This open document is a proposal to begin serious international consultation on the question of future
attempts deliberately to transmit electromagnetic signals from Earth to extraterrestrial civilizations. It was
prepared over a number of years in the SETI Committee of the International Academy of Astronautics by
a special subcommittee under the leadership of Michael Michaud. It has been endorsed by the Board of
Trustees of the Academy, which decided to make it a formal Academy Position Paper. It has also been
endorsed by the Board of Directors of the International Institute of Space Law. Both organizations consider
that the questions raised in the document are of sufficient import to warrant sending it to many nations with
a request that they consider bringing it to the attention of the Committee of the Peaceful Uses of Outer Space
of the United Nations, for further study, and possible action, on behalf of all humankind. To begin this
process, letters will be going out to the COPUOS nations shortly.
International Academy of Astronautics
March 22, 1996
Enclosure: IAA Position Paper
There is no copyright on this material.
International Academy of Astronautics Position Paper
A Decision Process for Examining the Possibility of Sending Communications to Extraterrestrial
This position paper outlines an approach to an international process for deciding whether and how to send
a communication to an extraterrestrial civilization.
For over thirty years, humans have used radio technology to conduct searches for evidence of extraterrestrial
intelligence (ETI). Collectively, these efforts are known as the Search for Extraterrestrial Intelligence
If SETI is successful in detecting an extraterrestrial civilization, it will raise the question of whether and how
humanity should attempt to communicate with the other civilization. How should that decision be made?
What should be the content of such a message? Who should decide? The same questions would apply to
proposals that signals be sent in the absence of detection, in the hope that they might be detected by an
The first section of this paper introduces the idea of extraterrestrial intelligent life, and describes our growing
scientific and technological capabilities for SETI. The second section addresses the issue of humanity's
sending a communication. The third section proposes the development of a Declaration of Principles
concerning the sending of communications to extraterrestrial intelligence.
I. The Science of SETI
Speculation about life on other worlds has a very long history, dating back at least as far as Classical Greece.
The Copernican revolution, which displaced the Earth from the center of the universe, accelerated
speculation about intelligent life elsewhere, as other worlds came to seem more equal to our own1.
Subsequent advances in astronomy and the study of evolution have made it seem more probable that life,
including intelligent life, may be widespread in the universe. The central hypothesis of SETI is that we have
the means to detect evidence of extraterrestrial civilizations, particularly the electromagnetic signals they
In 1959, Giuseppe Cocconi and Philip Morrison, noting the existence of powerful radio telescopes, proposed
that a search be made at frequencies near the hydrogen line (21 centimeters)2. In 1960, the American radio
astronomer Frank Drake independently carried out the first search using a radio telescope, aiming at two
nearby stars3. Since then, about sixty other searches have been carried out by American, Russian, Canadian,
French, and Argentine astronomers, though without detecting credible evidence of ETI4.
Within the radio spectrum, there is a region known as the free space microwave window, between 1
gigahertz and 60 gigahertz. This is the quietest region of the radio spectrum; it is the region in which it is
easiest to detect a faint radio signal emanating from another civilization against the noise of the natural
background. The 21 centimeter line is at the low frequency end of this window. Most radio searches for
ETI have concentrated on this region of the radio spectrum.
While the scientific and technological sophistication of these searches has grown in recent years, the central
strategy of SETI remains to listen. However, proposals also have been made to send our own signals in the
hope that they will be detected by another civilization and will generate a response. Whichever strategy we
pursue, our improving capabilities are making detection more likely.
The signal we detect could range from a simple carrier wave conveying little information to a message rich
in information. The signal could have been transmitted to attract the attention of other civilizations, or we
might "overhear" internal communications of the other civilization. In either case, we would know for the
first time that we are not alone. Our conception of the universe and our future as a species surely would
change, as it did after the Copernican revolution. Information from the other civilization could have a
significant impact on our science and our culture.
Ten years ago, the SETI Committee of the International Academy of Astronautics began discussing the
question of what Humankind should do after a detection. One result of these exchanges was a series of
papers in a Special Issue of Acta Astronautica, entitled "SETI Post Detection Protocol"5. The discussions
also led to the formulation of a "Declaration of Principles Concerning Activities Following the Detection
of Extraterrestrial Intelligence" (see Annex I, for full text or SPIE's OSETI I Proceedings). This document,
which is intended for voluntary agreement among researchers, has been endorsed by six international space
and astronomy organizations. While most of the principles in the Declaration deal with the dissemination
of knowledge of the discovery, one principle deals with the question of sending a communication in
response to the discovery.
