[HN Gopher] NASA Releases Hubble Image Taken in New Pointing Mod...
___________________________________________________________________
NASA Releases Hubble Image Taken in New Pointing Mode Using Only
Single Gyro
Author : isaacfrond
Score : 222 points
Date : 2024-06-19 07:53 UTC (1 days ago)
(HTM) web link (science.nasa.gov)
(TXT) w3m dump (science.nasa.gov)
| datadrivenangel wrote:
| The magic of hot fixes in production.
| madaxe_again wrote:
| I'd love to see some actual data on this - what's the impact on
| resolution, maximum exposure time, etc.?
| aejm wrote:
| "Once Hubble is on target, the steadiness of the telescope in
| one-gyro mode is almost comparable to that of a full three-gyro
| complement... Although one-gyro mode is an excellent way to
| keep Hubble science operations going, it does have limitations,
| which include a small decrease in efficiency (roughly 12
| percent) due to the added time required to slew and lock the
| telescope onto a science target... If Earth or the moon block
| two of the fixed head star trackers' fields of view, Hubble
| must move further along in its orbit until the star trackers
| can see the sky and its stars again. This process encroaches
| upon science observation time. Second, the additional time the
| fine guidance sensors take to further search for the guide
| stars adds to the total time the sensors use to complete the
| acquisition. Third, in one-gyro mode Hubble has some
| restrictions on the science it can do. For example, Hubble
| cannot track moving objects that are closer to Earth than the
| orbit of Mars. Their motion is too fast to track without the
| full complement of gyros. Additionally, the reduced area of sky
| that Hubble can point to at any given time also reduces its
| flexibility to see transient events or targets of opportunity
| like an exploding star or an impact on Jupiter. When combined,
| these factors may yield a decrease in productivity of roughly
| 20 to 25 percent from the typical observing program conducted
| in the past using all three gyros." [0]
|
| [0]
| https://science.nasa.gov/mission/hubble/observatory/design/h...
| SoftTalker wrote:
| It was launched 34 years ago with a 15-year expected service
| life. So that it's still operating at all today is quite an
| achievement.
| dylan604 wrote:
| The impact on Jupiter bit seems strange to me. Unless it's
| something that just pops up out of nowhere, it seems like
| we'd have been tracking the impactor for some time to be able
| to have plenty of lead time for Hubble to use its walker to
| slowly get into position.
| SiempreViernes wrote:
| Impactors are indeed not seen that far ahead in comparison
| to the Hubble time allocation time scale, so for scheduling
| purposes they do more or less pop up out of nowhere.
|
| Since its not very likely that you happen to have a
| scheduled science target lying close to Jupiter around the
| time of impact, you would have to do a long slew which now
| takes such a long time you likely have to cancel some other
| science. But I think this is a general issue that will
| discard most targets of opportunity that Hubble could
| otherwise have observed.
| EncomLab wrote:
| Pretty incredible what they are able to do with a i486!
| tanbog45 wrote:
| We used to get quake and Warcraft running on them from memory.
|
| It was - is! - a great chip.
| Freebytes wrote:
| I had a hard time getting Doom to run on my 486. I only had
| something like 4MB of RAM if I recall correctly so I had to
| restart my computer, edit the AUTOEXEC.BAT to remove options
| that I would use to load Windows, and then boot back into DOS
| to launch DOOM each time I wanted to play it to get that last
| bit of memory I needed. Then, when I wanted to run Windows, I
| had to edit the HIMEM.SYS stuff to get it running again. (I
| was a teenager with no Internet access. I have no idea how I
| figured out this stuff or where I got information from.)
| codesnik wrote:
| "norton commander" shell had a user defined menu where you
| could create short scripts, basically just a chain of DOS
| commands. As a fellow teenager with no Internet access,
| I've made a "game" submenu which replaced normal
| autoexec.bat with a slim one curated for a particular game
| and rebooted computer right into the game. After you exit
| the game it'll replace autoexec.bat with the backup of
| normal one and reboot again back into norton commander.
|
| I have no idea why I needed that level of automation, of
| course.
| duffyjp wrote:
| I recently installed DOS 6.22 on an old laptop. By old, I
| mean a core2duo with 4GB of ram. It was hilarious to me
| that I needed to google the correct settings to use to get
| a game that requires 4MB to work on a machine with 4GB.
