FAI Considers Lowering Boundary of Space

The second SpaceShipTwo is carried aloft by WhiteKnightTwo on its first captive carry flight. (Credit: Virgin Galactic)

Well, there’s some great news for Virgin Galactic as it prepares for an attempt to send SpaceShipTwo to space. The Fédération Aéronautique Internationale (FAI), which maintains records for aviation and spaceflight, is considering lowering the boundary of space from 100 to 80 km (62.1 to 47.7 miles).

Virgin Galactic’s SpaceShipTwo probably can’t reach the 100 km boundary, which is also known as the Karman line.

FAI issued the following statement last week:

The Karman line is the 100km altitude used by FAI and many other organisations to mark the “boundary” of space . In the last few years there have been many scientific and technical discussions around this demarcation line for the “edge of space” and variance around this as a boundary condition for recognition of “astronaut” status.

Recently published analyses present a compelling scientific case for reduction in this altitude from 100km to 80km. These analyses combine data/modelling from a number of differing perspectives (latitudinal variations during solar cycles, theoretical lift coefficients for different size/configuration satellites ranging from cubesats to the International Space Station, perigee/apogee elliptical analysis of actual satellite orbital lifetimes etc) to a level that has never been done before in relation to this issue. They also provide an accurate overview of some of the historical arguments and inadvertent misrepresentations of Karman’s actual analyses and conclusions from over half a century ago.

FAI has therefore been in contact with the International Astronautical Federation (IAF) to propose that an international workshop is held during 2019 to fully explore this issue with input and participation from the astrodynamics and astronautical community.

Such a seminar, to be held under joint FAI/IAF auspices, would enable discussion from a wide range of professionals with relevant expertise to analyse and discuss the issue and possible redefinition of the altitude used by international organisations including FAI to recognise human spaceflights.

If the findings lead to a redefinition of the boundary of space as it is in use by international organisations, FAI would review any performances made between today’s statement and the date of implementation of the revised definition in order to ensure that these performances already take into consideration the findings as they exist today.

  • SamuelRoman13

    Looks like he finally got some luck. Wonder how long a sat would last at that altitude.

  • Cameron

    So 80km is perhaps more accurate is it? Seems like a very round number. Not 81.763km?
    Why not define it as an altitude in which a 1kg sphere can remain in orbit without reboost for 365 days? It is all arbitrary in the end I suppose.

  • redneck

    One orbit if it is dense enough, less if it is high drag.

  • Elliot R.

    I was always under the assumption the 100km line was set because they didn’t want to give the Nazis credit for reaching space first.

  • duheagle

    You’d need to define the standard sphere beyond just its mass. You can make 1kg spheres of Osmium and of inflated aluminized mylar. Care to guess which is likely to last longer on orbit at any given altitude?

  • Jeff Smith

    At some point, something like this needs to be fixed for historical purposes. If people are talking about different Karman lines at different times, it gets confusing fast. I thought we’d already reached that point, BUUUUUUUUUUT…

  • Cameron

    Very true, I did mean (in my head at least) a fixed size.

  • Douglas Messier

    And we shall name this new lower boundary the Branson line. That is all.

  • ronsmytheiii

    I get the joke, but I would go with the Bob White line as it seems he will finally get international recognition.

  • redneck

    I fail to see the usefulness of lowering the boundary except as a legal fiction for some purpose. Even a 100 KM orbit would be short lived and 80 is not sustainable at all without heroic reboost efforts. Not that I have a vote but I vote against establishing the Branson Line.

  • Robert Sutton

    Clearly no one can know where above earth space begins unless they know what space is
    Which proves David Duchovny is right.

  • Robert Sutton

    But did the Nazi’s know?

  • Abdul M. Ismail

    The FAI can’t set the altitude now. They have to wait until the next flight of SpaceShip2 and it if gets to 47.7 miles; then they have say that space is 80km and Virgin Galactic will have fulfilled their legal obligations of getting commercial passengers to space.

  • publiusr

    Nah–the line should be **raised** to 200 nautical miles up–and/or anything with orbital velocity.

    Also–the late Delta II (and anything smaller) should have been classified as a sounding rocket. 😉