Payload G-38

"Payload G-38 generates a new definition of space art, as art created in and about space. The artist can now use the tools and prokesses of space technology to participate in and comment on man's adventure in space. was created as a unified Arts-Science payload that simultaneously explored the process of vapor deposition in the vacuum and weightlessness of the shuttle environment and created a series of space sculptures utilizing this process; seeking to experience the mysteries of space.

The methods and results of G-38 supply useful data for simplified coatings of large antennae, heat shields, solar collectors and optical mirrors in space; where size is not limited to the confines of a vacuum chamber.

Two separate and distinctly different thin film deposition processes were used in G-38. of five 500ml glass spheres. into the surface of a negatively charged metal target mounted in the center of each sphere, target molecules were ejected by the impact of the argon ions and First, a sputter deposition process was perf,ormed on the interiors By accelerating positively charged argon ions formed a coating on the inside of each sphere over a period of hours. The purpose of the experiment was to test the sputter deposition process in space and to create five subtle spherical sculptures with metallic coatings of gold, silver, platinum andchrome. These five experiments all functioned in the expected manner but did not create coatings as dense as anticipated. was traced to apparent arching in the vacuum manifold during the ionization process, which limited the charge being transmitted to the target. Thus, sculptures that were intended to have metal coatings applied in space ranging from opaque to semitransparent, returned with all semitransparent coatings instead; an unexpected but not unpleasing result.

The ninth and largest sphere (22,000ml) served as a sampling system, allowing the measurement of the working vacuum when the payload returned to earth. This sphere was connected to space via a high vacuum valve. period the interior of the sphere attained an equilibrium with the vacuum of the shuttle orbit, becoming one with the vacuum of space. connecting the sphere to the valve was cold welded, permanently sealing the sphere, creating the sculpture "S.P.A.C.E.". Attached to the sphere is a Baratron capasitance manometer, a vacuum gauge capable of a digital reading of the vacuum forming the sculpture inside the sphere.

The sculpture "S.P.A.C.E." is not the glass, but the outer space contained within. The sphere serves only to keep the one-g earth atmosphere from intruding on the space within, creating an anomaly of our common experience; a sculpture to observe and stimulate wonder about the nature and meaning of space, a sculpture to touch and know that only an 1/8" of glass separates one from space."

Source:

https://ntrs.nasa.gov/api/citations/19860017825/downloads/19860017825.pdf