|
| My actual goal was to setup QBasic for my son, which I
| did-- but he thought it was stupid and refused to even let
| me show him how to code a Hello World app on it. :(
| TheAmazingRace wrote:
| I'm sorry this happened to you. If you were my dad, I
| would have thought you showing me QBASIC would have been
| the coolest thing ever.
|
| It kind of reminds me of my dad when he built our first
| whitebox 486 PC in 1992. Getting to sit on his lap while
| we messed around in DOS and some games from the era
| really stuck with me forever. He also loved to mess
| around in a BBS and would show me how cool it was that we
| could communicate with other systems at a long distance
| via modem. :)
| xnorswap wrote:
| My friend had a 486 (We only had a 386), but it would play
| doom really well.
|
| However, the first step of any gaming session was to reboot
| the machine with the boot floppy in, which had the right
| boot settings for gaming performance.
| londons_explore wrote:
| Luckily the processing for this sort of control loop is usually
| very simple mathematically. It's gonna be a few multiplies and
| a bunch of adding and subtracting most likely. The challenge is
| _designing_ that mathematical formula, and making sure to take
| the readings from the sensors and output them to the actuators
| _on time_.
| regularfry wrote:
| It's not just designing the formula, getting the parameters
| right is going to be a right pain. You might have meant that
| as part of "designing" but it's a significant challenge in
| its own right, over and above having a formula that's the
| right shape.
|
| Not to mention numerical accuracy in the implementation, but
| I'd assume that's mostly known patterns at this point.
| ijustlovemath wrote:
| The beauty of using a Kalman filter is that its constantly
| refitting the model parameters to match the observed state.
| bongodongobob wrote:
| Is it though? All you'd need to control some gyros is a
| microcontroller. I can't imagine it'd be more than a couple
| hundred lines of code implementing a PID controller or
| something. In fact, you could probably do it with standalone
| controllers, some sensors and relays.
| kevvok wrote:
| Hell, even the JWST is powered by the same CPU as the first
| iMac running at half the speed
| tonetegeatinst wrote:
| NASA has such a tiny budget in comparison to other stuff....so
| they really have to stretch that money as far as they can, and
| especially considering spacecraft....its a very unforgiving
| production environment.
|
| Am I making a joke about deploying in production? Yes, yes I am.
| But I also know NASA really does the best they can and I am
| amazed at the insane work and effort that they do to make sure
| spacecraft they send actually work.
| go_elmo wrote:
| Its insane how far quality can push things, even with a tiny
| budget. And yes, Im also making jokes about burning money..
| tech is a strange world!
| trentnix wrote:
| NASA looks efficient because you're comparing it to the rest of
| government.
|
| I love the work they do. I wish they did more with what they
| have. And then I wish they had more to work with.
|
| When they are constrained, like they are with spacecraft
| already in flight, their ability to problem solve with the
| tools and systems they have available is absolutely impressive.
| phaedrus wrote:
| I'm sure at NASA as at all government agencies there are
| teams who work very efficiently and do more with less, and
| other teams whose mission does not have that characteristic
| and constraint.
| Tostino wrote:
| The majority of inefficiency seems to leek into NASA via
| our Congress.
| sgc wrote:
| I agree, NASA would be much further along without that
| bunch of turnips.
| bloomingeek wrote:
| Perhaps if they used Raspberry pi, they wouldn't be in
| such a pickle? (Sorry)
| nradov wrote:
| Pork-barrel politics are ugly and make federal programs
| like NASA less efficient. But in this case it serves a
| strategic value in preserving a geographically
| distributed aerospace industrial base. This ensures we
| won't lose too much capacity from a single disaster or
| enemy attack. If that "insurance" means fewer space
| missions then it's a premium worth paying.
| dlachausse wrote:
| This isn't specific to NASA or Congress. U.S. Government
| agencies will utilize whatever budget they are given,
| period.
|
| There is no incentive to be efficient. If there is
| leftover money in the final fiscal quarter you are highly
| encouraged to use every penny, even if that means buying
| new furniture and office supplies that you don't really
| need. Any leftover money will be given to someone else
| and you will receive a smaller budget the following year.
| doctorwho42 wrote:
| I think they are commenting on the requirements imposed
| on NASA with regards to where parts are made (what
| states), etc.
| dirtyv wrote:
| I've have personally seen instances where it is
| recommended to go over your budget, so it appears your
| budget needs to be increased.
| semi-extrinsic wrote:
| > NASA looks efficient because you're comparing it to the
| rest of government.
