Saturday, 25 October 2008

Indonesian Space Sciences & Technology School

Indonesian Space Sciences & Technology School

 Added & Edited

By: Arip Nurahman
Department of Physics Education, Faculty of Sciences and Mathematics
Indonesia University of Education


Follower Open Course Ware at Massachusetts Institute of Technology
Cambridge, USA
Department of Physics
Aeronautics and Astronautics Engineering

Space manufacturing

Space manufacturing is the production of manufactured goods in an environment outside a planetary atmosphere. Typically this includes conditions of microgravity and hard vacuum. Manufacturing in space has several potential advantages over Earth-based industry.

  1. The unique environment can allow for industrial processes that cannot be readily reproduced on Earth.
  2. Raw materials can be collected and processed from other bodies within the solar system at a relatively low expense compared to the cost of lifting materials into orbit.
  3. Potentially hazardous processes can be performed in space with minimal risk to the environment of the Earth or other planets.
Comparison of insulin crystal 
growth in outer space (left) and on Earth (right). NASA image.
Comparison of insulin crystal growth in outer space (left) and on Earth (right). NASA image.
The space environment is expected to be beneficial for production of a variety of products. Once the heavy capitalization costs of assembling the mining and manufacturing facilities is paid, the production will need to be economically profitable in order to become self-sustaining and beneficial to society. The most significant cost is overcoming the energy hurdle for boosting materials into orbit. Once this barrier is significantly reduced in cost per kilogram, the entry price for space manufacturing can make it much more attractive to entrepreneurs.
Economic requirements of space manufacturing imply a need to collect the requisite raw materials at a minimum energy cost. The economical movement of material in space is directly related to the delta-v, or change in velocity required to move from the mining sites to the manufacturing plants. Near-earth asteroids, Phobos, Deimos and the lunar surface have a much lower delta-v compared to launching the materials from the surface of the Earth to Earth orbit.



During the Soyuz 6 mission, Russian astronauts performed the first welding experiments in space. Three different welding processes were tested using a hardware unit called Vulkan. The tests included welding aluminum, titanium, and stainless steel.

The Skylab mission, launched in May, 1973, served as a laboratory to perform various space manufacturing experiments. The station was equipped with a materials processing facility that included a multi-purpose electric furnace, a crystal growth chamber, and an electron beam gun. Among the experiments to be performed was research on molten metal processing; photographing the behavior of ignited materials in zero-gravity; crystal growth; processing of immiscible alloys; brazing of stainless steel tubes, electron beam welding, and the formation of spheres from molten metal. The crew spent a total of 32 man-hours on materials science and space manufacturing investigation during the mission.

The Space Studies Institute began hosting a bi-annual Space Manufacturing Conference in 1977.
Microgravity research in materials processing continued in 1983 using the Spacelab facility. This module has been carried into orbit 26 times aboard the Space Shuttle, as of 2002. In this role the shuttle has served as an interim, short-duration research platform in lieu of the upcoming International Space Station.

The Wake Shield Facility is deployed
 by the Space Shuttle's robotic arm. NASA image.
The Wake Shield Facility is deployed by the Space Shuttle's robotic arm. NASA image.
In February 1994 and September 1995, the Wake Shield Facility was carried into orbit by the Space Shuttle. This demonstration platform used the vacuum created in the orbital wake to manufacture thin films of gallium arsenide and aluminum gallium arsenide.

On May 31, 2005, the recoverable, unmanned Foton-M2 laboratory was launched into orbit. Among the experiments were crystal growth and the behavior of molten-metal in weightlessness.