II. Sending a Communication from Earth
Detecting a signal from an extraterrestrial civilization would raise an important question: should we humans
send a message back to the civilization that we have detected, a "response from Earth"? This issue also has
been examined by a number of interested persons during recent years, notably in the SETI Committee of the
International Academy of Astronautics. Proposals to send messages to attract the attention of other
civilizations we have not yet detected (sometimes called "active SETI") raise essentially the same question6.
One approach would be to make no effort to prepare for this eventuality, addressing the question at the time
of a discovery. Another approach is to begin to address the question now, even in the absence of confirmed
evidence of extraterrestrial intelligence. Such a discussion could lead to the development of an agreement
or procedure on this issue.
Principle 8 of the Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial
Intelligence states that "No response to a signal or other evidence of extraterrestrial intelligence should be
until appropriate international consultations have taken place. The procedures for such consultations will
be the subject of a separate agreement, declaration, or arrangement.".
The substance of such a response has been discussed by several authors in recent years. In the mid-1980s,
Goodman and Ney proposed international agreements on this issue7, and Goldsmith proposed that the
International Astronautical Federation and the International Astronomical Union create a committee to
attempt to reach a consensus on an international "reply from Earth"8. More recently, Michaud et al. have
proposed that an agreement be developed creating an international process by which the species would
decide whether and how to reply if a detection is made9.
However one chooses to address this issue, an array of questions emerges. One is whether it is worth the
expenditure of any significant effort to address the question now. It could be years, decades, or even
centuries before we detect a signal, if we ever do. Despite this uncertainty, the fact remains that we could
detect a signal in the near future, particularly because of the increased scale and sensitivity of SETI searches.
If we decide that this question is worth addressing, how should we go about it? Should we make a decision
in advance of a detection that humanity should or should not send a message? Should we attempt to design
a generic response, or should we wait until we have a signal to analyze? If we decide to send a message,
what should be its content? Should humanity respond as one, or with many different messages from
separate nations or organizations? Who should decide on these questions?
The issues involved in sending messages to extraterrestrial civilizations raise profound philosophical and
political questions. These questions are of such weight for the future of our own civilization as to merit
extensive discussion, perhaps over a period of many years.
There also is the question of the institutional context for such discussions. Clearly, sending a message to
another civilization is more than just a scientific research project; it is a policy question that should be
addressed by policy bodies. The most universal of existing international policy bodies is the United
Nations; ultimately, it would seem appropriate for the issue to be addressed there, beginning with the
Committee on the Peaceful Uses of Outer Space (COPUOS). However, given their existing agendas of more
politically pressing issues, United Nations bodies would be unlikely to give much attention to SETI issues
in advance of a confirmed detection of a signal.
The initial work could begin outside the United Nations, perhaps in interested non-governmental bodies.
As a starting point, the International Academy of Astronautics, in consultation with the International Institute
of Space Law, has developed, as part of this proposal (See III below), a draft agreement or declaration of
principles for consideration by others. In the initial stages, this draft agreement or declaration could be a
focal point for discussion rather than a finished, formal document. Many mechanisms can be used to
stimulate discussion, including workshops, public debates, university seminars, and media coverage. This
implies a long, complex process that is unlikely to produce a quick agreement. Given the magnitude of the
questions involved, it will be important to allow time for the development of some degree of consensus.
International non-governmental organizations cannot themselves introduce matters for discussion by
COPUOS; only member governments can do this. If a draft agreement or declaration were developed, one
or more of the member governments would have to be persuaded to introduce it. This draft could then be
considered by the United Nations, through the COPUOS, and might be endorsed by the COPUOS and the
General Assembly as international policy.
Periodic reports or presentations by interested non-government bodies to the COPUOS would be useful to
keep governments informed and to facilitate subsequent approval of a draft declaration. If a signal were
received and confirmed, the COPUOS might be willing to devote more time and attention to the issue and
III. A Draft Declaration of Principles Concerning Sending Communications to Extraterrestrial
Rather than trying to decide the substance of our decisions in advance, it may be more fruitful to focus on
the process by which the human species as a whole might decide whether and how to send a message. It
probably is premature to try to develop the text of a formal international agreement on the subject. However,
this is not the only option. A technique used with some success in the United Nations system is to first
address issues through the development of non-binding declarations of principles. For example, the Outer
Space Treaty of 1967 originated from such a declaration. A declaration of principles could establish
consensus on procedures enabling all humans, through appropriate representatives, to participate in the
making of decisions on the sending of communications to an extraterrestrial civilization.
As a starting point for discussion, the draft agreement or declaration might include the following basic
1. The decision on whether or not to send a message to extraterrestrial intelligence should be made by an
appropriate international body, broadly representative of Humankind.
2. If a decision is made to send a message to extraterrestrial intelligence, it should be sent on behalf of all
Humankind, rather than from individual States or groups.
3. The content of such a message should be developed through an appropriate international process,
reflecting a broad consensus.
