[HN Gopher] Hubble telescope has new lease on life after compute... ___________________________________________________________________ Hubble telescope has new lease on life after computer swap appears to fix glitch Author : sohkamyung Score : 479 points Date : 2021-07-16 12:54 UTC (10 hours ago) (HTM) web link (www.sciencemag.org) (TXT) w3m dump (www.sciencemag.org) | js4ever wrote: | NASA and Space engineering is fascinating! Being able to do this | on 30 years old hardware ... In space | zabzonk wrote: | Hurrah! We may well need it if the James Webb doesn't go | according to plan. | | But really, aren't these spacecraft, rovers, exploration | programmes, etc. among the best example of what humans can do if | they put their minds to it? | Tomte wrote: | Hubble "sees" different wavelengths than JWT, also, both are | overbooked. So we really want Hubble as long as possible, no | matter how the JWT launch goes. | Mentoio wrote: | Hui, does that really matter? or lets ask other: Is JWT able | to make another but more crazy deep field image? | | I think i have to read up on it :D | smeyer wrote: | Yes, it really matters. It might not matter from the | perspective of just making cool looking images, because you | can do that in any wavelength. But for science, the | wavelengths matter a lot, and you can learn different | things at different wavelengths. | Mentoio wrote: | Oh no no, i was just worried that JWT would actually not | be able to do a deep field 2.0. im very curious on | potentially higher details on this and mentioning that | JWT and Hubble use different wavelength (or JWT might be | able to do more?) would have meant that JWT wouldn't be | able to do the same as Hubble in regards of a deep field. | rootbear wrote: | There is great interest in using both instruments to observe | the same target simultaneously, for example, a new supernova. | It would be a real loss not to have Hubble available for such | observations after JWST launches later this year. | [deleted] | zinekeller wrote: | The link is fine, but here's the news from NASA: | https://www.nasa.gov/feature/goddard/2021/operations-underwa... | platz wrote: | The article contradicts itself several times on what the actual | fix was. | 2Gkashmiri wrote: | What is the power generation or storage on Hubble? | odysseus wrote: | Finally, for fans of Weird Al Yankovic's White & Nerdy, an excuse | to reference Norm Sherman's Pimp My Satellite, which is all about | the Hubble: https://www.youtube.com/watch?v=xMXk5Y7Gv6Y | cyberlurker wrote: | " NASA announced that they had identified the Power Control Unit | (PCU), which is part of the SI C&DH, as the source of the | problem" | | So they had a spare PCU that they switched to. Hubble was | launched in 1990. Is 30+ years normal for a continuously | operating PCU? What is the expected lifespan of the "new" PCU | that has been sitting this whole time? | ceejayoz wrote: | Not just continuously operating, but in a _very_ harsh | environment. Impressive. | phonon wrote: | The original PCU was replaced in 2001. | | https://esahubble.org/about/history/sm3b_replacement_of_pcu/ | BeefWellington wrote: | NASA's hardware is deployed in anything but normal | circumstances, so normal for them vs normal for the consumer | are vastly different things. | | Given the longevity and how well engineered things are for | their other projects, I'd have to say yeah it seems pretty | "normal" to me. | | It seems like they overengineer and quality control to the | point of doubling planned mission length, if not longer. My | cynical take on it is they do it this way because of the nature | of their funding rather than any specific engineering goal. | rtkwe wrote: | Part of the source of the discrepancy is the planned mission | is basically just what they get initial funding for not | everything they would like to do and the entire mission | length they'd like to use. Because launch costs are such a | big part of the costs of ever replacing a Hubble or a | Curiosity it makes sense for them to last longer than they're | funded for because most likely they'll continue to get some | funding a long as there's good science and the equipment is | still usable. Also the cost of failure is pretty high, if you | have something break early there's not another | rover/satellite program there to replace it the science just | doesn't get done until the next program in 10 years gets sent | unless someone else was sending a similar device to that | destination. | Steltek wrote: | Anyone claiming to have a real answer to that would be torn to | pieces by Richard Feynman. I think you'll need to be satisfied | with best guesses and a metaphysical "as long as it lasts". | izacus wrote: | The designed life expectancy of Hubble as a whole (and thus, by | extension the minimal designed life expectancy of all | components) was 15 years. It's now been operating for 30 years, | doubling its design lifetime and intent to be replaced. | coldcode wrote: | It's too bad you couldn't just leave a space shuttle in orbit, | and then fly to it to use its arm when needed. Or build something | like a repair "truck" that once launched, never comes back. You | just load it with fuel and whatever you need, and drive it to | where it's needed. | p_l wrote: | Buran system had designs for that - one of the components was a | nuclear-powered space tug that could shift satellites around, | reducing launcher limitations. Design planned for endurance of | 100 "LEO->GEO" satellite moves. | | Hypothetical Hubble with support for such operation would have | docking port for the space tug, which could bring it back to | orbit that could be taken by service vessel, then bring it back | to proper orbit. | agloeregrets wrote: | So...are we gonna send up a replacement failover? Seems risky. | rootbear wrote: | There is currently no way to service Hubble, now that the | Shuttle fleet has been retired. | ordu wrote: | _> The PCU supplies a steady voltage supply to the payload | computer and either it was supplying voltage outside the normal | range or the sensor that detects the voltage was giving an | erroneous reading._ | | Swollen capacitors? =) | yoursunny wrote: | It's amazing how much redundancy was built into those out-of- | touch systems, 30 years ago. However, the number of backup units | is finite, so let's hope the now-operating system can last for | several more decades. | hawkesnest wrote: | The part that caught my eye was redundancy on memory. | | >> Hubble's operators initially thought a memory module was at | fault but switching to one of three backup modules produced the | same error. | | Apparently Hubble has 4 memory modules which are switchable! | I'd love to see how that works. Actually, I'd be fascinated to | get a walkthrough of the overall architecture. It might give | insights for how we keep business continuity by first accepting | that hardware and software will fail. | belter wrote: | Posted this before here. Maybe worthwhile to post again... | | Fig 5-10 is the Data Management Subsystem | | https://asd.gsfc.nasa.gov/archive/sm3a/downloads/sm3a_media_. | .. | | Concerning the computers: | | - First they had a DF-224 flight computer and a | | - Science Instrument Control and Data Handling (SI C&DH) | | Initially DF-224 between missions got installed a | coprocessor: | | https://asd.gsfc.nasa.gov/archive/hubble/a_pdf/news/facts/Co. | .. | | During another servicing mission they replaced it with | something called the Advanced Computer with Intel 80486: | | https://asd.gsfc.nasa.gov/archive/hubble/a_pdf/news/facts/FS. | .. | | There are some 50,000 lines of code in the C and Assembly | programming languages. https://www.nasa.gov/pdf/327688main_09 | _SM4_Media_Guide_rev1.... | | They also have a Help Desk... | | "Welcome to the Hubble Space Telescope Help Desk" | | https://stsci.service-now.com/hst?id=hst_index | Nition wrote: | Classic movie scenario. Hubble's