|
| NASA also looks quite efficient when you compare it to many
| tech companies. NASA has 18k employees and $25bn budget in
| 2023, let's compare it with some companies:
|
| Spotify and Stripe are each equal to half of NASA both in
| terms of employees and budget.
|
| Snapchat and Airbnb are both approx 1/3rd of NASA in both
| employees and budget.
|
| Yahoo has 1/2 the employees and 1/3 the budget of NASA.
|
| ByteDance is _6x larger_ than NASA on both metrics.
|
| Meta is 6x larger in budget and 4x larger in head count.
|
| These are just companies making social media apps and selling
| ads.
| TremendousJudge wrote:
| Spotify has a 12bn budget? What are they spending it on?
| Does it include licensing fees?
| justahuman74 wrote:
| Spotify doesn't have a great bargaining position against
| the record labels, they don't make much profit.
|
| This is why they've been trying to move into all the
| other stuff like podcasts
| zamadatix wrote:
| How do I read this employees/budget metric to properly rank
| efficiency?
|
| Is 1,000 employees each with an average burn rate per
| employee of a $1,000,000/y supposed to be more or less
| efficient than 2,000 employees with an average burn rate
| per employee of $500,000/y? If so, why is that a sign of an
| inherently more efficient company when we haven't even
| mentioned things like output yet? E.g. some of the
| companies in the list post a large loss, others post a
| large gain. If a company doubled it's employee count and
| posted a 10% change in profit due to staffing budgets why
| should that result in 100% or 50% change in this metric?
|
| Is 1,000 companies with 1 employee each and a budget of
| $1,000,000/y inherently supposed to be the same efficiency
| as 1 company with 1,000 employees and a budget of
| $1,000,000,000/y even if the other company is posting a
| profit and the small company just spending it all each
| year?
|
| I'm generally on the side of NASA but in this case I just
| don't understand how to apply this metric in a meaningful
| way. It seems almost everything else about the company is
| more relevant to overall efficiency the "amount of money
| spent in the last year for a given number of people working
| there". I.e., at the end of the day in terms of efficiency
| I don't really care if 1 person works at NASA or 100,000
| people work at NASA I care how quickly they get meaningful
| missions completed at a given budget.
| alistairSH wrote:
| I _think_ the point was these massive ad companies have
| similar resources as NASA and don 't do anything
| particularly useful* for society.
|
| * For some definitions of useful
| semi-extrinsic wrote:
| I'm not saying look at those two numbers divided by each
| other. In fact the ratio seems to be quite constant
| across companies.
|
| What I'm saying is, take what Spotify is actually
| producing, and compare that to half of what NASA is
| producing. Or compare Snap to a third of NASA, etc.
| zamadatix wrote:
| Similarly just because you and I don't like what Spotify
| produces as much as what NASA produces doesn't really
| help weigh their efficiency without a whole lot of other
| data that's more important (before even getting into the
| debate of what everyone considers worthwhile output). The
| most efficient pasta producer in the world could premix
| their pasta with pesto and I don't get to claim it's the
| same efficiency as every other place just because I
| despite pesto.
|
| I mean I get wanting to shit on adtech over NASA, the
| latters is... significantly more cool. I just don't get
| why it's related to explaining how efficient or
| inefficient NASA is at the significantly cooler stuff.
| fallingknife wrote:
| There's a billionaire who has offered to do a repair mission.
| NASA considers this too risky to let some random guy go up
| there and fix it. If they worked together on a plan I feel like
| they could get this done in a way that reduces the risk, but it
| seems like they just don't want to.
| dotnet00 wrote:
| It's worth adding that the proposal was mainly for reboosting
| the telescope, which can still be done later if needed.
|
| Trying to EVA and work on Hubble would be very risky right
| now with Dragon since you have to vent the entire capsule
| first, and this creates all sorts of optics contamination
| risks.
|
| They're also balancing this against upcoming technologies,
| possible cost reductions and the much improved capabilities
| of ground based telescopes due to advanced adaptive optics.
| fallingknife wrote:
| Couldn't they vent the capsule well before docking with
| Hubble? I assume the contamination comes from venting the
| capsule nearby the telescope.
| dotnet00 wrote:
| They could, but it might be considered risky or maybe
| outright not possible with the current design, since the
| EVA hoses would be different from the ones normally used
| within the capsule.
|
| It isn't that the problems can't be solved, just that
| NASA doesn't think it's worth working on just yet. Tbh I
| wouldn't be surprised if they're hoping to get government
| funding so that they can be the controlling party (vs a
| private mission, where, ultimately, they have to
| compromise with the specific things Isaacman would be
| willing to fund and within the timeline within which he's
| willing to keep funding).
