20 year old US military weather satellite mysteriously explodes in orbit.

[Beowolf]

Oh no! I should have been more careful testing out my new laser pointer. Sorry guys!

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Seriously though, just a boring hydrazine leak or battery short.

[TonyC]

Probably (in my limited knowledge) some tiny debris damaging a dangerous component, and then something else triggers a kaboom.

No one will know about my secret laser artillery in my garden !

[cantab]

I'm going with internal fault, rather than debris strike or deliberate attack. As mentioned, either a battery short-circuiting or a chemical reaction in monopropellant could account for it.

[SlabGizor117]

Thanks, Obama.

[Ikaneko]

"Considering that HSP has not even progressed past 0.17 yet (Puny Humans!!), I would say that the kraken took it."

Official Nasa Report.