down, and we need it now. | No-one can solve the errors. Old guy walks in, worked on | Hubble 30 years ago. | | "There's a backup module, with an override command to | activate it, but it won't work with the system down. You'll | have to use the manual override switch - on the telescope." | melling wrote: | ...or as I try to occasionally discuss here... let's simply | develop the unmanned robotic capability to service Hubble, etc | | I found one discussion from 7 years ago | | "... I think we should start a more extensive national unmanned | space program. For example, if the Hubble, or its replacement, | needs to be fixed, we should have an unmanned answer, for | instance." | | https://news.ycombinator.com/item?id=8540664 | gumby wrote: | I agree in a more general sense: space is a natural domain | for robots, not humans, and we should be designing out space | flight capability with that in mind. We have some almost 50 | year old robots advising us on the heliopause right now. | | The general problem of repairing Hubble robotically is | unlikely to be solvable within the lifetime of the telescope, | but future devices could be designed with that in mind. | dr_orpheus wrote: | While we don't have a direct capability to do this now, some | of the large programs of record are being built so that | robotic servicing may be possible. | | JWST has a docking port for a future robotic servicing | mission. | | Nancy Grace Roman (formerly WFIRST) space telescope has | grappling points on the spacecraft for robotic servicing. | chmod775 wrote: | I think 'simply' is precisely the wrong adjective. | | Plus you'd still need spare parts. Why would I build a robot | to swap parts, when I can simply put all of the spare parts | into the telescope and swap over to them electronically? | melling wrote: | Knowing what will go wrong is hard to predict. Having the | capacity to have robots service satellites, etc would be | extremely useful. | | Also, the vision is that robots can build on Mars, for | example. | | "Simply" means fund the research. My comment was from 7 | years ago. | | We also need the robots here on earth for dangerous tasks | | We'd make impressive progress over each decade with more | effort. | gwbas1c wrote: | > Why would I build a robot to swap parts, when I can | simply put all of the spare parts into the telescope and | swap over to them electronically? | | What if the system that swaps parts fails? | Xylakant wrote: | What if the robot fails? | melling wrote: | The robot fails to perform the task or fails reaching | orbit,etc? | | Send up another [improved] robot. These missions are less | costly than human missions. We get to iterate more often | kllrnohj wrote: | > Send up another [improved] robot. These missions are | less costly than human missions. | | Says who? And how? This seems like an unsubstantiated | claim. | gwd wrote: | <pedantic> adverb </pedantic> | | The other thing to remember was that Hubble was designed in | an era that the Space Shuttle was meant to make manned | missions to repair / upgrade commonplace. My understanding | is that this was actually done at least once to Hubble | (maybe more? I forget); but unfortunately for Reasons, NASA | turned out to be incapable of resisting cutting corners | which put people's lives at risk (Challenger, Colombia). A | system designed today would be designed assuming that it | would be robots or nothing. | mannykannot wrote: | I was curious myself, and it turns out there were five | missions, starting with the one to compensate for the | incorrectly ground mirror. IIRC the final one was in | doubt, as there was no possibility of a rescue mission in | the event of irreparable damage on launch. | | https://www.nasa.gov/mission_pages/hubble/servicing/index | .ht... | BurningFrog wrote: | Why don't we just build 5 Hubble copies and send them up? | Should be much cheaper now. | | Is the answer is that NASA doesn't know how to build them | anymore? Or that it's not politically feasible? | kitd wrote: | _Why don 't we just build 5 Hubble copies and send them up? | Should be much cheaper now._ | | "Just" is being extensively overused in this thread. | modeless wrote: | NASA doesn't know how to do _anything_ cheaply. They have | two space telescopes sitting in a warehouse since 2011 that | were donated by the NRO. They 're estimating $4 billion to | launch and run just one of them, more than a decade after | the donation. And you know it'll cost double the estimate | and take an extra 5 years. | 2Gkashmiri wrote: | Why dont they just give others to do their work? Last I | remember india sent a probe to Mars for less than amount | it took for making the movie Mars featuring Matt Damon ? | modeless wrote: | For the politicians that fund NASA, spending money is the | whole point. They call it "job creation". | 2Gkashmiri wrote: | agreed but what job creation is a project sitting dead | for 5 years? are they giving people salary for not doing | anything and then claiming too much costs or something | else? | Voloskaya wrote: | Ah yes, let's simply do something very hard. | | Huble was never meant for this, if you look at all the | systems present on ISS for automated docking, none of that is | on Hubble. Access to modules inside Hubble was never meant | for robots with very limited dexterity either. Being able to | do something like that would be a huge feat of engineering in | my opinion (and extremely expensive). | | I am fairly certain it would be faster and cheaper to just | build a new one from scratch. | | And even if you managed to make a robot to service Hubble, it | then would only be able to service Hubble and nothing else. | JWT for example is completely different. | | On the long term you are right that this is a capability we | need, but this needs to be taken into consideration while | building the telescope/satellite/whatever: automated docking | mechanism, standard ports and dimension of parts etc. etc. | mikepurvis wrote: | I'm pretty sure the pitch here is "a robotic being with | human perception, dexterity, and manipulation, but who | doesn't breathe air and never gets tired." | | So the idea is that you _don 't_ need to specialize it to | the thing it's meant to work on, because it works on | whatever a human works on. A similar idea drove a lot of | the DARPA Robotics challenge, with its emphasis on being | able to drive a normalish vehicle, open a door, climb a | ladder, use a regular power tool, etc. | | Anyway, I think the state of the art for all this is still | pretty far away, which is why the instinct is to assume | we're talking about something specialized. | Voloskaya wrote: | > I think the state of the art for all this is still | pretty far away, which is why the instinct is to assume | we're talking about something specialized. | | Yes, that's exactly what I thought. If we are talking | about AGI + human level robotic dexterity, then the use | of "simply" becomes even funnier. | parsecs wrote: | I'm not sure about AGI. You can just control the robot | remotely from earth. Sure, there will be a minor lag but | definitely won't justify need of AGI. | writeslowly wrote: | NASA was experimenting with this in the past with | Robonaut (apparently it also started as a collaboration | with DARPA) | | https://en.wikipedia.org/wiki/Robonaut | mikepurvis wrote: | I believe Robotnaut is back on earth as of sometime in | 2018, but it was briefly at the ISS and even ran ROS-- | there was an official NASA-supplied Gazebo simulator for | it: https://www.slashgear.com/nasa-robonaut-2-simulator- | stack-no... | cesarb wrote: | > Access to modules inside Hubble was never meant for | robots with very limited dexterity either. | | It was also never meant for humans with less limited | dexterity. | | I recall one of the Hubble servicing missions I watched on | NASA TV, in which they had to bolt a special adapter plate | over a cover, unscrew over a hundred tiny non-captive | screws (which the adapter plate was designed to catch, so | they wouldn't float away), and only then could they open | that cover. That part of the telescope clearly wasn't | designed to be serviced in space. | kiba wrote: | Pretty sure it's much easier and faster to do it with humans | and Starship, assuming the necessary interface is developed. | elif wrote: | starship wouldn't really fit the mission profile of sending | 2-3 astronauts to hubble orbit for EVA. The same starship | could instead deliver a fleet of replica hubbles to | lagrange points autonomously. | pantalaimon wrote: | Or built the telescope into Starship and use it as an | observatory. | pantalaimon wrote: | We can put much larger payloads into orbit now and will be | even moreso with Starship. | | It would make sense to start working on a replacement for | Hubble, even if that means it'll be ready in 20 years. | Gare wrote: | Or we could build a cheaper telescope that is less | redundant more quickly, and launch a new one every 5 years. | Launch prices are falling, so this could be more economical | than building expensive long-lasting telescopes. | gumby wrote: | Also swarms of telescopes that can collectively take | higher resolution, broad spectrum photos. | [deleted] | nerfbatplz wrote: | Considering Hubble was an old NRO design that they donated, I | bet there are more backup parts than are publically known to be | available. | hatsunearu wrote: | If you read up on it, the NRO gave a _shell_ for a Keyhole | something to do NASA. It had no optics and no sensor AFAIK, | that was on NASA to build. | MontyCarloHall wrote: | Just to clarify: Hubble was not an NRO donation, although it | bears some similarity to the KH-11, an NRO satellite from the | 70s. It is not confirmed whether the two actually share | parts, as the KH-11 is still classified. | | The NRO did donate two unlaunched telescopes to NASA in 2012 | (with optics present but sans electronics), which still have | not yet been retrofitted and launched. | not2b wrote: | I hope that as we move more and more to commercial space | development, we will continue to do the kinds of over-engineering | and redundancy that make recovery efforts like this even | possible, but fear that the mindset will shift: out of warranty, | abandon it, we will sell you a new one. | throwawayswede wrote: | I find the constant use of the term "glitch" in the title and the | lack of actual details of what happened extremely infuriating. | | Here's some actual details: | | The problem: | | > NASA has identified the possible cause of the payload computer | problem that suspended Hubble Space Telescope science operations | on June 13. The telescope itself and science instruments remain | healthy and in a safe configuration. | | The payload computer resides in the Science Instrument Command | and Data Handling (SI C&DH) unit. It controls, coordinates, and | monitors Hubble's science instruments. When the payload computer | halted, Hubble's science instruments were automatically placed | into a safe configuration. A series of multi-day tests, which | included attempts to restart and reconfigure the computer and the | backup computer, were not successful, but the information | gathered from those activities has led the Hubble team to | determine that the possible cause of the problem is in the Power | Control Unit (PCU). | | The PCU also resides on the SI C&DH unit. It ensures a steady | voltage supply to the payload computer's hardware. The PCU | contains a power regulator that provides a constant five volts of | electricity to the payload computer and its memory. A secondary | protection circuit senses the voltage levels leaving the power | regulator. If the voltage falls below or exceeds allowable | levels, this secondary circuit tells the payload computer that it | should cease operations. The team's analysis suggests that either | the voltage level from the regulator is outside of acceptable | levels (thereby tripping the secondary protection circuit), or | the secondary protection circuit has degraded over time and is | stuck in this inhibit state. | | Because no ground commands were able to reset the PCU, the Hubble | team will be switching over to the backup side of the SI C&DH | unit that contains the backup PCU. All testing of procedures for | the switch and associated reviews have been completed, and NASA | management has given approval to proceed. The switch will begin | Thursday, July 15, and, if successful, it will take several days | to completely return the observatory to normal science | operations. | | The team performed a similar switch in 2008, which allowed Hubble | to continue normal science operations after a Command | Unit/Science Data Formatter (CU/SDF) module, another part of the | SI C&DH, failed. A servicing mission in 2009 then replaced the | entire SI C&DH unit, including the faulty CU/SDF module, with the | SI C&DH unit currently in use. | | Launched in 1990, Hubble has been observing the universe for over | 31 years. It has taken over 1.5 million observations of the | universe, and over 18,000 scientific papers have been published | with its data. It has contributed to some of the most significant | discoveries of our cosmos, including the accelerating expansion | of the universe, the evolution of galaxies over time, and the | first atmospheric studies of planets beyond our solar system. | Read more about some of Hubble's greatest scientific discoveries. | | And the fix: | | > The switch included bringing online the backup Power Control | Unit (PCU) and the backup Command Unit/Science Data Formatter | (CU/SDF) on the other side of the Science Instrument and Command | & Data Handling (SI C&DH) unit. The PCU distributes power to the | SI C&DH components, and the CU/SDF sends and formats commands and | data. In addition, other pieces of hardware onboard Hubble were | switched to their alternate interfaces to connect to this backup | side of the SI C&DH. Once these steps were completed, the backup | payload computer on this same unit was turned on and loaded with | flight software and brought up to normal operations mode. | | https://www.nasa.gov/feature/goddard/2021/operations-underwa... | 0898 wrote: | So it's "lease on life" rather than "lease of life"? Never knew | that. | baggachipz wrote: | I remember when this telescope was first launched and deployed, | and how its initial lackluster performance was a great source of | mockery and derision of "government overspending for nothing" and | a general disdain for space-based science. Since then, it has | absolutely revolutionized our understanding of the universe and | provided untold inspiration for millions (The famous Deep Field | image being the prime example). It is a crowning achievement for | NASA and should be used as an example any time some elected | official questions the spending on research instruments like | this. | jordan314 wrote: | I can't believe the shuttle chased down a satellite to fix it | in five spacewalks. How many satellites have had service | missions like this? | reportingsjr wrote: | The public doesn't really know. The shuttle did a handful of | secret missions that could have involved satellite service. | | There is also a sort of mini shuttle that has launched a | number of times in the last decade called the X-37B which | some have speculated might be used for servicing satellites. | | It's definitely an interesting concept! The way you say the | shuttle chased down satellites makes me laugh, as if the | satellites were trying to escape and were zig zagging around! | In reality, every mission to the ISS does the same thing as | the shuttle rendezvousing with the Hubble. | heresie-dabord wrote: | > mockery and derision of "government overspending for nothing" | and a general disdain for space-based science. | | But nary a word from such commentators when a major commercial | software