Talk:James Webb Space Telescope

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[edit] Spectrum

I'd heard that the JWST had a different spectrum from the HST and, thus, was meant to augment rather than supplant the HST. Is this true? blahpers 04:18, 2005 Jan 22 (UTC)

This is true; JWST will be primarily an infrared observatory, whereas HST was mostly optical. AdamW 20:45, 20 Mar 2005 (UTC)

I agree with your dissagrement of
"intended to be a significant improvement on the aging Hubble Space Telescope"
It's like sayig This apple is redder than that orage is orange. Should we tag a citatin needed to the line and remove it if none is found? I remeber somewhere it said specifically it is not a replacement. I need a sorce for that thoug.--E-Bod 22:12, 26 March 2006 (UTC)
Ps I am verry persanally attached to the HST so it would be inapropreat for me to make that change. The JWT isn't even even disined to be esily servisable and not be an ongoing thing (i remeber a long time ago it will be for 4 years, but this artile says 5(probably more current))(of corse same for all the other projects they allways love to underestimate their equipent so they can't be dissaponted and they proclam How Wonderul a sucsess when the misson last way longer than "expected" --E-Bod 22:12, 26 March 2006 (UTC))
How can it be designed to be easily servicable when it is 1.5m km from Earth. Give me a break. Because you love HST doesn't mean you have to bag on JWST. How completely odd.

[edit] Deorbit date

Is it correct to talk about a "deorbit date" for a mission at L2? Something out there isn't going to come back to the Earth when it's finished with... AdamW 20:45, 20 Mar 2005 (UTC)

Not really. Generally the objects at L2 simply drift away from the Earth after stationkeeping activities cease, perhaps to crash into it some time in the very distant future. A more pertinent time is the nominal mission life (5 years) and the goal (10 years). Also, the launch date has been changed to 2013 due to budgetary limitations. I am a novice and reluctant to edit such a nice summary for the mission. PeterStockman 19:19, 28 October 2005 (UTC)

In 'Current Status,' it says "Recently NASA has decided to slip the launch date two years to 2013." Can someone throw a date there instead of "recently?" Maybe link to a press release? Shaggorama 10:25, 8 December 2005 (UTC)

[edit] Deorbit date wrong

The deorbit date has to be wrong, Hubble will last for at least 20 years yet this will last 5? If this is true then the project should be scrapped for being a waste of time and money.

That five years is more an artifact of the procurement process than an actual plan. Essentially they say "specify what observations you want your proposed instrument to make, design a platform that will achieve that, cost it, and the funding and science comittees will decide if that's good science-value-for-money". So when they say JWST will last five years they really mean that the observations they plan to do in those five years will justify the price of the telescope, and that the engineers are sure (to a reasonable degree of certainty) that the systems they've designed will last long enough to succeed in that goal. In practice things are overspecified, overdesigned, and overbuilt, and so many things last much longer. Nobody expected Voyager to be working after its planned encounters (certainly not a decade later), the Mars rovers were planned to work for a month or two and still work more than a year later, and Hubble was planned for a few years (I think seven). So it's likely that we'll see good science from JWST long after its official death-date. That said, its high altitude means it's way out of the reach of the Space Shuttle (and who knows what, or when, Crew Exploration Vehicle will actually be able to do); there's no chance of an in-flight upgrade - so it almost certainly will have a shorter life than Hubble. That's not such a bad deal, even if it is only five years. Once you amortise the cost of shuttle missions to maintain HST, or face the progressively poorer science you'd get from an aging, deteriorating obervatory, it's probably cheaper and smarter to launch a new, cutting-edge telescope when the old one fails. And just like other modern electronics products, if you don't have to make something repairable you can make it much much cheaper. -- Finlay McWalter | Talk 01:21, 16 January 2006 (UTC)

The website of JWST refers to a "design" mission length of 5 years and a "goal" mission length of 10 years. I've replaced "deorbit date" with those two numbers. Of course the actual mission length is not known ahead of time. Kingdon 16:49, 18 July 2006 (UTC)

Hubble wasn't supposed to last 16 years when they launched it. The Mars Rovers were supposed to last only 3 months (they're still working, more than 2 years later. The same observation can be made about the Galileo probe. What we should understand is that any probe or satellite has a primary mission, which lasts a finite amount of time. If everything goes fine, the mission is extended indefinitely... for as long as the piece of hardware keeps going (and going and going). Limitations can come from batteries or propeller tanks, from the inability to service it (due to the distance), or from degradation suffered from the space medium (cold, radiations, micro-meteorites). Best regards, Hugo Dufort 06:13, 3 October 2006 (UTC)

[edit] Failed Wikipedia:Version 0.5 nomination

I have failed this article for Wikipedia:Version 0.5 for several reasons:

  1. It has very few refs, and none are inline. Articles should have as many references as possible to verify the information.
  2. It isn't very comprehensive. This may be because it's far into the future, so this wasn't really the deciding factor.
  3. It's not very notable. It may be the most important astronomical telescope when launched, but that's at least 7 years away, and most people haven't heard of it now.

