# Will the Tesla Roadster/Falcon 9H 2nd stage ever be a navigation hazard to cis-lunar space?

The saying "What goes around, comes around" can apply to spacecraft on ballistic trajectories that are launched from Earth into bound heliocentric orbits. Since the Tesla Roadster/Falcon 9H 2nd stage's orbit will repeatedly pass by Earth's orbit, will it ever be a navigation hazard to cis-lunar space? In addition to satellites in LEO, there are plenty of goodies in MEO (e.g. GPS/GNSS) and GEO.

I am not asking about the likelihood of a collision, because that is low. But a navigation hazard requires significant time and effort to monitor to be sure, and so any near passes to Earth would have to be carefully considered.

Given that launch generally (and by treaty) requires government approval, I wonder if they were required to consider this and take the necessary steps to avoid it?

See for example:

• Scott Manley's new video after 05:40 which mentions a close approach to Earth in the year 2030.
• Max Fagin's video after 02:00 which mentions a possible use of a perturbation from a near approach to Mars to prevent future intercepts with Earth's orbit.

below: From here. Open in another view for full size.

• I could be wrong on this. For the first paet of the question, the two are, IMO, large enough to track at relatively less effort than unknown NEO. Particularly as far smaller bodies are tracked in lower orbits. Feb 8, 2018 at 6:33
• 17,759 near-earth objects of at least a meter in size are known and many more are not; the Roadster therefore can increase the (already negligible) navigation hazard by less than five one-thousandths of a percent. It's also almost just as likely to collide with another NEO in such a way as to prevent a future collision that would have occurred without it as to collide with an interplanetary spacecraft. en.wikipedia.org/wiki/Near-Earth_object#Near-Earth_asteroids hashtagspaceisbig Feb 14, 2018 at 23:35

This new, and aptly-named ArXiv preprint might help:

They iterated 48 estimates of Roadster's orbit, each for over 1000 years.

It's conclusion (my emphasis):

Its first close encounter that MAY come within a lunar distance of the Earth will occur in 2091. On timescales significantly longer than a century, continued close encounters will render precise longterm predictions of the object’s chaotic orbit impossible.

• Excellent find! It's nice to know that the authors also thought this was an interesting question. ;-)
– uhoh
Feb 15, 2018 at 2:51
• I modified the format somewhat and added the figure. You can click the word "edited" to the left of your icon and then use the rollback function to undo the changes if you like.
– uhoh
Feb 15, 2018 at 3:23
• Phys.org's write-up of the ArXiv preprint is also interesting. phys.org/news/2018-02-tesla-shot-space-collide-earth.html
– uhoh
Feb 18, 2018 at 3:35