product demonstrates yet another catastrophic security | failure. | renewiltord wrote: | Well, control is more important than many things. | | For instance, I'm happier if I pick my couch and then I'm | uncomfortable than if the government picks my couch and I'm | comfortable. | jrochkind1 wrote: | you'd be surprised. At a former job (in IT in academia)... | | me: I think we can build something in-house here better | than what the vendor will provide, I think the vendor's | solution is likely to be a failure for us. | | them: Yeah, but if do it in-house and it fails, it's our | fault. If the vendor's solution fails, it's _their_ fault | -- plenty of very prestigious universities are using this | vendor, nobody 's going to blame us for choosing them. [Ie, | "nobody got fired for picking IBM" basically]. | WalterBright wrote: | The couch example ins't just hypothetical. | | My dad was on an Air Force Base when the base commander | delegated to his wife picking out all the furniture for the | base housing. Naturally, every serviceman's wife hated it. | renewiltord wrote: | Positively comedic! Thanks for the funny anecdote! I can | imagine the whole situation. | BurningFrog wrote: | You can pick another commercial software vendor. | | With government, you can only complain. So you do. | harry8 wrote: | >You can pick another commercial software vendor. | | With what's left of your budget, which is now very, very | negative. Better to redefine abject failure as success to | minimize the chances of it ending your career if you're | involved in firm purchasing in any way. It's not like | boards of directors have a clue. The big consulting firms | will assist pulling the wool and priming the press so they | can move onto the next mark. It's impossible to by cynical | _enough_. | cptskippy wrote: | Software vendors like Oracle and SAP do everything in their | power to lock you into their services while doing the | absolute minimum to fulfill any contract. | | It took our IT over 4 years to migrate away from Siebel to | Salesforce and it's going on 3 years since. I just learned | the other day we still have a Siebel DB lingering around as | a dirty little secret. | | We move away from Lotus Notes over 10 years ago and we | still have some Notes Apps used by our Legal Department. | [deleted] | throwaway0a5e wrote: | Oh c'mon. Don't be thaaaat blinded by ideology. | | People love to shit on Oracle, IBM, etc when they bungle yet | another big project that was supposed to fix something. | WalterBright wrote: | Once the engineering of the telescope was complete, making | multiple scopes shouldn't have cost that much more. Launch 'em | all. | elihu wrote: | People underestimate the costs of these kinds of programs, but | they also underestimate the benefits. In the end it kind of | works out. | | (I came across this idea in a Tom DeMarco book called "Why Does | Software Cost So Much?": basically people complain about the | high costs of developing new software, but then for some reason | they keep paying to develop more software. Even though the | initial cost estimates may turn out to be fiction, it's still | worth it because the benefits are so big.) | [deleted] | BurningFrog wrote: | Hubble is 30 years old, and was probably based on a military | spy satellite (KH-11) design. | | I agree it was a milestone for astronomy, but it's been _very_ | long without any progress since. Why don 't we at least have 4 | more Hubbles in orbit? | patall wrote: | > Why don't we at least have 4 more Hubbles in orbit? | | Kepler, Spitzer, Herschel, WISE and more. I agree that there | ought to be more by now but its not like we did not see 'any | progress'. Today we know hundreds of earth sized planets in | the galaxy. If that's not progress, I feel the telescopes | JamesWebb and NancyGraceRose will only disappoint you ;) | | https://en.wikipedia.org/wiki/List_of_space_telescopes | geenew wrote: | There were in fact 4 large observatories, of which Hubble was | one. Hubble captures light in the visible wavelegnths, the | others captured light in other wavelenghts. Their pictures | aren't as pretty so they get less attention. There's also | JWST, as mentioned elsewhere. | | Hubble - Visible / NIR, 1990 - Present | | Compton - Gamma Ray / Xray, 1991 - 2000 | | Chandra - Xray, 1999 - Present | | Spitzer - Infrared, 2003 - 2020 | | https://en.wikipedia.org/wiki/Great_Observatories_program | pohl wrote: | Are there any plans for a next generation orbital | observatory for the visible part of the spectrum? | NortySpock wrote: | https://news.ycombinator.com/item?id=27857959 | | I posted a sibling comment, but both the proposed HabEx | and LUVOIR space telescope designs would be visible- | light. | Intermernet wrote: | ESA have PLATO ( | https://en.wikipedia.org/wiki/PLATO_(spacecraft) ) Which | looks very interesting. | | Meant to launch in 2026. | | "The PLATO payload is based on a multi-telescope | approach, involving 26 cameras in total: a set of 24 | "normal" cameras organised in 4 groups, and a set of 2 | "fast" cameras for bright stars. The 24 "normal" cameras | work at a readout cadence of 25 seconds and monitor stars | fainter than apparent magnitude 8. The two "fast" cameras | work at a cadence of 2.5 seconds to observe stars between | magnitude 4 to 8. The cameras are refracting telescopes | using six lenses; each camera has an 1,100 deg2 field and | a 120 mm lens diameter. Each camera is equipped with its | own CCD staring array, consisting of four CCDs of 4510 x | 4510 pixels. | | The 24 "normal cameras" will be arranged in four groups | of six cameras with their lines of sight offset by a | 9.2deg angle from the +ZPLM axis. This particular | configuration allows surveying an instantaneous field of | view of about 2,250 deg2 per pointing. The space | observatory will rotate around the mean line of sight | once per year, delivering a continuous survey of the same | region of the sky." | BurningFrog wrote: | Yeah, I was being overly negative. NASA _has_ produced some | very good observatories since Hubble | | > _There 's also JWST_ | | Which is 15 years late and still on the ground. | NortySpock wrote: | In 2016, NASA began considering four different Flagship | space telescopes, they are the Habitable Exoplanet Imaging | Mission (HabEx), Large UV Optical Infrared Surveyor | (LUVOIR), Origins Space Telescope (OST), and Lynx X-ray | Observatory. (text from wikipedia) | | https://www.greatobservatories.org/about | dr_orpheus wrote: | Also Kepler more recently - Visible 2009 - 2018 | | But again, even though it was "visible" it did not have | many pretty pictures because the mission was looking at | brightness variations in particular stars (planet | transients). | gizmo686 wrote: | The James Web telescope was supposed to launch in 2007 (and | should be launching in November), and began development in | 1996. | | Hubble was launch in 1990, and have 5 servicing missions for | repairs and upgrades, with the last one being in 2009. | | An exact clone of Hubble is not nearly as useful as the first | one, so it is reasonable to put your resources into a novel | telescope. Unfourtuantly that telescope hit some scheduling | challanges. | | Not to mention all the other space telescopes | https://en.m.wikipedia.org/wiki/List_of_space_telescopes | | Which includes a _gravitational_ telescope prototype. | wedesoft wrote: | The James-Webb telescope is supposed to launch this year: | https://www.nasa.gov/mission_pages/webb/main/index.html | [deleted] | cptskippy wrote: | Apart from the continued devaluing of Science in our country | and severe underfunding of any scientific institution? | adventured wrote: | > severe underfunding of any scientific institution | | NASA is well funded, not underfunded. It receives over | three times the funding of ESA by comparison. | | Why aren't the Europeans funding their scientific | institutions better? Because the combination