31 May 2020

Elite this is not! Docking SpaceX with the International Space Station simulation


Hello,
This is not one of my typical posts, but I was tipped off by my friend Tatwang to a simulation whereby you get to attempt the docking procedure between a SpaceX vessel with the International Space Station.
Decades ago, and the proud owner of a BBC B Micro, I played a lot of Elite, hours and hours and hours.  It was a lot of fun and it's amazing to think of the time and effort involved extracting every last bit of performance from the hardware - a radical change from contemporary coding practices with teetering stacks of frameworks.  Anyhow, I was good at Elite, so I should be good at this: how difficult could this be?  It's not like the ISS spins on an axis like the space stations did in Elite...


SpaceX Controls

Lateral controls
Rotational controls
Operated by mouse the SpaceX controls are more sophisticated than the simple roll, pitch and thrust you get in Elite - in addition to these, the SpaceX vessel provides yaw and lateral thrusters and even the ability to go backwards!  Though the ISS does not spin like a space station in Elite, successfully docking with the ISS requires more delicate control and has stringent final requirements on orientation: 0.2deg or better, velocity: 0.2m/s or less and positional alignment better than 20cm...


Could I do it? 

Of course, I could!
The process is definitely is a tad slower than I remember the practised equivalent in Elite.  This version is neither practised or a top-speed approach carefully tuned to make full and robust use of available shields to cushion the final 'landing', but surface to say the skills are similar.  I wonder about all the time saving that could be achieved if Elon had only outfitted all SpaceX craft with comparable shielding. :)


Yes, but how fast?

I recorded an Elite-esque demonstration for you to see my approach.  In retrospect, I think the creators missed an opportunity by randomising the initial position and orientation of the craft which appears to be fixed when starting each new game.


The SpaceX ISS simulation can be found here: https://iss-sim.spacex.com.  Let me know how you get on in the comments.