Angels Networks, Founders Fund, RRE Ventures, Data Collective, Bessemer, Lux Capital, Alphabet, Tencent Holdings, and Rothenberg Ventures. In June 2019, Miriam Kramer of Axios wrote that private spaceflight companies and investors were poised to capitalize on NASA's plan to open up the International Space Station to commercial space ventures. Commercial launchers The space transport business has, historically, had its primary customers in national governments and large commercial segments. Launches of government payloads, including military, civilian and scientific satellites, was the largest market segment in 2007 at nearly $100 billion a year. This segment is dominated by domestic favorites such as the United Launch Alliance for U.S. government payloads and Arianespace for European satellites. The commercial payload segment, valued at under $3 billion a year, was dominated by Arianespace in 2007, with over 50% of the market segment, followed by Russian launchers. See a complete list of launch systems. Spaceflight, Inc. operates as a launch broker, matching small-payload customers with launch providers in a "ridesharing" service. US government commercial cargo services The US government determined to begin a process to purchase orbital launch services for cargo deliveries to the International Space Station (ISS) beginning in the mid-2000s, rather than operate the launch and delivery services as they had with the Space Shuttle, which was to retire in less than half a decade, and ultimately did retire in 2011. On 18 January 2006, NASA announced an opportunity for US commercial providers to demonstrate orbital transportation services. As of 2008, NASA planned to spend $500 million through 2010 to finance development of private sector capability to transport payloads to the International Space Station (ISS). This was considered more challenging than then-available commercial space transportation because it would require precision orbit insertion, rendezvous and possibly docking with another spacecraft. The commercial vendors competed in specific service areas. In August 2006, NASA announced that two relatively young aerospace companies, SpaceX and Rocketplane Kistler, had been awarded $278 million and $207 million, respectively, under the COTS program. In 2008, NASA anticipated that commercial cargo delivery services to and return services from the ISS would be necessary through at least 2015. The NASA Administrator suggested that space transportation services procurement may be expanded to orbital fuel depots and lunar surface deliveries should the first phase of COTS prove successful. After it transpired that Rocketplane Kistler was failing to meet its contractual deadlines, NASA terminated its contract with