Olsen likes to put his money into high-risk start-ups. Olsen founded EPITAXX, a fiberoptic detector manufacturer in 1984 together with Vladimir Ban. It was sold in 1990 for $12 million. He then founded Sensors Unlimited in 1992 with Dr. Marshall J. Cohen. Sensors was sold to Finisar Corp. for $600 million in 2000. It was then repurchased by the management team in 2002 for $6  million, and sold once more to Goodrich, Corp. in 2005 for $60 million. Having flown to the International Space Station (ISS) with Soyuz TMA-7 (launched October 1, 2005, docked October 3) and landed with Soyuz TMA-6 (October 10), Olsen is the third self-funded space tourist to visit the ISS, following Dennis Tito (2001) and Mark Shuttleworth (2002) (all three space tourists flew through Space Adventures, Ltd.). Olsen has made some comments indicating that he is unhappy with the "space tourist" designation. The following is from National Geographic's coverage "Space Launch – Along for the Ride (2007)": "Greg: The term space tourist implies that you`ll write a check and you go for a joyride. And believe me that is not the case at all. Narrator: Greg worked hard to get this far, training for two years with the Russian Space Agency." Olsen had to train for a year and a half before being ready to go into space. During a routine x-ray, a black spot was found on his lung. He had to have a monthly medical check to obtain permission to fly. It took 9 months for him to pass the medical. He conducted several experiments in remote sensing and astronomy while aboard the space station. Olsen is a licensed Amateur Radio radio operator holding FCC callsign KC2ONX and spoke to students via ham radio from space through the ARISS project. In an informal presentation at a New Jersey high school, Dr. Olsen estimated the price of his space excursion at US$20 million.