Annex 2 presents a proposed text of a declaration of principles on the sending of a communication to
extraterrestrial intelligence. This is simply a draft, to be revised as necessary in later discussions. However,
it provides a starting point for an important and intellectually exciting debate with potentially profound
1. Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence
2. Draft Declaration of Principles Concerning Sending Communications with Extraterrestrial Intelligence
Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence
We, the institutions and individuals participating in the search for extraterrestrial intelligence,
Recognizing that the search for extraterrestrial intelligence is an integral part of space exploration and is
being undertaken for peaceful purposes and for the common interest of all mankind,
Inspired by the profound significance for mankind of detecting evidence of extraterrestrial intelligence, even
though the probability of detection may be low,
Recalling the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer
Space, Including the Moon and Other Celestial Bodies, which commits States Parties to that Treaty "to
inform the Secretary General of the United Nations as well as the public and the international scientific
community, to the greatest extent feasible and practicable, of the nature, conduct, locations and results" of
their space exploration activities (Article XI),
Recognizing that any initial detection may be incomplete or ambiguous and thus require careful examination
as well as confirmation, and that it is essential to maintain the highest standards of scientific responsibility
Agree to observe the following principles for disseminating information about the detection of
1. Any individual, public or private research institution, or governmental agency that believes it has
detected a signal from or other evidence of extraterrestrial intelligence (the discoverer) should seek to
verify that the most plausible explanation for the evidence is the existence of extraterrestrial intelligence
rather than some other natural phenomenon or anthropogenic phenomenon before making any public
announcement. If the evidence cannot be confirmed as indicating the existence of extraterrestrial
intelligence, the discoverer may disseminate the information as appropriate to the discovery of any
2. Prior to making a public announcement that evidence of extraterrestrial intelligence has been detected,
the discoverer should promptly inform all other observers or research organizations that are parties to
this declaration, so that those other parties may seek to confirm the discovery by independent
observations at other sites and so that a network can be established to enable continuous monitoring
of the signal or phenomenon. Parties to this declaration should not make any public announcement of
this information until it is determined whether this information is or is not credible evidence of the
existence of extraterrestrial intelligence. The discoverer should inform his/her or its relevant national
3. After concluding that the discovery appears to be credible evidence of extraterrestrial intelligence, and
after informing other parties to this declaration, the discoverer should inform observers throughout the
world through the Central Bureau for Astronomical Telegrams of the International Astronomical Union,
and should inform the Secretary General of the United Nations in accordance with Article XI of the
Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space,
Including the Moon and Other Bodies. Because of their demonstrated interest in and expertise
concerning the question of the existence of extraterrestrial intelligence, the discoverer should
simultaneously inform the following international institutions of the discovery and should provide them
with all pertinent data and recorded information concerning the evidence: the International
Telecommunication Union, the Committee on Space Research, of the International Council of Scientific
Unions, the International Astronautical Federation, the International Academy of Astronautics, the
International Institute of Space Law, Commission 51 of the International Astronomical Union, and
Commission J of the International Radio Science Union.
4. A confirmed detection of extraterrestrial intelligence should be disseminated promptly, openly, and
widely through scientific channels and public media, observing the procedures in this declaration. The
discoverer should have the privilege of making the first public announcement.
5. All data necessary for confirmation of detection should be made available to the international scientific
community through publications, meetings, conferences, and other appropriate means.
6. The discovery should be confirmed and monitored and any data bearing on the evidence of
extraterrestrial intelligence should be recorded and stored permanently to the greatest extent feasible
and practicable, in a form that will make it available for further analysis and interpretation. These
recordings should be made available to the international institutions listed above and to members of the
scientific community for further objective analysis and interpretation.
7. If the evidence of detection is in the form of electromagnetic signals, the parties to this declaration
should seek international agreement to protect the appropriate frequencies by exercising procedures
available through the International Telecommunication Union. Immediate notice should be sent to the
Secretary General of the ITU in Geneva, who may include a request to minimize transmissions on the
relevant frequencies in the Weekly Circular. The Secretariat, in conjunction with advice of the Union's
Administrative Council, should explore the feasibility and utility of convening an Extraordinary
Administrative Radio Conference to deal with the matter, subject to the opinions of the member
Administrations of the ITU.
8. No response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate
international consultations have taken place. The procedures for such consultations will be the subject
of a separate agreement, declaration or arrangement.
9. The SETI Committee of the International Academy of Astronautics, in coordination with Commission
51 of the International Astronomical Union, will conduct a continuing review of procedures for the
detection of extraterrestrial intelligence and the subsequent handling of the data. Should credible
evidence of extraterrestrial intelligence be discovered, an international committee of scientists and other
experts should be established to serve as a focal point for continuing analysis of all observational
evidence collected in the aftermath of the discovery, and also to provide advice on the release of
information to the public. This committee should be constituted from representatives of each of the
international institutions listed above and such other members as the committee may deem necessary.