The completion of the International Space Station is expected to provide expanded and improved facilities for performing industrial research. These will lead to improvements in our knowledge of materials sciences, new manufacturing techniques on Earth, and potentially some important discoveries in space manufacturing methods. The completion of this facility has been delayed due to safety problems with the Space Shuttle.
The Material Science Laboratory Electromagnetic Levitator (MSL-EML) on board the Columbus Laboratory is a science facility that can be used to study the melting and solidification properties of various materials. The Fluid Science Laboratory (FSL) will be used to study the behavior of liquids in microgravity.[1]


There are several unique differences between the properties of materials in space compared to the same materials on the Earth. These differences can be exploited to produce unique or improved manufacturing techniques.
  • The microgravity environment allows control of convection in liquids or gasses, and the elimination of sedimentation. Diffusion becomes the primary means of material mixing, allowing otherwise immiscible materials to be intermixed. The environment allows enhanced growth of larger, higher-quality crystals in solution.
  • The ultraclean vacuum of space allows the creation of very pure materials and objects. The use of vapor deposition can be used to build up materials layer by layer, free from defects.
  • Surface tension causes liquids in microgravity to form perfectly round spheres. This can cause problems when trying to pump liquids through a conduit, but it is very useful when perfect spheres of consistent size are needed for an application.
  • Space can provide readily available extremes of heat and cold. Sunlight can be focused to concentrate enough heat to melt the materials, while objects kept in perpetual shade are exposed to temperatures close to absolute zero. The temperature gradient can be exploited to produce strong, glassy materials.

Materials processing

For most manufacturing applications, specific material requirements must be satisfied. Mineral ores need to be refined to extract specific metals, and volatile organic compounds will need to be purified. Ideally these raw materials are delivered to the processing site in an economical manner, where time to arrival, propulsion energy expenditure, and extraction costs are factored into the planning process. Minerals can be obtained from asteroids, the lunar surface, or a planetary body. Volatiles could potentially be obtained from a comet or the moons of Mars or other planets. It may also prove possible to extract hydrogen from the cold traps at the poles of the Moon.

Another potential source of raw materials, at least in the short term, is recycled orbiting satellites and other man-made objects in space. Some consideration was given to the use of the Space Shuttle external fuel tanks for this purpose, but NASA determined that the potential benefits were outweighed by the increased risk to crew and vehicle[citation needed].

Unless the materials processing and the manufacturing sites are co-located with the resource extraction facilities, the raw materials will need to be moved about the solar system. There are several proposed means of providing propulsion for this material, including solar sails, magnetic sails, mini-magnetospheric plasma propulsion (which uses a cloud of ionized gas as a magnetic sail), electric ion thrusters, or mass drivers (this last method uses a sequence of electromagnets mounted in a line to accelerate a conducting material).

At the materials processing facility, the incoming materials will need to be captured by some means. Maneuvering rockets attached to the load can park the content in a matching orbit. Alternatively, if the load is moving at a low delta-v relative to the destination, then it can be captured by means of a mass-catcher. This could consist of a large, flexible net or inflatable structure that would transfer the momentum of the mass to the larger facility. Once in place, the materials can be moved into place by mechanical means or by means of small thrusters.

Materials can be used for manufacturing either in their raw form, or by processing them to extract the constituent elements. Processing techniques include various chemical, thermal, electrolitic, and magnetic methods for separation. In the near term, relatively straightforward methods can be used to extract aluminum, iron, oxygen, and silicon from lunar and asteroidal sources. Less concentrated elements will likely require more advanced processing facilities, which may have to wait until a space manufacturing infrastructure is fully developed.

Some of the chemical processes will require a source of hydrogen for the production of water and acid mixtures. Hydrogen gas can also be used to extract oxygen from the lunar regolith, although the process is not very efficient. So a readily available source of useful volatiles is a positive factor in the development of space manufacturing.

One proposed method of purifying asteroid materials is through the use of carbon monoxide (CO). Heating the material to 500 °F (260 °C) and exposing it to CO causes the metals to form gaseous carbonyls. This vapor can then be distilled to separate out the metal components, and the CO can then be recovered by another heating cycle. Thus an automated ship can scrape up loose surface materials from, say, the relatively nearby 4660 Nereus (in delta-v terms), process the ore using solar heating and CO, and eventually return with a load of almost pure metal. The economics of this process can potentially allow the material to be extracted at one-twentieth the cost of launching from Earth, but it would require a two-year round trip to return any mined ore.[citation needed]


Due to speed of light constraints on communication, manufacturing in space at a distant point of resource acquisition will either require completely autonomous robotics to perform the labor, or a human crew with all the accompanying habitat and safety requirements. If the plant is built in orbit around the Earth, or near a manned space habitat, however, telecheric devices can be used for certain tasks that require human intelligence and flexibility.

