Commercial space traveler Richard Garriott, son of NASA astronaut Owen Garriott, returned to Earth after a mission to the International Space Station, Space Adventures, Ltd. announced.

The company books commercial human space missions, such as Richard Garriott’s trip.

He and other crew members successfully landed in the Kazakhstan steppes, aboard the Soyuz TMA-12 spacecraft.

The others were Expedition 17 crewmembers Sergei Volkov and Oleg Kononenko, who both spent six months aboard the ISS.

Richard Garriott became the first second-generation astronaut, according to Space Adventures. The flight back to Earth marked another historical milestone as Garriott traveled with the first second-generation cosmonaut, Sergei Volkov.

On Oct. 12, Garriott launched aboard the Soyuz TMA-13 from the Baikonur Cosmodrome in Kazakhstan. He joined Expedition 18 crewmembers Mike Fincke and Yuri Lonchakov, for the flight. They arrived at the space station Oct. 14 and were greeted by the Expedition 17 crew.

In preparation for his spaceflight, Garriott completed a cosmonaut-training program at the Yuri Gagarin Cosmonaut Training Center located in Star City, Russia. During his stay aboard the ISS, Garriott focused on scientific and environmental research, as well as educational outreach:

For NASA, Garriott performed a series of experiments that examined the physical impact of spaceflight on astronauts. Garriott observed the reaction of the eyes to low and high pressure in a microgravity environment; the effects of spaceflight on the human immune system; and astronauts’ sleep/wake patterns and sleep characteristics.

On behalf of The Nature Conservancy, Garriott photographed a number of ecologically significant places on Earth. The photographs will be compared to shots taken 35 years ago by Garriott’s father while in space. Together, Garriott and The Nature Conservancy will review the images to document how the Earth has changed in one generation.

Garriott worked in cooperation with the European Space Agency to perform a series of experiments that observed early detection of osteoporosis, vestibular adaptation to G-force transitions and the occurrence of lower back pain.

Garriott supported a number of commercial partners. He assisted the biotechnology company ExtremoZyme, co-founded by Owen Garriott, by conducting Protein Crystal Growth (PCG) experiments. Additionally, Garriott tested a SEIKO Spring Drive Spacewalk watch, specifically designed for use in space. Garriott also conducted a physics experiment as part of an initiative sponsored by DHL, planned as an educational contest that will take place at the DHL Innovation Center in Bonn, Germany.

Garriott was born in Cambridge, England and raised in Nassau Bay, Texas. In 1980, Garriott attended the University of Texas at Austin where he developed the Ultima computer game series. Garriott, along with his father and brother, created Origin Systems, a private video game publisher. In 1992, Garriott sold Origin Systems to Electronic Arts. In 1999, Garriott left Electronic Arts and in 2000 he formed Destination Games and partnered with NCsoft. In November last year, his latest game, Richard Garriott’s Tabula Rasa, was launched in North America and in the European Union.

Separately, a Japanese businessman who sought to become a Space Adventures traveler to the space station — and a spacewalker — has sued the company, seeking return of a $21 million payment, The Washington Post reported today.

Daisuke Enomoto flunked a physical that astronauts and space travelers must pass, because he has kidney stones that would be hazardous during 10 days in space. He would have been the first private space traveler to participate in a spacewalk, or extravehicular activity.

Enomoto refused to pay Space Adventures another $10 million unless he could go spacewalking, and the company refused to return his $21 million because he flunked the physical and therefore a refund is not due. The case is in U.S. District Court in Alexandria, Va.