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> Hope Webb is safe in its Lagrange point for a long life JWST has a 5-year science mission requirement, with 10-year propellant life. Unfortunately it has a

> Hope Webb is safe in its Lagrange point for a long life JWST has a 5-year science mission requirement, with 10-year propellant life. Unfortunately it has a relatively short upper-bound on its lifetime, compared to say Hubble. Though apparently there's ~20-years of propellant onboard thanks to a precise launch, still a far cry form Hubble's 31 years and still ticking. Should we consider 20-years a long life for such an expensive instrument?

tux3 5y ago
The glass half full haruspicy is that it might mean we'll be forced to start thinking about designing an even better one 5-10 years from now :)
- ianai 5y ago
  I heard one option for addressing climate change is a huge sun shade between us and the sun. I figure that sounds like something that could be tuned into a radio telescope array or something. Maybe with the earth side being the side used for equipment? Idk.
  - kevin_thibedeau 5y ago
    A radio telescope would perform best if it was shielded by the moon.
  - BurningFrog 5y ago
    From memory, that sunshade needs to be many orders of magnitude bigger than any telescope. Which probably means it would have to be a "cloud" of millions of smaller shades.
    - EZ-Cheeze 5y ago
      If enough of a star's light can be blocked by polarized filters, data transmission can occur when they are switched on and off in a pattern. Maybe with the JWST we'll be able to download many different civilizations' Wikipedias if they're blinking their suns at us.
quantified 5y ago
Let’s get $5B/year out of it. Your $1K smartphone is expensive if it only lasts 1yr for fun and not so much if it lasts 5 years and you get business income via it.
wolfram74 5y ago
The Mission extension vehicles (MEVs) are demonstrated technology[0] for some geostationary orbit. I think I've heard some talk in the press releases that now they know they've got as much time as they do, and that it even got past it's 300+ single point of failures, they're chatting about what kind of maintenance missions they can carry out to extend JWST's life span. [0]https://www.northropgrumman.com/space/space-logistics-services/ https://www.northropgrumman.com/space/space-logistics-servic...
- WalterBright 5y ago
  > extend JWST's life span I recall a thread here when it was launched where I suggested building a twin simultaneously, and that the increment in cost was likely to be 10% of the cost of one. One of the critics of this idea said there was no need for another, as there was only so much the JWST could discover. But it's hardly been turned on before people are trying to figure out how to make it last longer. Sigh. P.S. I found out later that in the past NASA would build probes in pairs, and made extra parts in case one was damaged or didn't work. So it really couldn't be that expensive to have built a twin.
  - bryanlarsen 5y ago
    Perseverance was originally a twin of Curiosity, but it cost more than Curiosity. There's no way that a twin of JWST would cost only 10%.
    - WalterBright 5y ago
      > Perseverance was originally a twin of Curiosity, but it cost more than Curiosity. I can't imagine how that could come about. > There's no way that a twin of JWST would cost only 10%. It's kind of the way building things works. The cost of the prototype is enormous compared to the next one. For one thing, the additional R+D cost is $0. The additional cost of the software (and I bet the custom software is a big chunk) is $0. The additional cost of committee meetings to discuss competing alternatives is $0. And on and on. When cutting parts, the cost isn't in cutting the parts. The cost is setting up the machine to cut the parts. The cutting cost is trivial.
41b696ef1113 5y ago
20 years of expected propellant, but other critical parts that could fail before that time.
ISL 5y ago
One should not value the time of operation as much as the total value of science returned. If JWST can engage in science operations for even a year, it will transform our precision understanding of the universe. This is like switching on the first electron microscope when everyone has only ever had optical microscopes. We will see new and surprising things with unprecedented fidelity. The big question has always been, "will JWST's engineering actually work?" So far, it looks like it is working very well.
mulmen 5y ago
Maybe a shorter life is a feature if it adds capability. JWST was built to further investigate discoveries made with Hubble. Presumably whatever comes after JWST will similarly drill into discoveries we are about to make.

tux3 5y ago

The glass half full haruspicy is that it might mean we'll be forced to start thinking about designing an even better one 5-10 years from now :)

ianai 5y ago
I heard one option for addressing climate change is a huge sun shade between us and the sun. I figure that sounds like something that could be tuned into a radio telescope array or something. Maybe with the earth side being the side used for equipment? Idk.
- kevin_thibedeau 5y ago
  A radio telescope would perform best if it was shielded by the moon.
- BurningFrog 5y ago
  From memory, that sunshade needs to be many orders of magnitude bigger than any telescope. Which probably means it would have to be a "cloud" of millions of smaller shades.
  - EZ-Cheeze 5y ago
    If enough of a star's light can be blocked by polarized filters, data transmission can occur when they are switched on and off in a pattern. Maybe with the JWST we'll be able to download many different civilizations' Wikipedias if they're blinking their suns at us.

quantified 5y ago

Let’s get $5B/year out of it. Your $1K smartphone is expensive if it only lasts 1yr for fun and not so much if it lasts 5 years and you get business income via it.

wolfram74 5y ago

The Mission extension vehicles (MEVs) are demonstrated technology[0] for some geostationary orbit. I think I've heard some talk in the press releases that now they know they've got as much time as they do, and that it even got past it's 300+ single point of failures, they're chatting about what kind of maintenance missions they can carry out to extend JWST's life span. [0]https://www.northropgrumman.com/space/space-logistics-services/ https://www.northropgrumman.com/space/space-logistics-servic...

WalterBright 5y ago
> extend JWST's life span I recall a thread here when it was launched where I suggested building a twin simultaneously, and that the increment in cost was likely to be 10% of the cost of one. One of the critics of this idea said there was no need for another, as there was only so much the JWST could discover. But it's hardly been turned on before people are trying to figure out how to make it last longer. Sigh. P.S. I found out later that in the past NASA would build probes in pairs, and made extra parts in case one was damaged or didn't work. So it really couldn't be that expensive to have built a twin.
- bryanlarsen 5y ago
  Perseverance was originally a twin of Curiosity, but it cost more than Curiosity. There's no way that a twin of JWST would cost only 10%.
  - WalterBright 5y ago
    > Perseverance was originally a twin of Curiosity, but it cost more than Curiosity. I can't imagine how that could come about. > There's no way that a twin of JWST would cost only 10%. It's kind of the way building things works. The cost of the prototype is enormous compared to the next one. For one thing, the additional R+D cost is $0. The additional cost of the software (and I bet the custom software is a big chunk) is $0. The additional cost of committee meetings to discuss competing alternatives is $0. And on and on. When cutting parts, the cost isn't in cutting the parts. The cost is setting up the machine to cut the parts. The cutting cost is trivial.

41b696ef1113 5y ago

20 years of expected propellant, but other critical parts that could fail before that time.

ISL 5y ago

One should not value the time of operation as much as the total value of science returned. If JWST can engage in science operations for even a year, it will transform our precision understanding of the universe. This is like switching on the first electron microscope when everyone has only ever had optical microscopes. We will see new and surprising things with unprecedented fidelity. The big question has always been, "will JWST's engineering actually work?" So far, it looks like it is working very well.

mulmen 5y ago

Maybe a shorter life is a feature if it adds capability. JWST was built to further investigate discoveries made with Hubble. Presumably whatever comes after JWST will similarly drill into discoveries we are about to make.