Solar power provides a readily available power source for thermal processing. Even with heat alone, simple thermally-fused materials can be used for basic construction of stable structures. Bulk soil from the Moon or asteroids has a very low water content, and when melted to form glassy materials is very durable. These simple, glassy solids can be used for the assembly of habitats on the surface of the Moon or elsewhere. The solar energy can be concentrated in the manufacturing area using an array of steerable mirrors.

The availability and favorable physical properties of metals will make them a major component of space manufacturing. Most of the metal handling techniques used on Earth can also be adopted for space manufacturing, but a few will need significant modifications. The microgravity environment of space will necessitate modifications to some metal handling techniques.

The production of hardened steel in space will introduce some new factors. Carbon only appears in small proportions in lunar surface materials and will need to be delivered from elsewhere. Waste materials carried by humans from the Earth is one possible source, as are comets. The water normally used to quench steel will also be in short supply, and require strong agitation.

Casting steel can be a difficult process in microgravity, requiring special heating and injection processes, or spin forming. Heating can be performed using sunlight combined with electrical heaters. The casting process would also need to be managed to avoid the formation of voids as the steel cools and shrinks.

Various metal-working techniques can be used to shape the metal into the desired form. The standard methods are casting, drawing, forging, machining, rolling, and welding. Both rolling and drawing metals require heating and subsequent cooling. Forging and extrusion can require powered presses, as gravity is not available. Electron beam welding has already been demonstrated on board the Skylab, and will probably be the method of choice in space. Machining operations can require precision tools which will need to be imported from the Earth for some duration.

New space manufacturing technologies are being studied at places such as Marshall's National Center for Advanced Manufacturing. The methods being investigated include coatings that can be sprayed on surfaces in space using a combination of heat and kinetic energy, and free-form fabrication of parts. Approaches such as these, as well as examination of material properties that can be investigated in an orbiting laboratory, will be studied on the International Space Station.


There are thought to be a number of useful products that can potentially be manufactured in space and result in an economic benefit. Research and development is required to determine the best commodities to be produced, and to find efficient production methods. The following products are considered prospective early candidates:
As the infrastructure is developed and the cost of assembly drops, some of the manufacturing capacity can be directed toward the development of expanded facilities in space, including larger scale manufacturing plants. These will likely require the use of lunar and asteroid materials, and so follow the development of mining bases.

Rock is the simplest product, and at minimum is useful for radiation shielding. It can also be subsequently processed to extract elements for various uses.

Water from lunar sources, Near Earth Asteroids or Martian moons is thought to be relatively cheap and simple to extract, and gives adequate performance for many manufacturing and material shipping purposes. Separation of water into hydrogen and oxygen can be easily performed in small scale, but some scientists[1] believe that this will not be performed on any large scale initially due to the large quantity of equipment and electrical energy needed to split water and liquify the resultant gases. Water used in steam rockets gives a specific impulse of about 190 seconds; less than half that of hydrogen/oxygen, but this is adequate for delta-v's that are found between Mars and Earth[citation needed]. Water is useful as a radiation shield and in many chemical processes.

Ceramics made from lunar or asteroid soil can be employed for a variety of manufacturing purposes. These uses include various thermal and electrical insulators, such as heat shields for payloads being delivered to the Earth's surface.

Metals can be used to assemble a variety of useful products, including sealed containers (such as tanks and pipes), mirrors for focusing sunlight, and thermal radiators. The use of metals for electrical devices would require insulators for the wires, so a flexible insulating material such as plastic or fiberglass will be needed.
A notable output of space manufacturing is expected to be solar panels. Expansive solar energy arrays can be constructed and assembled in space. As the structure does not need to support the loads that would be experienced on Earth, huge arrays can be assembled out of proportionately smaller amounts of material. The generated energy can then be used to power manufacturing facilities, habitats, spacecraft, lunar bases, and even beamed down to collectors on the Earth with microwaves.

