The manufacture of the JWST mirror blanks http://www.irconnect.com/noc/press/pages/news_releases.mhtml?d=84293.
Despite this milestone, the fate of JWST is still somewhat precarious, because although the scientific bang from the telescope is expected to be huge, http://www.jwst.nasa.gov/tradestatus.html to a staggering $4.5 billion. A http://www.space.com/spacenews/businessmonday_050606.html on the squeeze in NASA's space-based astronomy plans gives some background.
The JWST home page can be found http://www.jwst.nasa.gov/.
The Space Telescope Science Institute, which runs Hubble, also has a site http://www.stsci.edu/jwst/. As does http://www.esa.int/science/jwst.
Just how does it end up costing $4.5B ( which will become $5B I'm sure)
That's just - wow. That's TEN Mer's.
TEN
I'm not saying "drop the scope, build Ten MER's" - but even the challenge of getting that mirror light enough, and deploying accurately enough surely cant cost $4.5B
Doug
Well, a 6.5m telescope is pretty big even on the ground. And the plan is to send it to L2, not LEO, so with no repair capability, it has to be REALLY well designed, with huge redundancy and margin etc. Plus, the thing weighs nearly seven tonnes.
A little more info at http://www.newscientist.com/article.ns?id=dn7423.
Back in 2003, it http://hst-jwst-transition.hq.nasa.gov/hst-jwst/JWST_Bahcall_v3.pdf. I'll see if I can find some more info on what is driving up the cost.
The JWST has always struck me as being a prime example of why men in space (or at least very capable robonauts) are a good idea. The mechanical requirements of unfolding those mirror segments and the sunshade, plus the inevitable limits on attitude-control and instrumentation really do demand some up-close-and-personal TLC. Hubble never really needed men (it was launched 'built') and the upgrades were always the jam on the cake (OK, they got the mirror wrong, and that fix *did* need men, but you can't say that such activities were a part of the rationale behind Hubble and the Shuttle - it was sheer luck that after a really bad start something could be done at all!). JWST, however, is exactly the sort of structure which could do with a quick tap from a guy with a rubber mallet when the main wossisname joint flange sub-assembly secondary cotter-pin stiffens up!
Personally, I'd put JWST on the back burner until it can be man-tended, and spend the money in the meantime on a series of state-of-the-art but disposable Hubbles II, III and IV. JWST smells too strongly of too many eggs in one basket for me, and after the Galileo antenna I'd as soon not have to trust my faith in interplanetary origami.
4.5 billion is a lot. If I'm not wrong, this is 2 B$ above Hubble, and still surpassing it even considering the cost of shuttle servicing missions.
How is possible? clearly, the aveniristic technology require strong investment... but consider that this will have many applications and can be an investment for future space telescopes!
[/quote]
It seems JWST is safe from outright cancellation for the moment. http://www.newscientistspace.com/article/dn7908-cost-cuts-likely-to-dim-space-telescopes-vision.html has some detail on how the project hopes to rein in the budget for JWST. Part of it is limiting testing. Scary. The other part is reducing the amount of polishing of the mirrors which will greatly slow down JWST's ability to image in the optical part of the spectrum. JWST was always billed as a near IR telescope, but the lack of any overlap with Hubble is going to hurt.
Launch is also delayed, probably to 2013.
IMHO, JWST should be put on hold, and then back out to competition - it's just going the way of the ISS, descoped and over budget, when Burt Rutan and Co would just build the damn thing, and hit it with a hammer as required until it was the right shape. If JWST fails, then (near) optical space astronomy goes down the tubes, period.
Failing that, a bunch of throwaway Hubbles (maybe with a He replenishment capability, but that's all).
Really, it's nuts to NOT make JWST man-tended!
First JWST mirror segment delivered for polishing.
http://www.irconnect.com/noc/press/pages/news_releases.mhtml?d=87394
"Really, it's nuts to NOT make JWST man-tended!"
Not when you consider that both its sensitivity and its available observation time are tremendously reduced if you put it anywhere near the radiated warmth of Earth. Considering that, it's still more scientifically cost-effective to put it at the Earth-Sun L2 point, even though it's beyond range of human repairmen. (Keep in mind that, once the design work for the first one has been done, the cost of an identical replacement would be considerably less.)
"The James Webb Space Telescope is a large, infrared-optimized space telescope scheduled for launch no earlier than June 2013."
http://www.jwst.nasa.gov/
http://space.com/spacenews/businessmonday_051121.html The article also says that the telescope will not be "descoped" to any great degree. Only some testing and instrumentation for low priority science will be removed. Cost is still $4.5 billion, but now has less risk, and a more even funding profile. And launch is likely to be on an Ariane 5, with a launch deal set for 2006.
With HSM 4 now more and more likely, this delay doesn't bother me so much. HST will last that long, and there will still be overlap between the two observatories.
And SIM, which is seen as a casualty of the JWST overruns, has been giving a funding boost by Congress, and is on track for a 2012 launch, according to http://www.pasadenastarnews.com/news/ci_3236041
I moved this from a thread I started to this one. Thanks to ljk4-1 for pointing it out to me.
I apologize if there is already a thread on JWST; I didn't take the time to look (very hard). However, if there isn't, I'll kick-start it by pointing out Tony Reichhardt's excellent news article in the March 9, 2006, issue of Nature:
US astronomy: Is the next big thing too big?
Tony Reichhardt
Nature 440, 140-143 (2006).
doi:10.1038/440140a
http://www.nature.com/nature/journal/v440/n7081/full/440140a.html
Excerpt:
My attempt to attach this article failed; it overloaded available space on this site. I'll have to do a summary of it later -- it makes a great many important points about the current space science proram.
Particularly interesting quotes from the article:
(1) "At the beginning of the millennium, US astronomers thought that their most-wanted project would cost $1 billion...NASA's latest budget puts the project's price tag, including $1 billion for a decade's worhthof operations, at $4.5 billion. That's more than the entire annual research and development budget of the National Science Foundation; it represents more than $1 million for each full member of the American Astronomical Society." Which, I think, makes my point again about the low cost-effectiveness of most space science, and the immense difficulty it would have competing for government funding in any honest competition with other kinds of scientific research.
(2) One part of the problem DOES seem to be NASA HQ's fault. "A delay in the government's decision to move from a US launcher to the Ariane added an estimated $300 million as highly paid engineers were unable to move forward until they knew which rocket they were designing for. The situation is particularly embarrassing given that the cost of delaying the decision ended up being greater than the cost of the launch." Ah, the rationality of government. Still, this is only 1/12 of the total cost rise.
(3) As for the other causes of the cost underestimate: "The Decadal Survey guessed the cost as $1 billion. Studies in the mid-1990s had pegged the price as between $500 million and $1 billion. These were based on the hope -- unfulfilled, as it happened -- that the Webb Telescope might take advantage of advances in building low-cost spaceraft developed by the military."
However: "Garth Illingworth of UC-Santa Cruz, who chaired the 1990 panel [which much more acurately predicted its current cost], chalks the anomalously low estimates from the 1990s up to a 'lack of reality' inherent in the 'faster, better, cheaper' philosophy of Dan Goldin...Reinhard Genzel of Germany's Max Planck Institute for Extraterrestrial Physics in Garchning says it was clear at the time that a $500 million estimate for the Webb Telescope was a 'political price'...
"Today, Illingworth inveighs against the 'extraordinarily bad, artificial cost estimates' of the Goldin era. But the 2000 Decadal Survey seems to have been happy to accept them. The world of big science is well used to projects being lowballed -- a process that gets schemes started on the basis of a low-cost estimate, with the implicit hope that by the time the true costs are known inertia and vested interests will make it impossible to pull out. Lowballing is not a practice anyone would like to defend on principle, but histories like the Hubble's show it can work." That is, our old friend the Camel's Nose again -- exactly the same technique NASA used to get Shuttle and Station funded.
(4) Where Hubble is concerned: "[Hubble project scientist Robert] O'Dell recalls that in 1972, Hubble's total price including its first year of operations was projected to be...$1 billion in today's prices. According to Robert Smith, a historian at Canada's Univ. of Alberta who wrote a political history of the telescope...'the development cost of Hubble to date is certainly more than $4 billion.'
"NASA's Eric Smith adds that when new instruments and operating expenses are added, that comes to $9 billion. This doesn't include the cost of four space shuttle servicing missions to Hubble, and a fifth being planned -- the cost of a shuttle launch can be put at about $500 million. All in all, building, launching, using and refurbishing Hubble has probably been the most expensive undertaking ever made in the name of pure science; the mission is still, remarkably, costing over $300 million a year." (And that's ignoring the fact that the true cost of each Shuttle mission, using honest accounting, is over $1 billion!)
(5) Charles Beichman of JPL, a leading light of the cancelled Terrestrial Planet Finder mission...thinks that the Webb Telescope will be 'a fine machine. It will do fantastic science.' In fact, he is on one of the instrument teams. But when he goes to professional meetings, he sees more young astronomers attending sessions on planet-finding than on Hubble or the Webb Telescope." Of course, Beichman couldn't POSSIBLY be a biased witness in this matter. Heavens, no. But I do find it at least plausible that the examination of other solar systems is considered, on balance, more romantic -- and thus more interesting -- by genuine astronomers than cosmology or other fields of space astronomy are, just as it is by the nonscientific public.
