Welcome back to Launch Pad, I'm Christian Ready, your friendly neighborhood astronomer.
In our last video, we talked about the problem with the Hubble Space Telescope; namely, that
it lost one of its three remaining gyros that it uses to keep itself pointed.
The gyroscopes don't actually point the telescope.
What they do instead is provide feedback as the telescope is changing its pointing from
one target to the next.
When it finally locks up onto a target, the gyros then spin up into a high-speed mode
in order to maintain an ultra-fine lock on target.
Now, there was one remaining gyro that hadn't completely failed yet, but was acting a little
strange, and it was this gyro that mission engineers were trying to recover the other
day.
In NASA's latest release, they announced that the gyro they tried to bring back online,
it was reporting a high rate of speed that is actually physically higher than the gyro
can actually make.
It's like driving down the highway and you're pretty sure you're going 55-60 mph, and you
look down at your speedometer and it says you're moving at 10,000 miles per hour - it's
just not possible.
So now the team needs to figure out if this third anomalous gyro can be reset and made
to report its true speed once again.
Or if not, at least compensate for this ridiculously high reading.
But either way, it's going to take a little bit of time and the Anomaly Review Board are
in no hurry.
They want to return Hubble to science as quickly as possible, but ideally, they'd like to get
it back to science using all three gyros.
If not, then they can at least switch down to a single-gyro mode.
Now the reason they would use just one gyro instead of both of the two good remaining
gyros is because this way they can keep the second remaining gyro as a reserve.
Gyros do grow old and will fail at some point or another, so the idea is to extend the mission
as long as possible.
Now as I said before, using two gyros, let alone one, is less than ideal.
After all, three gyros allow the telescopes to monitor its pointing very precisely and
quickly.
That allows it the telescope to correct its pointing up to 30 times a second in order
to stay on target.
By going down to two gyros, or even just one gyro, it's going to take a little bit longer
for Hubble to be absolutely certain where it's pointing.
Because a single gyro is going to be a little less sensitive to two of the three axes that
the telescope moves in, it's not going to be able to look in certain parts of the sky
at certain times of the year.
But hey, you know what?
We're still doing science with Hubble, and that's all that matters at the moment.
Nobody has a crystal ball.
Nobody can say for certain how long Hubble should last using just one gyro with a second
as the backup.
But right now the best estimates are somewhere around 5, 6, maybe 10 years, who knows?
And that's important because the James Webb Space Telescope is gonna launch in 2021 - we
hope - and that means maybe Hubble and James Webb can operate together.
And that would be tremendously useful for science.
So that's our quick update - at least we now have a slightly better idea of what's going
on with Hubble.
But in other news, we found that there's yet another space telescope that's having troubles
as well.
The Chandra X-Ray telescope went into safe mode on October 10th.
Now NASA has yet to release any details on what went wrong with Chandra, but that's probably
because the team at Chandra need a little extra time to figure out exactly what went
wrong and how to correct for it.
But like the Hubble telescope, Chandra maintained its solar arrays so that it's always facing
the Sun so that the telescope and the observatory can continue to receive power.
So Chandra is expected to return to full science operations, but this is a reminder that Chandra
is 19 years old and has long outlasted its planned design life.
And the Kepler Space Telescope has been commanded to go to sleep until it's able to download
its data to Earth.
It has maybe just a little tiny amount of fuel remaining on board, after which the telescope
will no longer be useful.
Our space telescopes are getting older, and we gotta do everything we can to extend their
missions until the next generation of space telescopes can get into orbit.
Well, that's our update for the time being, I'll let you know more as I find out.
And if you'd like to join me on this journey through this amazing universe of ours, well
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Until next time, keep watching the skies.