High altitude balloons. A scientist's guide to what's up there and why. Hear about it at Urban Legends and Stranger truths. When the Us. Government shot down a suspected surveillance balloon off the South Carolina coast on the 4 February, it ramped up geopolitical tensions with China and prompted officials to tighten their radar search for other high flying unidentified objects. Since then, the United States has shot down three more objects, which it now seems were probably not spy balloons at all