Still, as the article says, "anyone who doesn't realize that TPF would be costlier than the Webb Telescope is dreaming." I shudder to think what the real cost of THAT endeavor will end up being -- which is why I have no objection at all to protractedly deferring it until Kepler and/or SIM have given us the initial census of the frequency of potentially habitable planets which we need to make even the most basic decisions as to the design of TPF.
In summary, it is very hard to blame the Webb Telescope problem itself on NASA HQ -- although of course the cuts in space science spending as a whole can be blamed on the hypertrophied (or, to be more accurate, metastasized) manned space program. But where Webb's tendency to hog most of whatever the actual space astronomy budget turns out to be is concerned, I think that space astronomers -- to quote Popeye the Sailor -- "buttered their bread and now they've got to sleep in it."
To keep things tidy and prevent sprawling, disconnected threads, I moved Bruce's two posts to the JWST thread.
James Webb Telescope Sunshield Membrane Passes Tests
http://www.spacedaily.com/reports/James_Webb_Telescope_Sunshield_Membrane_Passes_Tests.html
Redondo Beach CA (SPX) May 15, 2006 - Northrop Grumman announced Monday its
engineering team has successfully completed a series of tests on a key element
of the James Webb Space Telescope.
ATK To Provide More Components For James Webb Space Telescope
Minneapolis MN (SPX) May 31, 2006
Alliant Techsystems announced Tuesday it has received a $65 million contract to provide more components and subsystems to Northrop Grumman for NASA's James Webb Space Telescope.
http://www.spacedaily.com/reports/ATK_To_Provide_More_Components_For_James_Webb_Space_Telescope.html
Astrophysics, abstract
astro-ph/0606175
From: Jonathan Gardner [view email]
Date: Wed, 7 Jun 2006 21:05:29 GMT (12223kb)
The James Webb Space Telescope
Authors: Jonathan P. Gardner, John C. Mather, Mark Clampin, Rene Doyon, Matthew A. Greenhouse, Heidi B. Hammel, John B. Hutchings, Peter Jakobsen, Simon J. Lilly, Knox S. Long, Jonathan I. Lunine, Mark J. McCaughrean, Matt Mountain, John Nella, George H. Rieke, Marcia J. Rieke, Hans-Walter Rix, Eric P. Smith, George Sonneborn, Massimo Stiavelli, H. S. Stockman, Rogier A. Windhorst, Gillian S. Wright
Comments: 96 pages, including 48 figures and 15 tables, accepted by Space Science Reviews
The James Webb Space Telescope (JWST) is a large (6.6m), cold (50K), infrared-optimized space observatory that will be launched early in the next decade. The observatory will have four instruments: a near-infrared camera, a near-infrared multi-object spectrograph, and a tunable filter imager will cover the wavelength range, 0.6 to 5.0 microns, while the mid-infrared instrument will do both imaging and spectroscopy from 5.0 to 29 microns.
The JWST science goals are divided into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the early universe.
The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present day.
The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall on to dust-enshrouded protostars to the genesis of planetary systems.
The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems including our own, and investigate the potential for the origins of life in those systems.
To enable these observations, JWST consists of a telescope, an instrument package, a spacecraft and a sunshield. The telescope consists of 18 beryllium segments, some of which are deployed. The segments will be brought into optical alignment on-orbit through a process of periodic wavefront sensing and control.
The JWST operations plan is based on that used for previous space observatories, and the majority of JWST observing time will be allocated to the international astronomical community through annual peer-reviewed proposal opportunities.
http://arxiv.org/abs/astro-ph/0606175
I'm looking forward to seeing alpha centauri images with this telescope.
http://www.irconnect.com/noc/press/pages/news_releases.mhtml?d=111850
- http://news.bbc.co.uk/2/hi/science/nature/6340703.stm
"6.6m (22ft) in diameter", that's fantastic !
NASA, ESA and the CSA are holding a technical review of the JWST in Dublin, Ireland, next month. Approximately 300 people will attend the meeting, which will be held in the Royal Hospital Kilmainham from Monday June 11th – Thursday June 14th. In addition to NASA, ESA and CSA personnel, representatives from a large number of US and European space technology companies will be present.
The JWST Chief Project Scientist John Mather will give two public lectures while in Dublin, one will be in association with the Royal Irish Academy.
We are currently transporting a full-scale model of the James Webb Space Telescope to Dublin (it will be placed in the grounds of the Royal Hospital Kilmainham and National Museum of Modern Art) for at least 6 weeks.
The School of Cosmic Physics at the Dublin Institute for Advanced Studies is directly involved in developing one of the four main instruments on board JWST - the MIRI - and is hosting next month's meeting.
As this is a technical event, there are limited public events associated with it, but I will post more precise details shortly.
Great stuff - finally something to go to that is close to home.
This thread will be useless without pics. You have your assignment. Do it
Doug
I'm on it boss.
Some one has posted some pics (2) of the Full scale model here http://www.flickr.com/photos/scifilaura/324603326/in/set-72157594424025181/
I'm in dublin, this is fantastic about the technical review meeting here in Dublin. Can't wait to see the model for real
That's two of you.
STEREO OBSERVATIONS.
Do it.
Doug
http://www.space.com/businesstechnology/070523_techwed_jwst_dock.html
By Brian Berger
Space News Staff Writer, Space.com
posted: 23 May 2007
6:00 am ET
Anyone have new info on events associated with next weeks technical review of the JWST in Dublin?
I stopped by the Royal Hospital today at lunchtime and found the crew busily putting the replica together - it really is a shock to see just how big it actually is. The idea that something that huge can be launched and will be able to go through that unfolding manouver is astonishing. I'll be going back on Sunday when it's more complete and once or twice next week depending on when it is actually finished to get shots of the fully built model.
http://picasaweb.google.co.uk/helvick/JamesWebbSpaceTelescopeReplicaAtKilmainham/photo#s5073687731825649090 http://picasaweb.google.co.uk/helvick/JamesWebbSpaceTelescopeReplicaAtKilmainham/photo#s5073687731825649090 http://picasaweb.google.co.uk/helvick/JamesWebbSpaceTelescopeReplicaAtKilmainham/photo#s5073687731825649090 http://picasaweb.google.co.uk/helvick/JamesWebbSpaceTelescopeReplicaAtKilmainham/photo#s5073687731825649090
http://picasaweb.google.co.uk/helvick/JamesWebbSpaceTelescopeReplicaAtKilmainham/photo#s5073689643086095970 These shots are all a bit rough and ready as I was in a bit of a rush but they'll give you an idea of the scale.
Members of this forum are especially welcome to the following. Just register as UMSF:
INVITATION & PHOTOCALL ALERT
The next generation of Irish astronomers will take time off from their
Leaving Cert and Junior Cert examinations on Monday to brief journalists
about Ireland's big involvement in a dramatic new space telescope project
that is to revolutionise space research.
Students sitting their Science examinations this week will be graduate
researchers at university by the time the new telescope is launched in 2013
and they will be ideally placed to continue Ireland's strong tradition of
space research.
The students will brief journalists in front of a huge full-scale model of
the two-storey-high James Webb Space Telescope (JWST), which is to be
launched aboard Europe's powerful “Ariane-5” rocket to replace the
legendary Hubble Space Telescope. A large model of the Ariane rocket will
also be on hand.
The briefing coincides with a major international meeting at the ROYAL
HOSPITAL KILMAINHAM (RHK), which is attracting scientists and engineers
from all over the world. The meeting is hosted by the DUBLIN INSTITUTE FOR ADVANCED STUDIES, a leading centre for research into our cosmic origins.
The full-scale space telescope model was developed by aerospace contractors Northrop Grumman to give a better understanding of the size, scale and complexity of the project. The model is constructed mainly of aluminum and steel, it weighs six tonnes and is the size of two tennis-courts.
The model was transported by ship from the United States after it was
unveilled on the National Mall in Washington DC last month. It required
four container lorries to bring it from Dublin Port to Kilmainham, and a
large crew – including many FÁS apprentices – are spending four days
assembling the model in a large meadow at the back of the RHK.
YOU ARE INVITED TO VIEW/PHOTOGRAPH THE MODEL TELESCOPE AND TO ATTEND A
BRIEFING TO HEAR AT FIRST HAND HOW IRELAND IS MAKING AN IMPACT IN THIS
EXCITING SPACE ENDEAVOUR.
WHEN: Monday, 11 June 2006
WHERE: Royal Hospital Kilmainham (RHK)
The Johnston Room
TIME: 11.30 a.m.
TO MEET: Professor Tom Ray, Dublin Institute for Advanced Studies
Dr John C Mather, joint winner of the 2006
Nobel Prize for Physics. This year, Dr. Mather was listed among Time
Magazine's 100 Most Influential People in the World.
Tony Mc Donald, Enterprise Ireland
Chair: Leo Enright, Chairman, Discover Science and Engineering.
