8 ms·

NASA's James Webb Space Telescope Launch Delayed to December

120 points by asmithmd1 5y ago

ekrebs 5y ago
They need a firm launch date because of the cascading research windows already allocated, but there are 344 single points of failure, and it will be virtually impossible to fixed once launched. I'm terribly excited for the advancements this telescope will bring, but I'm very nervous about the launch and deployment.
- jedberg 5y ago
  It seems like they could start scheduling windows for say June 2022, and then if it happens to be ready before that, have a lottery for slots that you have to use within a day or two of getting the slot. So basically for the folks who just happen to be ready to go and what they're looking at isn't time dependent.
  - dylan604 5y ago
    Since the telescope has to always point its shielding toward the sun, won't there be certain windows of opportunity to view things depending on where they are located in relation to the sun?
  - loonster 5y ago
    The simpler answer is just book for a date with no year. Someone gets Febuary 22 @ 4pm in the first year. It may happen in 2022 or 2023.
LeifCarrotson 5y ago
The good news is that the trajectory of timeline slip is less than one week per week, and if that holds true, the two will eventually rendezvous. In 1996, it was estimated for 2007, fast forwarding a bit to 2018, it slipped one year from an estimated launch in 2020 to 2021, in 2020 it slipped from March 2021 to July, by January 2021 it slipped to October 31st, and it's been known since June, 14 weeks ago, that it wasn't likely to meet that date. At this rate, I estimate the current date will intercept the target date in early 2022.
- tshaddox 5y ago
  > The good news is that the trajectory of timeline slip is less than one week per week, and if that holds true, the two will eventually rendezvous. Not if the timeline slips such that at each slip the delta between the current time and the launch time decreases by 50%.
  - feoren 5y ago
    It still works in that case, actually; you just have to pass through a singularity where the timeline is delayed infinitely many times, but the total amount of each of those infinite delays is finite. 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + ... = 1. This is the answer to Zeno's paradox. A sports reporter gives an update every time Hercules catches up to where the tortoise was the last time he gave an update. All that happens is the sports reporter eventually needs to talk faster and faster and faster, and eventually try to give infinite updates right as Hercules passes the tortoise. Then the reporter's vocal chords explode, but otherwise the race proceeds as you would expect. (That is, just because a description of an event is infinitely long, does not mean the event itself is infinitely long in any sense.)
    - tshaddox 5y ago
      Lol yeah, that was a goof. I had Zeno’s paradox in mind and intended to choose a divergent series but accidentally used the textbook convergent one. Let’s swap it out for the harmonic series.
- irrelative 5y ago
  See also: https://xkcd.com/2014 https://xkcd.com/2014
- nsxwolf 5y ago
  I cannot foresee a timeline where it does not explode on the pad.
  - mmazing 5y ago
avmich 5y ago
Why it's not made serviceable? Or at least able to be serviced, with non-herculean efforts? Manned missions to L2 would both maintain the truly unique device and move forward the manned space capabilities and experience. It's just - what? - four time farther than the Moon?
- sp332 5y ago
  It was hard enough to make it small and lightweight enough to get out there, with epoxy instead of bolts for example.
- Nekhrimah 5y ago
  At the time the design was locked in, there was nothing even planned that would be capable of supporting a crewed servicing mission. They have however included a grapple bar so that there is something to connect to should there be something in the future. SpaceX's Starship is the most likely vehicle at this stage, but that is still substantial development away from being capable of a James Webb servicing mission.
- knappe 5y ago
  How would we get there? There is no current vehicle that could be used to service anything at L2.
  - avmich 5y ago
    Orion ( https://en.wikipedia.org/wiki/Orion_(spacecraft) https://en.wikipedia.org/wiki/Orion_(spacecraft) ) - "Capable of supporting a crew of six beyond low Earth orbit, Orion can last up to 21 days undocked". Can be used, especially with booster which can be launched by e.g. Falcon-9 Heavy, or if more mass required, by SLS (!) or Big Falcon Rocket.
    - knappe 5y ago
      Orion is not viable. They haven't even launched Artemis 1, let alone Artemis 2 (which is scheduled for 2023!) which would be the _first_ crewed launch. I'm not sure why we would plan to service JWT when we have nothing to service it with.
Nevermark 5y ago
Upcoming wallpaper: 2,048 x 2,048 infrared, 1,024 x 1,024 near infrared. But I assume we will get composite pics much larger than that.

