Aging Hubble Telescope Moves To 'One-Gyro' Operations (science.org) 75
The 34-year-old Hubble Space Telescope is now operating with its final two working gyroscopes, necessitating a switch to a less productive "one-gyro" mode to extend its operational life. This contingency plan will reduce Hubble's productivity by over 12%, limit its ability to track fast-moving objects, and decrease the portion of the sky it can observe. That said, NASA expects it to keep functioning through 2035. Science.org reports: Normally, Hubble measures its location in space with a system that includes three gyroscopes -- rapidly spinning wheels that can sense forces in three directions. But in a 4 June press conference, NASA officials said one of the telescope's three remaining gyroscopes is on the fritz. The agency is now invoking a contingency plan: a "one-gyro" mode that keeps the other functioning gyroscope in reserve. The mode will reduce the telescope's productivity by more than 12% but preserve its ability to observe for years to come, Mark Clampin, NASA's astrophysics division director, said at the press conference. "We believe this is our best approach to support Hubble science through this decade and into the next."
Hubble's gyroscopes, which spin at 19,200 revolutions per minute, are extremely precise but finicky. The agency has flown a total of 22 gyroscopes across various servicing missions and is now down to the last two of the six currently onboard. In one-gyro mode, Hubble must rely on its less precise star trackers and other sensors to verify its position, a slower process that leads to reduced productivity. "It will take us more time to slew from one target attitude to the next, and to be able to lock on to that science target," said Patrick Crouse, Hubble's project manager at NASA's Goddard Space Flight Center.
A one-gyro Hubble will also struggle to track fast-moving targets, such as asteroids within the orbit of Mars, and to swivel to spot transient distant phenomena such as supernovae, according to a 2016 report (PDF) from the Space Telescope Science Institute, which operates Hubble. In addition, the inefficiencies of one-gyro mode will reduce the portion of the sky that Hubble can safely point to at any given moment, from 82% to roughly 40%, including a larger avoidance zone near the Sun. It won't be able to observe Venus or the Moon, nor will it be able to reliably spot comets when they're near the Sun. Its ability to scrutinize distant exoplanets will also be hampered, especially in gathering the spectral measurements used to discern alien atmospheres. Furthermore, a one-gyro Hubble won't be able to perform as many simultaneous observations with the new JWST space observatory. Moving forward, the two telescopes' fields of view at any given moment may overlap by less than 20%, according to a 2019 estimate anticipating this event from a Hubble advisory committee.
Hubble's gyroscopes, which spin at 19,200 revolutions per minute, are extremely precise but finicky. The agency has flown a total of 22 gyroscopes across various servicing missions and is now down to the last two of the six currently onboard. In one-gyro mode, Hubble must rely on its less precise star trackers and other sensors to verify its position, a slower process that leads to reduced productivity. "It will take us more time to slew from one target attitude to the next, and to be able to lock on to that science target," said Patrick Crouse, Hubble's project manager at NASA's Goddard Space Flight Center.
A one-gyro Hubble will also struggle to track fast-moving targets, such as asteroids within the orbit of Mars, and to swivel to spot transient distant phenomena such as supernovae, according to a 2016 report (PDF) from the Space Telescope Science Institute, which operates Hubble. In addition, the inefficiencies of one-gyro mode will reduce the portion of the sky that Hubble can safely point to at any given moment, from 82% to roughly 40%, including a larger avoidance zone near the Sun. It won't be able to observe Venus or the Moon, nor will it be able to reliably spot comets when they're near the Sun. Its ability to scrutinize distant exoplanets will also be hampered, especially in gathering the spectral measurements used to discern alien atmospheres. Furthermore, a one-gyro Hubble won't be able to perform as many simultaneous observations with the new JWST space observatory. Moving forward, the two telescopes' fields of view at any given moment may overlap by less than 20%, according to a 2019 estimate anticipating this event from a Hubble advisory committee.
Type of gyroscope in use (Score:2)
Re:Type of gyroscope in use (Score:5, Informative)
The gyroscopes are not sensors, they are actuators. You can keep a satellite into any attitude you want with paired small rockets, but that needs a lot of fuel and therefore does not last long. A better solution is to use gyroscopes as reaction wheels. This off course means shooting more mass into space and having fast spinning parts, but it is still far more efficient.