Currently - and remember these things can change - the following sessions on Monday morning are open to non-mission attendees. You will have to register, but staff have been told to expect UMSF members. If you have a problem, ask to speak with Dympna O'Callaghan. If you feel the need to attend other sessions, talk to Dympna on Monday. This is not a general invite to the public, but we at the Institute for Advanced Studies are very keen to facilitate anyone with a serious interest in astrophysics.
Great Hall (Main meeting room)
Registration Johnston Room (from 8:30)
09:00
Dublin Institute for Advanced Studies Welcome (Ray)
09:30
JWST Science Objectives (Gardner)
10:00
JWST Mission Overview and Status (Menzel)
10:30
JWST Observatory Overview and Status (Lynch)
11:00
Break
11:30
OTE and Wavefront Sensing Overview (Feinberg)
12:00
NIRCam (Rieke)
12:30
NIRSpec (Jakobsen)
13:00
Lunch (Baroque Chapel)
I just re-arranged my Monday schedule so I'll be there.
I'll take notes and post a report afterwards.
I went back to check on the model's progress and found that the construction team were just putting the last few pieces into place. The pictures really don't do it justice but you can get a good idea of scale by how small the crew on the boom lift look.
Thanks helvick.
I'll come to Ireland by mid august. Do you know if it'll still be there?
My understanding is that it is going to remain for around six weeks so it almost certainly will not still be here, unfortunately. One of the local web sites said it would be here until July 19th which more or less matches up. I don't have any official information though, maybe Ollopa can be more definite.
It is scheduled to be displayed at the Rochester Museum & Science Center, in Rochester, New York starting on August the 26th so it will definitely have to be deconstructed at least 10 days before so that it can be shipped back across the Atlantic. I find it really amusing that it has to travel by ship - it's too big to fly.
Helvick, do you know the rest of its schedule? Hoping it'll make a stop in Los Angeles...
Direct from its Washington premier just last month, the next really big thing in space exploration has arrived in Dublin this week to highlight the past, present and future of Ireland's contribution to space research. Construction crews at the Royal Hospital in Kilmainham spent three days assembling a full-scale model of the two-storey-high behemoth that will replace the legendary Hubble Space Telescope as humanity's sharpest eye on the cosmos.
The Dublin Institute for Advanced Studies, through it's School of Cosmic Physics, has been actively involved in space missions since the earliest days of space exploration, and this week it is hosting an international meeting of the scientists and engineers who are designing a revolutionary new observatory, the James Webb Space Telescope (JWST). Approximately 300 people will attend the meeting, which will be held in the Royal Hospital Kilmainham from Monday June 11th. to Thursday June 14th .
The JWST is named after the public servant who led America's project to land astronauts on the Moon, but it is a truly international enterprise. The Dublin Institute is providing optical filters for a key instrument aboard the telescope.
“We are immensely proud to be involved in this exciting new project,” said Professor Tom Ray, who works with a team of graduate students in the Institute's School of Cosmic Physics to understand how stars like our own Sun came to be in the first place. The new telescope will also study supermassive black holes and help in the search for planets that might harbour life.
The Dublin Institute for Advanced Studies is involved in the telescope project through Ireland's membership of the European Space Agency, and special funding for this Irish contribution came from Enterprise Ireland. Barry Fennell of EI’s International Science & Technology Dept explained that while Ireland contributes to ESA, it also gets much in return: “In the last 7 years, over 50 Irish companies and 10 University research teams have secured contracts with a cumulative value of €35 million. In addition, commercial business being generated by Irish companies and academics directly from ESA-supported developments is estimated to be worth about €25 million a year”.
The large telescope model was brought to Ireland with the help of the Northrop Grumman corporation, prime contractors for the space telescope project. Additional sponsorship came from Omega Air, the Dublin-based aviation services company, and from FÁS, whose skilled apprentices found themselves working on something out of this world.
The Dublin Institute for Advanced Studies plans to use the huge model of the space telescope as the centrepiece of a summer-long campaign to raise public awareness of Ireland's involvement in cutting-edge science. The Institute is probably best-known to Dubliners as the custodian of Dunsink Observatory, a much-loved Dublin landmark with a unique place in the history of astronomy.
This is gonna sound trite, but damn that thing is big! Exciting times ahead...
What an impressive shot, allopa!
I'm fascinated by the contrast between past and future there...
As promised by Ollopa UMSF folks were allowed to attend. As it transpired I think I could have stayed for the entire day but I had to get back to work for the afternoon so I missed out on the sessions after lunch. These are just my notes so they come with absolutely no warranty whatsoever.
Todays Agenda:
Oh and I forgot to thank Ollapa for the inivtation - it was very much appreciated.
Good job - your forum title has been appropriately adjusted
Doug
It seems to be one of the worst-kept secrets in Astrophysics, but my spies tell me that ESA and NASA will finally sign the MOU for JWST at Le Bourget on Monday. I gather there will also be an agreement on LISA Pathfinder.
BTW, if anyone gets an early copy of AvWeek I'm curious to know if they included a pic of the model in Dublin. My snail-mail copy may not arrive till JWST launches!
JWST Partner's Workshop - Dublin 11 June 2007 (Part II of III)
NIRCam – Marcia Rieke University of Arizona (PI)
The instrument is quite advanced now compared to some of the other systems due to the critical role it plays as both a science instrument and as the sensor for calibration and Wavefront Sensing and Control. The CDR took place in May 2006 and the instrument is now (well) into the Engineering Test Unit phase.
Selection of the HgCdTe Rockwell sensor units has started and Dr Rieke made a point of the fact that they had no problems getting good characteristics for the short wavelength units but the long wavelength sensors are proving a bit harder. This latter difficulty extends to NIRSpec also as this requires similar characteristics.
Overall NIRCam represents 2-3 orders of magnitude increase in sensitivity in the wavelength it is designed to cover – in particular the design goal was to hit sensitivity in the nanoJansky range and that is being achieved (see below).
As NIRCam is used as the sensor for the Wavefront Sensing and Control capability it has to be fully redundant. This has resulted in a design with 2 fully independent halves to the instrument covering a total FOV of 2.2'x4.4'. That 10 square arcminute FOV makes it well suited for wide area surveys in search of (rare) first light event. Its dual purpose also means that (according to Dr Rieke) it has been exquisitely designed in an optical sense.
Dr Rieke mentioned that NIRCam could\would be used for surface characterization of KBO's. This is obvious enough and part of the "Planetary Systems and Origins of Life" theme for the mission but this was one of many instances where the presenters were at pains to point out that JWST would be useful as an observatory for Solar System objects.
NIRCam homepage - http://ircamera.as.arizona.edu/nircam/
For those unfamiliar with the instrument the basic design is a dichroic refractive optic camera covering the 0.6 to 5 micron wavelength range allowing for two concurrent observations in short and long(er) wavelengths. The incoming beam is split into 0.6-2.3micron short band and 2.4 – 5.2 micron long band). There are coronographs available in both long and short modules.
Each short wavelength channel is directed to a 4096x4096 pixel sensor array comprised of a grid of 4 separate 2048x2048 pixel HgCdTe Rockwell sensors. The corresponding long wavelength channel is directed to a 2048x2048 pixel single HgCdTe Rockwell sensor. There are a total of 40 megapixels between the two halves.
I've taken some key sensitivity & resolution data for NIRCam (from http://ircamera.as.arizona.edu/nircam/features.html ) and attempted to compare them to Hubble's NICMOS ( from http://www.nasa.gov/pdf/160431main_fact_sheet_NICMOS.pdf%20 ) to try and put this instrument into some perspective.
This is entirely my reading of these two documents so I may be incorrect, if so let me know.
0.8-1.35micron NICMOS1 2.4e-7Jansky : NIRCam 1.1e-8Jansky (22x)
1.4-1.8 micron NICMOS1 5.7e-7Jansky : NIRCam 1.0e-8Jansky (57x)
0.8-1.35micron NICMOS3 4.5e-8Jansky : NIRCam 1.1e-8Jansky (4x)
2.3-2.5 micron NICMOS3 1.6e-6Jansky : NIRCam 2.5e-8Jansky (60x)
The resolution\FOV comparisons are:
NICMOS1 – 0.043" /pixel , 11" square FOV
NICMOS2 – 0.075" /pixel , 19" square FOV
NICMOS3 – 0.200" /pixel , 51" square FOV
NIRCam(short)– 0.0317"/pixel, 2'12" x 4'24" FOV
NIRCam(long) – 0.0648"/pixel, 2'12" x 4'24" FOV
NIRCam(short) covers approximately 288x the FOV of NICMOS1 at a slightly better angular resolution per pixel and 20-60x the sensitivity*. It covers 14x the FOV area of NICMOS3 at 6x finer angular resolution per pixel and 4-60x the sensitivity*. NIRCam(long) covers the same FOV at 1/4 the areal resolution.
* The sensitivity numbers (Jansky's) don't appear to be directly comparable to me. Anyone who can comment on the difference between sensitivity to achieve a "S/N of 5 over 5 orbits" (Hubble NICMOS) and "10 sigma over 10000 seconds" (NIRCam) please jump in. My understanding is that 10 sigma corresponds to an S/N of 100, if that is true then the above NIRCam numbers would need to be reduced by a factor of 20 in order to compare them with NICMOS. I believe that the 5 orbit number for Hubble equates to 5000 seconds but I'm not sure.
