Space Junk Is A Real, And Growing... Problem -- ESA.int Edition.

I've never been good at keeping secrets -- or, at least "scientific" secrets. Here then, a full day early, is the answer to the above poser:

This is a European Space Agency mission to study Earth's magnetic field changes (mystery solved!), using a trio of craft, to triangulate, and generate real-time 3D dynamic models of our magnetosphere. And it was put in a fair bit of danger, this past week -- by space junk, of indeterminate origin.

Here's the story -- and a bit -- from the 14^th of July:

. . .A small piece of human-made rubbish circling our planet – known as space debris – was detected hurtling towards Alpha at 16:00 CEST, on 30 June. A potential collision was predicted just eight hours later, shortly after midnight. The risk of impact was high enough that Alpha needed to get out of the way -- fast. . . .

Carrying out evasive action -- known as a ‘collision avoidance manoeuvre’ -- requires a lot of planning. You have to check that you’re not moving the satellite into a new orbit that puts it at risk of other collisions and you have to calculate how to get back to your original orbit using as little fuel and losing as little science data as possible.

In this case, we only got eight hours’ notice.

And worse, the alert meant that the Swarm team was now suddenly racing against two clocks. Another manoeuvre was planned for just a few hours after the potential collision and had to be cancelled to give Alpha enough time to duck out of the way of the debris. That manoeuvre was also very time sensitive and had to be entirely replanned, recalculated and carried out within a day. . . .

Alpha is now safe from a collision with that piece of debris and has completed its climb to safer skies alongside Charlie. . . .

Now you know what was up, with the weekend mystery header. Grin. . . .

नमस्ते