If the gyroscopes are spinning so fast that they are approaching their limits, paired rockets can still be used to offload them.
Especially Hubble needs a lot of attitude adjustments, as it is regularly pointed at different parts of the sky to investigate.
Re: Type of gyroscope in use (Score:3)
"This off course"
It does lead to that, yes.
Re:Type of gyroscope in use (Score:5, Interesting)
No, we are talking about gyroscopes [esahubble.org] used as sensors, not the reaction wheels [esahubble.org] that are used as actuators. This paper [aiaa.org] discusses the arrangement, and elaborates on the difference between how HST uses gyros vs reaction wheels.
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Ah, so my suggestion of just using Google Maps like everyone else does would be dead in the water.
*Shrug* It never turns out to be as simple as you think it will be... :-(
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The gyroscopes are not sensors, they are actuators.
Gyroscopes are spinny things. You can do all sorts of things with spinny things such as control the speed of their spin to exert momentum, or thanks to their momentum we can use gimbals to measure how we are changing relative to a the gyroscope to determine if our angular velocity is changing.
You'd have your mind absolutely blown by the sheer number of components we use in the world that can be used as both actuators and sensors, and in some cases at the same time. Your speaker can create a voltage related
Less gyro comes with aging. (Score:5, Funny)
I mean, when I was young I was eating 4 gyro pita sandwiches in one go, now I can barely do one.
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They started off with 22 gyros. Which you can only get if you order two party trays a day in advance.
Re: Less gyro comes with aging. (Score:2)
They have a good Caeser salad. But they are so small, I coulda' et tu.
Space shuttle repair (Score:2)
The consensus these days seems to be that the space shuttle was an expensive white elephant. However one area it did excel in was accessing satellites in LEO and either repairing or recovering them. If it was still flying hubble could have been kept running indefinately (unless something major failed such as the mirror) but without the shuttle its only a matter of time until it has to be de-orbited.
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Re:Space shuttle repair (Score:5, Informative)
I don't think that the dragon capsule is rated for that at all. If anything, I think that SpaceX is waiting on Starship for those sorts of capabilities.
For a servicing mission, you need an airlock system. A way to don an EVA space suit (as opposed to a lighter weight IVA) and exit the craft in it. You should probably have some sort of robotic arm. You might want a bay that can provide light from multiple angles, shielding from other orbital stuff, carry parts, and all that.
Basically, the shuttle was a super duty pickup truck. The Dragon capsule is like a Tesla Model 3 in comparison.
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Upcoming there is going to be a Dragon capsule EVA experiment mission. But I don't know if Dragon can fulfill such gyroscope replacement mission if the EVA experiment succeeds.
Starship is still some years away from human-rated operation.
Re:Space shuttle repair (Score:4, Interesting)
The experiment is not much more than Ed White floating outside a Gemini capsule at the end of an umbilical - a good demonstration, but not performing much practical work. The EVA suit being used [google.com] does not permit the mobility or dexterity of what was available during the Shuttle servicing missions. Nor does it have self-contained life support capabilities - that tether/umbilical is very much going to be in the way. And the crew-mates all have to be in their own pressurized suits, because Dragon doesn't have an airlock. The forward hatch has to be wide open the whole time.
By and large: no. The biggest shortfall is that Dragon has no way to grab hold of Hubble and keep it in place, and the astronaut servicers have no way to keep themselves in place while working. The Shuttle servicing missions used the Canadarm to first grab Hubble, which was then docked in the Shuttle bay. Then the Canadarm was used to move the astronauts and parts around.
A servicing mission today would require some kind of work platform (with its own power, guidance, propulsion, and probably most of the spare parts) get sent up ahead of time and capture Hubble. Then you could send up Dragon, and have the work platform to capture it, then you can pop the hatch and start repair work.
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Hmm... I will say that some sort of generic work platform that has the capability to intercept satellites and provide work surfaces/robotic arms wouldn't be a bad thing. I'm picturing something with around 4 arms - one each for the satellite, capsule, astronaut, and replacement parts/tools. On that note, 5 might be better, even if it's only bifurcated at the end, so it can hold the tools and parts separately. Or astronaut and parts. Whatever, extra arm = more flexibility.