of soaring | entitlement costs and stagnant growth robs them of the | necessary tax revenue for that. Which is exactly what's | happening in the US, and it's going to get a lot worse yet. | The US has a bit less of an excuse, seeing as it could | safely cut $200b off of its military. However, that $200b | spread around to every squeaky wheel still won't go very | far (it's equal to a mere ~2.3% of total government | spending), you might be able to fairly boost NASA's budget | by $3b per year if you slashed the military. Back in | reality, that $200b in cuts should probably be entirely | allocated to healthcare, which brings us right back to the | central issue of priorities; and the Europeans know that | quite well, which is why ESA is poorly funded. | lizknope wrote: | Ground based telescopes have improved significantly in those | 30 years. | | The mirror in Hubble is 2.4 meters | | Large ground based telescopes now have mirrors in multiple | segments with motors keeping them at the right curvature. | | The largest has 10.4 meter mirror. That is about 11 times | larger area than Hubble. | | https://en.wikipedia.org/wiki/List_of_largest_optical_reflec. | .. | | One of the original reasons for Hubble was to have a | telescope above the atmosphere. The atmosphere distorts the | light as it passes through making stars "twinkle." | | Now we we use a laser beam to energize sodium atoms in the | upper atmosphere. We see how that is distorted by the | atmosphere so that with software we can cancel it out. | | https://en.wikipedia.org/wiki/Laser_guide_star | | Combined with lucky imaging where instead of taking a single | long exposure we take thousands of images in the 100 | millisecond range. We can toss out the images where the | atmosphere was moving a lot and combine the other good | images. | | https://en.wikipedia.org/wiki/Lucky_imaging | cowmix wrote: | So I worked on a contract for STScI (the peeps who wrote all | the Hubble software). The turnover there is insanely low. As of | a few years ago, almost ALL the people I worked with had been | there since the initial launch of the Hubble. Anyway, as you | walk around the cubes in their offices, many had copies of the | political cartoons from the time which mocked the Hubble as a | total failure. They are all mission focused, took the initial | failure very, very seriously. | vidanay wrote: | And that's on top of the fact that the original problems were | the epitome of "That's a hardware problem, not a software | problem." | spookthesunset wrote: | The hardware dudes have it harder than software dudes. It's | easy to fix software. Hardware, not so much. | | I guess the worst thing you can fuck up in space fairing | software is the boot loader. Mess that up and you can't | update the software. | | Note: I have never designed software for space. I have no | clue what I'm talking about. | RobertoG wrote: | >>"I have no clue what I'm talking about. " | | Nobody told me we have to specify that! I thought that | was the default and we only have to say when we are | experts in something! | | Now I have to delete all my posts. | WalterBright wrote: | That's why you _always_ have an independent backup | system. One that uses different software, developed by a | different team, using different languages, and different | algorithms. | NortySpock wrote: | I thought one of the Viking landers was lost when a | software update pointed the big antenna at Mars rather | than at Earth... hard to send software updates after | that. | zarq wrote: | That's an easy fix; just put a repeater on Mars... | cowmix wrote: | I mean, it really was a hardware problem. However, the | software guys were not pointing any fingers. | dylan604 wrote: | Hubble is a great example of just working the problem. | xhkkffbf wrote: | I sometimes eat lunch with friends at the STScl. When they | were in the middle of the fix, I'm told that some of the | engineers stayed up all night at the office. Not because | there was anything to do. Just because they wanted to see | what would happen and the Internet wasn't so pervasive back | then. They couldn't log in remotely and do much. | jordache wrote: | Are these people highly compensated? | cowmix wrote: | They are all considered to be in academia I think so you | can put them in that bucket. My impression they all did OK | in the compensation department however I'm sure they all | could make much more in the private sector. EVERYONE I | worked with on that project was a high performing / expert | level. | smabie wrote: | I'm going to guess, no. | saganus wrote: | Any particular reason that they stay for so long at their | jobs? | | Obviously working on such cool projects must be a major | factor, but it's probably not the only one. | fidesomnes wrote: | Government job. Low pay. Much stability. | cowmix wrote: | They all really, really believe in the mission. Many are | well into their 60s and are waiting for JWST to launch to | finally retire. It was supposed to launch YEARS ago, so | they are (as a group) getting antsy. | | The project I worked one was migrating data from their in | house ticket tracking system to Jira. I was importing | tickets from 1985 into Jira which obviously didn't exist at | that time. | saganus wrote: | Interesting. | | Thanks for the insight! | | I guess it IS very different to believe, for decades, in | a mission that includes space telescopes than in the | latest SaaS or productivity app or something more | "mundane". Not that there's anything bad working on those | kind of projects, but it sure has a different scope (no | pun intended) | elliottkember wrote: | I just wanted to let you know that "mundane" is an | excellent pun when talking about space projects, because | it means "of this earthly world rather than a heavenly or | spiritual one". The original word is "mundus", meaning | "world" - "monde" in French today. | raverbashing wrote: | They're probably at a "local optimum" (maybe even global) | in their careers. Peak salary, peak expertise match, etc. | | Though probably a "different world". It would be hard to | retrain to do react development, for example. | spookthesunset wrote: | I mean at the age of 60... it's gonna be hard to top a | career that had you writing code sent to space. | | That being said, I imagine it would be very hard to be a | junior employee in such an environment. Fresh and green | behind the ears, full of ideas and surrounded by people | almost ready to retire and pretty set in their ways. | | Who knows. Maybe these folks make an effort to stay | current with progress in development tools and whatnot. | But it is easy to imagine them being very stuck in their | ways. Some for good reason but some because "that's how | we've always done it". | | I'd love to be told I was wrong and all their shop did a | good job staying on top of industry wide progress. | cowmix wrote: | True. These guys were maintaining (and updating) software | for a hardware platform that was 35+ years old. | jimhefferon wrote: | > That being said, I imagine it would be very hard to be | a junior employee in such an environment. | | My father was a senior admin in the vendor that made the | mirror, so I had summer jobs working on Hubble-adjacent | projects. One summer my cubicle was next to the cubicle | of a new engineer who worked on it. | | They ground the mirror in one facility and then trucked | it to another one, many miles away, for silvering. This | new engineer was tasked with drawing up the protocol for | loading it on the truck (it was driven down in the early | morning on a Sunday to reduce problems with traffic). | | He finishes the document draft and calls down the senior | engineer for a look-over. They are discussing the part | where the cranes (kind-of like fork lifts) lift the | mirror. There are three cranes, and three places built | into the mirror where they hook on. | | "How do you know the cranes will take the