10 ms·

Then you're going to be disappointed by all satellites I'm afraid. They all need to do station-keeping, and have a way to maintain orientation when they spin-d

Then you're going to be disappointed by all satellites I'm afraid. They all need to do station-keeping, and have a way to maintain orientation when they spin-down their reaction wheels. "Solar-powered" thrusters use fuel too but use an electric field to accelerate it. 20 years is still a rather long time. Expect something else fragile to fail before then. And that's still double the target life time! (And unless they've made it almost maliciously difficult to add fuel, I'm sure there will be some Space Bro who'll offer to refuel it for likes / tax reasons.)

musesum 5y ago
> some Space Bro who'll offer to refuel it for likes / tax reasons Maybe a new kind of blockchain: https://news.ycombinator.com/item?id=26117587 https://news.ycombinator.com/item?id=26117587
dahfizz 5y ago
> Then you're going to be disappointed by all satellites I'm afraid. Except we launch well over 1000 satellites a year. The JWT is clearly a bigger deal than that. This has been advertised as NASA's magnum opus. The fact that it was only supposed to last 10 years makes it feel much less significant...
- FourHand451 5y ago
  I mean, is there something you'd suggest they should have done differently? I'd imagine they gave it as much fuel as they possibly could while meeting all of the other design goals. Is is possible you're more disappointed with the advertising than the observatory itself?
  - dahfizz 5y ago
    My real concern was the difficulty we had getting the JWT ready. If JWT's successor will also take 20 years to produce, then we better start working on it tomorrow. A 10-20 year lifespan on the telescope would be perfectly fine if we could launch a new one every 5-10 years. I'm worried that NASA has spent all its money and political will (and then some) getting JWT over the finish line.
    - jimkleiber 5y ago
      I'd be surprised if other NASA programs weren't nearly as long. Maybe not that long, but heck, I've heard to design a new car at a major car company normally takes 6 years or so, I would imagine a brand new type of one-off space project may take at least 10.
    - btbuilder 5y ago
      Cost-wise and time-wise the JWST is inline with Hubble.
    - mlyle 5y ago
      Maybe a big infrared space telescope isn't the highest priority to build next compared to other instruments we could put in orbit. I mean, we'll still have some big terrestrial infrared 'scopes. And we'll be coming off 20 years of very good space infrared scope data... And we'll have had the smaller Nancy Grace Roman Space Telescope up in L2 also (launching in 2027, nominal life 5 years).... ESA is launching an exoplanet-focused infrared scope to L2 in a similar timespan... Presumably other "smaller" infrared scopes will fly by 2042. So... There's so many wavelengths and different possible space telescope missions. Let's not replace JWST (assuming it gets a normal mission life)-- let's keep some infrared capability and do something else.
      - baq 5y ago
        'terrestrial' is an issue in the context of JWST... as the wavelengths that it observes are absorbed by Earth's atmosphere. wonder if we could put a telescope on the moon for $10B though.
        mlyle 5y ago
        Yes, infrared scopes on earth have challenges and are not equally viable for all wavelengths. But VISTA, UKIRT, IRTF, etc, cover a substantial amount of the near and intermediate infrared-- the latter two are high enough to reach into a reasonable amount of the far infrared. Most of JWST's wavelength coverage is energies that terrestrial telescopes can do (just less well). It's not like Herschel which went into the far, far infrared (and had its life limited by liquid He as a result). Re: Moon-- Why put a telescope down a gravity well? Most of the discussion of telescopes on the moon I've heard has been about radio telescopes, where a huge hunk of rock between you and Earth can be a feature.
- Fordec 5y ago
