Possible Clues:

• Sounds as if the visitor from outer space becomes increasingly fleshy
• Earth threatener
• Has one's travelling in space made one put on weight, by the sound of it?
• Coming from space, one sounds less thin
• Space traveller needs gauge containing zero indicator
• Overnight success
• Body entering earth's atmosphere
• Body falling from space
• Small body of soldiers beyond boundary
• Measure, or bright streak