pa href="https://news.yahoo.com/reuters-science-news-summary-125741322.html"img src="" width="130" height="86" alt="Reuters Science News Summary" align="left" title="Reuters Science News Summary" border="0" /aFollowing is a summary of current science news briefs. Stratolaunch Systems Corporation, the space company founded by late billionaire and Microsoft Corp co-founder Paul Allen, is closing operations, cutting short ambitious plans to challenge traditional aerospace companies in a new "space race," four people familiar with the matter said on Friday. The company, a unit of Allen's privately held investment vehicle Vulcan Inc, had been developing a portfolio of launch vehicles including the world's largest airplane by wingspan to launch satellites and eventually humans into space.pbr clear="all"