| tempnow987 wrote:
| Except you look at what they are spending on the entire SLS
| infrastructure vs what they are getting (vs other science
| options and/or space exploration options) and basically your
| mind is blown at how wasteful NASA is.
|
| SLS is a $2-$3 billion per launch DISPOSABLE rocket. The orion
| capsule is going to be something like $20 billion(!). I think
| things like launch abort and service module with all the
| propulsion etc are also disposable.
| FactolSarin wrote:
| I don't think NASA would have chosen the SLS platform though.
| It was basically mandated by Congress.
| el_toast wrote:
| Same story with shuttle and that's why it looks the way it
| is and was as expensive as it was. It would have been a
| completely different vehicle if Congress weren't meddling.
| dingnuts wrote:
| Congress is the owner. Want a different management
| ideology? Get different management.
|
| NASA is wasteful, eh? Maybe that's because they have no
| incentive not to be wasteful..
| eggy wrote:
| NASA is neither a public or private company, but rather a
| government agency. Congress is an employee of the US
| taxpayer. I think that makes them more of a manager of
| NASA and we should hold Congress accountable.
| margalabargala wrote:
| The leadership and composition of Congress has changed
| numerous times over the years without change to
| management ideology. It does not seem likely that
| electing mildly different people will change the
| management ideology. Management acted in accordance with
| the incentives they were presented with.
|
| I can't say NASA seems particularly wasteful outside ways
| in which they are mandated to be so.
| wongarsu wrote:
| What NASA wanted was a space station, a small tug to move
| stuff in space, and a small shuttle to move people and
| cargo from earth to that station.
|
| The whole point of the space shuttle was to have it
| service the space station, but the station wasn't
| greenlit. Instead we got a much bigger shuttle that was
| useful as a military asset but was a money pit with
| terrible safety record. Luckily the Soviet Union
| collapsed and the ISS was funded as a job program for
| Soviet rocket scientists (out of fear they could be
| poached to work on ICBMs for other nations).
| eggy wrote:
| I think a matching industry company, but not necessarily a
| better counter example, would be SpaceX vs. NASA, for better
| or worse, and obvious reasons. They are trying to change the
| launch-and-trash model to reuse, so this requires a paradigm
| shift. When NASA chose SpaceX and Boeing to compete in 2014,
| SpaceX won, and after seeing Boeing's current fiasco decline,
| that's a good thing.
|
| I was a member of the L5 Society [1] in the 80s where we
| would meet on the Intrepid aircraft carrier in Manhattan to
| discuss all things space and space colonization (L5 being the
| Lagrangian point in the Earth-Moon system to place space
| habitats 60-degrees behind or ahead of the Moon's orbit for
| stable gravitational equilibrium to minimize fuel or energy
| to maintain that position). L5 later merged with the National
| Space Institute under the National Space Society (NSI was
| Werner von Braun's baby).
|
| I had read O'Neill's 1974 article, "The Colonization of
| Space" when I was 10, in Physics Today that got me hooked
| before L5. I bought a Commodore PET 2001 in 1977/78 and was
| writing a program to show the on orbital plane view of
| Jupiter's 4 major moons - Io, Ganymede, Callisto, and Europa
| to better identify which was which when using my binoculars
| at night. I left L5 in 1988/89. Good times at the Galaxy
| Diner after the monthly meetings on the Intrepid.
|
| I stopped devoting time to space around then and didn't pick
| up an avid interest again until SpaceX, even though I had
| done some machining work for some models of subassemblies for
| the Spirit and Opportunity Mars rovers in the early 2000s. I
| am now back at making machines and dreaming of space again!
| [1] https://en.wikipedia.org/wiki/L5_Society
| photochemsyn wrote:
| NASA's manned mission division does seem to have the bigger
| problem with bloated contracting budgets and inefficiency,
| relative to the rest of the organization. I'd guess that's
| due to direct political influence (the Richard Shelby - Bill
| Nelson effect in that case). From 2010:
|
| https://www.politico.com/news/stories/0911/62767_Page3.html
| akira2501 wrote:
| > SLS is a $2-$3 billion per launch DISPOSABLE rocket.
|
| That's the estimated cost for the first four launches only.
|
| > The orion capsule is going to be something like $20
| billion(!).