  And those satellites, by bulk, are in low earth orbit with a lifetime of usually 4 years, and a legally mandated reentry in 25 years. JWTs location in L2 (a mathematically unstable location that requires energy to not roll back into a gravity well in any direction) is like putting it on the satellite equivalent of K2 and not coming down from the peak for 20 years and you compare it to the thousands of commuters that made it up the hill down the road from your house.
  - dotancohen 5y ago
    > legally mandated reentry in 25 years. What is this requirement?
    - jaywalk 5y ago
      There is no legal requirement of that sort that I'm aware of. However, it is recommended that LEO satellites should re-enter the atmosphere within 25 years of mission completion. This is to try and mitigate the ever-growing issue of space junk in LEO.
    - K5EiS 5y ago
      I couldn't find any legal requirements, but the ESA recommends a reentry withtin 25 years of mission completion to reduce waste in orbit. https://www.esa.int/Safety_Security/Space_Debris/Mitigating_space_debris_generation https://www.esa.int/Safety_Security/Space_Debris/Mitigating_...
      - dotancohen 5y ago
        I am aware of this, but it is not legally mandated as GP states.
    - Fordec 5y ago
      A few, but he one that is the closest rubber that hits the road is part of the FCC filing for radio spectrum access on satellite projects. Without which, you're not getting on most rockets.
- easton_s 5y ago
  10 years of operation, but hundreds of years of data to analyze. We are still analyzing data captured from terrestrial telescopes that haven't operated in decades.
  - _joel 5y ago
    Is that due to the format or availability of the data?
    - slenk 5y ago
      The sheer amount of data. The black hole that was imaged recently alone was four petabytes of data https://www.hpcwire.com/2019/06/24/a-behind-the-scenes-look-at-the-hardware-that-powered-the-black-hole-image/ https://www.hpcwire.com/2019/06/24/a-behind-the-scenes-look-...
      - smallerfish 5y ago
        Are there any interesting private companies / startups in this space?
        _joel 5y ago
        No idea, but if it's difficult for acedemia to get hold of this then how could startups? More to the point, what would be the value add to make the commercials viable? Interested to hear if you think there could be? Perhaps there's some altrusitic archive.org style site that needs to exist for science, that features datasets of multiple PB in magnitude and allows anyone to pull the full archive. Maybe in the future, but still, people still have access to source imagery and they regularly make spectacular images and material from public domain data from space agencies and interest groups. You don't need 4PB unless doing something like, well, imaging a black hole. It's fun, not sure how much there is run a business from it, unless you plan on taking the data and creating spectrographs for some future mining mission way in the future? :D
- jimkleiber 5y ago
  The Mars Opportunity rover was planned to last only 92 days but lasted about 5200 (~14 years). I think many NASA programs have short expected timelines and then hopefully outlast them. https://en.m.wikipedia.org/wiki/Opportunity_(rover) https://en.m.wikipedia.org/wiki/Opportunity_(rover)
  - nindalf 5y ago
    The Spirit rover did very well too - https://xkcd.com/695/ https://xkcd.com/695/
    - jimkleiber 5y ago
      Ahhh XKCD, my heart! I hadn't seen this one, thank you for sharing.
- verytrivial 5y ago
  .. and 99% of those probably spend 100% of their time trying to sit utterly still in their orbit, staring down at Earth, maybe twitching around to point a bit if they're doing spy work. JWST pivots the entire spacecraft to point the 6 meter mirror. I'm sure they've optimized the consumables on the schedule, but it simply 'costs resources' to do this sort of work. I assure you there are gruellingly dense and optimized observations plans afoot. Compare to e.g. the very successful Herschel Space Observatory -- it too went out to L2(-ish), did everything it was meant to do in its three year mission, and managed to extend to four before (drum roll) running out of fuel, this time for cooling. JSWT solves this cooling issue by some incredibly funky mechanical resonance cooling. Herschel "only" cost about $1 billion, and it will be interesting to compare the science results.