JWST Partner's Workshop - Dublin 11 June 2007 (Part III of III)
NIRSpec – Peter Jakobsen EADS Astrium
http://www.stsci.edu/jwst/docs/flyers/NearInfraredSpectrograph_2400.pdf
"A Pretty Picture is not Enough" or Imagery is Astronomy but Spectroscopy is Astrophysics.
NIRSpec is a multi object dispersive spectrograph that uses a MEMS shutter array to enable it to take up to 100 spectral samples concurrently. Sampling in one of three resolutions (R=100, R=1000, R=2700) using 2 x 2048x2048 HgCdTe Rockwell sensors. The twin detectors do not abut perfectly so there is a detector gap in the layout which mostly just causes targeting complications for R=100 sampling but causes dropout in the middle of spectra for many R=1000 samples and all R=2700 samples. These dropouts will require re-shooting the target using a different array location to recover the dropout regions.
In addition to its MOS mode it also supports an Integral Field Spectrograph mode and a classical long slit spectrograph mode.
Physically it's a monster 185kg mass measuring ~1.8mx1.4x1m 2m on a side. The prism\refraction wheel is sufficiently massive that it acts as an (undesirable) reaction wheel for the observatory.
Internally it uses an all silicon carbide reflective optics (14 reflection) optical path.
FOV is 3.4' x 3.6' with a 0.2milliarc second nominal slitwidth.
The MEMS shutters consist of 4 arrays of 365x171 micro shutters. In operation targets selection requires the opening of three shutters in a line perpendicular to the spectral spread direction – the central shutter covers the target and the shutters on either side are used for background removal. Combined with the fact that 2nd and 3rd order effects prevent the use of multiple collinear (in array terms) targets the effective maximum number of concurrent samples is ~100.
The MEMS arrays make this a very powerful instrument however manufacturing the array is extremely difficult and it is clearly pushing the limits of today's micro mechanical manufacturing expertise. The arrays are individually electrostatically latched open and reset in bulk magnetically (to closed). Manufacturing challenges mean that the arrays have clear salt and pepper effect flaws – Peter Jakobsen did not say what the error rate was but it was very obvious in the sample images he displayed. I would estimate that it was probably in the order of 2-3%. In general the fail closed flaws are more frequent than fail open flaws and happily fail-closed shutter flaws result only in aiming\planning problems as the only effect is that certain individual shutter locations cannot be used. Fail open flaws are much more problematic as any open shutter could contaminate a spectral sampling anywhere else on the same horizontal line of the array and so fail-open flaws result in the loss of an entire row of sampling locations from the MOS array (actually they reduce the effectiveness of the row immediately above and below also). Fortunately fail-open flaws can be converted to fail-closed flaws pre flight so at launch there should be no fail open flaws. Peter Jakobsen gave no indication of the expected reliability of the array. The detectors and the MEMS array are supplied by NASA.
In addition to the MEMS arrays there is an IFU image slicer with a a 0.1" resolution of 3"x3" and 5 fixed non interfering slits of width 0.1", 0.2" and 0.4".
More details here. http://www.eso.org/gen-fac/meetings/3Dspec05/dir_talks/arribas_JWST.pdf Page 9 shows the MEMS shutter array, IFU and fixed slit layouts and the direction of dispersion relative to the detector layout. The detector gap is not shown but corresponds approximately to the mid point gap between the MEMS shutters.
Peter Jakobsen closed out with some additional comments about exoplanet spectroscopy. My notes say that he said the challenge there is that they will need to get the S/N ratio past 10^4, specifically capturing >10^10 photons into the detector in <1hr time frame. This difficulty arises (in part) because NIRSpec does not have a coronograph.
Just superb: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41816
Air & Cosmos oct 17th issue says that a mockup of JWST is currently on display at Deutsches Museum: http://www.deutsches-museum.de/index.php?id=1&L=1
I think this is the best deployment animation:
http://www.jwst.nasa.gov/resources/newdeploy/08jwstb_depall_dv.wmv
A full-sized mockup of the James Webb Space Telescope is on display in lower Manhattan, New York City at Battery Park from now through June 6th. On Friday night, local astronomers will bring their telescopes to the site to show the planets and stars to people attending the panel discussion scheduled to include John Mather, John Grunsfeld, and Heidi Hammel, with journalist Miles O’Brien moderating. Neil deGrasse Tyson, will host the stargazing party.
http://www.worldsciencefestival.com/the-james-webb-space-telescope
http://www.worldsciencefestival.com/from-the-city-to-the-stars
bob kelly
Xinhua has some really great pictures of the mock-up http://news.xinhuanet.com/english2010/photo/2010-06/03/c_13331724.htm
Photo of the mock-up from the world science festival last night in Battery Park, New York City (too large to post here, see
http://bkellysky.wordpress.com/2010/06/05/james-webb-space-telescope-mock-up/
(edited to add full url, since this post has fallen way down on my blog site!)
bob
bob,
That is a great picture! Thanks.
Oh dear, the spectre of cancellation of the JWST is being raised...
http://spaceflightnow.com/news/n1107/06jwst/
I can think of a few expenditures that can be slashed to pay for the HST successor....
I became ill when I read about this yesterday.
I think a lot of us want to say some things that would violate UMSF's posting terms.
I'll just say it made me consider (someday) moving to a different country. And I know my sentiment is shared by a lot of engineers.
Let's all take a deep breath, calm down, and hope for the best...and keep http://www.unmannedspaceflight.com/index.php?act=boardrules firmly in mind.
Surely the components already made won't be trashed, will they? (Assuming this actually happens; remember Dawn's resurrections!)
If it goes like SIM(-lite), the hardware will probably be disposed of.
If no one has any new facts to bring to the discussion, I'm not sure we can accomplish much just speculating about it. I remember Kepler was in trouble at one point for similar reasons (poor management) and NASA forced them to reorganize, but I don't remember the details. Does anyone know any details?
--Greg
Also recall that Dawn WAS effectively cancelled for many of the same reasons, but of course did fly. It's way, way too early to begin mourning for JWST, people.
http://scienceblogs.com/startswithabang/2011/09/news_flash_james_webb_space_te.php?utm_source=sbhomepage&utm_medium=link&utm_content=channellink
The news has just come in: the United States Senate has decided to fully fund the James Webb Space Telescope, and it should be set to launch in 2018, which is the earliest it can possibly go ahead at this point.
How many times do I have to clean up this thread because of rule 1.2?
Is the JWST going to be used for any Solar System observations? Such as asteroid imaging, monitoring weather on outer planets, moons of outer planets (such as IO), moons of Uranus and so forth. If so, what would be the resolution?
I looked through the FAQs and even posted a question on their fb page, but never got a reply regarding whether there was any chance of coupling JWST with the StarShade project.....
http://planetquest.jpl.nasa.gov/video/15
I believe you have to specifically design the instrumentation on the 'scope end to match the StarShade - and the JWST instrument manifest has been solidly defined and in development/test/build for many years.
Time-lapse: The Assembly of the James Webb Space Telescope Primary Mirror
https://www.youtube.com/watch?v=1d1sHLkmNQI
Looks like the optics have been mated to the ISIM. Group photos are being taken as I type.
http://jwst.nasa.gov/webcam.html
With the launch 2 years away, I've tried to find out what the Solar System observation resolution will be on Webb, and I need it broken down to very basic layman's terms.
ON LINE: How good is the angular resolution?
CONVOLUTED ANSWER: The specification is that the telescope is diffraction limited at 2 μm, which means a Strehl ratio of 0.8 and a wavefront error of 150 nm rms. With a 6.5 m telescope, 1.22 λ/D = 0.077 arcsec at 2 μm. The smallest pixels (NIRCam 0.6-2.5 μm) are just 0.034 arcsec. But a lot of the wavefront error is due to imperfect alignment of the parts, and it's possible to do better for a small part of the field of view
For a space enthusiast, not an astronomer, this is like converting kilo-Newtons in to pounds of thrust (and who decided to switch from a very simple and easy to understand Lbs of thrust to a kilo-Newton as if anyone is expected to know what a kilo-Newton is) . So what kind of resolution can we expect for Mars, or objects in the asteroid belt such as Pallas, or Io, or Triton, for example? How many pixels across or resolution per pixel pair? Something that is in plain English would be awesome.
Thanks.
One issue I hadn't appreciated until recently is how the design of JWST isn't exactly optimized for solar system observations. It has to keep the sun shield between it and the sun, but the telescope points at right angles to the sun shield. So it can't point at things when they are at opposition, only at geometries roughly tangent to JWST's orbit. Doesn't matter as much for resolution on distant targets but makes a big difference for Mars and asteroids, and limits when things can be observed.
Uh-oh!
http://spaceflightnow.com/2016/12/20/engineers-examine-unexpected-readings-from-jwst-shake-test/
I don't imagine that they crank up the shaker table to 11 until later in the test sequence. I would hope that this was discovered early on at a low vibration setting. Hopefully nothing more than an incorrect test setup.
