WATCH LIVE: Memorial service underway at the National Cathedral to honor 7 World Central Kitchen workers killed by Israeli strikes in Gaza
JUST IN: Prince George’s Co. to enforce youth curfew at National Harbor starting Friday
LOCAL UPDATE: First cargo ship passes through newly opened channel in Baltimore since Francis Scott Key Bridge collapsed
WTOP Staff | WTOP_Web_Team@wtop.com
February 15, 2013, 2:50 PM
Greg Redfern, NASA ambassador to the solar system and space contributor to WTOP