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Let's Know More About The Space Debris!

In this page, we will report basic information about space debris.
You can slide the page to where you want by clicking the navigation bar on the left.
Fifty years have passed since the first artificial satellite "Fifty years have passed since the first artificial satellite sprtnik1 was launched.



Human beings did not stopped their walk, and now, communications satellites have come to be an indispensable to our lives.
In march ninth 2014, a astronaut whose name is Mr.Koichi was installed as captain as the first Japanese to be so. He came back to earth in May fourteenth.
We often say that space is limitless, bet the place we start from is earth, and the earth only has limited space.
If that limited entrance would be shut, we wouldn't be able to start on a trip to our dream called "space".
You haven't thought about anything like that before, have you? I haven't either. However this problem is actually happening now.

What Are Space Debris?

 What Are Debris?

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"This is from the mission control of Endeavour. We can't restart the count down for five minutes to avoid collision."

This really happened when launching STS 72 (Endeavour).


Kochi Wakata(wikimediacommons)

All the people who were watching over this felt insecure.
Luckily, after the hold of five minutes they restarted the count down and have launched it.
The cause of this was rubbish floating in space which is called space debris.
Space debris are called debris for short."Debris" means "bits" in French.
"Space debris" means "rubbish in space".


Impact scar(wikimediacommons)

Crashes happening in space are far more faster than car crashes happening on earth.
Even it is about a size of a soft ball's ball, it would be a disaster if it bumps into something.
If it bums into manned facilities, that would be a big problem.

Will It Be Able to Live in Space?

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The first person who figured out the principle of rockets was Konstantin Eduardovich Tsiolkovskiy.
The person who really made a rocket and launched it was Wernher Magnus Maximilian Freiherr von Braun.


Wernher Von Braun(wikimediacommons)

After humans get a way to go to space, they start to think whether if it is able to live in space or not. At first, there isn't any air in space or anything we can eat to live.
So we have to use stuff brought from earth with wearing a space suit in an airtight chamber.
These are implicit terms, but we can solve these problems by using technology.
Secondly, space is an unknown environment which can't be understood from on earth, and we are concerned about radioactive rays and meteoroids too.

Lifespan of Debris

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How are Debris Made?


 How do you think debris is made? There are three big ways how debris is made.

(1) Artificial satellites that aren't able to use anymore and a ruin of launched rocket comes to be space debris.
(2) The number of space debris increase by bumping in each other.
(3) They increase in artificial ways to.

Let's take a look at these.

Appearance of Debris

(1)Artificial satellites that aren't able to use anymore comes to be debris.

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① A rocket was launched into space.
② It goes higher and higher.
③ When it reaches nearly 250 kilometers high, the lower part of the rocket where has the fuel tank in and the higher part where is the body are going to be in a part.
④ The lower part will be left in space and becomes space debris.
⑤ It moves to the graveyard orbit, the same as the others.


(2)The number of space debris increase by bumping in each other.

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① There are artificial satellites that haven't finished their jobs on the graveyard orbit but on the geostationary orbit.
② Imagine that a retired artificial satellite and a working artificial satellite bumped into each other. The fragments that were made when this happened are generally called microscopic debris, and the clustor them is called "debris cloud".
③ Broken satellites can't do very work after.
④ Debris crashed other debris.

The Last of Debris

Debris exist various orbits the same as satellites. 
Debris disappear by gravity and atmosphere resistance.
The big architecture made of burning-resistance has probability that falled into the Earth.



Risk of Debris

Power of Debris

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This photo is experiment result that hit plasticand extra super duralumin which is very hard .
In this experiment, extra super duralumin was penetrated though it's speed is half speed.
Like this , we can know debris have big power.

Effects of Debris

Space debris are revolving around earth about at a speed of eight kilometers per second.
This speed is about eight times faster than that of a bullet of a rifle.
And in this speed, you could go around the earth in an hour.
What is the danger of these space debris then? Let's think about this. Even a small one whose size is smaller than ten centimeters can make an artificial satellite explode.
The kinetic energy when an aluminum ball which is advancing at the speed of 10 kilometers an second and is three millimeters across, and when a bowling ball which is advancing at the speed of 100 kilometers an hour is the same.
If those debris bump into the international space station or an artificial satellite, it would be destroyed in ease even if it was only 10 centimeters large.
Our life is supported by the function of many artificial satellites.
For example, something like the internet, weather forecast, GTS are.
What do you think will happen when the artificial satellites were destroyed by debris, and these things stop?