120 points by asmithmd1 5y ago

They need a firm launch date because of the cascading research windows already allocated, but there are 344 single points of failure, and it will be virtually impossible to fixed once launched. I'm terribly excited for the advancements this telescope will bring, but I'm very nervous about the launch and deployment.

jedberg 5y ago
It seems like they could start scheduling windows for say June 2022, and then if it happens to be ready before that, have a lottery for slots that you have to use within a day or two of getting the slot. So basically for the folks who just happen to be ready to go and what they're looking at isn't time dependent.
- dylan604 5y ago
  Since the telescope has to always point its shielding toward the sun, won't there be certain windows of opportunity to view things depending on where they are located in relation to the sun?
- loonster 5y ago
  The simpler answer is just book for a date with no year. Someone gets Febuary 22 @ 4pm in the first year. It may happen in 2022 or 2023.

LeifCarrotson 5y ago

The good news is that the trajectory of timeline slip is less than one week per week, and if that holds true, the two will eventually rendezvous. In 1996, it was estimated for 2007, fast forwarding a bit to 2018, it slipped one year from an estimated launch in 2020 to 2021, in 2020 it slipped from March 2021 to July, by January 2021 it slipped to October 31st, and it's been known since June, 14 weeks ago, that it wasn't likely to meet that date. At this rate, I estimate the current date will intercept the target date in early 2022.

tshaddox 5y ago
> The good news is that the trajectory of timeline slip is less than one week per week, and if that holds true, the two will eventually rendezvous. Not if the timeline slips such that at each slip the delta between the current time and the launch time decreases by 50%.
- feoren 5y ago
  It still works in that case, actually; you just have to pass through a singularity where the timeline is delayed infinitely many times, but the total amount of each of those infinite delays is finite. 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + ... = 1. This is the answer to Zeno's paradox. A sports reporter gives an update every time Hercules catches up to where the tortoise was the last time he gave an update. All that happens is the sports reporter eventually needs to talk faster and faster and faster, and eventually try to give infinite updates right as Hercules passes the tortoise. Then the reporter's vocal chords explode, but otherwise the race proceeds as you would expect. (That is, just because a description of an event is infinitely long, does not mean the event itself is infinitely long in any sense.)
  - tshaddox 5y ago
    Lol yeah, that was a goof. I had Zeno’s paradox in mind and intended to choose a divergent series but accidentally used the textbook convergent one. Let’s swap it out for the harmonic series.
irrelative 5y ago
See also: https://xkcd.com/2014 https://xkcd.com/2014
nsxwolf 5y ago
I cannot foresee a timeline where it does not explode on the pad.
- mmazing 5y ago

avmich 5y ago

Why it's not made serviceable? Or at least able to be serviced, with non-herculean efforts? Manned missions to L2 would both maintain the truly unique device and move forward the manned space capabilities and experience. It's just - what? - four time farther than the Moon?

sp332 5y ago
It was hard enough to make it small and lightweight enough to get out there, with epoxy instead of bolts for example.
Nekhrimah 5y ago
At the time the design was locked in, there was nothing even planned that would be capable of supporting a crewed servicing mission. They have however included a grapple bar so that there is something to connect to should there be something in the future. SpaceX's Starship is the most likely vehicle at this stage, but that is still substantial development away from being capable of a James Webb servicing mission.
knappe 5y ago
How would we get there? There is no current vehicle that could be used to service anything at L2.
- avmich 5y ago
  Orion ( https://en.wikipedia.org/wiki/Orion_(spacecraft) https://en.wikipedia.org/wiki/Orion_(spacecraft) ) - "Capable of supporting a crew of six beyond low Earth orbit, Orion can last up to 21 days undocked". Can be used, especially with booster which can be launched by e.g. Falcon-9 Heavy, or if more mass required, by SLS (!) or Big Falcon Rocket.
  - knappe 5y ago
    Orion is not viable. They haven't even launched Artemis 1, let alone Artemis 2 (which is scheduled for 2023!) which would be the _first_ crewed launch. I'm not sure why we would plan to service JWT when we have nothing to service it with.

Nevermark 5y ago

Upcoming wallpaper: 2,048 x 2,048 infrared, 1,024 x 1,024 near infrared. But I assume we will get composite pics much larger than that.