While some of the balloons will livestream 360-degree video and photos, others will collect data on what happens to Earth's atmosphere during a total solar eclipse. NASA's Nationwide Eclipse ...

They were thin-skinned Mylar balloon satellites. These gassed-up balloons — Echo 1 expanded to 100 feet (30.48 meters), while Echo 2 inflated to 135 feet (41 m) — tested the reflection of ...