What would the SpaceX's BFR flight trajectories look like?

Question

SpaceX recently announced their plans for creating a 1-hour flight service using BFR rockets which would fly higher than commercial airliners but lower than ISS. It implies that within 1 hour it would be able to reach any point on the globe (with a suitable launchpad).

I'm curious and a bit worried about the potential of intersecting trajectories with airliners and satellites on lower orbits. There are also plans from SpaceX to launch around 12 thousand satellites starting in 2020 to serve internet connection. All of this makes me wonder what the chances are of colliding with so many flying objects.

There's the famous XKCD illustration for "going to space", and to me it seems like BFR is going to fly in a similar manner. What are the actual trajectories going to look like? How will they compare to airline trajectories?

Also, I'd like to see a visual representation of intersecting airspaces of airliners, existing satellites and the planned internet satellites, to get a general idea of it all.

Answer 1

Satellites in LEO are between 100-1240 miles, and the BFR is certainly intending to reach LEO to deliver satellites. For global transport, the BFR would enter this region - but that doesn't make a huge chance of colliding with "so many objects" as space is still really empty.

In terms of collision risk with aeroplanes - no, this really isn't an issue. Airspace is also very empty except around major airports, and the location of aircraft is well known. A rocket will only be at the same altitude as aircraft (up to 40000ft or so) for a very short period of time, and while planes fly horizontally, a ballistic trajectory is almost vertical at the same altitude.

So you shouldn't be worried about this as an issue at all.

(There are many other reasons why this is unlikely to work, unfortunately)