A test rocket aimed at kickstarting satellite launches from Europe fell to the ground and exploded less than a minute after takeoff from a Norwegian spaceport on Sunday, in what the German startup Isar Aerospace had described as an initial test. The uncrewed Spectrum rocket was billed as the first attempt at an orbital flight to originate from Europe, where several nations, including Sweden and Britain, have said they want a share of the growing market for commercial space missions. Isar Aerospace, which had warned that the initial launch could end prematurely, said the test produced extensive data that its...