|
| We developed it from scratch and it took 20 years and it's
| capable of sending a crew to Mars.
|
| What do you think this _should_ have cost?
| tho23i43244244 wrote:
| Imagine the leaps the humanity would see if the US spent a
| tenth on NASA as it does on "defense" (it'd likely still
| outspend the next 10 countries, combined, even then on the war-
| dept.).
|
| JFK, come back.
| BurningFrog wrote:
| The NASA budget is $25B, or about $75 per American.
| dahart wrote:
| That's an average for the year 2024, but as income taxpayers
| we only pay around half of that, or around $36.40 per
| American (using the $24.9B 2024 budget and 342M for the 2024
| population), or maybe about one week's morning Starbucks
| habit for some of us. :P The rest is paid by businesses and
| other sources. Of course, compared to the amount the military
| costs & spends, NASA's really small.
| qrush wrote:
| In case anyone just wants the download:
| https://science.nasa.gov/wp-content/uploads/2024/06/hubble-n...
| jagger27 wrote:
| Hubble is such a productive piece of an equipment. What a shame
| there has been only one pointing outwards all these years.
| 1970-01-01 wrote:
| >What a shame there has been only one pointing outwards all
| these years.
|
| Let's not forget that initially it was considered a _massive_
| failure. There simply was no way for NASA to build another in
| the 90s. What 's truly remarkable is how the ROI went from
| unknown, to negative, and then was a massive long-term success.
| solarkraft wrote:
| > Let's not forget that initially it was considered a massive
| failure
|
| Why was that? Were fewer discoveries made than hoped?
| xnorswap wrote:
| https://science.nasa.gov/mission/hubble/observatory/design/
| o...
| munchler wrote:
| Spherical aberration in its primary mirror (and other
| issues) discovered shortly after launch.
|
| https://www.skyatnightmagazine.com/space-missions/what-
| was-w...
| jessriedel wrote:
| It initially was a massive failure? They made a preventable
| mistake that cost ~$1B.
| dylan604 wrote:
| Let's not forget that NRO donated multiple Hubble level
| satellites. NASA had no budget to utilize them, so they were
| not used. Of course there were other logistics involved that
| made the "gifts" not so practical. However, the thing that
| gets me is that if the NRO was willing to donate these
| satellites tells me that they have _better_ than Hubble
| quality imaging looking inwards and absolutely have multiple
| of them.
| consp wrote:
| Aren't they using one right now? [1]
|
| [1] https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_T
| elesc...
| dylan604 wrote:
| I guess you can say "using right now", but from your
| link:
|
| "October 2026 (contracted) - May 2027 (commitment)"
|
| So more like, in the works to use one of them. It does
| appear that it is beyond the planning to use stage. I did
| not see the word Boeing once in that link, so maybe they
| have an actual shot of hitting those dates.
| pkaye wrote:
| The Nancy Grace Roman Space Telescope is one of them. They
| still had to change the optics for astronomical purposes.
| LeifCarrotson wrote:
| It's a sad state of affairs that we as a society have only been
| able to prioritize sending up one single Hubble, while the US
| alone has sent up several dozen equivalent KH-9 and superior
| KH-11 satellites to look at Earth for classified military
| purposes.
|
| I know there are other space-based telescopes (James Webb being
| larger and superior, others being much smaller and more
| specialized than Hubble) and lots of ground-based telescopes. I
| don't dispute that keeping an eye on Soviet missile development
| and other spy satellite tasks was and is an important mission
| that has significant, immediate consequences for our species
| than the informative and gorgeous photos of space that the
| Hubble mission produces. I'm just disappointed that the
| combination of human nature and politics makes this a
| reasonable outcome.
| mturmon wrote:
| It's not quite that bad.
|
| Hubble is primarily optical wavelengths. The other Great
| [space-based] Observatories are in IR, X-rays, and gamma rays:
|
| https://en.wikipedia.org/wiki/Great_Observatories_program
|
| The notion of grouping them as "Great Observatories", AFAIK,
| came circa the mid-1980s, after Hubble was already getting
| underway in earnest.
| jgalt212 wrote:
| Scott Manley recently did a video on Hubble's single gyro mode.
|
| https://www.youtube.com/watch?v=Ra2IpumLMfs
| yellow_lead wrote:
| Are the two other gyros broken?
| solarkraft wrote:
| The others are broken, two theoretically work. They're
| disabling one to keep as a spare.
