
Design call for 'solar sentinel' mission - sonabinu
http://www.bbc.com/news/science-environment-42922898
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chiph
I would guess that the particles of a mass ejection/flare are travelling
sufficiently below the speed of light to make a warning system worth while.

Also - How much debris has collected at Lagrange points over the millennia?
Would it be a danger to a spacecraft parked there?

~~~
ekimekim
L1, L2 and L3 are unstable - if you start to drift away even a tiny bit, that
drift gets amplified over time. Staying at one of these points requires at
least some station-keeping.

L4 and L5, by contrast, are stable - even if you're not perfectly on the dot,
you'll kind of "orbit" around the point if you're close enough. See [1].

These L4 and L5 points have, over the eons, collected many natural satellites
(ie. asteroids) which are commonly called Trojans[2].

However, space is really, really big[3] so this isn't of too much concern to
spacecraft.

[1]
[https://en.wikipedia.org/wiki/Horseshoe_orbit#Tadpole_orbit](https://en.wikipedia.org/wiki/Horseshoe_orbit#Tadpole_orbit)

[2]
[https://en.wikipedia.org/wiki/Trojan_(astronomy)](https://en.wikipedia.org/wiki/Trojan_\(astronomy\))

[3] Hitchhiker's Guide to the Galaxy, Douglas Adams

Edit: better link for [1]

