Abstract: A method for deploying an airtight envelope (8) around an object (1) comprising providing a cylindrical, elongated envelope with two mutually opposite poles (3, 9) at each of its ends, inverting this envelope on itself and longitudinally pleating it accordion-wise when in this inverted position, the pole (9) of this envelope (8) being in the inverted part and being solidly joined to the object (1), the opposite pole (3) being connected to the object (1) by a link mast (2) comprising a cylindrical balloon initially in the deflated state, the deployment of the envelope (8) comprising inflating the link mast until it is full, then inflating the envelope (8) until it is full and at which time it will be deployed around the object (1).

Abstract: A mounting structure for securing a payload such as a telescope or other sensitive optical bench, to a spacecraft, in such a manner that accleration loads are transferred to the telescope in a normal manner, but deformations in the spacecraft are isolated from the telescope. The mounting structure includes two trunnion supports and two keel supports, arranged to isolate the telescope from deformations caused by thermal gradients or other phenomena.