| MobiusHorizons wrote:
| Hubble was down to three working gyros, but one broke. This new
| single gyro mode, lets them take the other offline so that they
| can hold it in reserve for when this one breaks
| wongarsu wrote:
| Breaking gyros are a recurring issue for Hubble. Hubble has 6
| (3 spares, 3 for full operation). They replaced them 3 times
| with space shuttle missions because they kept breaking. Now
| Hubble is down to 2 functioning gyros again and we no longer
| have a space craft with the capability to service satellites.
| They decided to shut one of the gyros off so they still have a
| slightly used spare once this one breaks.
| jccooper wrote:
| Dragon has capability for a Hubble servicing mission. It
| would need more development than a Shuttle visit, but it's
| not a huge hurdle since the last visit installed a soft-
| capture mechanism. (It'd probably cost less than an
| equivalent Shuttle mission, just due to Shuttle's high launch
| costs.) SpaceX even prepared a proposal in a Space Act
| Agreement but NASA declined it recently. Sierra Nevada also
| has looked at doing it with Dream Chaser.
|
| Sure, Hubble's way past its design lifetime, and it can
| probably limp along for another decade as is, and maybe
| something besides gyros will fail soon. But also there's no
| equivalent capability successor that's more than a study, and
| even if they manage to build HWO or something like it, it
| won't be operation for at least 20 years. A Hubble servicing
| mission would be a relatively cheap way to get a decade or
| two more time on a high-capability instrument.
| nick238 wrote:
| The Nancy Grace Roman telescope is a replacement in most
| respects, though it doesn't have the deep UV capabilities
| (HST could go down to 115 nm, Roman goes down to 480 nm).
| Not sure why UV isn't as important to newer telescopes, but
| if it was as critical to have high-spatial-resolution UV
| measurements, they'd probably have flown one in addition to
| Webb and Roman.
| justsocrateasin wrote:
| "My kind didn't really slither out of a tidal pool, did we? God,
| I need to believe you created me: we are so small down here."
| Lillie Emery
|
| What a beautiful image
| shagie wrote:
| Tangentially related (taking pictures of things on spacecraft
| with impaired systems for tracking the objective)...
|
| https://llis.nasa.gov/lesson/394
|
| > The Voyager 2 scan platform, on which are mounted the
| spacecraft cameras and several science instruments, is rotated in
| elevation and azimuth by actuators. Near the end of the Voyager 2
| Saturn encounter, the scan platform azimuth actuator exhibited an
| anomaly. This anomaly was evidenced by the azimuth actuator
| seizing, causing a scan platform pointing error that resulted in
| a loss of some data. Through a series of ground commands, the
| problem was alleviated to the extent that the scan platform could
| perform its function. ...
|
| https://www.nytimes.com/1981/08/27/us/camera-swivel-on-voyag...
|
| https://www.nytimes.com/1981/08/28/us/swivel-on-voyager-stil...
|
| Voyager engineering improvements for Uranus encounter -
| https://ntrs.nasa.gov/citations/19860063178
|
| > Finally, engineering improvements made in order to enhance
| scientific findings at the Uranus encounter are reviewed in
| detail. The two most important were the increased gyro drift turn
| rate capability to accommodate image motion compensation for the
| close fly-by of Miranda and the reduction in spacecraft rates to
| accommodate increased imaging exposure times without incurring
| excessive image smear.
| cubefox wrote:
| Naive question: Today, smartphones use microscopic gyroscopes
| based on MEMS (micro-electromechanical systems) technology. Would
| these also work on Hubble? I suspect they'd work fine in space,
| perhaps while also being more durable (the failing Hubble
| gyroscopes were only installed in 2009). Though I guess their
| precision is not good enough for a telescope.
| bordakt wrote:
| You are thinking of the sensor in smartphones, in this case it
| is a spinning disc that uses gyroscopic torque to rotate the
| spacecraft.
| cubefox wrote:
| So there are two different technologies that are both called
| "gyroscope"? One a sensor detecting rotation, the other an
| actuator inducing rotation?
| olleromam91 wrote:
| The sensor you're describing is usually called an
| accelerometer.
| cubefox wrote:
| No, accelerometers detect acceleration in linear
| direction (up/down, left/right, forward/backward), while
| gyroscopes detect rotation (pitch, yaw, roll).
| Smartphones have both, to detect all six degrees of
| freedom.