Give it some solar panels, thru
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Or
NASA can just abandon Hubble as it always planned to do, and spend another $16 billion (2021 dollars) to build a replacement *optical* telescope and put it into polar LEO orbit.
Or
Build an optical telescope for the "dark" side of the Moon. We're supposed to be able to go there now, and with hab modules (a decade from now), be able to send humans to repair that. It probably won't even need complex gyroscopes to orient itself, just be sealed and raised above the lunar "atmosphere" (a foot or two above the
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One of the last shuttle missions to Hubble was to attach a docking system for a future deorbiting module, to decommission the telescope. I wonder if that same docking system could be used instead to connect a service module. a tug satellite that can operate along the Hubble's main systems, taking over the task of aiming and maneuvering.
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The docking target is just that: a bit of metal that can be used to attach a spacecraft to Hubble. There's no interface to talk to Hubble's computers, which makes it difficult to have a tug take over those functions.
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You know, that sounds like a design feature that would be good for some theoretical "hubble 2" project?
With SpaceX making launch a lot cheaper, I'm picturing a much more modular satellite setup. Something like:
Satellite core: Computers, control busses, etc...
Control: Thrusters, Gyros, and such
Power: Solar panels, batteries, and such
Communication: Antennas, laser data links, that sort of thing
Mission: The telescopes in the case of the Hubble.
Auxilliary: We decided we need to add more to the telescope.
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Using the X-37 also makes no sense, because it was never designed for human use: it doesn't have a cabin or life support. It's also laughably small [google.com] for a servicing mission: you could fit two of them in the Shuttle cargo bay, while it's own cargo bay isn't large enough for the r
Re: Space shuttle repair (Score:3)
Technology gets better. It's probably cheaper and faster to send up a brand new telescope with no people involved.
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The Roman space telescope is under construction now and is built off one of the same frames Hubble was that the NRO had just you know, lying around in storage.
Like Webb though it's an infrared scope
https://roman.gsfc.nasa.gov/ [nasa.gov]
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"Like Webb though it's an infrared scope"
You need an infrared scope for looking at stuff that is "a long time ago in a galaxy far, far away"
IE red shifted because of the expansion of the universe
It would be a good idea to invest in a new optical space telescope for observing our solar system, and nearby stars. And spotting potential dinosaur killer asteroids and comets.
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Yeah I understand but one of the main appeals of Hubble to general public was the fact it operated in human visual wavelengths but we likely learned the limitations of that spectrum from Hubble itself thusly all new scopes focus on IR, Xray, etc.
Agree on aditional scopes and when I was at Goddard they mentioned they have ideas for the second frame they were gifted but they just only have the budget for the Roman scope currently and likely won't get more for the second since the next big project is gettign m
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Yeah I understand but one of the main appeals of Hubble to general public was the fact it operated in human visual wavelengths but we likely learned the limitations of that spectrum from Hubble itself thusly all new scopes focus on IR, Xray, etc.
I don't know if Hubble gave any insights on limitations of visible spectrum. It is not exactly a secret that the visible spectrum is a very small part of EM and red shifting was already known in astronomy. NASA launched an infrared telescope, IRAS [wikipedia.org], before Hubble.
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Yeah I am just thinking in the sense that the visible spectrum capability was a great PR for space in general with all those purty pictures and useful but but not as useful for the science portion so another scope with that capability it should be understood that's what it's for and it should because the public appeal aspect is important, without that I doubt we'd have gotten Hubble as long a life as it got. Today, to me, while absolutely still doing great work Hubble is more important as an ambassador tha
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Part of the deal is that while a telescope in space is much more effective for the size of its mirror, we developed technologies that allowed much, much larger mirrors here on earth. Ergo, at least in the visual spectrum which penetrates the atmosphere, you have 10+ meter telescopes here on earth, vs Hubble's 2.4M mirror. It's been passed by.
There are still unique capabilities though, which is why it wasn't outright decommissioned. But for a new orbital telescope to have the scale of additional capabilit
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>The Roman space telescope is under construction now a
but is being held up as they try to sync the XXII sundials and hourglasses . . .
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Are you trying to sarcastically refer to the shuttle program?