load?" | | "Here are the manufacturer's specifications, saying that | each will take more than half the total weight. There are | three cranes, so there is sufficient capacity even if one | crane fails." | | "How do you know the crane will take the specified | weight?" | | "They were vendor certified last week; I was there." | | "That's not enough. The night before, you and another | engineer will personally go down there and personally | load the specified weight on each crane. Then you will | each sign a paper. The mirror will not move without that | paper, containing both your personal names." | | Made a big impression on me. | TeMPOraL wrote: | Amazing story! | | In space projects there's no space for human error. | | Reminds me of that one SpaceX mission failure, with F9 | exploding shortly after launch. IIRC, it was quickly | determined that the cause was a strut from a third-party | vendor that wasn't up to declared spec. | patrickthebold wrote: | I'm still anxious about the James Webb Space Telescope though. | Fingers crossed. | BurningFrog wrote: | One reason JWT has taken so long and is so expensive is that | launch costs used to be "astronomical". | | In the SpaceX era of reusable rockets, those costs become 1-2 | orders of magnitude smaller, and I expect a flurry of simpler | space telescopes in the nearish future. | | That's the theory. Does anyone know if such things are being | worked on? | terramex wrote: | Not to my knowledge. Actually, it was said that lack of | smaller space projects was catalyst for creation of | Starlink. They expected tons of launches once launch prices | dropped but it never materialized so they decided to become | their own biggest client. | henrikeh wrote: | Who's theory? | | JWST costs upwards to 9 billion USD. An Ariane 5 launch | maybe 200 million. | | Just because the launch is cheaper doesn't make the rest of | the project less complicated and costly. | BurningFrog wrote: | JWST costs $9B when NASA does it. | | I think other actors can do similar things _much_ cheaper | and faster. | qayxc wrote: | > I think other actors can do similar things much cheaper | and faster. | | Think again. JWST was criticised for being too ambitious | and rightly so. It uses technology that was (and in some | areas still is) cutting edge. | | It baffles me how people always seem to assume that some | company can miraculously solve scientific and engineering | challenges quicker and cheaper than the teams that are | working on it. | | JWST was designed with no serviceability in mind, that | is, unlike HST it _absolutely_ has to work. Every detail, | from the folding mirror, to the sun shield, to the | computer systems to the instrumentation. ZERO room for | error and no "fail early, fail often"-option here. | | Most of the delays have been caused by engineers and | scientists wanting to make 100% sure they get it right, | because there's no STS servicing for fixing imperfect | mirrors or switching out hardware. | spullara wrote: | We live in an age where companies can and do almost | miraculously solve technical problems that the government | has failed to do, so it isn't surprising to me. | | https://www.youtube.com/watch?v=Tkk9VIKWw2w | qayxc wrote: | It wasn't "the government" that built JWST, though, it | _was_ companies (and universities). edit: I 'm also | getting tired of the "but rockets!"-trope. It's not a new | invention, Saturn V was more powerful, and a rocket is | not a space telescope. | spullara wrote: | I don't think you understand how contracting works, but | ok. | | The James Webb Space Telescope (JWST or "Webb") is a | joint NASA-ESA-CSA space telescope | HenryKissinger wrote: | If the rocket explodes on the launch pad, it will be a bad | day. | | At the same time, it shouldn't take twenty years to build a | space telescope, especially since it's not like it's the | first one ever. The first atomic bomb was built in 4 years. | rtkwe wrote: | It is a completely novel design for a space telescope | though. On top of that there's no capability [0] to go | patch up a sloppy job like we did with Hubble. | | [0] Currently at least. Starship could I guess but it was | planned way ahead of Starship even being a glimmer in | Musk's eye. Do they have any grapple points on it as | insurance? I would at this point, just put one of the posts | they use on the ISS for Canada Arm to grapple. | frosted-flakes wrote: | There is a docking ring on the JWST. | dr_orpheus wrote: | Yeah, there is a docking ring as a "maybe we can design | something to use this in the future". Since JWST is going | out to a Lagrange point it would definitely be robotic | servicing at this point unless our human spaceflight | capabilities expand very significantly. | | The Nancy Grace Roman (formerly WFIRST) space telescope | also has grappling points for robotic servicing so it is | something that is being considered in designs for | programs of record. | spookthesunset wrote: | And that is the problem with 20 year (30 year?) product | lifecycles. A _lot_ can change in 20 years. For example | the ability to service it might now be feasible. But | since it's almost entirely built, good luck making it | serviceable! | wizzwizz4 wrote: | The first atomic bomb was nowhere near as precisely-built | as the James Webb telescope has to be. | scrozart wrote: | It's not the first space-based observatory, but it's still | a _wholly novel_ device, containing instrumentation | designed by scientists and engineers in concert to leverage | every piece of bleeding edge technology available at the | time, and some throughout the process. Everyone of the | flagship observatories is moon shot. It's not a mass- | produced helicopter or missile. This project in particular | is easily one of the wildest feats of science and | engineering _ever_ just like Hubble, Cern, and LIGO. | | Regarding the bomb, we were trying to end a global | conflict, so the comparison couldn't be further off base. | airstrike wrote: | Plus the bomb was built with the literal opposite purpose | of the JWST: blowing up! | | Worst case scenario it doesn't blow up exactly right and | you just build another one? | cmpb wrote: | I see your point, but you could also argue that worst | case scenario for atomic bomb malfunction is much more | awful than worst case for JWST | lazide wrote: | With the mindset at the time, the worst case scenario for | the atomic bomb would have been it not going off in | anyway way, and then they just handed their greatest | enemy dud version if a top secret weapon. | | Since it likely would have just blown up (fizzle) even if | it didn't fully detonate that is a pretty remote | possibility. | | Second worst would be it went off on a base somewhere and | nuked a US base. Considering the location of these bases | and the nature of the war at that point, it would have | been a footnote causality wise, but embarrassing. | retzkek wrote: | The worst case considered at the time was an uncontrolled | chain-reaction annihilating the planet. It was calculated | to be impossible, but it still weighed on the minds of | many scientists involved, even well into the hydrogen | bomb era. | | https://www.insidescience.org/manhattan-project- | legacy/atmos... | [deleted] | dekhn wrote: | there has never been and never will be anything like the | Apollo or Manhattan projects. They had levels of | productivity that are not normally seen. | sebzim4500 wrote: | If the Starship program succeeds in reaching the moon in | the next few years then I think that is comparable to | Apollo. Ofc it is easier to do things the second time | than the first but safety standards are higher and this | time it will have been done at an enormously reduced | price. | Swenrekcah wrote: | Well, there were the Egyptian Pyramids, Great Wall of | China, Roman Aqueducts and a whole bunch of Great | Projects in the past and I certainly hope there will be | lots more in our