It sounds like the anomalous vibration at least did no harm:
http://phys.org/news/2016-12-nasa-webb-telescope-vibration-anomaly.html
Switching subtopics mid-post, I've read some more encouraging things about JWST's expected ability to observe exoplanets, including Proxima B. If all is well on the engineering side, those results may be only ~3 years away.
Good news. The problem has been resolved ...
http://spaceflightnow.com/2017/01/25/nasa-resumes-jwst-vibration-testing/
One more (hopefully final) launch delay. No one thing in particular, just a lot of little things adding up. They claim there will be no cost penalties as a result.
https://spaceflightnow.com/2017/10/04/jwst-launch-slips-to-early-2019/
And that last delay was not final. Now we're hoping for an early 2020 launch.
Damage suffered during testing is at least some of the cause.
This article lays out the facts and adds some insightful commentary on how this delay might affect future planning.
https://www.scientificamerican.com/article/nasas-james-webb-space-telescope-slips-to-2020-and-astronomy-suffers/
From the standpoint of exoplanet observations, I will add that the ability of the JWST to observe exoplanets, and if so, to what extent, inevitably will be known in detail only after it attempts such observations. It also closes the gap between when JWST was going to make such observations and when new ground based telescopes will be able to demonstrate their capabilities for similar, but not identical observations. Of course, the dates when those telescopes will become operational aren't guaranteed yet, either.
This is not a great surprise, but work on the JWST has been put on pause.
Unlike many other missions, JWST has no dependencies on any particular launch window. Of course, any changes to a program are a potential source of trouble.
https://www.extremetech.com/extreme/308063-nasa-pauses-work-on-james-webb-space-telescope-due-to-covid-19-pandemic
Spaceflight Now article: https://spaceflightnow.com/2020/07/16/nasa-announces-seven-month-launch-delay-for-jwst/
A good article just released.
https://www.nasa.gov/feature/goddard/2020/nasas-webb-telescope-will-study-jupiter-its-rings-and-two-intriguing-moons
There is at least one more launch delay. A launch date of late October has slipped, and now November or December would be the earliest opportunities. Aside from technical matters, COVID protocols at the launch site in South America introduce a wildcard that can't be predicted yet.
I note that at the top of this page there was a post from late 2016 calling the launch two years away. It might be interesting to see a graph of how the projected launch date has changed over time. We may need to rename Zeno's paradox to "honor" this telescope.
Already done!
https://xkcd.com/2014/
That is a perfect display of the data and observation about it!
On the bright side, the longer that it takes to get JWST into space, the longer in the future before its operation ceases. One of its main purposes will be to observe exoplanets and more of them are being discovered through other means before JWST launches. It's entirely possible – even probable? – that the delays will end up providing some important opportunities for exoplanet science that would have been missed with earlier launch dates.
True, but many ephemeral objects (and events) have come and gone in the past few years. I wonder what it would have made of ‘Oumuamua?
JWST will have about the same resolution as HST, so it wouldn't have given us anything but a dot, but the IR spectral coverage may have turned something up. I don't think that 'Oumuamua plays to any of JWST's strengths, but a Rumsfeldian maxim applies: You don't know what you don't know.
Presumably, there will be as many interesting rare events in any decade as in any other decade, and I would imagine that the steady increase in sky surveys that can find those means, again, that JWST will have a better chance of seeing more in the future than in the past. The survey system that discovered 'Oumuamua, for example, had its two telescopes go online in 2008 and 2014. If JWST had been up in the sky in 2013 and a similar event had happened then, it would have been more likely that we simply would have missed it. It's not a pure coincidence that we've discovered two interstellar interlopers in the past four years and zero in the previous four hundred years.
The JWST has completed all testing and is being buttoned up for transport to Kourou, French Guiana.
Launch is planned for this November.
https://www.esa.int/Science_Exploration/Space_Science/Webb/Webb_completes_testing_and_prepares_for_trip_to_Europe_s_Spaceport
https://www.nasa.gov/feature/goddard/2021/nasa-s-james-webb-space-telescope-has-completed-testing
Launch of the James Webb Telescope is finally becoming a thing.
JWST now has an announced launch date of December 18, 2021. Our long patient wait is nearing an end!
It's happening. JWST has left on a boat and is on the way to the launch site.
Link: https://spaceflightnow.com/2021/09/30/webb-on-the-way-to-french-guiana/
UPDATE 10/13 - The telescope has arrived at the launch site.
Link: https://spaceflightnow.com/2021/10/12/webb-completes-sea-voyage-to-launch-base-in-french-guiana/
The probe will launch next week on the 22nd
https://jwst.nasa.gov/content/about/launch.html
Fingers crossed for this launch date - it's been a while....
Has there been a more complicated sequence of unlocking/unfurling of the science platform/sub-systems post-launch on an unmanned mission before??
I've every faith that all will go to plan - I reckon JWST will be a game-changer in the same way that Hubble was/is.
Can't wait.
Another Delay.
No earlier than the 24th of December.
The weather forecast at the launch site is for thunderstorms every day for the indefinite future. Launch is delayed at least another day.
Launch window opens at 1220 GMT, https://www.nasa.gov/multimedia/nasatv/#public begins at 0800 GMT.
GO JWST!!!
Fingers crossed...
Nice https://www.nasa.gov/multimedia/nasatv/#media, when the birds began to sing!
2 mins...
HERE WE GO!!!
Textbook launch & separation, successful array deployment, spacecraft is power-positive.
All I wanted for Christmas this year.
Everything perfect throughout launch and 30 minutes into the flight. JWST has separated from the upper stage and has deployed its solar panels, all nominal. Now cruise to its destination continues.
A long journey is over, but another long one has just begun!
Cool tracking page here: https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
Also cool that there are "amateurs" out there receiving and decoding telemetry from JWST. https://destevez.net/2021/12/decoding-james-webb-space-telescope/
The tracking page's numbers are derived from precalculated flight dynamics data. Means that the numbers are approximate & pre-computed prior to playback you see.
As it stands I understand the telescope's trajectory is spot-on. MCC-1a had the potential to last as long as 3 hours, but thanks to excellent launcher performance the burn only needed to be a paltry 65 minutes. This is a bonus. Means more fuel for stationkeeping.
Yes interesting that the burns can only speed up JWST due to its constrained orientation. The 2nd 9-minute course correction burn https://blogs.nasa.gov/webb/2021/12/27/webbs-second-mid-course-correction-burn/. Here are the https://blogs.nasa.gov/webb/.
Forward and aft sun-shield pallets successfully deployed.
https://blogs.nasa.gov/webb/2021/12/28/forward-pallet-structure-lowered-beginning-multiple-day-sunshield-deployment/
NASA is reporting that they have already used less fuel than anticipated, so a longer mission is now possible.
https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-excess-fuel-likely-to-extend-its-lifetime-expectations/
The possibility of a longer lifetime is phenomenally good news. The observational demands of exoplanet atmosphere studies alone – to say nothing of all of the other competing priorities – is going to require years of observation, and one paper regarding the TRAPPIST-1 system alone determined that if astronomers could only plan on 6 years of JWST operation, they would need to coordinate as a community to get a baseline amount of observation completed in that time. (This is further constrained by the constraints of pointing away from the Sun and near-ecliptic targets like TRAPPIST-1 having a limited interval each year during which observation is possible.)
Even a substantial increase in lifetime will still leave many desirable observations unattainably expensive in terms of observation time. If we had 10 JWSTs with lifetimes of 20 years each, they'd each be booked for every second of their time. Time is going to be a precious, finite, and ultimately scarce resource for this mission.
As I recall, missions that run out of fuel usually do so many years after their nominal mission lifetimes. If NASA says there is no enough fuel for 10 years of operation, that would be based on conservative estimates of fuel during operations. These estimates do usually end up being conservative.
Let's all get together in 20 years and I'll bet there will be a new JWST image to share (assuming that fuel does end up being the limiting factor and nothing else critical fails).
Positioned in the the second Lagrange Point JWST will not have to use much fuel to maintain position. In any case give the advances being made by SpaceX with "Starship" upgrade/refuelling of JWST may be a possibility within the next decade. Or perhaps an observatory on the far side of the moon?
JWST's mirror and instruments will be in the dark, so there should never be a photo of them.
Project scientist John Mather said, "In-space refueling of #JWST? Logically possible but difficult." I would presume that this will not occur.
In the case of Intelsat, it was just attached and used its own thrusters to push the satellite where needed. No need to open anything up. Though I digress, this is is all strictly academic, and hopefully will remain so for a very long time to come!
Pretty sure I recall a NASA official saying they would not even think about a robotic refueling mission till the telescope was on-station and operational and proving its worth. Then they would begin work. Might have been Zurbuchen.
Whether it would be a robotic arm uncapping the gas tanks, or clip-on module, or something else, wasn't said. Since this is likely 10-15 years out, there's plenty of time to develop and refine the technicals.
... is there an engineering camera that can return "unfolding images" ... it seems that for $10,000,000,000 they could put one 1024x1024 camera on JWST --- and test out the radio and such -- You could always shut it down when unfolded...