The one that turned out to be more dangerous than soyuz capsules? That had an extremely large launch cost? That basically needed to be refurbished 100% between flights?
It turned out to be ahead of its time, the necessary technologies to do it right hadn't been developed quite yet, and the compromises made for capabilities desired but never used, combined with cost cutting and material availability meant that it actually ended up incredibly expen
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Re:Space shuttle repair (Score:4, Informative)
There is a proposal for using a Dragon to service Hubble, but this is going to require significant effort.
1. the exhaust from Dragon's thrusters must be kept away from the telescope. The Shuttle could approach the Hubble at an angle that would do this, using the robotic arm to capture Hubble and maneuver it into the payload bay while never having to fire thrusters in Hubble's direction. How Dragon could do this has not been worked out yet.
2. The robotic arm was instrumental to the Shuttle's Hubble servicing missions, providing a platform for astronauts to stand on so they had both arms available for the repair itself, instead of having to use one arm to position themselves. Without that, servicing becomes a lot more complicated.
3. You need handrails etc. on the Dragon to get from the hatch to the Hubble. The grapple fixture that would capture Hubble is in the Dragon's trunk so the astronaut has to move down the capsule and past the trunk to get to the Hubble.
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An airlock is nice to have but not a necessity. Apollo showed that just venting the entire capsule to do an EVA is viable, if cumbersome for the people who stay in the capsule.
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An airlock is nice to have but not a necessity. Apollo showed that just venting the entire capsule to do an EVA is viable, if cumbersome for the people who stay in the capsule.
But for how many EVAs is that procedure viable? The last time Hubble was repaired, it had 5 separate EVAs with a total of 36 hours. I can imagine that not all the gyroscopes are in the same place and be handled with one EVA. That means people who stay in the capsule have to either stay in their suits the entire EVA (hours at a time). The capsule has to be designed to be operated in suits. Or pressurize the capsule after every time the hatch is opened and closed.
hubble is stil on the 486 cpu? maybe time to upgra (Score:2)
hubble is stil on the 486 cpu? maybe time to upgrade that as well?
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No. Believe it or not, in spaceflight, older is better.
First of all, those 486's are rad-hardened. Second, they are deterministic, which makes proving software correct a hell of a lot easier.
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If I'm not mistaken the 386 was the last 100% deterministic x86 chip.
The 486 has a pipeline and needs to clear the pipeline on branch miss (for 486, branch taken = branch miss). In the strictest hard real-time sense it's not deterministic. (It's deterministic in the sense that the branch prediction is static and various outcomes could be predetermined based on input, but the result would arrive at different times depending on the number of branch misses).
Re: hubble is stil on the 486 cpu? maybe time to u (Score:2)
It doesnt use a random number generator to do branch prediction. Given the exact same opcodes, data (i/o and ram) it will produce the exact same output.
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I too, had the same thoughts back 23 years ago when i was working on NOAA weather satellites, then my mentor (one of the original designers) enlightened me to the rigors of space flight/launch on things like data processing hardware.
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yeah, flipping bits is a real issue, and if your satellite cuts the Van Allen belts, then you are in real trouble and need much more than the level of hardening for satellites lower down in orbit.
While the Van Allen belts absorb many cosmic rays, they do not filter out 100% of them. For life on Earth the Van Allen belts are crucial as enough rays are filtered; for satellites in space, they do not provide blanket protection. CPUs still need to be hardened.
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SpaceX has sent several manned missions into orbit now, not including flights to the ISS. I'm sure there are challenges but surely it's possible to use a Dragon capsule to for a servicing mission?
1) How does a Dragon capsule attach itself to the Hubble? The shuttle used its arm to grab objects. 2) How does an astronaut perform an EVA from a Dragon capsule? The capsules are designed to deliver things to the ISS not perform repair missions so they have no airlock designed for this. An airlock module would have to be designed. 3) What spacesuits would be used? The shuttle spacesuits are retired and NASA is designing new ones for Mars missions but a spacesuit for EVAs would have to be designed and fabri
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Maybe a clamp-on module to the Dragon capsule that comes up with it with the rocket, so from top to bottom you have the capsule, the module, then the rocket.
