
Hubble Space Telescope Is In Safe Mode After Gyro Failure - waserwill
http://nasawatch.com/archives/2018/10/hubble-space-te.html
======
justreadthe
It was originally asserted that the telescope required three working gyros.
Later a method was devised to operate using two. [1]

Background information describing Hubble's Pointing Control System.

[https://www.spacetelescope.org/about/general/gyroscopes/](https://www.spacetelescope.org/about/general/gyroscopes/)

[1] 2005 article: [https://www.newscientist.com/article/dn7051-gyro-
sacrifice-m...](https://www.newscientist.com/article/dn7051-gyro-sacrifice-
may-extend-hubbles-life)

~~~
baldfat
There is going to be no way to use it with just one. If someone figures out a
solution they will be the hero of the decade.

To bad the replacement James Webb Space Telescope is not scheduled till March
20, 2021, 14 years past it's initial launch date of 2007.

It's initial budget was 1.6 billion and it will hit over 9.5 billion when it
launches, if it launches. In 2011 Congress moved to cancel the whole thing. If
the cost estimate exceeds the $8 billion cap Congress put in place in 2011, as
is unavoidable, NASA will have to have the mission re-authorized by the
legislature.

Fingers Crossed (My Nasa Photo of the Day Wall Paper isn't going to be so
great for the next 3 years I am afraid)

~~~
melling
Yes, we figured it out years ago. Instead of spending a fortune on manned
space flight, spend the money on developing advanced robotics to explore
space. In addition, the technology will be usable on earth in manufacturing,
etc.

We’ve had this discussion several times:

[https://news.ycombinator.com/item?id=4315339](https://news.ycombinator.com/item?id=4315339)

We can iterate faster, making less costly mistakes, and blanket the solar
system with robots.

It took about a decade for humans to get to the moon once America entered the
space race. Everything is taking several times longer now.

~~~
snowwrestler
These are all very practical arguments, but spaceflight is not a practical
endeavor. It is fundamentally an emotional activity.

The will to do science originates in the urge to explore. Whether we're
spending the money to send people or robots, it's not a rational pursuit. We
explore because we want to. Why do we want to? No one knows for sure.

Human spaceflight is valuable because things are emotionally different when a
human is doing them. That's why spaceflight is so much more expensive when
humans are aboard: because we have higher standards for humans, despite the
obvious evidence that human life is abundant and cheap. The value of a human
to another human is primarily an emotional calculation, not economic.

Even when the mission remote asset is a robot, we focus on the human element.
Coverage of robot missions always includes a lot of people cheering at the
launch, reactions in the control room, interviews with project leads, etc.

So, I would not be so quick to dismiss human spaceflight based on metrics of
efficiency. The whole thing of exploring space is inefficient, and serves no
practical purpose. Spaceflight runs on inspiration, and that's something we
haven't figured out how to automate (and IMO never will).

~~~
cannonedhamster
As others have already mentioned, spaceflight has useful applications at
creating a long term stable population center outside of Earth. There's also
the commercial application of being able to gather vast resources relatively
cheaply from the asteroid belts once there's a platform to routinely and
cheaply transfer cargo up to space, down is relatively easy. We're going to
run out of raw resources at some point and this will be the least costly
application. Deep well drilling could access large amounts of trapped
resources however the cost is prohibitive for the return.

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bdamm
Maybe someone who knows satellites can help here. I assume with one gyro the
satellite still has pointing function because one gyro senses in 3 axis, but
that if that one gyro were to go it would no longer know where it was pointing
or perhaps without enough accuracy for science.

But... it’s a telescope. Couldn’t it determine direction from images received
from a spotting or wide angle lens? Does it not have one?

~~~
sandworm101
No. The gyros are more accurate. If it were to use reference stars, through
the big camera, any detected motion would be at least one pixel. So every
image would be blurry. It has to react before any drift results in movement
more than a pixel.

~~~
PopePompus
Actually, you can do substantially better than one pixel, because the point
spread function is bigger than one pixel. Even a technique as simple as
centroiding will get you sub-pixel accuracy.

~~~
sandworm101
Yes but to get there you need detectable movement, a change in the image
because of motion. A pixel has to change somewhere, the definition of blur.
Sub-pixel blur is still blur.

~~~
rcxdude
No, you can get sub-pixel accuracy with a static image. The point is the star
takes up multiple pixels, and when it moves by less than a pixel, some pixels
get brighter while others get dimmer.