Other possibilities for space manufacturing include propellants for spacecraft, some repair parts for spacecraft and space habitats, and, of course, larger factories. Ultimately, space manufacturing facilities can hypothetically become nearly self-sustaining, requiring only minimal imports from the Earth. The microgravity environment allows for new possibilities in construction on a massive scale, including megascale engineering. These future projects might potentially assemble space elevators, massive solar array farms, very high capacity spacecraft, and rotating habitats capable of sustaining populations of tens of thousands of people in Earth-like conditions.

See also


  1. ^ Staff (July 18, 2007). "Columbus laboratory". ESA. Retrieved 2007-07-18.
  2. ^ Eric Cardiff of NASA's Goddard Space Flight Center, as quoted at
  3. ^

External links

Friday, 24 October 2008

Para Peraih Nobel

Penghargaan Nobel dianugrahkan setiap tahun kepada mereka yang telah melakukan penelitian yang luar biasa, menemukan teknik atau peralatan yang baru atau telah melakukan kontribusi luar biasa ke masyarakat. Hal ini saat ini dianggap sebagai penghargaan tertinggi bagi mereka yang mempunyai jasa besar terhadap dunia. 

Penghargaan Nobel pertama kali diberikan berdasarkan wasiat Alfred Nobel, seorang industrialis Swedia, dan seorang penemu dinamit. Dia menandatangani wasiat tersebut di Swedish-Norwegian Club di Paris pada tanggal 27 November 1895

Hal ini dilakukan karena ia terkejut melihat hasil penemuannya justru dimanfaatkan untuk tujuan-tujuan yang merusak, dan dia menginginkan agar penghargaan Nobel diberikan kepada mereka yang berjasa besar terhadap kemanusiaan. 

People Who Got Nobel Prize
Tentang Penghargaan Nobel

Seremoni untuk penghargaan Nobel di bidang literatur, fisika, kimia dan obat-obatan pertama kali diadakan di Old Royal Academy of Music di Stockholm pada tahun 1901. Sejak tahun 1902, penghargaan ini secara formal dianugrahkan oleh Raja Swedia. Awalnya, Raja Oscar II tidak menyetujui pemberian penghargaan kepada orang asing, namun kemudian beliau mengubah sikapnya, setelah menyadari nilai publisitas penghargaan tersebut terhadap negara Swedia.

Penghargaan Nobel dianugrahkan setiap tahunnya pada tanggal 10 Desember, yaitu tanggal Alfred Nobel wafat. Biasanya, nama calon penerima diumumkan pada bulan Oktober oleh komite dan institusi yang berwenang sebagai badan seleksi penerima penghargaan.

Kategori Penghargaan

Penghargaan dianugrahkan setiap tahun sejak 1901 untuk pencapaian dalam:
Setelah Nobel meninggal ternyata dia belum meminta badan penentuan apakah mereka bersedia menjalani tugasnya; mereka memutuskan untuk melakukannya setelah begitu banyak keraguan.

Dalam 1968, Sveriges Riksbank, Bank Swedia, menambah "Penghargaan dalam Sains Ekonomi untuk mengenang Alfred Nobel".
  • Ekonomi (ditentukan oleh Royal Swedish Academy of Sciences)
Oleh karena penghargaan ini tidak berdasarkan keinginan Nobel, dan tidak dibayar dengan uangnya, secara teknis ini bukan Penghargaan Nobel (dan keluarga Nobel sekarang juga tidak menerimanya).

Tetapi penghargaan ini diberikan bersamaan dengan penghargaan Nobel.

Dalam 1968, ditetapkan keputusan untuk tidak menambah penghargaan lainnya "untuk mengenang Nobel".

