AST SpaceMobile (NASDAQ:ASTS), which went public in a SPAC-sponsored reverse merger last week, have declined more or less steadily ever since that event took place. They're down again today -- 9.9% as of 1:30 p.m. EDT. So what To refresh your memory, New Providence Acquisition touted AST SpaceMobile stock as a play on a "$1 trillion global mobile wireless services market" in which "five billion" potential customers would like to be able to use their ordinary cellphones to place calls via satellite. AST promised to make that happen by launching a constellation of satellites to carry the calls, using technology that "is highly proprietary" -- so much so that the company declined to disclose "exactly how it works."