System-level design trades for the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS)

The Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) is a proposed mission being considered by NASA to take high resolution sky images at the submillimeter wavelengths. At these wavelengths, we can observe highly red-shifted light that has been traveling towards the Earth over a great deal of time, allowing observation of the developing universe in the distant past. To achieve Hubble class resolution, the system must synthesize an aperture that is 1000 meters in diameter, making interferometry the only currently reasonable approach to design. This paper addresses a high level system trade of a general class of rotating tethered architectures that reel apertures in and out radially to fill the u-v plane. A metric of cost per image is used to identify how aperture area and number of apertures should be selected, and considerations of how spectral information is acquired is used to generate design ideas for reducing the overall system mass.