28 Mar 2024, 07:29 [ UTC - 5; DST ]
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 07:34 |
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Joined: 01/31/12 Posts: 3094 Post Likes: +5447 Company: French major Location: France
Aircraft: Ejet
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Username Protected wrote: fascinating to me how slow it is going now. only .2 mi/sec (880 mi/hr if I did the math right). slow for a celestial device. .2mi/sec relative to? If you can "time" it just so that you don't need a massive thrust boost to stop it at the right spot and the forces are balanced...Even cooler! Stupid question: is anyone working on the next space telescope?
_________________ Singham!
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 12:44 |
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Joined: 01/06/08 Posts: 4665 Post Likes: +2678
Aircraft: B55 P2
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After that, there will be https://asd.gsfc.nasa.gov/luvoir/Just recommended by the Astro2020 decadal survey - a group that drives a lot of large scale astronomy decisions. (sadly the X-ray telescope we were working on got killed) (LYNX) Username Protected wrote:
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 16:27 |
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Joined: 07/06/14 Posts: 2978 Post Likes: +1967 Location: MA
Aircraft: Cessna 340A
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Username Protected wrote: Regarding Webb's velocity: One of experts at the video press conference that celebrated the full deployment said that on its current trajectory, the telescope will "just fall into L2."
Earlier posts at the Webb blog explained that they've always planned to arrive at L2 needing a boost, if necessary, rather pay the much higher cost in fuel of correcting for an overshoot. Huh, I had read that the way it was configured, it could only push itself out -- they were going to sit just barely on the near side of L2, with all corrections pushing them outward, but never far enough over the hump so that it starts to fall away. The thrusters are only on the sunward side. Maybe this is not absolute, and they could rotate the craft to give an inward thrust, but they prefer not to. Rotating so that the mirrors were sunward could damage the cold side equipment.
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 18:35 |
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Joined: 02/01/21 Posts: 206 Post Likes: +149
Aircraft: A55 President 600
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Admittedly I haven't looked at the details but I assume there will be an orbit about L2 (as opposed to a "hover") and I don't think that it's perfectly stable. That is, I think all the other mass around makes things a little less than ideal and some mild orbital corrections will be required over time. I think you will need at least one small boost to fall into a circular orbit (if that's their goal) just like you would for any insertion.
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 21:29 |
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Joined: 03/13/13 Posts: 1397 Post Likes: +4957 Location: Conroe, TX
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This strikes me as something near the pinnacle of human achievement. Anyone who actually has perspective care to commment?
_________________ Strive for a ruthless understanding of reality.
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Post subject: Re: James Web Telescope Posted: 09 Jan 2022, 23:54 |
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Joined: 04/26/13 Posts: 19753 Post Likes: +19425 Location: Columbus , IN (KBAK)
Aircraft: 1968 Baron D55
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Username Protected wrote: I had read that the way it was configured, it could only push itself out -- they were going to sit just barely on the near side of L2, with all corrections pushing them outward, but never far enough over the hump so that it starts to fall away. The thrusters are only on the sunward side. Maybe this is not absolute, and they could rotate the craft to give an inward thrust, but they prefer not to. Rotating so that the mirrors were sunward could damage the cold side equipment. This is what I heard too. They can’t perform a braking boost, which is why they are “sneaking up on” L2 with small burns that are just under that is needed. They have no brakes, so they can’t afford to overshoot or they’ll lose the instrument to space.
_________________ My last name rhymes with 'geese'.
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Post subject: Re: James Web Telescope Posted: 10 Jan 2022, 01:55 |
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Joined: 01/06/08 Posts: 4665 Post Likes: +2678
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JWST is awesome - but there are a surprising number of amazing scientific instruments. LIGO: can see two weights, 4 kilometers apart move but 1/10,000 of the size of a proton (or one one hundred billionth of the size of a hydrogen atom). Its able to see colliding neutron stars and black holes billions of light years away The LHC accelerates protons to trillions of volts. Or SLAC where the electrons reach 99.9999% of the speed of light before they make an X-ray laser BICEP telescope at the south pole is expected to soon see direct evidence of an effect (cosmological inflation ) that happened 1e-32 seconds after the big bang. (I can't think of words to describe such a small number). It works basically by using then entire universe as a gravity wave detector. (and these are just the very few projects I've personally interacted with in some way - there are many many more). we have spacecraft near the sun, beyond pluto, at Jupiter, and driving around on Mars. Username Protected wrote: This strikes me as something near the pinnacle of human achievement. Anyone who actually has perspective care to commment?
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Post subject: Re: James Web Telescope Posted: 10 Jan 2022, 09:40 |
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Joined: 11/25/11 Posts: 9168 Post Likes: +17159 Location: KGNF, Grenada, MS
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Truthfully, I'm a little behind on my reading of books on physics and cosmetology, That's a joke fellows. My most recent interests have been seeking the similarities of the politics of the pre-civil war years with those of today and the effect of news media in both those times. I found more than you might think and professional political scientist and historians are now getting aboard. So, now, back to science. To get me more "up to date". You guys who are more physics and engineering based, what books would you recommend that are not so dry and technical as to cause a severe case of dandruff? Remember, I'm old and getting senile. Jg
_________________ Waste no time with fools. They have nothing to lose.
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Post subject: Re: James Web Telescope Posted: 10 Jan 2022, 10:07 |
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Joined: 11/09/14 Posts: 2445 Post Likes: +2391 Location: KOMN
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Username Protected wrote: My friend, come to France, we'll have some exceptionally good wine with proper bread, then we'll take a 320kph ride on the TGV, powered by nuclear power plants I understand that invitation wasn't addressed to me, but if my wife and I happen to make it to France this spring/summer, I fully intend to take you up on that. I'll even buy the wine.
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Post subject: Re: James Web Telescope Posted: 10 Jan 2022, 11:19 |
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Joined: 12/13/07 Posts: 2604 Post Likes: +2740 Location: DFW, TX (KGKY)
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Username Protected wrote: The wine is in a cellar already, don't worry about it! Definitely send me a pm. Can't promise I won't be flying but... No worries, Fabien. Leave the key under the mat and we'll let ourselves in and outl...ha!
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Post subject: Re: James Web Telescope Posted: 10 Jan 2022, 12:24 |
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Joined: 01/31/12 Posts: 3094 Post Likes: +5447 Company: French major Location: France
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Username Protected wrote: The wine is in a cellar already, don't worry about it! Definitely send me a pm. Can't promise I won't be flying but... No worries, Fabien. Leave the key under the mat and we'll let ourselves in and outl...ha!
For every bottle facing one way, there is the same facing the other. Anything on the top shelfs is before 2006. Of course you don't see the crates with the more mundane wines...Or the champagne
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_________________ Singham!
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