Once the sunshield is partially unfolded, the rest of JWST will be in the dark for the remainder of its mission and they don't want sunlight on it, even now. Any sunlight on the mechanisms now is just a delay before the long passive cooling process will complete.
If you want to picture JWST during its mission, picture the night side of an atmosphere-less world. That's what it's going to look like: black on black.
For reference, the operational temperature will be a little warmer than Triton but a little cooler than the satellites or Uranus. The effect of perpetual shade will be about like having it out at 25 AU.
Perhaps a low light camera can see the silhouette and/or use starlight (if it doesn't emit too much heat energy, or somehow get in the way of the deployment)?
As for refueling, IIRC the fuel tank may be accessible just in case.
The sunshield covers have now been released and rolled up!
https://blogs.nasa.gov/webb/2021/12/30/webb-team-releases-sunshield-covers/
Maybe they left out cameras to eliminate any unnecessary heat generating activities, especially on the cold mirror side.
Some suspense with a successful first side arm deployment of the sun shield:
https://blogs.nasa.gov/webb/2021/12/31/first-of-two-sunshield-mid-booms-deploys/
It looks like they're giving themselves some time after successfully extending both booms.
Tensioning will start tomorrow.
https://blogs.nasa.gov/webb/2022/01/01/webb-sunshield-tensioning-to-begin-tomorrow/
Edit -
Here it is, the next day. The JWST team has decided to take another day and proceed tomorrow.
https://blogs.nasa.gov/webb/2022/01/02/deployment-timeline-adjusted-as-team-focuses-on-observatory-operations/
The first layer has been tensioned.
https://blogs.nasa.gov/webb/2022/01/03/first-layer-of-webbs-sunshield-tightened/
That was quick!
https://blogs.nasa.gov/webb/2022/01/03/second-and-third-layers-of-sunshield-fully-tightened/
Sunshield fully tensioned!
https://www.nasa.gov/press-release/sunshield-successfully-deploys-on-nasa-s-next-flagship-telescope
Some live coverage here, secondary mirror already deployed and about to be latched:
https://www.youtube.com/watch?v=21X5lGlDOfg
Secondary mirror deployed and latched.
https://blogs.nasa.gov/webb/2022/01/05/secondary-mirror-deployment-confirmed/
https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope
Questions : is Chang’e 2 orbiter still in L2 ? I believe it’s the only one active there. Does it have any chance to take a picture of Webb ?
Amateur telescopes will be able to image JWST (as a dot), given ephemeris and depending upon the reflective properties of the exposed sunshield. In fact, an amateur already did so while it was about 1/6 of the way to L2, and longer exposures will enable this to occur during its main mission. Of course, larger professional telescopes including HST will be able to image it.
But the sunshield will be the only part in sunlight, by design. We are never going to see pictures of it deployed looking elegant.
It's worth adding - the Lagrange points are not.....'points'. The spacecraft at L1, for example....there can be >500,00km between them, as they halo-orbit they way around.
For example, right now it's 468,000km between SOHO and DSCOVR, and 694,000km between DSCOVR and WIND, and 482,00km between WIND and SOHO
Even for something as powerful as HiRISE JWST would be a fraction of a pixel at those distances.
Thanks Doug, I knew it was a halo but didn’t knew it was that large
The left wing of primary mirror segments has been successfully deployed. Right wing deployment should begin next. There's no single moment when we will suddenly say that the risks of a successful JWST mission are all behind us, but things are definitely looking good now.
The telescope is now fully deployed, though latching activities continue.
Congratulations to the team!
https://twitter.com/NASA/status/1479837936430596097?s=20
This is a slowly-unfolding victory taking place. There are still many, many fine-tunings to be made with the actuators that will reorient each mirror segment to fine precision, and that step is crucially important to attaining proper focus. With memories of HST's focus problems, I don't want to count JWST's deployment as complete before this is done, but it certainly seems like the biggest points of failure – certainly by far the largest number of them – have been put behind the mission.
Not really worried about optics or focusing. Each primary segment has 7 degrees of freedom. I'm sure there's enough range to compensate for all sorts of scenarios. Hubble had nowhere near this level of control for focusing. JWST's testing was more integrated too.
Now.. Will the already 10+ years old electronics hold up? Computers/semiconductors, detectors, capacitors..
CE-2 is in solar orbit after flying by Toutatis.
CE-5T1 is reportedly at the Earth-Moon L2, like the CE-4 relay satellite
The status of return module of CE-5 is not clear. After spending some time at one of the Earth-Sun Lagrangian points it is now back in lunar orbit or in a distant Earth orbit
Edit: CE-5 has just been recovered by radio-amateurs in lunar orbit https://twitter.com/coastal8049/status/1479619134681800704
Heidi Hammel addressed this at today's excellent JWST news conference and Q&A. She indicated that ground based images (already being taken by the amateur community for example) would be more likely than using Hubble. This question at 1:08:40 in the video.
https://www.c-span.org/video/?517137-1/james-webb-space-telescope-jwst-final-unfolding-briefing&live
She then pivoted the question to joint science between Hubble and JWST. Also a good summary of solar system observations by JWST.
I hope that the images that JWST will actually take can attract as much enthusiasm as some have for a hypothetical photo of JWST.
Of the Cycle 1 plans, one of the most imaginative campaigns will image the Galileans while they're in Jupiter's shadow for the purpose not of imaging them (they will be ~black in the given wavelengths) but for seeing the silhouettes of them against the background radiation from the galaxy. These two brightness measurements will tell us the brightness of the zodiacal light, which is the reflection of sunlight from dust between Earth and Jupiter, and then the brightness of the galaxy, which will be the brightness of the area around the Galileans minus the brightness of their silhouettes.
Then we have many exoplanet campaigns, many solar system campaigns (of course, mainly outer solar system and small body targets) and many observations of black holes, stellar objects, and objects of cosmological interest.
Out of curiosity does the public know the actual first target planned?
I can't seem to find much about the first public photos planned.
An analyst who put their mind to it might be able to make some guesses, but it's not possible to know the exact schedule of observations until it's known when commissioning will end and science observations begin. Some of the planned observations are time-limited and if, say, the start of science were delayed a week, it might mean that one observation would have to be shifted from, eg, August 2022 to August 2023.
Basically, targets on the ecliptic are limited to about 100 days of accessibility each year. Targets far from the ecliptic are limited little or zero. Solar system targets have their own complex timing constraints. And exoplanet transits have their own complex periodicity (particularly if the period is relatively longer). So it's impossible to fully schedule the first year until the precise start of science observations is known.
Here is the proposal. As you note, Jupiter is well off the galactic plane; the study is looking at extra-galactic background luminosity, and must be made before Jupiter returns to the galactic plane.
If the signal is strong enough, the complicating sources of noise can be accounted for. Eg, light from Jupiter will occur above and below the moon's silhouette as well. The thermal contribution of each moon should be a known quantity. Europa, Ganymede, and Callisto will all be observed.
https://www.stsci.edu/jwst/phase2-public/2134.pdf
Yes the background Milky Way galaxy glow is something that would be interesting to map around different galactic lat/lons. Even ground based deep imaging (both professional and amateur communities) can show faint galactic cirrus when looking away from the galactic plane. A related key question is what is the brightness of extragalactic glow (as noted in the post/proposal just above). This would ostensibly be from unresolved galaxies that wouldn't be seen in something like the Hubble Deep Field. Can this proposal really discriminate between galactic cirrus (DGL) and extragalactic background glow (EBL)? They are both of comparable brightness.
Was wondering to what extent Jupiter being relatively hot in the infrared could impart 'backshine' brightening the moon's silhouette, but the proposal seems to suggest otherwise:
"...However, Jupiter is dark at F140M owing to the methane absorption in the Jovian atmosphere, thus stray light from Jupiter is also reduced..."
So this will indeed take us to the edge of the optical Universe.
Next step: VLB radio space telescopes to go microwave and beyond.
--Bill
For context, Planck has already mapped the microwave background, seeing back further than JWST will see – but at very low resolution.
Spitzer imaged at IR wavelengths comparable to JWST – but at less resolution and with far, far less light gathering.
HST images at about the same resolution as JWST – but different wavelengths.
JWST isn't so much extending capabilities in some single dimension that hasn't been investigated before, but in a combination of dimensions, a corner of the space so to speak, that will be entirely new.
Yeah, Planck (and others) have mapped the cosmic microwave background (CMB) at much lower resolution than JWST is capable of, but there very likely isn't much to see in the CMB at JWST resolutions, since the CMB was emitted well before the first stars and galaxies formed, when the Universe was extremely smooth.
JWST should, for the first time, be able to see back to the first stars, which is one of its main goals. UV light from those stars reionized the gas, which was neutral and transparent since recombination when the CMB was emitted. The time of reionization is considered one of the half dozen or so parameters that describe the Universe in bulk, so this will be a big thing for cosmology.
An individual mirror segment deployment tracker is on display! (that's enough detail for anyone!)
https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
They are cranking on moving the mirrors. Down to 2.0 mm on all mirrors except A3 and A6 which still have 12.3mm to go. Somehow A3 and A6 get measured differently and are moved after all the others. The mirrors are cooling down, now at -206C on way to -233C. Webb is 93% the way to L2 and the insertion burn is in about 5 days.