future. | spenczar5 wrote: | Those projects took centuries to complete. | DLWormwood wrote: | Or just a few turns, depending on your difficulty | setting. (-; | delecti wrote: | As far as I know, the pyramids were each constructed for | a single pharaoh, and during their single lifetime. I | don't know about all of them, but that's at least true of | Great Pyramid of Giza. | dmos62 wrote: | We don't know how some of the Egyptian pyramids were | constructed, or when, or how long it took. | gumby wrote: | It took 25 years to replace the SF Bay Bridge, a much less | complex endeavor. | | It's simply how things are done around here these days. | m0llusk wrote: | That is not a good comparison. The SF Bay Bridge | replacement project was conducted as a competition. The | design that won was so much more complicated than all the | other entries that at first it was not clear that it | could be built and in fact the finished product is flawed | with cracks and other failures. There is nothing | particularly complex about the basic problem and the | simple viaduct design that was advocated by the Governor | at the time was expected to involve an order of magnitude | less cost and time of construction but was rejected for | being too simple and not beautiful enough. This | management structure and these considerations have not | been used for any space missions. | belter wrote: | Keep in mind its an orbiting Infrared Observatory so not an | alternative to Hubble. Of course it will be an amazing | scientific instrument and we should hope that nothing happens | during launch. | CWuestefeld wrote: | My grandfather worked on the Hubble's mirror - the part with | all the controversy. It was, simultaneously, both what he was | most proud of and most ashamed. | | One thing he would point out, that I never see discussed, was | that at the time they built the mirror, there was an | expectation that it may not be perfect, on account of how the | Earth's gravity would slightly deform the mirror during | manufacturing. As he tells the story, they'd tried to factor | that into the design, but had less confidence in it. This, of | course, was not the reason for the eventual problems, but to | illustrate that this _kind of_ thing was understood. | | The big picture of the failure relates to the Shuttle program | as well. At the time Hubble was being developed, its mission | was supposed to allow for a lot more around the "shuttle" | aspect: not just that it could be reused, but that it could be | reused in an actual shuttling capacity, like an orbital pickup | truck. So it was supposed to be possible to bring the telescope | up into orbit (away from gravitational stresses), see how it | worked, and if necessary, bring it back down for corrections. | Since the end result of the Shuttle design cut down | significantly in its capabilities in this regard, the Hubble | program was left without its "Plan B". | walrus01 wrote: | In the end it turned out that for the life of the shuttle | program, each launch ended up costing between 700 million and | 1.2 billion, so the 1970s goal of an economically reusable | spacecraft was definitely not achieved. | jessaustin wrote: | _This, of course, was not the reason for the eventual | problems, but to illustrate that this kind of thing was | understood._ | | For some reason I had thought this (gravity stuff) was the | problem. What was the actual problem? | azernik wrote: | A device for measuring the final grinding had been | miscalibrated (by a known, constant amount). The result was | a spherical aberration, of a kind that is familiar to a lot | of users of cheaper lenses and mirrors but on a much | smaller scale. | krisoft wrote: | Exactly as azernik says. If you are interested in a lot | more detail this reports spills the tea: | https://www.ssl.berkeley.edu/~mlampton/AllenReportHST.pdf | dr_orpheus wrote: | It still amazes me that one, the mirrors are sensitive enough | to the deformation of Earth's gravity to have an effect and | two, that we are now very good at compensating for this now. | | Also consider that the mirrors on James Webb space telescope | need to account for both deformation from gravity when they | are manufactured but also that they are manufactured at room | temperature and will be operated at cryo temperatures. But | JWST is also special since they have actuators to put stress | on the mirror segments to be able to reshape them slightly | on-orbit to focus. | downrightmike wrote: | To be fair, Kodak made a sister mirror that wasn't chosen | to go up, and when the issue on Hubble was found out, | Kodak's mirror was found to be perfect. | jcims wrote: | It's fun to think that there is a bullet list of | directions that would take me from where I'm typing this | comment to standing in front of that exact mirror. | eckmLJE wrote: | Great tidbit -- found this in the NYT archive (likely | paywall): https://www.nytimes.com/1990/07/18/us/hubble- | has-backup-mirr... | CWuestefeld wrote: | My same grandpa that worked on the Hubble mirror also | worked on anti-ICBM lasers back in the 70s. Apparently | these devices had a tendency to melt their own mirrors, and | that led to the development on self-deforming mirrors to | deflect heat from hotspots. | | (He also worked on the TEAL AMBER and TEAL BLUE satellite | surveillance systems, and probably others that he never | even talked about.) | tobmlt wrote: | Hey I saw self deforming mirrors as a missile defense | intern circa 15 years ago! I thought they were dang cool | at the time myself. I recall (for these designs) self | deformation being used to help with tracking and | compensate for, ya know, the shock of a little steering | boost motors lighting off and such, in some cases. | 23B1 wrote: | Is there a good book I can read about all of this cold- | war era tech? I find it endlessly fascinating the number | of programs and technology advancements that happened | during this period. | patrick0d wrote: | There's a book called "Skunk Works" by Ben Rich about the | making of different spy planes. There's some mentions in | the book about satellites and what existed at the time | how projects were carried out. | panda88888 wrote: | Skunk Works is a great read. Highly recommend it for | people interested in the defense technology. | ChuckMcM wrote: | You may (or may not :-) find it surprising that there is | a vibrant ecosystem of research and development on both | defensive and offensive systems on going to this day. The | IEEE used to give a talk about "Black Silicon Valley" | which was not about people of color and their | contributions (although that would be an awesome talk | too) but about the origins of the technology focus in | Silicon Valley with regard to radio and RADAR development | starting in WW2 and continuing on to this day. When I | first moved to Sunnyvale my neighbor worked at Lockheed | and all he could tell me was that he worked with | electricity :-). He said he hoped that some of the stuff | he had worked on was disclosed in the future so that he | could tell is kids and/or grand kids about it. | | Having gone to school in LA where, at the time, ALL of | the EE jobs were in the Defense sector, I specifically | moved up to the Bay Area to work on cool stuff I could | actually talk about with others[1]. | | One thing of note is that ageism is MUCH less of an issue | in jobs that require security clearances. So a number of | engineers who are suddenly perceived as "too old" to | contribute to the latest hot startup find themselves | recruited by the Raytheons and General Dynamics type | companies that recognize their skills are valuable. | | [1] As an new college grad [NCG] I was not yet aware of | the myriad ways in which employers would use non- | disclosure agreements to thwart such conversations. | dundarious wrote: | Not a book, and not Cold War, but I think this talk does | a good job outlining just how much of the silicon | revolution came directly from WW2 military research. It | also does a decent job of explaining how technologically | advanced the aerial part of that war really was. | | https://youtu.be/ZTC_RxWN_xo | toss1 wrote: | I don't have a good book to recommend offhand, but | wandering a bit offotpic here, I know someone who worked | on a military orbital program in the late '70 that was | transmitting data from orbit at 800MB/s. | | Some congressmen had not heard of this technology and | were working to fund a completely different (iirc, | civilian) program intending to develop essentially the | same capabilities. They had to go give a few TS briefings | to the congressmen to dissuade them from writing the | redundant funding into the next defense spending bill. | reflectiv wrote: | Just wanted to say your grandpa sounds pretty damn cool | yawz wrote: | Definitely sounds like a very cool grandpa! | Florin_Andrei wrote: | > _It still amazes me that one, the mirrors are sensitive | enough to the deformation of Earth 's gravity to have an | effect and two, that we are now very good at compensating | for this now._ | | I make telescope mirrors. | | This problem was well understood since the time of | Herschel. We just have better solutions now. | | The fact that this is a space scope is irrelevant to the | fact that gravity will cause issues. For any telescope, you | have to account for differences in the way the mirror is | deformed in manufacturing vs in actual usage, and the ways | the deformation will change in usage as the scope is | leaning at different angles. That is _always_ a thing. | | What is particular to the Hubble is that the load in usage | is zero (which is unusual), so you have to think about it | that way in manufacture. But deformations in manufacture | are always an issue you have to account for somehow. | | Look at it this way: there is an ideal shape that the | mirror needs to have, usually a revolution surface of some | conic section (parabola, hyperbola, ellipse, circle). The | performance of the mirror will track the difference between | the ideal surface and the actual mirror. The error | allowance depends on the wavelength l of the observed | radiation. | | Telescopes where the error is greater than l/4 just suck, | and are unusable. Good performance begins around l/8. A | great mirror may do better than l/20. | | For visible light, l/4 is 100 nm, or 0.1 microns. That's 10 | thousand times less than 1 mm. On that scale, the mirror is | made of jelly. If you put it on a rough surface, it will | deform. If you put your thumb on it, hold it for a minute | so it heats up from your skin, then pull away, there will | be a "mountain" left behind on the mirror, under your | thumb, until it cools off again. | | In many cases, the support structures for large mirrors are | complex mechanisms that ensure the force is uniformly | distributed across a large number of points on the back of | the mirror. Even amateur telescopes built using the | Dobsonian template use passive self-balancing support with | 3, 6, 9, 18, or even more points, depending on the size / | thickness ratio. | petertodd wrote: | > My grandfather worked on the Hubble's mirror - the part | with all the controversy. It was, simultaneously, both what | he was most proud of and most ashamed. | | I think a simple way to explain what your grandfather should | feel proud of, is they documented the construction process so | thoroughly that they were able to _precisely_ figure out what | they did wrong, and fix it, on their first try! | CWuestefeld wrote: | That's a really positive way to frame it. Thanks for the | perspective. | spullara wrote: | Fascinating story about how the null corrector that was | supposed to ensure that the mirror was correct was flawed: | | https://en.wikipedia.org/wiki/Null_corrector | awiesenhofer wrote: | Thats great news! I wonder though, if there will ever be a need | for another repair mission, could ie. Crew Dragon support such a | mission or has that possibility passed with the retirement of the | shuttles? | trashface wrote: | Scott Manley had a video on you tube about this recently, don't | remember which one, but it may have been where he was talking | about the computer problem itself. | | As I understand it, there is no current vehicle that combines | the Space Shuttle's ability to both dock with a satellite (via | a docking arm) and allow astronauts to do EVA. | | So I guess James Webb is possibly screwed if it has a problem | in orbit like the Hubble's mirror issue. Too bad we won't bring | back the Space Shuttle. | blhack wrote: | Does crew dragon have the appropriate airlock to allow for a | spacewalk? | mLuby wrote: | I don't think it does. But what's to stop the whole (limited) | crew from suiting up (without MMUs), slowly venting the | interior air, doing the EVA, then returning and re- | pressurizing the atmosphere from interior tanks? My guess is | it's just uncertified for that procedure, not that it's | impossible. And there's no recourse if one of the suits fail. | mikepurvis wrote: | This is how it worked for all of the capsule-based | missions-- the entire cabin space is the airlock. | p_l wrote: | There might also be not enough space to move with a full | EVA suit - which is a wildly different thing from in- | capsule survival suit. | jvzr wrote: | In case it wasn't a rhetorical question, Crew Dragon does not | have an airlock that would allow for a suited astronaut to | leave the craft while maintaining atmosphere inside it. Plus, | a big thing missing is a manipulator arm, such as Canadarm, | which was used to capture the telescope, and essentially make | the shuttle and telescope one body. | nomadluap wrote: | I always thought it would be interesting if Spacex | developed a "dragon utility module". It would launch in | Dragon's trunk and consist of a docking port on one end, an | airlock on the other, a miniature manipulator arm and a | bunch of cargo mounted around the outside. After separating | from the second stage the Dragon would flip around and dock | to this module, which would give it all the extra bits | needed for a mission like servicing the Hubble. | krylon wrote: | I was 9 years old when Hubble was launched, today I am 40 years | old, so it has been around for all of my adult life and then | some. | | Also, it has provided lots and lots and lots of beautiful | pictures that are stunning to look at even for people who | otherwise do not care about astronomy at all. I think it's fair | to say that no other project/mission/device since the Moon | landing had a bigger impact in making astronomy "cool". The | Hubble Deep Field pictures alone are breath-taking, and they may | very well have had as much of an impact on our current model of | the universe as Hubble's original discovery of an expanding | universe, at least from the perspective of a non-scientist. | | As far as I can recall, Hubble was supposed to go down in flames | quite a few years ago, but it just kept working, and no | equivalent replacement was available. James Webb Space Telescope | is not _exactly_ a replacement, as it is an infrared telescope. | It will be quite interesting to see how long they can keep Hubble | working. It had a rough start, but the fact that after some | initial corrections, it has lasted way longer than it was | supposed to speaks of the quality of engineering that created it. | javier10e6 wrote: | Ah! Another case of who police the police. The police police the | police. Good news that the spare PCU took over and it was good. | We all hope that the spare PCU was not part of an unlucky | manufacturing batch. Great article. | zamalek wrote: | The Hubble Telescope is a gift that keeps on giving. I'm starting | to wonder if the thing will survive the heat/entropy death of the | universe. ___________________________________________________________________ (page generated 2021-07-16 23:00 UTC)