Kessler Syndrome

It's a theory which says that a new space debris may be made if they bump into each other or an artificial satellite.

We call this Kessler Syndrome.
This name comes from the name of one of the people proposed this whose name is Donald J. Kessler.
Another point of danger of space debris is that it's number may could increase naturally.
If a debricloud appears by debris' bumping into each other, and the probability they will bump into each other increase, we won't be able to do any space development anymore.

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History of Debris


A Chronological Table of Debris

  • 1957 10

    Sputnik 1 was the first artificial Earth satellite. It was a 58 cm diameter polished metal sphere, with four external radio antennas to broadcast radio pulses.
    The Soviet Union launched it into an elliptical low Earth orbit. This weight is 83.6kg. The life of battery is three weeks, but Sputnik was moving for 22 days after battery was dead.     

  • 11

    Sputnik 2 was the second spacecraft launched into Earth orbit. Sputnik 2 weighed 508kg, that number is larger than Sputnik 1. the first to carry a living animal, a dog named Laika.

  • 1959

     COPUOS was installed to the United Nations

  • 1961 4

    The first human spaceflight took place on April, 1961, when cosmonaut Yuri Gagarin made one orbit around the Earth aboard the Vostok 1 spacecraft.  After his returning, he said "The earth was bluish." 

  • 6/29

    Break up is first observed in the universe

  • 1963 5/9

    The United States scattered 400,840,000 microneedles under the pretense of "a space communication experiment" in the space.

  • 1964

    Soviet reconnaissance satellite were exploded in universe

  • 1965 11/26

    Astérix, the first French satellite, was launched on November 26, 1965.

  • The same year

    SO TitanC is very powerful rockets , them transformer broke up at an altitude of 740km and observed 475 fragnents.

  • 1966 7

    Cerise which is French satellite crashed part of Arian which was destroyed in 1986.

  • 1968 12

    Apoll8 is first space ship which returned the earth safely.

  • 1969 6/16

    Armstorong and Aldrin stood in the surface of the moon.

  • 1970

    Osumi was launched in space observatory in space abservatory in Kagoshima . It made to do experiments about satellites and learn launch skill.

  • The same year

    America begins to plan for development of the Space Station.

  • 1971

    Britain satellites Ariel 1st was launched . It is first satellite part of Britain satellite program , Ariel plan. In 1970 , America started planning space station . Looking NASA's the inside date , we can understand that crashing risk in the space were discussed then.

  • 1978

    Russian nuclear reactor satellite "COSMOS 954" was lanched in 1977 but after used it failed moving to stable orbit and falled in Canada . There wasn't casualities but spattered fragment which have radioactivity.

  • 1979 7

    Aryabhata was made to do experiments of X-ray astronomy , aeronomy and solar physics

  • The same year

    NASA launched sky love which was American first space station. This is finished product of American space station plan.

  • 1981 4/10

    Space shuttle Colombia started off for the space . The insulators had about 300〜400 chips because of falling fragments and broken piece of ice .

  • 1983 7/18

    Kosmoc-1402, Russian satellite, fell in Canada.

  • 1984

    In 1984, Van ,who was astronaut, repaired satellite solar max from space shuttle. This was first challenge .

  • The same year

    Long-duration exposure facility (LDEF) discovered a large amount of space debris.

  • 1985 9/13

    American Orbiting Solar Observatory was broken by the missile.

  • 1986 1

    Space shuttle Challenger's explosion happened. 7 crew passed away .

  • 2

    Mir falled in 2003. Mir means peace and world.

  • 1987

    Cooperation between NASA and ESA started to reduce debris.

  • 1988 2

    Reagan , who was American president decided nation policy which wrote about decreasing debris.

  • 1990 5

    Recovery of Long-duration exposure facility (LDEF) started.

  • The same year

    In 1995, ISTS was holded . The topics about debris were discussed in them spare time.

  • 1992

    In 1992, Mamoru Mohri went to space as Payload Specialist.

  • 1993

    The Inter-agency Space Debris Coordination Committee(IADC)was inaugurated.