|
| Edit: Apparently, for smartphones, all these sensors are
| integrated into a single MEMS chip, one sensor for each
| degree of freedom, three accelerometers and three
| gyroscopes: https://youtube.com/watch?v=9X4frIQo7x0
| dekhn wrote:
| BTW, smartphone acceleromoters are also packaged for
| hobbyists; a board like
| https://www.adafruit.com/product/2019 can be easily used
| to make any number of applications when coupled with a
| microcontroller. https://learn.adafruit.com/adafruit-
| mma8451-accelerometer-br...
| mintplant wrote:
| And the reason accelerometers can be used for sensing
| orientation here on Earth is, of course, because of the
| constant force of gravity :)
| SaberTail wrote:
| No, the comment you're replying to is confused. These
| gyroscopes are entirely used for determining Hubble's
| orientation. Reaction wheels effect the actual rotation,
| and Hubble's are fine.
|
| I think the confusion is a result of imprecise language
| talking about how they are used to slew the telescope. They
| are "used" but as feedback, in conjunction with other
| systems. Also, there have some prominent reaction wheels
| failures on other missions, and that contributes to the
| confusion.
| cubefox wrote:
| Thanks, this makes sense. I guess I should look up the
| difference between gyroscopes and reaction wheels next.
| ijustlovemath wrote:
| Per your name:
| https://m.youtube.com/watch?v=n_6p-1J551Y&pp=ygUG
| Rebelgecko wrote:
| FWIW I think 2 of the Hubble's 4 reaction wheels are
| dead, which also requires some interesting workarounds
| dr_orpheus wrote:
| No, these are actually referring to the gyroscopic sensors on
| the spacecraft. This article [0] makes it a little bit more
| clear. While there are actuators that use gyroscopic torque,
| referred to as Control Moment Gyros (CMG) Hubble uses
| reaction wheels for pointing the spacecraft.
|
| [0] https://science.nasa.gov/mission/hubble/observatory/desig
| n/h...
| dr_orpheus wrote:
| The accuracy of MEMS gyros is orders of magnitude worse than
| the gyros on Hubble. I suspect based on this article [0] that
| Hubble uses hemispherical resonator gyros (HRG [1]). The really
| high accuracy rate sensors that you find in spacecraft are
| usually HRGs or Fiber Optic Gyroscopes (FOG).
|
| [0]
| https://science.nasa.gov/mission/hubble/observatory/design/h...
|
| [1] https://en.wikipedia.org/wiki/Gyroscope#HRG
| cubefox wrote:
| Oh, this made me worried about JWST (as it can't be serviced
| once the gyroscopes break), but I found this:
|
| > To detect changes in direction JWST uses hemispherical
| resonator gyroscopes (HRG). HRGs are expected to be more
| reliable than the gas-bearing gyroscopes that were a
| reliability issue on Hubble Space Telescope. They cannot
| point as finely, however, which is overcome by the JWST fine
| guidance mirror.[18]
|
| https://en.wikipedia.org/wiki/Spacecraft_bus_(James_Webb_Spa.
| ..
|
| So Hubble uses gyroscopes that are more precise but less
| reliable than the HRGs used in JWST.
| dr_orpheus wrote:
| Interesting, TIL that Hubble uses gas-bearing gyroscopes. I
| been struggling to find any other spacecraft that use those
| gas-bearing gyros. The only other one that seems to be
| using them (that is still operational) is the Chandra X-ray
| Observatory.
| BurningFrog wrote:
| I just think it's sad that they're doing fixes on a 34 year old
| telescope instead of sending up a new improved model every 10
| years.
| moffkalast wrote:
| Well the JWST is in fact a thing. Why not keep getting science
| from the old ones while they're still working?
|
| NASA really needs to just fill their telescopes with gyros upon
| gyros, like just plaster the things with gyros and reaction
| wheels for 50x redundancy since that's always the mission
| critical thing that fails first. Or maybe a xenon powered ion
| reaction control system or something that would last longer
| then hydrazine.
| gammarator wrote:
| > NASA really needs to just fill their telescopes with gyros
| upon gyros
|
| It's an interesting tradeoff. Missions are designed (and
| costed) for a nominal mission lifetime; adding more
| redundancy increases costs. But it's true that the successful
| missions tend to stay in operations much longer than their
| normal lifetime.
| svachalek wrote:
| JWST is an infrared telescope though, which doesn't really
| replace the Hubble. It is suited for the interesting science
| of our times though. An upgraded optical space telescope
| would probably be less groundbreaking but still very valuable
| to science.
