We have designed a 7-element, SIS heterodyne array receiver
for the SMTO. The array will operate in the 870 
m atmospheric window,
with a tuning range between 315 and 380 GHz.
Due to the prevailing physical conditions in the interstellar medium,
this wavelength range is one of the richest in the submillimeter
portion of the spectrum. The 870 m window also has the highest
atmospheric transmission of any submillimeter band. An array designed
for this wavelength range will make excellent use of the telescope,
the available atmospheric transmission, and provide a new perspective
on stellar, chemical, and galaxy evolution in the present as well
as past epochs.
The proposed system uses the most sensitive detectors available in
an efficient, compact optical system. The instrument has the potential
of being the fastest and most sensitive heterodyne receiver ever to operate
in the 870 m window.