From the beginning, New Shepard was designed to fly above the Kármán line so none of our astronauts have an asterisk next to their name. For 96% of the world’s population, space begins 100 km up at the internationally recognized Kármán line. pic.twitter.com/QRoufBIrUJ— Blue Origin (@blueorigin) July 9, 2021
Richard Branson, CEO of Virgin Galactic and founder of the Virgin Group, recently flew aboard his company’s VSS Unity to 86 km above planet Earth. With this mission, Branson became the first among today’s billionaires to reach space. His trip on July 11 came just days ahead of Amazon founder, Jeff Bezos’ space trek. But scientists are now debating on whether Branson actually made it to space.
Kármán Line Explained
The debate around Branson’s space flight comes down to one point -- where does space actually begin. Branson’s flight reached an altitude of 86 km above Earth. While the United States and the National Aeronautics and Space Administration (NASA) define space as starting from 80 km (50 miles) above the mean sea level of the Earth, the international community has set a different standard.
The international community defines the edge of space as an imaginary line 100 km (62 miles) above the Earth. The limit was set by the Fédération Aéronautique Internationale (FAI) in the 1960s to record aeronautical activity.
The 100-km line is known as the Kármán line, named after Theodore von Kármán, a Hungarian American engineer and physicist. He had estimated the distance as where the air would be thin enough that aircraft would not be able to generate lift by flying. He suggested that the edge of space would be where orbital forces would be stronger than aerodynamic forces that create lift for airplanes.
What about Bezos’ Flight?
Bezos, the CEO of Blue Origin, will be boarding his New Shepard spaceship and flying to space on July 20. The planned flight will be reaching an altitude of above 100 km (62 miles), reaching the widely accepted boundary of the Kármán line.
Blue Origin even tweeted an infographic, taking a potshot at Virgin Galactic ahead of the latter’s flight.
“From the beginning, New Shepard was designed to fly above the Kármán line so none of our astronauts have an asterisk next to their name. For 96% of the world’s population, space begins 100 km up at the internationally recognised Kármán line.”
What an Astrophysicist Said
Noted science writer, astrophysicist and author Neil deGrasse Tyson noted that Branson had not actually made it into space but only made a suborbital journey.
“First of all, it was suborbital. NASA did it 60 years ago with Alan Shepard, took off from Cape Canaveral and landed in the ocean. If you don't go fast enough to reach orbit you will fall and return to Earth,” explained deGrasse in an interview with CNN.
Tyson said that both Bezos and Branson were not actually going into ‘space’ or into orbit.
“It's okay if you want to call it 'space' because average humans haven't gotten there before and it's a first for you. That's why it takes eight minutes to get into orbit and three days to reach the moon. That is actually space travel. So I don't see it as 'oh, let's go into space'. No. What you are going to have is a nice view of the Earth," he added.
“So, did you get high enough? Did you go into orbit? Did you actually go anywhere? Did you go to the Moon, to Mars or beyond?" he wondered.
What Other Scientists Say
While the Kármán line was established at 100 km (62 miles), many researchers have decided that the number was chosen by von Kármán just because it was a good round number. Others researchers like Andrew Gallagher Haley -- the world’s first practitioner of space law -- have estimated that the Kármán line would be much lower in altitude, according to the principles that the physicist had set out.
According to spaceflight historian Jonathan McDowell, Haley had calculated the edge of space to be at 84 km (52 miles) above the ground. The calculation roughly corresponds to the same altitude where the meteors entering the Earth’s atmosphere start to burn up -- called the mesosphere.
Other researchers have posited the edge of space at higher altitudes, like 118 km above mean sea level, and even lower, like 80 km above sea level.
The limit between Earth and outer space is incredibly political and the answer depends on who is being questioned. What can be said about the ‘billionaire space race’ is that it is breaching new boundaries, even if those new boundaries are not that of actual space itself. And with NASA’s rules of awarding the title of an astronaut to individuals reaching altitudes of 80 km (50 miles) and above, there can be no doubt that Branson, and Bezos will soon be commercial astronauts.