The Polaris Dawn mission will likely target a peak altitude of about 870 miles (1,400 kilometers), higher than NASA’s Gemini 11 mission crewed by commander Pete Conrad and pilot Dick Gordon in 1966, which set the altitude record for an astronaut flight in Earth orbit at 853 miles (1,372 kilometers), according to NASA.
“There’s very little reason to go much higher than 1,400 kilometers,” Isaacman said. “You’re just dramatically increasing radiation (exposure), and you probably won’t learn a whole bunch more from it. We’re already anticpating getting a lot of really good data after just a couple of laps at a 1,400-kilometer orbit. I don’t expect to go much farther than that.”
en.wikipedia.org