With improvements, this may be good enough for Wikipedia:Version 1.0 in the future, but it is not at written encyclopaedia quality yet. I would rate it a strong start class. --Rory096 05:35, 15 June 2006 (UTC)

[edit] Possible grammar error

Shouldn't the bold phrase be changed to 6 times as large? Although JWST has a planned mass half that of the Hubble, its primary mirror (a 6.5 meter diameter beryllium reflector) has a collecting area which is almost 6 times larger.68.238.103.129 05:26, 30 January 2007 (UTC)

Without a source, we can't tell which is correct. It would not be a grammar error; it would be a math error. Mathematically, "six times as large" equates to 6 x 1. "Six times larger" equates to 1 + (6 x 1). Remember that 1.0 is the same as 100%, so the language can be demonstrated logically like this:
  • Let's say you have a weight that is 100 pounds. If you have another weight that is 50% (half) as heavy, it would be 50 pounds. 100 x 0.5 = 50
  • Now again let's say you have a weight that is 100 pounds. If you have another weight that is 50% heavier, it would be 150 pounds. 100 + (100 x 0.5) = 150
--JHP 08:35, 11 May 2007 (UTC)

CNN has reported that "The Webb telescope will be given a primary mirror whose surface is about six times the size of the one on Hubble." [1] 999mal 07:04, 12 May 2007 (UTC)

[edit] Possible source

I saw this article on the subject, so I thought I'd list it here as a possible source.

[edit] Simulated pictures

It seems to me that the simulated pictures are just hubble deep field pictures. —The preceding unsigned comment was added by Dylanjbyrne (talk • contribs) 12:03, 11 May 2007 (UTC).

[edit] Docking ring

Regarding the docking ring, the New Scientist article URL (added by Ericpsmith (talk · contribs)) works fine for me. I'm not sure why Tuvas (talk · contribs) had trouble accessing it. The spin in this article is very different from the space.com article, that's for sure. But I'm not sure the two quite contradict each other. In the space.com article, the NASA guy is quoted as saying "We are going to design for the James Webb Space Telescope a little ring". Note that he says they will design the ring, not whether they will include the ring in the final design for Webb. If we really wanted to cover whether the ring will happen or not in an NPOV way, we could elaborate more on the pros, the cons, what has been analyzed, what still needs to be analyzed, what has been recommended by whom to whom, etc, etc. But I'm skeptical that we really want that level of detail when we can just use words like "is considering" and link to the articles (and any others which are more authoritative than media news articles, if available). I've made an edit which does roughly that but if we still have problems with what to say, we should probably hash things out on the talk page. Kingdon 00:27, 29 May 2007 (UTC)

Sorry about that, it's working for me now... I must have had the one minute that I couldn't connect to the site for some reason... Anyways, I don't have enough time to figure out what's right right now, but thanks for correcting me. Tuvas 01:15, 29 May 2007 (UTC)

[edit] Can't take optical pictures like Hubble

I've read that since the JWST is primarily infrared (with some optical capability), that it won't be able to take pictures in the optical spectrum anywhere near as amazing as the Hubble has been doing, anyone have more info on that? --Fxer 18:02, 9 August 2007 (UTC)


Actually the JWST is not even sensitive in the optical spectrum. It's instruments are designed for Near Infrared and Mid Infrared. Hubble is sensitive to a MUCH larger part of the spectrum than the JWST. JWST will only replace the Infrared capabilities of Hubble.--Martin Cash 16:02, 15 August 2007 (UTC)


The JWST is being designed to operate from the very red part of the visible spectrum (0.6 micrometers) through the mid-infrared (27 micrometers). Because of its larger mirror diameter than the HST it will have HST-like angular resolution in the near-infrared (1-5 mircometers). What this means is that images from the JWST will be just as sharp as the ones we have all gotten used to from the HST. The multi-color capabilities of the JWST (i.e., different filters) will allow one to reconstruct the images with cooler areas/objects colored 'redder' and higher temperature areas/objects colored "bluer", again just like we are used to seeing from the HST. The pictures will be just as amazing, but from a portion of the spectrum not directly observable with the naked eye. JWST is NOT meant to be a replacement for HST. It is the scientific successor to the HST. It will help astronomers further the study of very faint, distant (highly redshifted) galaxies. These galaxies, formed early in the history of the universe, are filled with objects emitting strongly in the restframe ultraviolet and optical. This radiation is shifted into the near and mid infrared by the expansion of the universe. Hence, to study them one needs to optimize the observatory for that portion of the spectrum. This infrared optimization also opens a wealth of observations in areas other than distant galaxy studies.--ericpsmith 21:49, 27 August 2007

[edit] Timeline

I think a timeline would be helpful, I'd like to know when the project was first announced, major milestones etc...78.21.62.65 (talk) 01:54, 6 January 2008 (UTC)

Don't know if a timeline is the best format (there's some discussion at WP:Proseline although nothing there tells us we must or must not format things as a timeline) but we are indeed lacking a reasonable history of the mission (first concepts, getting it approved, budgetary battles, fleshing out the design, etc). If someone has written a real history (like the many for Apollo), that makes it easier, but we could get in some basic facts without getting in too much trouble with WP:SYN. Kingdon (talk) 04:19, 21 January 2008 (UTC)

[edit] Why is it named after some not notable bureaucrat?!

? —Preceding unsigned comment added by 195.242.255.83 (talk) 18:47, 27 May 2008 (UTC)