  • 1998

    Assembling of the International Space Station started

  • 2001年3月23日

    In 2001, Mir ,which was Rossian space station decided to throw . This used only 15 years . Japan paniced because it was passing over Japan just before it falled.

  • 2002

    IADC made Debris Mitigation Guidelines in 2002. This guidelines refered to suggestion from JAXA , ESA ,NASA and Russian Federal Space Agency.

  • 2003

    The shuttle named Colombia happened boming accident during return.

  • 2007 1/12

    China blasted them satellite ,Huun1c, so that many debris spreaded in the space.

  • 6

    In 2007, this guidelines Inherited by UNCOPUOS, and “Debris Reduction Guidelines”was made. But, there are the countries which don't obey because of not penalty.

  • 2008 2/21

    The United States blows up own satellite.

  • 2009 2/10

    The 2009 satellite collision was the first accidental hypervelocity collision between two intact artificial satellites in low Earth orbit. Iridium 33 and Kosmos-2251 collided on altitude of 789 kilometres above the Taymyr Peninsula in Siberia.

  • The same year

    Kibo, is a Japanese science module for the International Space Station (ISS) developed by JAXA.

  • 2013 11

    Wakata became the commander of the International Space Station with Expedition 39. This marked the first time a Japanese astronaut became station commander.

Opinions of Specialists

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Our Opinion

Understing by reading “opinion of scientists”,many scientists have been saying that spacedebris is vary dangerous for long time.

However, in space, spacedebris is increasing because of military experiment, break up and collision of satellites.
Although this problem is very serious, spacedebris isn't kown.
Unbelievably, there is experiment to shoot down satellites even now.

We tihnk that…
Why does the voice of scientists not arrive?Why are measures not performed?

Many questions were born.

It is not only a technical factor that a solution to the problem does not reach well.

Debris Environment

How Many Debris Are They?



In fact, the number of objects in space has not been revealed.

Ten or more centimeter in low orbit and a meter in high orbit objects are kept under supervision with the radar and the telescope.

Such objects are used satellites now, not moved satellites and top of rockets and released fragments of satellites when they are

launching and be detached.

In fact, most of the objects in the catalogue are fragments, and, surprisingly, they occupy half of all. By the way, used satellites is
6 percent of all. → Therefore, space debris are 94 percent of all.

Orbit Is Crowded!?

Orbit , such as satellite SNN is managed by the ( US space surveillance network ) , must be such as to whether the applicant to use in a cycle of how much how much of a high degree of location before making the launch .

The graph below summarizes some of the orbit by the catalog object shown in the figure above .

When the Number of Debris Decreace

Number of space debris is increasing in soaring , but there are times when it is reduced to every 11 years.

This is due to the dynamism of solar activity , when active atmospheric density of advanced 500~1000km atmospheric layer of Earth bulge greatly increased .
Since the air resistance of an object is proportional to the density , falling objects is promoted during this period .

But now it is the amount also insignificant when viewed from the overall decrease , does not resolve space debris problem is you're relying on only when to decrease once in this '11 .

Break Up












Our Opinion

As you see, the space is in quite danger because there are many space debris in. In this page, we would like to insist on our opinion about.

1・2 Object to〝Intentional Destruction"

When people think it is dengerous that not using man-made satellites fall to the ground, there is no helpe for destruction of them.

However, just as expected, is fracture experiment of satellite necessary?

We do not think many space debris should be breaken out because noone has the space.

Present international law has not force of constraint in the least, and it says "if you can".
(this is the same for the problem of the United Nations)

We think it is necessary to form the international law has strong force of constraint for the ban of fracture experiment of satellite.

3・4 Object to "Explosion of Propulsion system"

When man-made satellites is detached, propellants keep left in tanks, which is the very cause of breakup of explsion in propulsion.

Threfore, it is necessary to open valves and to be empty tanks.

Since breakup in explosion of propulsion system was observed in 1982, every countries and institution, such as NASA, as soon as, made the airframes which excrete propulsion systems in tanks. these have never exploded yet.

That is only our opinion not to break about the accident which caue increase of space debris.

If people go on launching man-made satellites, the problem does not radically solve because space debris continue increacing.

Howevere, we think it is very important to take measures one by one for control of space debris.