Slashdot Mirror
Hubble Telescope Hit By Mechanical Failure (bbc.com)
The Hubble Space Telescope is operating with only essential functions after it lost one of the gyroscopes needed to point the spacecraft. From a report: The observatory, described as one of the most important scientific instruments ever created, was placed in "safe mode" over the weekend, while scientists try to fix the problem. Hubble had been operating with four of its six gyroscopes when one of them failed on Friday. The telescope was launched in 1990. After the gyro failure at the weekend, controllers tried to switch on a different one, but that was found to be malfunctioning. That leaves Hubble with only two fully functional gyros. At any given time, Hubble needs three of its gyroscopes to work for optimal efficiency.
This could be pretty bad news for NASA if they can't manage to jury rig something. Hubble's successor, the James Webb Space Telescope, isn't scheduled for launch until 2021. Though I suppose they could try to do another repair mission on the Hubble like they did in '93 and four other times since (the last was 2009), but, that was back before they retired the space shuttle in 2011. Doing another maintenance run on the Hubble is probably beyond the spec/capabilities of the first manned SpaceX launch, currently planned for mid 2019.
It's flat, not planar you clod. There is a bottom. That's where the little people live.
Hubble Telescope Hit By Mechanical Failure
That's not fair... that's not fair at all. There was time now. There was... was all the time I needed. That's not fair! That's not fai-ai-airrrr!
Our reign has gone on long enough. Indeed. Summon the meteors.
Do we really need Hubble that badly anymore?
Apparently adaptive optics technology is allowing ground-based telescopes to surpass Hubble's capability.
https://www.airspacemag.com/sp...
Rather than firing up an expensive space mission (I remember each shuttle mission was $500M), would it genuinely be better to just take that money and build or retrofit a ground-based telescope with adaptive optics? A telescope that you could easily maintain thereafter?
This doesn't help with wavelengths of light that don't go through Earth's atmosphere, but that's not what Hubble does. Seems like we could do without Hubble nowadays.
--PeterM
I thought that's where the turtles are.
... and the mole people. Don't forget the mole people.
Just as soon as you overlook the mole people, that's when they strike. Then we're looking at a worldwide shortage of turnips and beets, and you'll have your own lack of vigilance to thank.
Won't you please think of the turnips and beets?!
Slashdot still doesnâ(TM)t support Unicode after it was added to the HTML standard in 1997.
Iirr the gyroscopes all have issues with their gyroscopes' bearings, that were not discovered in earth-based duration tests. Cosmic rays erode the surface of the metal ball bearings, causing them to fail eventually way before their predicted life span. They changed to ceramic bearings since which solved the problem.
They've found several things:
One lesson learned was that gyros assembled using pressurized oxygen to deliver suspension fluid were prone to failure due to electric wire corrosion. Gyros are now assembled using pressurized nitrogen.
But ultimately all the gyros were replaced in the final service mission in 2009, before that they were also replaced in 1999. These new ones were supposed to last longer but it seems ~10 years is still all we get. I wonder if the Dragon can be retrofitted for spacewalks.. I don't think you could use the same airlock as for docking, they'd need full vacuum spacesuits and June next year is just supposed to be a test flight...
Live today, because you never know what tomorrow brings
I found this from thirteen years ago:
The Earth is flat. You only need 2 gyros to point oneself in 2D space.
That's true but they need 3 because the telescope can rotate, which messes with the image. There's X, Y, and rotation, that need to be controlled for. They can operate with a single gyro but that means they can't stop rotations, and in fact use the rotation to their advantage to reposition the gyro for controlling X and Y alternately as rotation puts the gyro in the proper plane. Hubble launched with 4 gyros, meaning it had a spare from the start. With the first gyro failure they simply lost the spare. With the second failure they lost the ability to control rotation and/or ability to position with as much speed and accuracy. Going down to one means they can still move but very very slowly.
I am armed because I am free. I am free because I am armed.
How embarrassing.
Lissajous curves are the family of curves described by [...] parametric equations ...
Go away.
The James Webb Space Telescope will not be in orbit around the Earth, like the Hubble Space Telescope is - it will actually orbit the Sun, 1.5 million kilometers (1 million miles) away from the Earth at what is called the second Lagrange point or L2.
It little behooves the best of us to comment on the rest of us.
Whoops, make that 2021, not 2019 for the Webb launch.
Who can blame you? Hard to keep up with every time they delay the Webb launch for another 2-3 years.
Kind of like you have 4 dicks in your mouth. ...
Thanks for that imagery. My safe word is now "gyroscope".
It must have been something you assimilated. . . .
If you are trying to refute the GP, you are doing so very, very badly. The G.P. is correct, and nothing you said actually contradicts him. The only thing he said incorrectly was that the craft will orbit the point - it doesn't, it orbits the sun, but it does move around the Lagrange point in a semi-stable manner.
Orbits are, *of course* curves described by parameters. It so happens that in the co-ordinate system centered on the Lagrange point, and aligned to the sun, that the movement of spacecraft around the Lagrange point is, in fact, described by a Lissajou curve.
Since this isn't a scientific paper, I'll direct the curious here:
That wiki thing
And once the JWST gets unfolded, if it succeeds at unfolding at all, you won't have to worry about repair/refurbish missions, even if SLS or BFR could take a crew out to its location. Its coolant tanks aren't designed to be refilled, and parts that are bolted into place on the Hubble are glued permanently. It would take a saw or a torch to remove anything you wanted to replace. After a few years of awesome science, it becomes just another metallic asteroid. Could its mirror and sunshade justify a salvage mission? Doesn't seem likely to me.
Taxation without representation is tyranny! Statehood for DC, Puerto Rico, Virgin Islands & Pacific Territories!
Yeah the shuttle was an absolute disaster financially. IIRC it was just a dick competition with Russia.
It was a good idea, the Air Force made demands on performance (IIRC, flying over the USSR and returning to its launch site in one orbit) that crippled it for routine missions. As well the engines needed much more servicing then planned.
https://en.wikipedia.org/wiki/Inverted_totalitarianism