How does this clamp-on module maneuver to clamp-on? The reason the shuttle used an arm is that it could move independently of the shuttle to grab things. While the capsule could do that it is far trickier using the capsule maneuvering rockets. Airlocks on the ISS are more forgiving in alignment this clamp on to the Hubble.
Maybe the module stays in space?
The Hubble was not designed for anything to attach to it long term. As such, any module attached to it might rip off parts of it during maneuvers. Hubble, like other satellites, do not sta
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Think it out. It's an idea, not a finished product. The capsule doesn't need to handle all of the maneuvering, the module can contain its own thrusters. The module doesn't necessarily need to be fixed at all once it's in a starting orbit.
The Hubble was not designed for anything to attach to it long term. As such, any module attached to it might rip off parts of it during maneuvers.
I said stays in space. I didn't say stays attached to Hubble. Something like this can possibly be kept in space to service other craft, with smaller rockets designed to rendezvous with it. A capsule could possibly put it in the appropriate space for whatever maintenance mis
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Think it out. It's an idea, not a finished product. The capsule doesn't need to handle all of the maneuvering, the module can contain its own thrusters. The module doesn't necessarily need to be fixed at all once it's in a starting orbit.
Again, Hubble was not designed with hard points to attach to anything long term. Something with thrusters would exert force on different points of it and could damage it. The last mission added hard points for rockets to later push it out of orbit once it is decommissioned. At that point damaging it is less of a concern.
I said stays in space. I didn't say stays attached to Hubble. Something like this can possibly be kept in space to service other craft, with smaller rockets designed to rendezvous with it. A capsule could possibly put it in the appropriate space for whatever maintenance mission it has.
Why? Again, orbits are not perfect. Anything in orbit requires periodic corrections. Your proposal is to send an unmanned capsule in orbit that does nothing but wait while it spends fuel. Th
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"Mike broke the Hubble! Mike broke the Hubble!"
Hubble Repair Plan (Score:4, Informative)
Related to discussion above about SpaceX/Dragon EVAs, there is a plan for this. As noted( https://science.slashdot.org/c... [slashdot.org] ), an upcoming mission is expected to include an EVA from a Dragon.
Also, there is a full Hubble Repair Plan that has been proposed. https://www.npr.org/2024/05/16... [npr.org]
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That "repair plan" sounds little more than some guy putting up money. Very little on how it would actually be done other than some vague waffle about a space walk. If it was that easy it wouldn't have needed the shuttle with its robotic arm and payload bay.
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About the plan...
"Andrew Feustel, who performed three spacewalks to refurbish Hubble in 2009, says he found the mission proposal to be "quite a reasonable and admirable concept.""
STS-125
Feustel's first mission was STS-125, which was successfully launched to repair the Hubble Space Telescope on May 11, 2009. On this mission, Feustel was a mission specialist, and performed three spacewalks to help repair the telescope itself.[9] During the mission, Feustel accumulated a total EVA time of twenty hours and thir
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About the plan...
"Andrew Feustel, who performed three spacewalks to refurbish Hubble in 2009, says he found the mission proposal to be "quite a reasonable and admirable concept.""
Does the proposal include an actual plan or is it little more than "go and do this" while glossing over the details?
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Very much the latter by the looks of it. The guy probably just wants publicity.
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But no one has gone on a spacewalk from a SpaceX capsule yet, and the company has only just developed its spacewalking suits, so NASA has "no history on which to base future predictions of success," says Feustel.
He adds that it would be helpful to have a demonstration of the team's spacewalking, as well as the functionality of the new suit, to understand how these capabilities might be compatible with a Hubble repair.
It's an intriguing concept to him and everyone however he acknowledges there are fundamental missing first steps from the plan. Like working EVA suits. Like SpaceX has yet to perform a spacewalk.
Irrelevant anecdote (Score:3)
When I was K-12, one of my teachers had her friend come in to talk with the class about his work on the mirrors while it was being built. It was pretty fucking cool to talk to him.
That's all I have to say about that.
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Was the the fucked up mirror, which was built wrong?
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Lol, yes, this guy was on the team that made the mirror that needed 'glasses'.
Time and Feta Catching Up With Hubble (Score:2)
It's now one gyro short of a combo platter...