This is a common fallacy in computer vision. Often people get to a within a
pixel and stop because they assume they can't get better. Most times you can
get substantially better. I worked on a qr-code like system where the scanner
could reconstruct the code from an image with (slightly) less pixels than
'pixels' in the code.

~~~
FabHK
Interesting observation. This works presumably because the output of a pixel
is not just one bit, but some sort of continuous brightness reading
(discretised, of course, sooner or later)?

Not obvious a priori, but makes sense.

~~~
dekhn
[https://en.wikipedia.org/wiki/Point_spread_function](https://en.wikipedia.org/wiki/Point_spread_function)

The light is blurred, with a fairly predictable pattern, so if you fit a
function to the shape, you can find the peak of the function and that is the
most likely center position for the point source.

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TimTheTinker
“No longer in operation” - not strictly true. Looks like it will return to
operation soon, but in 1-gyro mode, which means its operations will be
restricted.

~~~
Arkight
1-gyro mode..... I am counting on how long can we keep Hubble up there, or how
long until we need to put another costly service mission up there.

~~~
maxnoe
It only needs to be operational until the James Webb Telescope is available.

As soon as this happens, most astronomers will jump ship anyway

~~~
baq
completely different devices built for completely different purposes. there's
nothing quite like the hubble.

~~~
yholio
Sure, but the jump is still tempting for the scientific top brass. There's
only so much that can be learned in the visible spectrum and only so many
Noble prizes, PhDs, tenures and grants to be had. Staying on Hubble is
scraping the barrel when the new sexy JWST promises to open whole new fields
of scientific inquiry.

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xupybd
I know the shuttle is long gone but are we at the point where robotic repair
could be an option. The Hubble might be out of date but that would be a great
exercise in developing repair tech.

~~~
nervousvarun
Could be wrong but my understanding is the issue preventing repair is the
expense in getting to the Hubble.

So whether it's via robot or human spacewalk (though a manned operation is
even more expensive obviously) the issue is the prohibitive expense of getting
to the Hubble to fix it.

~~~
mabbo
Orbital apogee is only 540.9 km[0]. SpaceX launched a satellite to an orbit of
640km last night for what I presume was it's usual $60m launch price.

So 'getting to the Hubble' is pretty low in price, all things considered. Now
the hard part: building something that can _fix_ the Hubble. Humans would be
good at making repairs, but the SpaceX Dragon capsule doesn't have an airlock,
so that won't work easily. Repairs might be doable by a robot, but I suspect
the easier option would be to simply attach new parts to it to perform the
broken functionality.

If you can build the new piece for $40m, that's $100m to add another 20+ years
to the lifespan of this incredible piece of equipment. Heck, sounds like
something Bezos might do just for fun and as a test for his New Glenn rockets.

[0]
[https://en.wikipedia.org/wiki/Hubble_Space_Telescope](https://en.wikipedia.org/wiki/Hubble_Space_Telescope)

~~~
swerling
Rather than repair it in space, would it be easier to bring it back to earth,
refurbish it and relaunch? That would be $120M plus refurbish costs. Or am I
underestimating how hard it would be to bring it back to the ground?

~~~
JumpCrisscross
> _would it be easier to bring it back to earth, refurbish it and relaunch?_

At that point you’d just launch a new one. Earth’s gravity well assesses a
steep tax.

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gazarullz
Hubble has been in the orbit since 1990, out of curiosity, what is the
designated program life and what replacements are scheduled?

~~~
docbrown
There have been five (5) successful missions to Hubble—beginning in 1993, then
1997, 1999, 2002, and 2009.[1]

The final mission, STS-125/SM4 (servicing mission 4), was done to prolong the
life of the telescope. During the 12-day mission, they installed two (2) new
instruments and performed two (2) repairs of failed equipment, and six new
batteries in addition to replacing gyroscopes. This expected to extend
Hubble’s lifespan by five (5) years from 2009.[2] So we were looking at an
expected 2014 EOL date.

The 2009 mission was an interesting event in itself with Hubble’s durability
aside. During a talk from Dr. Andrew Fuestel, he mentioned how NASA developed
specialized tools for him to repair Hubble mid-orbit—which he said were the
scariest times of his life—during his three (3) spacewalks.

[1]
[https://asd.gsfc.nasa.gov/archive/hubble/missions/sm4.html](https://asd.gsfc.nasa.gov/archive/hubble/missions/sm4.html)

[2][http://www.cbsnews.com/network/news/space/home/spacenews/fil...](http://www.cbsnews.com/network/news/space/home/spacenews/files/1ae7cac0d167055e41e1f0da7b0ac6a3-588.html)

~~~
saganus
Any idea what made it the scariest times?

I mean, obviously going on a spacewalk must be pretty intense. But is there a
particular difference in doing it to the Hubble?

