objects like paint
flakes. The rest of the orbital debris is broken up
into non-functional spacecraft, like the long ago
defunct Vanguard 1the oldest piece of space junk
currently in orbit--an orbiter launched by NASA to
study the Earths oblateness
2
and geographic
phenomena in 1958. Other orbital debris consists of
mission-related debris, like garbage from space
stations, and remaining pieces of rockets, such as
fuel tanks or rocket motors (NASA, Orbital Debris
Education, p. 4).
As of 1998, the U.S. Space Commands Space Surveillance Center in Cheyenne Mountain,
Colorado, tracked approximately 8,500 pieces of space junk, with only 500 of those being of any use
to Earth. In other words, a shocking 6% of detectable objects are operational spacecraft (Cowen,
Science and Technology: Science, 1998). Nowadays, there are approximately 11,000 objects floating
around Earth that are larger than ten centimeters. Tracking these objects from ground level makes for
a difficult assessment of the total numbers of junk floating around in orbit; only those objects of the
approximate ten centimeter size can be tracked to some degree of accuracy. Ground-based radars can
give an estimate to objects above three millimeters, but the smallest piecesthe ones that are less

1
Thermal blanketing is a form of insulation used to keep satellites and spacecraft from freezing while in orbit, as well as
protection from microscopic orbital debris (NASA, Thermal, para. 3).
2
Oblateness refers to a spherical object in which the
length of the diameter at the equator [is] greater than the length
from pole to pole (oblate, 2005).

Orbital Debris Percentages
42%
19%
17%
22%
Fragmentation Debris
Mission Related Debris
Rocket Bodies
NonFunctional Space Craft
NASA, Education
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than one mm in size--can only be estimated in their numbers by assessing damage to spacecraft upon
its return from orbit. These microscopic pieces have the highest numbers of all the space junk in
orbit; their numbers exceeding into the tens of millions (NASA, Orbital Debris: Frequently, p. 2).
Most orbital debris is located in what is known as Low Earth Orbit (LEO), which is the
realm of space around Earth from an altitude of 2000 km and below. LEO objects, regardless of size,
tend to travel at approximately seven kilometers per second, which is equivalent to the speed of a 90-
mph fastball in a baseball game (NASA, Orbital Debris Education, p. 14). Imagine getting hit head
on with something that fast.
With less than a thousandth of a percent of all the refuse
orbiting Earth being accurately tracked, crafts like the ISS or
NASAs human manned Space Shuttles need to be specially
equipped with extra safety features to help minimize the risk of
accidentally bumping into any of these pieces. One of these
features is the whipple bumper or whipple shield, an idea
originally proposed by the
American astronomer Fred
Whipple, in 1946 (Tenn, 2003).
This Whipple Shield is based on a concept that a small fragment of
orbital debris will vaporize when it impacts a thinner, outer wall
around the spacecraft because of its excessive orbital speed and
high kinetic energy. This outer wall is usually about a tenth of the
thickness as the main wall, as shown in this image. When the micro
sized object strikes the outer wall, it literally disappears; exploding
on impact due to the objects high velocity, thus leaving no
potentially harmful objects left to strike the thicker inner wall.
Other forms of protection include thermal blanketing insulation, which acts as both a
heater for the satellites as well as padding. This padding can protect the satellites from collisions
with small objects during its flight pattern. In addition to thermal blanketing, actual flight patterns of
satellites and spacecraft can also be basic protection against flying debris. The Shuttles usually fly
upside down and backwards, to help minimize damage from head on collisions with debris
(Armstrong, 2004).
LEO view of Earth;
Planet Newsstand
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Regardless of size, all of these objects pose a major threat to satellites, Shuttles, and the
International Space Station (ISS), with the ISS currently being at the highest risk. In 1997, the
National Academy of Sciences issued
a report stating that during the extent
of its ten-year orbit (fully assembled),
the ISS had a 19% chance of collision
with orbital debris to a pressurized
module
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. All of the areas on the ISS
image in red are equipped with
whipple shields to reduce the
probability of impact with smaller
pieces of debris, but considering the
size of the ISS, it is nearly impossible
to prevent all collisions with orbital
debris. So far while in orbit, the ISS
has missed a few large objects,
including pieces from a Russian satellite that blew apart in November of 2000, and pieces of a
Chinese Long March 4 rocket (David, para. 1, 3; Weinstock, para 3). But on November 26, 2003,
Michael Foale, a crewman on the ISS, reported to have heard a loud noise described as a metal can
being crushed and then unfolded. The most logical explanation was that a piece of debris about the
size of one centimeter collided with the outer plating of the station, crushing the metal it struck. The
ISS module that was struck was pressurized unlike the outside vacuum of space, so the pressure then
pushed the plating back out, creating the double crunching sound heard by the crewman. (Bell, para
6). The Space Station seems to be a very large and expensive accident waiting to happen.
Assessing Responsibility
There have been several documents and treaties created over the years to help organize a
foolproof policy in regards to assessing orbital debris liability. The first treaty that made a simple
attempt at curbing space junk was the Outer Space Treaty, ratified in 1967 by the United Nations
(UN) and signed by the United States, the United Kingdom, and the former U.S.S.R. It established
basic laws and principles regarding space exploration, including states shall be liable for damage
caused by their space objects. It also requires that states shall avoid harmful contamination of