Go Webb!!
Now down to 0.0mm for all segments but A3 and A6, which are down to -10.0mm.
Really motoring!
Thanks for presenting your understanding of what makes A3 and A6 different--very likely mostly correct..
The movement of the mirrors was substantially faster than 1mm/day--so moving faster than grass grows by 2-4x.
Do the motors that performed the mirror extension out of launch position also adjust positioning and tilting?
That's my understanding.
JWST has entered its mission orbit around L2! The next steps are to focus the mirrors, cool down passively, and prepare for science to begin.
Such exciting news! This whole journey has had just the right amount of drama. And by that, I mean none. Well done to that team. I can't wait until we see the first image in several months!
https://blogs.nasa.gov/webb/2022/02/11/photons-received-webb-sees-its-first-star-18-times/ (and a selfie to boot!).
Even more detail on this tracking page has been added:
https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
Now including instrument temperatures, mirror steps too.
More forward progress:
Webb Team Brings 18 Dots of Starlight into Hexagonal Formation
https://blogs.nasa.gov/webb/2022/02/18/webb-team-brings-18-dots-of-starlight-into-hexagonal-formation/
NASA held an informative press conference today to announce completion of alignment of the JWST’s primary mirror and the capture of a fully-focused image. I watched it on a live stream and since then haven’t been able to find an archived copy. (My track record for finding archived copies of NASA and JPL press conferences is remarkably poor.)
Here’s an early press account, from New Scientist. https://www.newscientist.com/article/2312646-the-james-webb-space-telescope-has-sent-back-its-clearest-image-yet/
Still can't find a youtube link to today's press conference, but here's a twitter link to the video:
https://twitter.com/NASA/status/1504125485969772544
As Tom reported, here is the first aligned and collimated image from Webb. Note the many distant galaxies around the reference star!
https://amp-abc-net-au.cdn.ampproject.org/v/s/amp.abc.net.au/article/100916480?amp_js_v=a6&_gsa=1&usqp=mq331AQIKAGwASCAAgM%3D#aoh=16474837074832&csi=0&referrer=https%3A%2F%2Fwww.google.com&_tf=From%20%251%24s&share=https%3A%2F%2Fwww.abc.net.au%2Fnews%2F2022-03-17%2Fnasa-telescope-spiky-star-surrounded-by-galaxies-science-image%2F100916480
--Bill
The MIRI is now actively being cooled. For the past week it's temperature has dropped about 5 degrees kelvin/day and is now at 53 K on its way to 6 K.
April 28: "...Alignment of NASA’s James Webb Space Telescope is now complete (...) Upon completing the seventh and final stage of telescope alignment (...) Webb is ready to move forward into its next and final series of preparations, known as science instrument commissioning. This process will take about two months before scientific operations begin in the summer..."
https://blogs.nasa.gov/webb/2022/04/28/nasas-webb-in-full-focus-ready-for-instrument-commissioning/
"NASA will hold a media teleconference at 11 a.m. EDT on Monday, May 9, to discuss progress toward preparing the James Webb Space Telescope for science operations. The agency will livestream audio of the teleconference on its website": https://www.nasa.gov/live
https://www.nasa.gov/press-release/nasa-to-discuss-webb-telescope-alignment-instrument-setup
The first release of images and data from actual operations has been announced (well in advance!) for July 12.
I expect that the first months and years of JWST operations will produce more amazing results (not to mention beautiful eye candy) than any but the most fervent fans will even be able to follow. Only six more weeks of waiting and it begins!
JWST got hit by micrometeroite a couple weeks back but luckily able to shake it off. https://www.space.com/james-webb-space-telescope-suffers-micrometeoroid-impacts
In one week, NASA will be releasing the first JWST science operation images, and it seems that we can expect impressive results, with pre-release commentary including phrases like "emotional," "deeply personal," and "moved me… as a human being."
At least two specific results will include a deep field image, which is a bit surprising given that the deepest HST image was the result of 23 days of observations collected over a span of ten years. Certainly JWST cannot have devoted that much time yet, but this speaks to the advantage of the IR bands to collect red-shifted visible light. JWST, it seems, will image most distant galaxies in its very first release than Hubble was able to in decades of operation.
The second specific release that has been promised is the spectrum of an exoplanet atmosphere. There are lots of those to choose from, and many more will be observed over the next months and years. If I were to hazard a guess, that first planet might be LHS 1140 b, which is a very large terrestrial-density planet midway in mass between Earth and Uranus with a high escape velocity, orbiting a small, inactive red dwarf. HST observations produced some uncertain evidence that LHS 1140 b has H2O in its atmosphere. All of those factors boost the prospects that the planet will have an atmosphere, that the signal will be favorably strong, and that it will be impactful in the search for earthlike conditions elsewhere. However, there are many other targets they could choose, so it's hard to be sure what will be in the first release. Larger planets would more likely return a strong signal but would also be a bit less interesting, as those types of planets have been the subject of successful atmospheric composition observations before.
Some memorable landmark results are a week away.
Here we go : https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images
Interesting! The two nebulae and Stephan’s Quintet should be impressive eye candy, and also scientifically interesting as common examples of their type of object, imaged for the first time with JWST.
The deep field image using gravitational lensing is an interesting complicated case. I don't think anyone could say with certainty what that will reveal until it's been seen.
WASP-96 b, rather than being a particularly challenging exoplanet to study, is a relatively easy one (strong signal) that's been partially characterized already. So, rather than JWST providing some low-signal data from a new class of exoplanet, it should probably offer some really good characterization of a planet that we already know something about.
1.5 days left to wait.
Much less than 1.5 days actually! https://www.space.com/james-webb-space-telescope-science-photos-webcast
The commissioning of JWST instruments is now complete.
From the website blogs.nasa.gov/webb -
The first image, of galaxy cluster SMACS 0723 lensing more distant galaxies, has now been posted:
https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet
Beautiful!
https://www.nasa.gov/sites/default/files/thumbnails/image/main_image_deep_field_smacs0723-5mb.jpghttp://https://www.nasa.gov/sites/default/files/thumbnails/image/main_image_deep_field_smacs0723-5mb.jpg
The more you zoom in the more you see. It's beautiful.
Worth the wait, I would say!
https://archive.stsci.edu/prepds/relics/color_images/smacs0723-73.html has some HST images to compare with this one (found by user leovinus over at NSF.)
https://forum.nasaspaceflight.com/index.php?topic=54269.960
The lensing is caused by the entire foreground galaxy cluster, which should be dominated by dark matter, so the individual foreground galaxies probably don't contribute much to the total lensing. This is also why the lensed arcs are quite symmetric about the centre of the frame - the dark matter distribution is probably fairly close to spherically symmetric.
The Carina Nebula.
PNG image, 14575 x 8441, 127.4 MB download
https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png
Jupiter! (from https://www.stsci.edu/files/live/sites/www/files/home/jwst/documentation/_documents/jwst-science-performance-report.pdf which also has other goodies including a transit of the ~1.4 R_earth planet transiting GJ 4332).
Trivia note about Einstein at work: The old "Corpuscular" theory of light also predicts gravitational bending, though just exactly half of what Einstein's theory predicts. Interesting coincidence to me about the simplicity of the difference.
Even Mars (which has a higher surface brightness than Jupiter) isn't too bright for JWST to observe, and will be observed by it. Mercury and Venus are off limits, of course.
Despite the extensive exploration that Mars, Jupiter, and Saturn have already received, JWST still has spectroscopic capabilities that none of the spacecraft that have visited those places could match.
For those curious about the jewel of exoplanet targets, TRAPPIST-1 has already been observed by JWST, will be observed again in the next day or so, and yet again within a week. Based on at least two approved programs, it will be targeted a minimum of 17 times during the first year (Cycle 1), timed to match predicted transits of all seven of its known planets. So, in a nutshell, this much anticipated work is underway, and it's anyone's guess when the first results will be announced, but it seems like a good bet that preliminary results will be released by early 2023 if not sooner, but, as the signals accumulate over many repeated observations, it won't be anytime soon that JWST is done with this amazing system of multiple high-interest targets.
Thanks for the update, Mongo – double what I had found, and then some.
Mongo, I did a search for each program and didn't find the 2590 that you mention, but 2589 seems to match the description; perhaps an ID number was changed or mistyped?
Many of those programs now have planned observations more than a year from now, which may be why I had missed them. The first two listed also have some observations with status "Not ready for long range planning."
Here are the months in which observations are to be made (or have been made!) for each program. Because of the obstacle that the Sun provides, TRAPPIST-1 is only observable in June, July, October, November, and December. Essentially, some observations will be made in each possible month from now through December 2023, and there's no doubt that this will continue for much if not all of the time that JWST is operational.
The first of these to conclude will be GO 2589, which in fact concludes eight days from now! This program has no proprietary period, so data will apparently be made public very soon. To temper the hype, this program will not observe planets d, e, or f, which are the ones expected to have the most earthlike temperatures.
GTO 1177 Not ready for long range planning
GTO 1201 Jul 2022, Oct 2022, Nov 2022, Dec 2022, Jun 2023, Nov 2023, Dec 2023, +?
