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 You are in: Under Secretary for Arms Control and International Security > Bureau of International Security and Nonproliferation (ISN) > Releases > Fact Sheets > 2002
Fact Sheet
Bureau of Arms Control
Washington, DC
August 14, 2002

Open Skies Treaty

Origin and Purpose

The Treaty on Open Skies establishes a regime of unarmed aerial observation flights over the entire territory of its participants. The Treaty is designed to enhance mutual understanding and confidence by giving all participants, regardless of size, a direct role in gathering information about military forces and activities of concern to them. Open Skies is the most wide-ranging international effort to date to promote openness and transparency of military forces and activities. The original concept of mutual aerial observation was proposed by President Eisenhower in 1955; the Treaty itself was an initiative of President George H.W. Bush in 1989. The Treaty was negotiated by the then-members of NATO and the Warsaw Pact, and was signed in Helsinki, Finland, on March 24, 1992. The United States ratified it in 1993. The Treaty entered into force on January 1, 2002.

Membership and Area of Application

The 26 States Parties to the Open Skies Treaty are: Belarus, Belgium, Bulgaria, Canada, Czech Republic, Denmark, France, Georgia, Germany, Greece, Hungary, Iceland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Slovak Republic, Spain, Turkey, United Kingdom, Ukraine, and United States. Kyrgyzstan has signed but not yet ratified. The Treaty depositaries are Canada and Hungary. The Open Skies regime covers the national territories - land, islands, and internal and territorial waters - of all the States Parties, and thus includes the territory of most member states of the Organization for Security and Cooperation in Europe (OSCE). The Treaty is of unlimited duration and open to accession by other states as follows: (1) states of the former Soviet Union that have not already become States Parties to the Treaty may accede to it at any time; (2) other members of the OSCE may apply for accession to the Treaty at any time; (3) any other interested state may apply for accession to the Treaty six months after it enters into force (i.e., from July 1, 2002 onward). All applications for accession (i.e., categories 2 and 3 above) are subject to a consensus decision by the Open Skies Consultative Commission (OSCC), the Vienna-based organization charged with facilitating implementation of the Treaty, to which all States Parties belong. So far, the OSCC has approved applications for accession by Finland, Sweden, Lithuania, Latvia, Croatia, and Bosnia-Herzegovina -- all of which are members of the OSCE.

Basic Elements of the Treaty

  • Territory. The Treaty specifies that all territory of the States Parties is open to observation on a reciprocal basis. Observed States Parties may restrict observation flights only for reasons of flight safety and not for reasons of national security.
  • Aircraft. Observation aircraft may be provided by either the observing state party or (the "taxi option") by the observed state party, at the latter's choice. All Open Skies aircraft and sensors must pass specific certification and pre-flight inspection procedures to ensure that they meet Treaty standards and that only Treaty-permitted sensors are installed. The official U.S. Open Skies aircraft is the OC-135B (a military version of the Boeing 707).
  • Sensors. Open Skies aircraft may have video, optical panoramic and framing cameras for daylight photography, infra-red line scanners for a day/night capability, and synthetic aperture radar for a day/night all weather capability. Photographic image quality will permit recognition of major military equipment (e.g., permit a State Party to distinguish between a tank and a truck), thus allowing significant transparency of military forces and activities. Sensor categories may be added and capabilities improved by agreement among States Parties. All equipment used in Open Skies must be commercially available to all participants in the regime.
  • Quotas. Each State Party has agreed to an annual quota of observation flights it is willing to receive - its passive quota of observation flights. Each State Party may conduct as many observation flights - its active quota - as its passive quota. During the first three years after EIF, each State will be obliged to accept no more than seventy-five percent of its passive quota. Since the overall annual passive quota for the United States is 42, this means that it will be obligated to accept no more than 31 observation flights a year during this three-year period. Only 4 of the 31 potential flights over the United States were requested during the first year of Treaty operation, all by Russia/Belarus (which functions as a single country for quota allocation purposes). During this period (2002/03), the United States is entitled to 8 of the 31 annual flights available over Russia/Belarus. Additionally, the United States is entitled to one flight over Ukraine, to be shared with Canada.
  • Data Sharing/Availability. Collected imagery from Open Skies missions will be available to any State Party willing to pay the costs of reproduction. The Treaty provides that at the request of any State Party, the observing state will provide it a copy of the data collected during a mission over the observed state. As a result, the data available to each State Party is much greater than that which it can collect itself under the Treaty quota system.

Implementation of the Treaty

Provisional application of portions of the Treaty took place from signature in 1992 until entry into force in 2002. During that period, participants conducted joint trial flights for the purpose of training flight crews and testing equipment and sensors. Now that the Treaty has entered into force, formal observation flights have begun in August 2002 -- in accordance with the agreed distribution of active and passive quotas -- starting with a Russian mission over the United Kingdom (August 6-9). During the fourth quarter of 2002, France, the UK, and Italy are also planning to conduct missions over Russia/Belarus.

Since the signature of the Open Skies Treaty in 1992, the security environment in Europe has changed significantly. Nevertheless, the Open Skies Treaty remains an important element of the European security structure, along with the Treaty on Conventional Armed Forces in Europe (CFE), and the Vienna Document 1999 Agreement on Confidence-and Security-Building Measures (CSBMS) under the auspices of the OSCE.

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