What Are Debris?

"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?

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

Firstly

　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.

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.

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.

（wikimediacommons）

Power of Debris

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.

A Chronological Table of Debris

• The first artificial satellite were launched 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. 　　　　
  

• "Sputnik 2" was launched along with the dog 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.
  
  

• COPUOS was installed to the United Nations 1959

  　COPUOS was installed to the United Nations

• Manned space flight first of mankind 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."　

• "Break up" is first observed in the universe 6/29

  Break up is first observed in the universe

• America spreaded a lot of microneedles 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.

• Soviet reconnaissance satellite were exploded in universe 1964

  Soviet reconnaissance satellite were exploded in universe

• The first artificial satellite were launched in France 1965 11/26

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

• American rocket was "break-up" The same year

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

• French satellite collision with space debris 1966 7

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

• Apollo 8 was launched 1968 12

  Apoll8 is first space ship which returned the earth safely.

• Apollo 11 was launched 1969 6/16

  Armstorong and Aldrin stood in the surface of the moon.

• Japan's first satellite; "Osumi" was launched 1970

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

• America begins to plan for development of the Space Station. The same year

  America begins to plan for development of the Space Station.

• United Kingdom's first satellite was launched 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.

• Soviet reactor satellite is failed to Canada 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.

• India's first satellite was launched 1979 7

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

• America's first space station "Skylab" was falling The same year

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

• First flight of the space shuttle 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 .

• Accident of the space shuttle No. 7 1983 7/18

  Kosmoc-1402, Russian satellite, fell in Canada.

• First time recovery and repair an artificial satellite 1984

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

• LDEF discovered a large amount of space debris The same year

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

• American satellite was destroyed by missiles 1985 9/13

  American Orbiting Solar Observatory was broken by the missile.

• Explosion of the space shuttle "Challenger" 1986 1

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

• Soviet Union launched a space station "Mir" 2

  Mir falled in 2003. Mir means peace and world.

• Cooperation between NASA and ESA started to reduce debris. 1987

  Cooperation between NASA and ESA started to reduce debris.

• America was debris minimize national policy 1988 2

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

• Recovery of LDEF 1990 5

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

• "Space Debris Study Group" was organized The same year

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

• Japanese was the first space flight 1992

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

• IADC was inaugurated 1993

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

• International Space Station assembly start 1998

  Assembling of the International Space Station started

• Russia of falling space station "Mir" is part 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.

• IADC is creating "space debris mitigation guidelines" 2002

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

• Space shuttle "Columbia" explosion 2003

  The shuttle named Colombia happened boming accident during return.

• China blow up their own satellite missile 2007 1/12

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

• Move the "debris mitigation guidelines" from the IADC to COPUOS 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.

• America blow up their own satellite missile 2008 2/21

  The United States blows up own satellite.

• Collision of human history's first artificial 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.

• Japanese International Space station "Kibou" completed The same year

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

• Mr.Koichi Wakata became the first Japanese captain 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

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.

How Many Debris Are They?

NASA提供

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

ここでは、先ほどの章で述べたブレークアップをさらに詳しくみていきます。
ブレークアップとは、人工衛星などが何らかの原因で爆発し破壊され大量のデブリが発生してしまう現象です。

①意図的な破壊

｢意図的な破壊｣とは、衛星破壊実験や回収に失敗した衛星を破壊するものです。
自国の衛星にミサイルを打ち込むとどのように破壊されるのか、また軍事衛星が他国に落下し情報が流出する危険性があるときに破壊したり自爆させたりします。
このような人為的な破壊はブレークアップとしての件数では最も多く、割合としては3分の1を占めています！

→具体的な例
･衛星破壊実験…コスモス249号

･中国が自国の衛星「風雲1号C」を地上からミサイルで爆破

②偶発的な破壊

意図的に人工衛星を破壊するのに対し偶発的に人工衛星が破壊されることがあります。
先程述べたような衛星内の自爆機能が偶然作動して大量のデブリが生じる危険性があります。

③・④電気回路・推進系の爆発

人工衛星などは宇宙に行く際にロケットで運ばれますが、ロケットの電気回路が突然ショートして爆発したり、宇宙に行くための推進系と呼ばれるロケットのエンジンなどが何らかの原因により爆発したりしてブレークアップを起こすことがあります。
(原因としては、燃料が入っている壁に亀裂が発生し推進剤が漏れだした状態で他の機体などと衝突することで大規模な爆発が起こると考えられます。)

⑤不明

①〜④以外の約40%のブレークアップの原因はわかっていません。
これらの中にはデブリ同士の衝突による爆発もかなり存在すると考えられています。
→アニメーション
　•スペースデブリのできかた2

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.