I noted late last month that the New Horizons spacecraft (on its merry way to Pluto) has had a bit of difficulty. The problem is that the solid state recorder (SSR) gave an indication that it was drawing too much current. The control system then properly decided to shut it down, temporarily, and use the spare.

That’s fine, and indeed, that’s the proper response. The kicker was that NH (and in particular, the Autonomous Control System) went a little overboard and put the space craft in safe mode. Well, that’s not too serious – it’s just a bit of an overreaction that causes some re-scheduling to be necessary. It takes a bit of time to come out of safe mode, because it’s supposed to be a slow, painstaking procedure so that everyone concerned is convinced that it’s okay to proceed to the next step. The team immediately began working on an update to the Autonomous Control System to allow it to diagnose the condition and distinguish it from current overloads in other places (like instruments and on-board processors) where it becomes much more vital to shut down everything.

But the over-current happened again last week.

I don’t know how much of an overcurrent was detected – I’ve seen no indication that they were seriously over the limits, or if the events could be considered transitory. I suspect the former is closer to the truth.

It could also be just a one-time glitch that unfortunately just happened twice, and those kinds of things do happen in space. But as of now, the real, proximate cause is still under investigation.

Other than that concern the space craft is very healthy.

You can subscribe to New Horizons e-news to keep abreast of the latest developments. With a bit of luck, the news will be boring until 2015 when we get to Pluto.

Explore posts in the same categories: New Horizons

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