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Why isn't SpaceX doing this?

by amichail 5y ago

varjag 5y ago
The project and the choice of contractors predates SpaceX.
ddalex 5y ago
SpaceX wasn't a thing when the project constraints were defined.
NikolaeVarius 5y ago
Because the contracts were made before SpaceX was deemed reliable.
adventured 5y ago
The launch partner/platform wasn't chosen recently and it's part of what ESA is providing as a partner in the program. "In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an Ariane 5 ECA launcher, and manpower to support operations. The CSA will provide the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph plus manpower to support operations." https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Partnership https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Par...
- khuey 5y ago
  "not recently" is underselling it a bit. ESA agreed to launch it before Falcon 9 (let alone the Heavy version) had ever flown.
  - rrss 5y ago
    It looks like it was even before Falcon 1’s first success.
_fizz_buzz_ 5y ago
Ariana 5 can transport a larger/heavier payload than Space X rockets. And even then the telescope has to be folded up in this really complicated way.
- jcfrei 5y ago
  A fair comparison would be to Falcon Heavy (Ariane 5 uses boosters as well) which has about twice the payload capacity. Just doesn't yet have the launch history required for such an important payload.
sprucely 5y ago
Contracts or momentum? Haven't looked at actual dates, but my guess is that this project was established long before SpaceX was a viable option.
fnord77 5y ago
ariane 5 has had 111 launches. Falcon heavy has had 3. the falcon heavy probably didn't even exist when they were drawing up the contracts
- sidkshatriya 5y ago
  I think Falcon heavy is not needed. Webb's weight is ~6200 kg. Falcon 9 is 8300 kg to GTO (Geostationary transfer orbit). This leaves about ~2000 kg fuel equivalent to spare which should be more than enough for the special location Webb is aiming for. But yes, the contract for the webb launch was probably locked a very long time ago. (Though it's also possible that Falcon 9's fairing wont be able to accommodate Webb)
ur-whale 5y ago
> Why isn't SpaceX doing this? Reliability (as in: established track record). Although, if Ariane decides to explode tomorrow, this comment will look ... odd.
- rrss 5y ago
  Important to note that the agreement was made in 2007, so reliability as a factor would be reliability as assessed in 2007, not 2021. I think that in 2021, Falcon 9 ‘s track record arguably suggests it is more reliable than Ariane 5, but it doesn’t matter because the Falcon fairing is too small for JWST.
- architravesty 5y ago
  Falcon 9 has a better track record than Ariane 5 at this point, but SpaceX wasn't really a thing at the time these contracts were signed.
  - adgjlsfhk1 5y ago
    also falcon heavy would be required which only has had 3 launches (all success though)
- InTheArena 5y ago
  This has to be launched by Ariane - it's constraints are tightly bound to what that platform can do, and it's fairing size. Ariane is optimized for GEO insertion, while Falcon is optimized for LEO orbits. You could have used a Falcon, but a payload like this was actually built around the rocket's capability, and this was designed prior to Falcon being a thing. All that said it's worth nothing that SpaceX's flight success rate is 98.5 (135/137), while Ariane V's is 95.5 percent (106/111). The really gobsmaking thing about that is that this is that SpaceX's rate is over 11 years, while Ariane's is over 25 years. It's time to stop thinking of SpaceX as the plucky, untrustworthy startup. In the future space telescopes like this really need to be built in LEO, and then boosted to Lagrange points. The number of failure modes beyond the typical rocket / stage / fairing, secondary burns that the folding mechanism and the lack of a ability to test a ton of new technology in zero-g orbit makes this far more likely to fail then anyone is comfortable with, given the overall cost to this.
deleted 5y ago
[deleted]

Why isn't SpaceX doing this?

varjag 5y ago

The project and the choice of contractors predates SpaceX.

ddalex 5y ago

SpaceX wasn't a thing when the project constraints were defined.

NikolaeVarius 5y ago

Because the contracts were made before SpaceX was deemed reliable.

adventured 5y ago

The launch partner/platform wasn't chosen recently and it's part of what ESA is providing as a partner in the program. "In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an Ariane 5 ECA launcher, and manpower to support operations. The CSA will provide the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph plus manpower to support operations." https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Partnership https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Par...

khuey 5y ago
"not recently" is underselling it a bit. ESA agreed to launch it before Falcon 9 (let alone the Heavy version) had ever flown.
- rrss 5y ago
  It looks like it was even before Falcon 1’s first success.

_fizz_buzz_ 5y ago

Ariana 5 can transport a larger/heavier payload than Space X rockets. And even then the telescope has to be folded up in this really complicated way.

jcfrei 5y ago
A fair comparison would be to Falcon Heavy (Ariane 5 uses boosters as well) which has about twice the payload capacity. Just doesn't yet have the launch history required for such an important payload.

sprucely 5y ago

Contracts or momentum? Haven't looked at actual dates, but my guess is that this project was established long before SpaceX was a viable option.

fnord77 5y ago

ariane 5 has had 111 launches. Falcon heavy has had 3. the falcon heavy probably didn't even exist when they were drawing up the contracts

sidkshatriya 5y ago
I think Falcon heavy is not needed. Webb's weight is ~6200 kg. Falcon 9 is 8300 kg to GTO (Geostationary transfer orbit). This leaves about ~2000 kg fuel equivalent to spare which should be more than enough for the special location Webb is aiming for. But yes, the contract for the webb launch was probably locked a very long time ago. (Though it's also possible that Falcon 9's fairing wont be able to accommodate Webb)

ur-whale 5y ago

> Why isn't SpaceX doing this? Reliability (as in: established track record). Although, if Ariane decides to explode tomorrow, this comment will look ... odd.

rrss 5y ago
Important to note that the agreement was made in 2007, so reliability as a factor would be reliability as assessed in 2007, not 2021. I think that in 2021, Falcon 9 ‘s track record arguably suggests it is more reliable than Ariane 5, but it doesn’t matter because the Falcon fairing is too small for JWST.
architravesty 5y ago
Falcon 9 has a better track record than Ariane 5 at this point, but SpaceX wasn't really a thing at the time these contracts were signed.
- adgjlsfhk1 5y ago
  also falcon heavy would be required which only has had 3 launches (all success though)
InTheArena 5y ago
This has to be launched by Ariane - it's constraints are tightly bound to what that platform can do, and it's fairing size. Ariane is optimized for GEO insertion, while Falcon is optimized for LEO orbits. You could have used a Falcon, but a payload like this was actually built around the rocket's capability, and this was designed prior to Falcon being a thing. All that said it's worth nothing that SpaceX's flight success rate is 98.5 (135/137), while Ariane V's is 95.5 percent (106/111). The really gobsmaking thing about that is that this is that SpaceX's rate is over 11 years, while Ariane's is over 25 years. It's time to stop thinking of SpaceX as the plucky, untrustworthy startup. In the future space telescopes like this really need to be built in LEO, and then boosted to Lagrange points. The number of failure modes beyond the typical rocket / stage / fairing, secondary burns that the folding mechanism and the lack of a ability to test a ton of new technology in zero-g orbit makes this far more likely to fail then anyone is comfortable with, given the overall cost to this.

deleted 5y ago

[deleted]