Black Brant IX Rocket (IMAGE) NASA/Goddard Space Flight Center Caption This Black Brant IX rocket carried two instruments designed to study charge exchange, a physical phenomenon that occurs when the solar wind collides with Earth's exosphere and neutral gas in interplanetary space. Credit Credit: NASA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.