NASAs #DARTMission is crashing a spacecraft into an asteroid to try to change its motion in space. But how will we know if this test worked? Thats where Johns Hopkins APL scientist Andy Rivkin comes in. Hell be studying the precise change in the asteroids motion right here from Earth. Have questions about DART? Submit them using #askNASA and tune in on Monday, Nov. 15 at 4:30 pm ET for a LIVE Q&A with Andy.