ARK, the investment firm founded by Cathie Wood, launched the much-awaited ARK Space Exploration & Innovation ETF (ARKX) on March 31. The fund was able to attract more than $500 million within a week, making it one of the most successful ETF launches ever.ARK and Cathie have huge retail following, thanks to excellent performance delivered by their actively managed ETFs last year. And even though those ETFs have struggled this year, investors continue to pour money into them.ARK uses a quite broad vision of space exploration and includes companies that benefit from better connectivity and navigation due to satellites. Netflix (NFLX), Amazon (AMZN), Alibaba (BABA) and Deere & Co. (DE) are among the holdings that surprised investors. The ARK 3D Printing ETF (PRNT) is also one of top holdings as some rocket parts are 3D printed.According to Morgan Stanley, the global space industry could generate revenue of $1.1 trillion or more in 2040, up from approximately $350 billion in 2018. However, some of the most high-profile companies in this industry such as Space X and Blue Origin are privately owned and not accessible to retail investors.The Procure Space ETF (UFO), the first pure-play space ETF, holds companies that generate a significant portion of their revenue from space related businesses. Its top holdings include ORBCOMM (ORBC), Trimble (TRMB) and Garmin (GRMN).The SPDR S&P Kensho Final Frontiers ETF (ROKT) holds companies associated with exploration of outer space and deep sea. Its top holdings include Boeing (BA), Northrop Grumman (NOC) and Lockheed Martin (LMT).To learn more about these ETFs, please watch the short video above.Want key ETF info delivered straight to your inbox?Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week. Get it free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Northrop Grumman Corporation (NOC): Free Stock Analysis Report Deere & Company (DE): Free Stock Analysis Report The Boeing Company (BA): Free Stock Analysis Report Amazon.com, Inc. (AMZN): Free Stock Analysis Report Trimble Inc. (TRMB): Get Free Report Lockheed Martin Corporation (LMT): Free Stock Analysis Report Garmin Ltd. (GRMN): Free Stock Analysis Report Netflix, Inc. (NFLX): Free Stock Analysis Report ORBCOMM Inc. (ORBC): Free Stock Analysis Report Alibaba Group Holding Limited (BABA): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report