Once again, we are going through a summer of coronavirus pandemic making headlines around the world. What grabbed my attention, though, was the news about the success of private space travels, which seems to indicate some important points in space development. This was a big news for me, because one of the future possibilities I had been told as a child was turned into reality when private citizens successfully traveled to outer space even for a brief period.

One question popped up in my mind while watching the news on TV: How far away from the Earth should we go to reach outer space? This boundary between Earth’s atmosphere and outer space has long been designated by the International Astronautical Federation as the Kármán line, which is located 100 kilometers above the Earth. It was named after Hungarian-born American aerospace engineer and scientist Theodore von Kármán. Meanwhile, different definitions have been introduced by other organizations. The U.S. Air Force sets the boundary at around 92 kilometers above the Earth while the Federal Aviation Administration draws it at 80 kilometers from Earth’s surface.

Amazon’s founder Jeff Bezos and other crew members launched into space on board a vertical-takeoff rocket developed by his company Blue Origin. The company says the space travel was a success as the space vehicle went over the 100-km boundary. Meanwhile, Virgin Galactic says its spaceship VSS Unity successfully flied over the 80-km boundary after being separated from its carrier mothership. Both companies have apparently adopted definitions that are convenient for them based on the type of spaceship they use. There isn’t any meaningful difference between the two boundaries as the videos taken around each boundary sufficiently convey the image of outer space. What’s interesting for me is that different definitions are adopted behind the scenes of commercial space development.

I personally believe that if outer space is seen as a contrast to earth’s atmosphere, the boundary between them should be drawn at an altitude where space travelers are freed from gravitational effects to a certain degree. Some information sources establish that satellite orbits come into effect at altitudes between 130 and 150 kilometers above the Earth. I’d say it’s appropriate to draw the boundary around there.

If we compare space travels to going to the beach, beachgoers rarely go out into the open sea and find enough pleasure in swimming near the beach. Going to space may be something like this.

Commercial space travels will likely continue in the future. I look forward to watching the news that talk us through the space travels from the viewpoint of their styles, spaceship they use, and boundaries they cross.

Takeshi Umemoto

Digital Strategic Dept.

Unit Leader