This is TBSI on the world behind the black Bob Zimmerman is here

the author of Universe in a mirror the biography of Hubble and now Hubble needs Bob's attention. There's trouble, something about

the gyroscope. Bob, how bad is the trouble? This is a serious problem, it's been an

ongoing serious problem now for about a year and a half, but we have more problems.

Hubble originally had six gyroscopes. That gives them redundancy for three-dimensional pointing.

The gyroscopes allow them the pointed very accurately

in three dimensions and they gave them six so that you had a redundancy. You only need

three to do three dimensions. Well, those six gyroscopes had to be replaced on Hubble many, many times and in the

2009 maintenance mission, the last one that occurred, they gave Hubble six new gyroscopes

to give it as much time as possible. This is not a

incompetence issue. This is a difficult issue because they're moving parts and they do

break. They've been a lot of improvements in making gyroscopes and

nonetheless they have a limited lifespan.

So now Hubble has only had three working gyroscopes now for, I'd say, about two years now.

And once they lose one of those three gyroscopes

they're only going to have two left and at that moment the decision has been made to go

to one gyroscope mode they can kind of point the telescope with only one gyroscope

and they'll keep the second gyroscope as a backup.

But that means that Hubble will no longer be able to take really sharp images anymore.

The images will be compromised significantly.

But so, where are we?

Well, one of the three working gyroscopes

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