WELLINGTON—New Zealand entrepreneur Peter Beck said his space firm Rocket Lab was the result of a lifelong quest for signs of life outside earth, as the startup hit a new milestone with a Nasdaq listing on Thursday. The small satellite launch firm, often compared to Tesla Inc CEO Elon Musk’s SpaceX, listed on the Nasdaq Composite on Thursday with a market capitalisation of about $4.4 billion. Rocket Lab agreed in March to go public through a merger with a blank-check firm backed by private equity firm Vector Capital, the latest in a series of space firm listings involving special purpose acquisition companies (SPAC). “For me personally, the biggest question that I can possibly answer in my lifetime, and the biggest question for everybody on earth really comes down to are we the only life in the universe or not,” Beck told Reuters from New Zealand after the listing. Growing up …