| SiempreViernes wrote:
| I think its sad that single use consumerism culture is so
| pervasive that anyone would actually bemoan a thing as
| extremely niche as a cutting edge scientific instrument getting
| over tens years of use.
| BenFranklin100 wrote:
| That's a bad faith take. The OP is clearly expressing their
| opinion that space exploration is underfunded. No one is
| unhappy the Hubble is going on 35 years. Think how much we
| would be learning if we had additional similarly scoped
| astronomical missions in 2000, 2010, and 2020 though.
| BurningFrog wrote:
| What was cutting edge in 1990 is very far from it today.
|
| Sending up Hubble II and Hubble III would of course not mean
| that Hubble I stops being used.
| phyzome wrote:
| On the contrary, I think it's great.
| pohl wrote:
| Why not both? Send up new telescopes and keep the old ones
| running.
| BurningFrog wrote:
| If feasible, sure.
|
| But I'd expect it's often cheaper to send up a new telescope
| than to repair an old one.
| barbegal wrote:
| There's a technical description of how the one gyro control
| system here
| https://ntrs.nasa.gov/api/citations/20080023344/downloads/20...
|
| Essentially using other sensors (star tracker and magnetometer)
| and kalman filtering for sensor fusion.
| zootboy wrote:
| Very cool that they were developing the one-gyro control mode
| all the way back in 2004, and had in-flight tested it by 2008.
| Seems like they were well prepared for this eventuality.
| pavon wrote:
| That's because this isn't the first time Hubble has been down
| to two working gyros. It happened before in 1999 (replaced a
| few months later), and they were worried it would happen
| again after 2003 when the Shuttles were grounded (actually
| got down to three/six working before replacement in 2009).
| Synaesthesia wrote:
| That's a really spectacular image.
| foxyv wrote:
| This thing went up when I was in Kindergarten! It blows my mind
| that it's still running.
| jeffrallen wrote:
| You think that's amazing, read up on Voyager!
| unchocked wrote:
| Missing from the article: Jared Isaacman offered to fix Hubble
| for free, and NASA turned him down.
| josefresco wrote:
| >It basically seems like the risks involved aren't necessarily
| worth taking right now, seeing as Hubble is technically doing
| just fine.
|
| *https://www.space.com/jared-isaacman-hubble-space-
| telescope-...
| Log_out_ wrote:
| Who needs proper gyros, just give nasa three rumble packs.
| codexb wrote:
| It's pictures like this that seem to make Dark Matter not all
| that mysterious. It's clear that the galaxy is surrounded by _a
| lot_ of dust, and you can clearly see that even as you extend
| outward and the light drops off, there is still a lot of dust
| that is just not illuminated.
| Laremere wrote:
| Dust that isn't in light is accounted for, and is a different
| thing from non-baryonic dark matter.
|
| See: https://en.m.wikipedia.org/wiki/Baryonic_dark_matter
| hagbard_c wrote:
| Hey SpaceX, here's an idea: put a few of your 'Atlas' robots on
| one of the upcoming Starship test vehicles - maybe the one where
| you plan to test in-orbit refuelling since it probably takes a
| bit of extra fuel to get to Hubble's orbit - and get the thing to
| meet up with Hubble. Have the robots replace the failed gyros,
| replace the batteries and whatever other consumables that old
| relic contains. Have them take back the old parts in Starship so
| they can be studied. The result would be revived Hubble as well
| as one of the biggest PR coups imaginable. Or, maybe, one of the
| biggest hits against human space flight if it turns out robots
| can do the job well enough not to have to send up their meat-
| based masters, take your pick.
| toomuchtodo wrote:
| Would Hubble fit in Starship for a return flight to ground?
| Would look nice hanging in the Smithsonian. Flight proven space
| observatory.
| lupusreal wrote:
| What even is the point of looking at space if we give up the
| pretext of sending people there? It just turns into an
| expensive way to mint PhDs on the taxpayer's dime, studying
| things which cannot have economic relevance on Earth (which is
| why they can't be studied on Earth.)
| Laremere wrote:
| Jared Isaacman and SpaceX already made a proposal to NASA to do
| a Hubble servicing mission. NASA recently responded with "no
| thanks". NASA feels the risk of potentially damaging Hubble in
| some way (eg, gas from thruster getting on a mirror) outweighs
| the benefits. Basically a high probability of worse performance
| is chosen to be more favorable than a lower probability of
| better performance.
| zdragnar wrote:
| This is amazing, though not quite as amazing as how I first read
| the title (sandwich, not device).
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