To facilitate the convocation of such a committee at some unknown time in the future, the SETI
Committee of the International Academy of Astronautics should initiate and maintain a current list of
willing representatives from each of the international institutions listed above, as well as other
individuals with relevant skills, and should make that list continuously available through the Secretariat
of the International Academy of Astronautics. The International Academy of Astronautics will act as
the Depository for this declaration and will annually provide a current list of parties to all the parties
to this declaration.
Draft Declaration of Principles Concerning the Sending of Communications to Extraterrestrial
The States participating in this Declaration,
Recognizing that a scientific search for evidence of extraterrestrial intelligence is being conducted with
increasingly effective means,
Acknowledging the possibility of discovering such evidence,
Recognizing the potentially profound importance of such a discovery for Humankind,
Noting the existence of procedures for the verification and announcement of a detection of evidence of
Conscious of the question of whether and how Humankind should send a communication to extraterrestrial
Desiring to establish an orderly process for dealing with that question,
Agree to the following Principles:
International consultations should be initiated to consider the question of sending communications to
Consultations on whether a message should be sent, and its content, should take place within the Committee
on the Peaceful Uses of Outer Space of the United Nations and within other governmental and
non-governmental organizations, and should accommodate participation by qualified, interested groups that
can contribute constructively to these consultations.
These consultations should be open to participation by all interested States and should be intended to lead
to recommendations reflecting a consensus.
The United Nations General Assembly should consider making the decision on whether or not to send a
message to extraterrestrial intelligence, and on what the content of that message should be, based on
recommendations from the Committee on the Peaceful Uses of Outer Space and from governmental and
If a decision is made to send a message to extraterrestrial intelligence, it should be sent on behalf of all
Humankind, rather than from individual States.
The content of such a message should reflect a careful concern for the broad interests and well-being of
Humanity, and should be made available to the public in advance of transmission.
As the sending of a communication to extraterrestrial intelligence could lead to an exchange of
communications separated by many years, consideration should be given to a long-term institutional
framework for such communications.
No communication to extraterrestrial intelligence should be sent by any State until appropriate international
consultations have taken place. States should not cooperate with attempts to communicate with
intelligence that do not conform to the principles in this Declaration.
In their deliberations on these questions, States participating in this Declaration and United Nations bodies
should draw on the expertise of scientists, scholars, and other persons with relevant knowledge.
Should a decision be made to send a communication, the encoding and transmission of the message should
be assigned to scientists and engineers specializing in the technologies required.
1. An elegant overview of the extraterrestrial life debate is provided by Karl S. Guthke in The Last
Frontier: Imagining Other Worlds, from the Copernican Revolution to Modern Science Fiction.
Cornell University Press, Ithaca and London (1990).
2. G. Cocconi and P. Morrison, "Searching for Interstellar Communications," Nature, Vol. 184, pp.
3. F.D. Drake, "Project Ozma." Physics Today, Vol. 14, pp. 40-46 (1961).
4. For recent surveys of SETI activities, see D. Goldsmith, "SETI: The Search Heats Up." Sky and
Telescope, pp. 141-143 (Feb. 1988), and J.C. Tarter, "SETI Observations Worldwide." The Search for
Extraterrestrial Life: Recent Developments, M.G. Papagiannis (Ed.), Reidel, Dordrecht, The
Netherlands, pp. 271-290 (1985).
5. See "SETI Post-Detection Protocol," a Special Issue of Acta Astronautica, Vol. 21, No. 2, J.C. Tarter
and M.A. Michaud (Eds.) (Feb. 1990).
6. See, for example, G.A. Lemarchand and D.E. Tarter, "Active Search Strategies and the SETI Protocols:
Is There a Conflict?" Space Policy, Vol. 10, No. 2, pp. 134-142 (May 1994).
7. See A.E. Goodman, "Diplomacy and the Search for Extraterrestrial Intelligence." Acta Astronautica,
Vol. 21, No. 2, pp. 137-142 (Feb. 1990), and P. Ney, "An Extraterrestrial Contact Treaty?" Journal of
the British Interplanetary Society, Vol. 38, pp. 521-522 (1985).
8. D. Goldsmith, "Who Will Speak For Earth?" Acta Astronautica, Op. Cit., pp. 149-151.
9. M.A. Michaud, J. Billingham, and J.C. Tarter, "A Reply From Earth: A Proposed Approach to
Developing a Message From Humankind to Extraterrestrial Intelligence." Paper presented at the
Congress of the International Astronautical Federation, Dresden, Germany (Oct. 1990).
Fonte – The Columbus Optical SETI Observatory