Article 15 Signature, Ratification and Accession 1. This Convention shall be open for signature by the States that took part in the Conference of Plenipotentiaries on the setting-up of a European Organisation for the Exploitation of Meteorological Satellites. 2. The said States shall become Parties to this Convention either — by signature not subject to ratification, acceptance or approval, or — by the deposit of an instrument of ratification, acceptance or approval with the depositary if the Convention was signed subject to ratification, acceptance or approval. 3. From the date of entry into force of this Convention, any State that did not take part in the Conference of Plenipotentiaries referred to in paragraph 1 of this Article may accede to it following a Council decision taken in conformity with the provisions of Article 5.2 (a). A State that wishes to accede to this Convention shall notify the Director accordingly and the latter shall inform the Member States of the request at least three months before it is submitted to the Council for decision. The Council shall determine the terms and conditions for the accession of the State in question, in conformity with Article 5.2 (a). 4. The instruments of ratification, acceptance, approval and accession shall be deposited with the Government of the Swiss Confederation, referred to as "the depositary".