Or was it scary because he was repairing a very expensive piece of equipment?

~~~
docbrown
IIRC, there were a few different reasons why it was scary.

One of the first was this mission was the last one, it was a difficult
repair—SC4 did the first in-orbit repair—to do at the time, especially outside
of the telescope. Because when you leave the safety of the shuttle, you’re
traveling at a rate of ~17,000MPH and where the hubble orbits, there is a much
higher chance of debris floating around than as if they were lower in the
atmosphere. So in laymen terms, you’re attached to a cord that is supplying
you with O2 and spinning at 17,000 MPH while trying to avoid rocks and other
dangerous floating objects.

One other danger was the O2 levels. He said the suits are heavy, all of your
tools are attached to you via cords and you have limited time to be outside.
If something where to happen in this situation, not only would you become
unconscious within seconds from the lack of O2, you’d pretty much be a forever
piece of debris floating around the galaxies as your body will never decompose
or fall from orbit.

The latter part was one of his biggest worries. He knew that he’s on limited
time, he also had to renter the shuttle slow because it’s similar to divers
and decompression. If for some reason he went too fast or there was a leak
somewhere, his suit would have instantly filled up and the pressure would have
blew him apart inside the suit.

~~~
saganus
Oh wow. Awesome.

Definitely not a walk in the proverbial park.

Thanks for the details!

------
ssijak
Can`t wait for James Webb telescope to be launched! And I`m a bit anxious
about the process of putting it safely into space.

~~~
codetrotter
Why anxious? They’ve put other telescopes into space before. Is that one more
sensitive or something?

~~~
dahauns
Apart from being the largest and most complex of its kind ever sent to space,
the tricky thing is that it will be positioned at the Sun-Earth L2 point, far
beyond the orbit of the moon.

Hubble was as successful and long-living as it was because of several manned
maintenance, upgrade and repair missions mentioned by others already - but
Hubble is in a LEO, only a few 100km from Earth. The JWST? 1.5 million km. So
missions like these aren't going to happen, this has to work on the first try.

~~~
ygra
Have the Hubble servicing missions been actually cost-effective or was that
more something that could be done because the Space Shuttle existed, although
building a replacement would have been cheaper? (The latter would probably
have had a problem having its budget approved, compared to the servicing
missions, I guess.)

~~~
dredds
Hard to put a price on astroscience or cosmology. Hubble was just recently
assisting in the search for the very first discovered exo-moon.

[http://earthsky.org/space/1st-exomoon-neptune-sized-
kepler-1...](http://earthsky.org/space/1st-exomoon-neptune-sized-
kepler-1625b-hubble)

In the mid-1990s, after Hubble had its optics corrected, researchers were
already planning its successor. The catch phrase in NASA at the time was
“faster, better, cheaper.” JWT was announced in 1996 to a standing ovation,
yet it's current planned launch is due 25 years after that announcement. (note
that it's infrared, not optical)

~~~
marcosdumay
> Hard to put a price on astroscience or cosmology.

It's pretty easy. Did those missions cost more or less than making a copy of
Hubble and launching it?

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DocTomoe
Would it be possible to dock a second satellite, with new gyros, to he
deorbiting rendevouz ring they installed a few years ago?

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foobarbecue
Scott Manley released an excellent video today about what this really means in
the context of Hubble's various attitude sensing and control systems:
[https://www.youtube.com/watch?v=MY169HtCazE](https://www.youtube.com/watch?v=MY169HtCazE)

------
wazoox
What about these two other, very similar space telescopes that were made
available by some intelligence service (CIA?) to NASA?

~~~
Keyframe
[https://en.wikipedia.org/wiki/Wide_Field_Infrared_Survey_Tel...](https://en.wikipedia.org/wiki/Wide_Field_Infrared_Survey_Telescope)
that's one of the two.

~~~
wazoox
Ah yes, that's the context I was looking for:
[https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...](https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA)

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megakluntjes
Oh no :( Safe mode is bad! The pictures will be limited to 640x480x256.
Looking into the neighborhood will not be possible, too.

~~~
NKosmatos
Let's hope they select "Safe Mode with Networking" otherwise they'll have a
"brick" in orbit ;-) As a side note (nightmare scenario), image if HST had
Windows 10 and was forced to do the fu$%ed up updates from M$ every now and
then :-)

~~~
fastbeef
Slashdot is that way, buddy.

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dang
Url changed from
[http://Twitter.com/NASAWatch/status/1049111536550273024](http://Twitter.com/NASAWatch/status/1049111536550273024),
which points to this.