  - Fordec 5y ago
    Also don't forget it at no point can it turn around and face the earth or sun or the light coming from the suns direction will burn out the optics. If it does it once, and it's mission over. All the while essentially driving most of the way up out of the gravity well and letting it get pulled back to earth a little and repeating. If it goes too far over the peak of the hill it will go over the other side with no way to reverse even if the rocket has the fuel.
    - hoseja 5y ago
      No no no, it's circling the top of the "hill".
  - hnaccount_rng 5y ago
    I think you are misinterpreting where the fuel consumption comes from. It isn't the reoriantation. That you can do with internal reaction wheels. All you want is rotation, not movement. Turn something inside in one direction and the outside will turn the other way. The only problem is movement for that you need to eject stuff the opposite way you want to go. And that is needed because L2 is unstable. I.e. you roll down over time. Which needs to be counteracted by station keeping. I'm pretty sure they'll use the fuel usage to measure the local gravitational field around L2 and from that update mass distribution estimates around the inner solar system.
- CrazyStat 5y ago
  10 years was not quite worst case but definitely a conservative estimate. L2 is an unstable orbit and needs constant corrections to not drift away, so JWST has much more significant fuel needs than if it were in say Hubble's orbit. How much fuel it would have left for these maneuvers depended on how precise the launch was (i.e. how much fuel it needed to spend on corrective burns just to get to L2). This was obviously uncertain until after the launch, but ten years was a lower bound above which the launch would not be considered a major issue--if it only had say 5 years of fuel left after the launch that would be an indication that the launch was flubbed some how. TLDR: JWST was not "supposed" to last only 10 years. It was designed and built to last much longer, that was just a lower bound assuming nothing went very wrong. cf. Mars rovers operating long past the "planned" mission length, e.g. Opportunity's "planned" 90-day mission turning into over 5,000 days. It is vastly unfair to the people who designed and built Opportunity to say it was "supposed" to last only 90 days. It was built to last much longer; 90 days was a lower bound for the mission to be considered a success.
- anonymousab 5y ago
  The scale and intensity of the problem is much bigger though. This one is hundreds to thousands of times further out than any of those satellites, for instance. It also has a far longer lifetime compared to the average, even before this news. Four times the distance of the moon from Earth. There's no luxury of being able to repair, service and refuel such a thing without approaching or exceeding the costs of just making a new, better one with the learnings and savings from before.
  - shagie 5y ago
    The site https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.htm... is neat. Change the scale from Time to Distance to get an idea of how far out it is. (edit - the "earth moon" distance isn't to scale with respect to planetary diameters... the distance from the earth to the moon is about the same as the sum of all the diameters of all the planets - that's a long way itself)
- tomr_stargazer 5y ago
  The primary deliverable isn't the satellite; it's the scientific data (and associated breakthroughs) the satellite will deliver.
kiriberty 5y ago
Space Bro, I like it
- echelon 5y ago
  Is Elon Musk the very first space bro, followed by Bezos? Or do we get to go all the way back to Shuttleworth, Tito, and Branson? Surely Branson is the first space bro.
  - unzadunza 5y ago
    Nope, Han Solo is the first space bro.
  - WJW 5y ago
    Was Youri Gagarin not a bro?
    - oofabz 5y ago
      Gagarin was a cosmonaut. The Russian equivalent to those mentioned would be Sergei Korolev.
    - fennecfoxen 5y ago
  - flipflipper 5y ago
    https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky

musesum 5y ago

> some Space Bro who'll offer to refuel it for likes / tax reasons Maybe a new kind of blockchain: https://news.ycombinator.com/item?id=26117587 https://news.ycombinator.com/item?id=26117587

dahfizz 5y ago

> Then you're going to be disappointed by all satellites I'm afraid. Except we launch well over 1000 satellites a year. The JWT is clearly a bigger deal than that. This has been advertised as NASA's magnum opus. The fact that it was only supposed to last 10 years makes it feel much less significant...

FourHand451 5y ago
I mean, is there something you'd suggest they should have done differently? I'd imagine they gave it as much fuel as they possibly could while meeting all of the other design goals. Is is possible you're more disappointed with the advertising than the observatory itself?
- dahfizz 5y ago
  My real concern was the difficulty we had getting the JWT ready. If JWT's successor will also take 20 years to produce, then we better start working on it tomorrow. A 10-20 year lifespan on the telescope would be perfectly fine if we could launch a new one every 5-10 years. I'm worried that NASA has spent all its money and political will (and then some) getting JWT over the finish line.
  - jimkleiber 5y ago
    I'd be surprised if other NASA programs weren't nearly as long. Maybe not that long, but heck, I've heard to design a new car at a major car company normally takes 6 years or so, I would imagine a brand new type of one-off space project may take at least 10.
  - btbuilder 5y ago
    Cost-wise and time-wise the JWST is inline with Hubble.
  - mlyle 5y ago
    Maybe a big infrared space telescope isn't the highest priority to build next compared to other instruments we could put in orbit. I mean, we'll still have some big terrestrial infrared 'scopes. And we'll be coming off 20 years of very good space infrared scope data... And we'll have had the smaller Nancy Grace Roman Space Telescope up in L2 also (launching in 2027, nominal life 5 years).... ESA is launching an exoplanet-focused infrared scope to L2 in a similar timespan... Presumably other "smaller" infrared scopes will fly by 2042. So... There's so many wavelengths and different possible space telescope missions. Let's not replace JWST (assuming it gets a normal mission life)-- let's keep some infrared capability and do something else.
    - baq 5y ago
      'terrestrial' is an issue in the context of JWST... as the wavelengths that it observes are absorbed by Earth's atmosphere. wonder if we could put a telescope on the moon for $10B though.
      - mlyle 5y ago
        Yes, infrared scopes on earth have challenges and are not equally viable for all wavelengths. But VISTA, UKIRT, IRTF, etc, cover a substantial amount of the near and intermediate infrared-- the latter two are high enough to reach into a reasonable amount of the far infrared. Most of JWST's wavelength coverage is energies that terrestrial telescopes can do (just less well). It's not like Herschel which went into the far, far infrared (and had its life limited by liquid He as a result). Re: Moon-- Why put a telescope down a gravity well? Most of the discussion of telescopes on the moon I've heard has been about radio telescopes, where a huge hunk of rock between you and Earth can be a feature.
Fordec 5y ago
And those satellites, by bulk, are in low earth orbit with a lifetime of usually 4 years, and a legally mandated reentry in 25 years. JWTs location in L2 (a mathematically unstable location that requires energy to not roll back into a gravity well in any direction) is like putting it on the satellite equivalent of K2 and not coming down from the peak for 20 years and you compare it to the thousands of commuters that made it up the hill down the road from your house.
- dotancohen 5y ago
  > legally mandated reentry in 25 years. What is this requirement?
  - jaywalk 5y ago
    There is no legal requirement of that sort that I'm aware of. However, it is recommended that LEO satellites should re-enter the atmosphere within 25 years of mission completion. This is to try and mitigate the ever-growing issue of space junk in LEO.
  - K5EiS 5y ago
    I couldn't find any legal requirements, but the ESA recommends a reentry withtin 25 years of mission completion to reduce waste in orbit. https://www.esa.int/Safety_Security/Space_Debris/Mitigating_space_debris_generation https://www.esa.int/Safety_Security/Space_Debris/Mitigating_...
    - dotancohen 5y ago
      I am aware of this, but it is not legally mandated as GP states.
  - Fordec 5y ago
    A few, but he one that is the closest rubber that hits the road is part of the FCC filing for radio spectrum access on satellite projects. Without which, you're not getting on most rockets.
easton_s 5y ago
10 years of operation, but hundreds of years of data to analyze. We are still analyzing data captured from terrestrial telescopes that haven't operated in decades.
- _joel 5y ago
  Is that due to the format or availability of the data?
  - slenk 5y ago
    The sheer amount of data. The black hole that was imaged recently alone was four petabytes of data https://www.hpcwire.com/2019/06/24/a-behind-the-scenes-look-at-the-hardware-that-powered-the-black-hole-image/ https://www.hpcwire.com/2019/06/24/a-behind-the-scenes-look-...
    - smallerfish 5y ago
      Are there any interesting private companies / startups in this space?
      - _joel 5y ago
        No idea, but if it's difficult for acedemia to get hold of this then how could startups? More to the point, what would be the value add to make the commercials viable? Interested to hear if you think there could be? Perhaps there's some altrusitic archive.org style site that needs to exist for science, that features datasets of multiple PB in magnitude and allows anyone to pull the full archive. Maybe in the future, but still, people still have access to source imagery and they regularly make spectacular images and material from public domain data from space agencies and interest groups. You don't need 4PB unless doing something like, well, imaging a black hole. It's fun, not sure how much there is run a business from it, unless you plan on taking the data and creating spectrographs for some future mining mission way in the future? :D
