CREATE TABLE table_6856 ("Date" TEXT, "Rocket" TEXT, "Type" TEXT, "Launch site" TEXT, "Satellite" TEXT)

On what date was the rocket a TBD with a satellite of GPS IIIA-1?
SELECT "Date" FROM table_6856 WHERE "Rocket" = 'tbd' AND "Satellite" = 'gps iiia-1'
SELECT "Date" FROM "table_6856" WHERE "Rocket" = 'tbd' AND "Satellite" = 'gps iiia-1'