Dalam Februari 1995, penghargaan ekonomi dinamai penghargaan ilmu sosial, membuka kesempatan bagi bidang ilmu politik, psikologi, dan sosiologi. Komite penghargaan ekonomi ini juga memasukkan 2 orang non-ekonom, dimana sebelumnya terdiri dari 5 orang ekonom.

Ucapan Terima Kasih;

1. DEPDIKNAS Republik Indonesia
2. Kementian Riset dan Teknologi Indonesia
3. Lembaga Ilmu Pengetahuan Indonesia (LIPI)
4. Akademi Ilmu Pengetahuan Indonesia

Disusun Ulang Oleh:

Arip Nurahman
Pendidikan Fisika FPMIPA Universitas Pendidikan Indonesia
Follower Open Course Ware at MIT-Harvard University, USA

Semoga Bermanfaat  dan Terima Kasih

Monday, 20 October 2008

Sciences Behind Angels and Demons

In Angels & Demons Tom Hanks plays Harvard academic Robert Langdon, who discovers evidence of the resurgence of an ancient secret brotherhood called the Illuminati - the most powerful underground organization in history.
When Langdon finds evidence that the Illuminati have stolen antimatter from a secret laboratory at CERN, which they plan to use as a devastating weapon to destroy the Vatican, he and CERN scientist Vittoria Vetra begin a race against time to recover the antimatter and prevent catastrophe.
But what is antimatter? Is is real? Is it dangerous? What is CERN?

Is it possible to make a bomb out of antimatter?

Large-scale annihilation of antimatter and matter could theoretically be used in a destructive way - but could it be used to make a bomb?

Does antimatter exist?

Matter's secret twin? This sounds like science fiction - is it?

Tuesday, 14 October 2008

Astrophysics for Poets


A Vast and most Excellent Science

How often at night
When the heavens were bright
with the light of the glittering Star and Moon
have I stood there amazed and asked as I gazed
if their glory exceeds that of ours.

Pengalaman adalah:

Jika Hidup ini seumpama rel kereta api dalam eksperimen relativitas
maka pengalaman demi pengalaman yang mengempur kita dari waktu ke waktu
adalah cahaya yang melesat-lesat di dalam gerebong di atas rel itu.
Relativitasnya berupa seberapa banyak kita dapat mengambil pelajaran dari pengalaman yang melesat-lesat itu,
maka analoginya adalah jika pengalaman yang sama dapat menimpa siapa saja,
namun sejauh mana dan secepat apa pengalaman itu memberi pelajaran pada seseorang,
hasilnya akan berbeda, relatif satu sama lain.
-Andrea H-

Anyone who has never made a mistake has never tried anything new.

E= mc2 and All That

What is matter? - Never mind.
What is mind? - It doesn't matter.

The Birth of Relativity

But in Physics I soon learned to scent out the paths that led to the depths, and to disregard everything else, all the many things that clutter up the mind, and divert it from the essential, the hitch in all this was, of course, the fact that one had to cram all this stuff into one's mind for the examination, whether one liked it or not.

"The Velocity of light is the same for all observers, in all direction, regardless of the motion of either the observer or the light source"

The Wedding of Space and Time

Light laugh:"There's no use trying."
He said:"One cannot believe impossible things."
"I dare say you haven't had much practice" said Moon
"When I was your age, I always did it for 2 hours a day. Why, sometimes I've believed in as many as 8 impossible things before breakfast.

Space-Time: The Fourth Dimension

S2 = L2-(ct)2 = Lo2
Where: L = Distance between two poles way greater than Lo
S = Space-Time separation is equal to Lo
c = Speed of Light
t = Time

-Albert Einstein-

One Last Part for the Machine

With Earth's first clay they did, the last man knead
there of the last Harvest sowed the seed:
And the first Morning of Creation wrote what the last Dawn
of Reckoning shall read.

F=k qQ/r2 (Charles Coulomb law)
where: F= Force of Electricity,
k= a Universal constant,
qQ= are the electric charges to express this in a formula, we define something called"field strength" E,
Coulomb's law become two formulas. E=kQ/r2 & F= qE
-Fitz Gerald, the Rubaiyat of Omar K.-


There is something Fascinating about science. one gets such whole sale returns of conjecture out such trifling investments of fact.

-Mark Twain-

Does the Earth Really Move?

It may be that it does not move, or moves but for some other reason:
Then let it be your boast to prove
(though some may think it out of season and worthily of a fossil Druid )
There is no Electric Fluid.

-James Clerk Maxwell-

Did God Have any Choice?

Within every creature incarnate sleeps the infinite Intelligent unevolved,
hidden, unfelt, unknown-yet destined from all eternities to waken at last,
to rend away the ghostly web of sensuous mind, to break forever it's chrysalises
of flesh, and to pass to the extreme conquest of Space and Time.


"What really interests me is whether God had any choice
in the creation of the world" (H2O)

The Atoms Returns

The telescope at one end of his beat
and at the other end the microscope two
instruments of nearly equal hope

-Robert Frost-

The Universe is not only queerer than
we imagine, it is queerer than we can imagine

-J.B.S. Haldone.-

The Atom and the Quantum

Hail to Max Planck, Einstein, Bohr, Pauli, Broglie, Schrödinger, Feynman,
and Young man in the Future from the worshipful! You are the Master by
whom we are led. Awed by your cryptic and proud affirmations. Each of us,
driven half out of their head, still remains true to you
wouldn't say boo to you, Swallows your theories from Alpha to Zed,
Even if (drink to him, tankards must clink to him!) None of us fathoms
a word you have said

-George G.& H2O-

Particles and Waves

We are trapped by language to such
a degree that every attempt to formulate
insight is a play on words.
(2πrmv = n h)
n = 2πr/λ
n = an integral number
λ = wave length
h = Planck's Constant
2πr = Circle's Constant (Orbit equation)

-Niels Bohr& H2O-

Does God Play Dice?

But you tell me of an invisible planetary system
where electrons gravitate around a nucleus. You explain
this to me with an image, I realize then that you have been
reduced to poetry:
" I shall never know. I have the time to become indignant?
you have changed theories. so that the sciences that was
to teach me everything ends up in a hypothesis,
that lucidity founders in metaphor, that uncertainty
is resolved in a work of art

-A.Camus, The Myth of Sisyphus.-

Schrödinger's Cat

The law of chaos is the law
of ideas, of improvisations
and seasons of belief

The Dreams stuff is made of

Like a gleam in the darkness, we have appeared
for an instant from the black nothingness of the
ever-unconscious matter, in order to make good
the demands of reason and create a life worthy
of ourselves and of the Goal we only dimly perceive
-Andrei Sakharov-

Quantum field Theories
"The nature of a field is completely determined by
the properties of the particle that transmit it,
while the nature of a particle depends solely on
the ways in, which it couples to fields.

QED = Quantum Electrodynamic
α = e2/ħc
QCD = Quantum Color Dynamic (Quantum Foam)
rp = Second root of Għ/c3 = 1,6 x 10-35(power) it is Planck's Length

-Richard Feynman,Julian Schwinger, Murray Gell-mann and George zweig

The whole Shebang

I am astounded by people who want
to "know" the universe when it's hard
enough to find your way around the world

Tentang Harapan dan Mimpi


Arip Nurahman


"I Have A Dream"

I have a dream, a song to sing
To help me cope with anything
If you see the wonder (wonder) of a fairy tale
You can take the future even if you fail
I believe in angels
Something good in everything I see
I believe in angels
When I know the time is right for me
I'll cross the stream - I have a dream

Oh yeah
I have a dream (have a dream), a fantasy (fantasy)
To help me through (help me through) reality (reality)
And my destination (destination) makes it worth the while
Pushing through the darkness
([Mark:] pushing through the darkness baby)
Still another mile

I believe in angels
Something good in everything I see
([Mark:] everything I see yeah)
I believe in angels
([Mark:] I believe in angels )
When I know the time is right for me
([Mark:] time is right for me)
I'll cross the stream - I have a dream

I have a dream (oh yeah), a song to sing(song to sing)
To help me cope with anything
If you see the wonder (if you see the wonder) of a fairy tale (of a fairy tale)
You can take the future even if you fail (yeah yeah yeah yeah)
I believe in angels
Something good in everything I see (everything)
I believe in angels (yeah)
When I know the time is right for me (right for me)
I'll cross the stream (cross the stream) - I have a dream (have a dream)
I'll cross the stream (cross the stream) - I have a dream


"I HAVE A DREAM" (1963)

"I Have A Dream" is the popular name given to the historic public speech by Martin Luther King, Jr., when he spoke of his desire for a future where blacks and whites among others would coexist harmoniously as equals. King's delivery of the speech on August 28, 1963,

from the steps of the Lincoln Memorial during the March on Washington for Jobs and Freedom, was a defining moment of the American Civil Rights Movement. Delivered to over two hundred and fifty thousand civil rights supporters, the speech is often considered to be one of the greatest and most notable speeches in history and was ranked the top American speech of the 20th century by a 1999 poll of scholars of public address.[1] According to U.S. Congressman John Lewis, who also spoke that day as the President of the Student Non-Violent Coordinating Committee, "Dr. King had the power, the ability and the capacity to transform those steps on the Lincoln Memorial into a modern day pulpit. By speaking the way he did, he educated, he inspired, he informed not just the people there, but people throughout America and unborn generations."[2]
At the end of the speech, King departed from his prepared text for a partly improvised peroration on the theme of "I have a dream", possibly prompted by Mahalia Jackson's cry "Tell them about the dream, Martin!".[3] He had delivered a speech incorporating some of the same sections in Detroit in June 1963, when he marched on Woodward Avenue with Walter Reuther and the Rev. C.L. Franklin, and had rehearsed other parts.[4]

"I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation.
Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of their captivity.
But 100 years later, the Negro still is not free. One hundred years later, the life of the Negro is still sadly crippled by the manacles of segregation and the chains of discrimination. One hundred years later, the Negro lives on a lonely island of poverty in the midst of a vast ocean of material prosperity. One hundred years later, the Negro is still languished in the corners of American society and finds himself an exile in his own land. And so we've come here today to dramatize a shameful condition.
In a sense we've come to our nation's capital to cash a check. When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men - yes, black men as well as white men - would be guaranteed the unalienable rights of life, liberty, and the pursuit of happiness.
It is obvious today that America has defaulted on this promissory note insofar as her citizens of color are concerned. Instead of honoring this sacred obligation, America has given the Negro people a bad check, a check that has come back marked "insufficient funds."
But we refuse to believe that the bank of justice is bankrupt. We refuse to believe that there are insufficient funds in the great vaults of opportunity of this nation. And so we've come to cash this check, a check that will give us upon demand the riches of freedom and security of justice. We have also come to his hallowed spot to remind America of the fierce urgency of now. This is no time to engage in the luxury of cooling off or to take the tranquilizing drug of gradualism. Now is the time to make real the promises of democracy. Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice. Now is the time to lift our nation from the quicksands of racial injustice to the solid rock of brotherhood. Now is the time to make justice a reality for all of God's children.
It would be fatal for the nation to overlook the urgency of the moment. This sweltering summer of the Negro's legitimate discontent will not pass until there is an invigorating autumn of freedom and equality. Nineteen sixty-three is not an end but a beginning. Those who hoped that the Negro needed to blow off steam and will now be content will have a rude awakening if the nation returns to business as usual. There will be neither rest nor tranquility in America until the Negro is granted his citizenship rights. The whirlwinds of revolt will continue to shake the foundations of our nation until the bright day of justice emerges.
But there is something that I must say to my people who stand on the warm threshold which leads into the palace of justice. In the process of gaining our rightful place we must not be guilty of wrongful deeds. Let us not seek to satisfy our thirst for freedom by drinking from the cup of bitterness and hatred. We must forever conduct our struggle on the high plane of dignity and discipline. We must not allow our creative protest to degenerate into physical violence. Again and again we must rise to the majestic heights of meeting physical force with soul force. The marvelous new militancy which has engulfed the Negro community must not lead us to a distrust of all white people, for many of our white brothers, as evidenced by their presence here today, have come to realize that their destiny is tied up with our destiny. And they have come to realize that their freedom is inextricably bound to our freedom. We cannot walk alone.
And as we walk, we must make the pledge that we shall always march ahead. We cannot turn back. There are those who are asking the devotees of civil rights, "When will you be satisfied?" We can never be satisfied as long as the Negro is the victim of the unspeakable horrors of police brutality. We can never be satisfied as long as our bodies, heavy with the fatigue of travel, cannot gain lodging in the motels of the highways and the hotels of the cities. We cannot be satisfied as long as the Negro's basic mobility is from a smaller ghetto to a larger one. We can never be satisfied as long as our children are stripped of their self hood and robbed of their dignity by signs stating "for whites only." We cannot be satisfied as long as a Negro in Mississippi cannot vote and a Negro in New York believes he has nothing for which to vote. No, no we are not satisfied and we will not be satisfied until justice rolls down like waters and righteousness like a mighty stream.
I am not unmindful that some of you have come here out of great trials and tribulations. Some of you have come fresh from narrow jail cells. Some of you have come from areas where your quest for freedom left you battered by storms of persecution and staggered by the winds of police brutality. You have been the veterans of creative suffering. Continue to work with the faith that unearned suffering is redemptive.
Go back to Mississippi, go back to Alabama, go back to South Carolina, go back to Georgia, go back to Louisiana, go back to the slums and ghettos of our northern cities, knowing that somehow this situation can and will be changed.
Let us not wallow in the valley of despair. I say to you today my friends - so even though we face the difficulties of today and tomorrow, I still have a dream. It is a dream deeply rooted in the American dream.
I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self-evident, that all men are created equal."
I have a dream that one day on the red hills of Georgia the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood.
I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice.
I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.
I have a dream today.
I have a dream that one day down in Alabama, with its vicious racists, with its governor having his lips dripping with the words of interposition and nullification - one day right there in Alabama little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers.
I have a dream today.
I have a dream that one day every valley shall be exalted, and every hill and mountain shall be made low, the rough places will be made plain, and the crooked places will be made straight, and the glory of the Lord shall be revealed and all flesh shall see it together.
This is our hope. This is the faith that I go back to the South with. With this faith we will be able to hew out of the mountain of despair a stone of hope. With this faith we will be able to transform the jangling discords of our nation into a beautiful symphony of brotherhood. With this faith we will be able to work together, to pray together, to struggle together, to go to jail together, to stand up for freedom together, knowing that we will be free one day.
This will be the day, this will be the day when all of God's children will be able to sing with new meaning "My country 'tis of thee, sweet land of liberty, of thee I sing. Land where my father's died, land of the Pilgrim's pride, from every mountainside, let freedom ring!"
And if America is to be a great nation, this must become true. And so let freedom ring from the prodigious hilltops of New Hampshire. Let freedom ring from the mighty mountains of New York. Let freedom ring from the heightening Alleghenies of Pennsylvania.
Let freedom ring from the snow-capped Rockies of Colorado. Let freedom ring from the curvaceous slopes of California.
But not only that; let freedom ring from Stone Mountain of Georgia.
Let freedom ring from Lookout Mountain of Tennessee.
Let freedom ring from every hill and molehill of Mississippi - from every mountainside.
Let freedom ring. And when this happens, and when we allow freedom ring - when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God's children - black men and white men, Jews and Gentiles, Protestants and Catholics - will be able to join hands and sing in the words of the old Negro spiritual: "Free at last! Free at last! Thank God Almighty, we are free at last!"
(8 OKTOBER 2008 PUKUL; 00:01)