jimkleiber 5y ago
The Mars Opportunity rover was planned to last only 92 days but lasted about 5200 (~14 years). I think many NASA programs have short expected timelines and then hopefully outlast them. https://en.m.wikipedia.org/wiki/Opportunity_(rover) https://en.m.wikipedia.org/wiki/Opportunity_(rover)
- nindalf 5y ago
  The Spirit rover did very well too - https://xkcd.com/695/ https://xkcd.com/695/
  - jimkleiber 5y ago
    Ahhh XKCD, my heart! I hadn't seen this one, thank you for sharing.
verytrivial 5y ago
.. and 99% of those probably spend 100% of their time trying to sit utterly still in their orbit, staring down at Earth, maybe twitching around to point a bit if they're doing spy work. JWST pivots the entire spacecraft to point the 6 meter mirror. I'm sure they've optimized the consumables on the schedule, but it simply 'costs resources' to do this sort of work. I assure you there are gruellingly dense and optimized observations plans afoot. Compare to e.g. the very successful Herschel Space Observatory -- it too went out to L2(-ish), did everything it was meant to do in its three year mission, and managed to extend to four before (drum roll) running out of fuel, this time for cooling. JSWT solves this cooling issue by some incredibly funky mechanical resonance cooling. Herschel "only" cost about $1 billion, and it will be interesting to compare the science results.
- Fordec 5y ago
  Also don't forget it at no point can it turn around and face the earth or sun or the light coming from the suns direction will burn out the optics. If it does it once, and it's mission over. All the while essentially driving most of the way up out of the gravity well and letting it get pulled back to earth a little and repeating. If it goes too far over the peak of the hill it will go over the other side with no way to reverse even if the rocket has the fuel.
  - hoseja 5y ago
    No no no, it's circling the top of the "hill".
- hnaccount_rng 5y ago
  I think you are misinterpreting where the fuel consumption comes from. It isn't the reoriantation. That you can do with internal reaction wheels. All you want is rotation, not movement. Turn something inside in one direction and the outside will turn the other way. The only problem is movement for that you need to eject stuff the opposite way you want to go. And that is needed because L2 is unstable. I.e. you roll down over time. Which needs to be counteracted by station keeping. I'm pretty sure they'll use the fuel usage to measure the local gravitational field around L2 and from that update mass distribution estimates around the inner solar system.
CrazyStat 5y ago
10 years was not quite worst case but definitely a conservative estimate. L2 is an unstable orbit and needs constant corrections to not drift away, so JWST has much more significant fuel needs than if it were in say Hubble's orbit. How much fuel it would have left for these maneuvers depended on how precise the launch was (i.e. how much fuel it needed to spend on corrective burns just to get to L2). This was obviously uncertain until after the launch, but ten years was a lower bound above which the launch would not be considered a major issue--if it only had say 5 years of fuel left after the launch that would be an indication that the launch was flubbed some how. TLDR: JWST was not "supposed" to last only 10 years. It was designed and built to last much longer, that was just a lower bound assuming nothing went very wrong. cf. Mars rovers operating long past the "planned" mission length, e.g. Opportunity's "planned" 90-day mission turning into over 5,000 days. It is vastly unfair to the people who designed and built Opportunity to say it was "supposed" to last only 90 days. It was built to last much longer; 90 days was a lower bound for the mission to be considered a success.
anonymousab 5y ago
The scale and intensity of the problem is much bigger though. This one is hundreds to thousands of times further out than any of those satellites, for instance. It also has a far longer lifetime compared to the average, even before this news. Four times the distance of the moon from Earth. There's no luxury of being able to repair, service and refuel such a thing without approaching or exceeding the costs of just making a new, better one with the learnings and savings from before.
- shagie 5y ago
  The site https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.htm... is neat. Change the scale from Time to Distance to get an idea of how far out it is. (edit - the "earth moon" distance isn't to scale with respect to planetary diameters... the distance from the earth to the moon is about the same as the sum of all the diameters of all the planets - that's a long way itself)
tomr_stargazer 5y ago
The primary deliverable isn't the satellite; it's the scientific data (and associated breakthroughs) the satellite will deliver.

kiriberty 5y ago

Space Bro, I like it

echelon 5y ago
Is Elon Musk the very first space bro, followed by Bezos? Or do we get to go all the way back to Shuttleworth, Tito, and Branson? Surely Branson is the first space bro.
- unzadunza 5y ago
  Nope, Han Solo is the first space bro.
- WJW 5y ago
  Was Youri Gagarin not a bro?
  - oofabz 5y ago
    Gagarin was a cosmonaut. The Russian equivalent to those mentioned would be Sergei Korolev.
  - fennecfoxen 5y ago
- flipflipper 5y ago
  https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky