a program to develop a simple, foolproof, all-vacuum solar cell manufacturing process which can be completely automated and which results in medium efficiency cells which are inherently environmentally resistant is described. all components of the completed cells are integrated into a monolithic structure with no material interfaces. the exposed materials (si, al sub 2 o sub 3 , al, ni) are all resistant to atmospheric attack and the junction, per se, is passivated to prevent long term degradation. such cells are intended to be incorporated into a simple module consisting basically of a press-formed metallic superstructure with a separated glass cover for missile, etc., protection. a 5 cm x 5 cm test cell configuration was designed in which the various efficiency loss factors were adjusted to yield a 10 ami cell. each of the cell elements was individually optimized for combination with the others the basic cell consists of alloyed front (al) and back (ag plus ni) contacts, a multi-purpose (ar, hermetic seal, implantation oxide) front surface coating of al sub 2 o sub 3 , and an implanted front junction. implantation damage annealing and contact alloying are carried out in a simple one step thermal treatment at 870 exp 0 c using a resistance heated furnace in vacuum. the use of non-analyzed and semi-analyzed beams for fabricating these cells was developed by kci. a final lot of 50 cells made using the semi-analyzed beam method had an average efficiency of 10.4 at ami (28 +- 1 exp 0 c). an economic analysis predicts a manufacturing cost of $.45/peak-watt for these cells usi