During the period from 2001 to 2009, 7 space tourists made 8 space flights aboard a Russian Soyuz spacecraft brokered by Space Adventures to the International Space Station. The publicized price was in the range of US$20–25 million per trip. Some space tourists have signed contracts with third parties to conduct certain research activities while in orbit. By 2007, space tourism was thought to be one of the earliest markets that would emerge for commercial spaceflight. Space Adventures is the only company that has sent paying passengers to space. In conjunction with the Roscosmos and RSC Energia, Space Adventures facilitated the flights for all of the world's first private space explorers. The first three participants paid in excess of $20 million (USD) each for their 10-day visit to the ISS.