GTO 1279 Nov 2022, Oct 2023
GTO 1331 Jun 2023, Oct 2023
CO 1981 Jul 2023, Nov 2023, Dec 2023
CO 2304 Nov 2022
CO 2420 Jul 2022, Oct 2023, Nov 2023
GO 2589 Jul 2022
CO 2590 ?
The previously linked https://www.stsci.edu/files/live/sites/www/files/home/jwst/documentation/_documents/jwst-science-performance-report.pdf document also includes fairly detailed information about the performance impact of the large-ish micrometeoroid strike.
Do we know the size of the crater that was caused by that hit on the mirror?
It's interesting that some impacts can affect the figure of a segment in a way that can be measured by wavefront sensing. It looks like the scope as a whole had a 10% increase in the rms wavefront error from the impact. Smaller more frequent impacts might ding the segments in a way that scattered light is the main noticeable effect. Sounds like a good idea to point behind the orbital motion direction, after all here on Earth meteors happen much more after midnight than before.
Indeed - Fig 3 in the commissioning document shows the wavefront error after the big hit:
I thought there was supposed to be a further release of solar system images today, following the informal release of Jupiter images in the commissioning report. Haven’t found anything so far.
Edit: I was misled by a few terse tweets from yesterday.
According to an article on inverse.com, a general-interest site that's new to me, what’s happening today, or soon, is a release of data from the commissioning period.
JWST Commissioning data is now available
https://blogs.nasa.gov/webb/2022/07/14/webb-images-of-jupiter-and-more-now-available-in-commissioning-data/
Scott Manley on the Webb initial image release:
https://youtu.be/0FWO1Pvbhq4
--Bill
Hello !
Did the JWST observe a supernova ?..
https://twitter.com/gbrammer/status/1547690869704208392?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1547690869704208392%7Ctwgr%5E%7Ctwcon%5Es1_&ref_url=http%3A%2F%2Fwww.astrosurf.com%2Findex.php%3Fapp%3Dcoremodule%3Dsystemcontroller%3Dembedurl%3Dhttps%3A%2F%2Ftwitter.com%2Fgbrammer%2Fstatus%2F1547690869704208392
A supernova, or a red dwarf in the foreground that appears much dimmer in shorter wavelengths? There are about eight objects that appear much brighter in the JWST image than the HST image. And I'm sure it didn't observe eight supernovae.
Bonjour,
Thanks to StargazeinWonder for his comment.
Moreover :
https://twitter.com/drbecky_/status/1548982149231132674?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1548982149231132674%7Ctwgr%5E%7Ctwcon%5Es1_&ref_url=http%3A%2F%2Fwww.astrosurf.com%2Findex.php%3Fapp%3Dcoremodule%3Dsystemcontroller%3Dembedurl%3Dhttps%3A%2F%2Ftwitter.com%2Fdrbecky_%2Fstatus%2F1548982149231132674
https://www.stsci.edu/jwst/phase2-public/2589.pdf
On the "dust illuminating" powers of the IR vision of Webb.
https://www.forbes.com/sites/jamiecartereurope/2022/07/19/the-webb-telescopes-latest-science-images-show-the-phantom-galaxy-and-more-in-breathtaking-depth-and-detail/?utm_source=facebook&utm_medium=news_tab&sh=3675e13c79d9
Bonjour ou bonsoir, au choix
Just weeks into its mission, the James Webb Space Telescope (JWST) has broken the record for the oldest galaxy ever observed by nearly 100 million years.
https://images.newscientist.com/wp-content/uploads/2022/07/20123026/SEI_115555193.jpg?width=778
GLASS-z13 is the oldest galaxy ever seen. Naidu et al, P. Oesch, T. Treu, GLASS-JWST, NASA/CSA/ESA/STScI
Seeing some of the first galaxies to form after the big bang 13.8 billion years ago is one of the key goals of the JWST. When these emerged is currently unknown: the previous oldest identified galaxy, found by the Hubble Space Telescope, is called GN-z11 and dates back to 400 million years after the birth of the universe.
…
Source : https://www.newscientist.com/article/2329601-jwst-has-found-the-oldest-galaxy-we-have-ever-seen-in-the-universe/
And the following publication :
https://arxiv.org/pdf/2207.09434.pdf
Bonsoir,
I’m afraid of being thrown out of the forum ! I’m taking you so far away from the solar system !
What ?! The JWST would already observe at z 16 !!!
https://arxiv.org/abs/2207.12356
New JWST observations of the Cartwheel galaxy https://www.nasa.gov/feature/goddard/2022/webb-captures-stellar-gymnastics-in-the-cartwheel-galaxy
A good summary of the various caveats for the claims of large, early galaxies in Webb images from https://skyandtelescope.org/astronomy-news/webb-telescope-shatters-distance-records-challenges-astronomers/
In short, we need proper spectroscopy and ratios of massive to light stars may differ in the distant past from today, and it'll take time to sort through this.
With all the fanfare over the initial image presentstion, Webb is now settling into doing the science it was designed for. The images may not be as spectacular, but the science is significant.
In a manner of speaking, we are past the "pretty pictures" phase.
--Bill
https://blogs.nasa.gov/webb/2022/08/22/webbs-jupiter-images-showcase-auroras-hazes/?utm_source=TWITTER&utm_medium=NASAWebb&utm_campaign=NASASocial&linkId=178177184
Jupiter from JWST!!! Spectacular.
Phil
Can you please remind me what detail to expect for images of dwarf planets ?
Hubble can see some features of Ceres and can barely resolve Pluto.
Webb in the main IR wavelengths should match Hubble resolution in visible light. I'm unsure if Webb could/will show higher resolution if they took images just concentrating on its shortest wavelengths around 0.6 microns. The diffraction effect is less at 0.6 microns and the wavefront errors appear low enough to support higher resolving power. The F070W NIRCam filter might do the trick around 0.7 microns:
https://jwst-docs.stsci.edu/jwst-near-infrared-camera/nircam-instrumentation/nircam-filters
With the dwarf planets I suppose Webb might be able to help learn to things spectroscopically using MIRI.
In general, the IR spectroscopic capabilities of Webb are unmatched, and will provide a superior capacity to that of missions that have actually visited those worlds. JWST will provide IR spectroscopy of Mars better than that of any spacecraft that has ever orbited Mars. Better of Saturn than Cassini. Etc. Of course the spatial resolution of JWST will not match the spatial resolution of MRO at Mars or Cassini at Saturn, but will still resolve and differentiate large features quite well.
For any specific target, it's another matter whether or not IR spectroscopy answers the question we would like to answer. Sometimes the composition of aerosols and surface units is addressed with spectroscopy and sometimes not. We really won't know before the observations are made. Surely it will answer some questions and leave some unanswered.
As scalbers noted, the spatial resolution of JWST is comparable to HST's visible-light resolution. The highest spatial resolution achievable with HST is in UV, which provides better diffraction limits than visible light. JWST won't beat that resolution. And ground-based observations, which already better spatial resolution than HST and JWST, will be even more impressive when the larger telescopes being constructed now begin operation in the next decade.
It seems safe to say that, when possible, taking the highest possible spatial resolution image of a target concurrent with the great spectral resolution of JWST will allow better science than either would produce alone.
For amusement purposes only, I have taken a shot of Pluto from New Horizons and a shot of Jupiter from JWST and adjusted their sizes to show what kind of details we could expect from a Pluto JWST image. Pluto is only 1.7% the diameter of Jupiter, but assuming we can get similar resolution we should see some real features. And since we already have closeups we can probably deconvolute a better picture than Hubble did without prior knowledge of the surface.
Thanks to all for your insight !
Uranus, Neptune, and the uranian satellites will indeed be studied by JWST soon/already. I don't notice Triton being mentioned, but maybe it's hidden in another proposal, or maybe it didn't make the cut for Cycle 1; it's certainly a worthy target that wouldn't be ignored indefinitely.
https://www.stsci.edu/jwst/science-execution/approved-programs/cycle-1-go
https://www.stsci.edu/jwst/science-execution/program-information.html?id=1585
https://www.stsci.edu/jwst/science-execution/program-information.html?id=1598
https://www.stsci.edu/jwst/phase2-public/1786.pdf
I would expect some outstanding science to result. To some extent, we won't know what spectroscopy in JWST's wavelengths is capable of until we get the first results, but the potential is excellent.
JWST images the Phantom Galaxy M74 https://www.esa.int/Science_Exploration/Space_Science/Webb/Webb_inspects_the_heart_of_the_Phantom_Galaxy
In the M74 views there is a circular cavity in the dust and gas at all wavelengths, visible at about the 7:00 position angle. Has there been any comment about that, or is it just a random coincidence in the distribution?
I would guess that a large supernova took place at the center of that region long ago. We have something like that close to us, the Veil Nebula, which is not visible to the naked eye but is a whopping 3° of arc in diameter (6 full Moons wide).
There are still plenty of stars inside that volume. If the supernova interpretation is correct, it would be like a wind that blew dust and certain gas out to the edge, but of course have no perceptible force on dense things like stars.
Interesting interview of Scott Acton on the commissioning of the telescope (wavefront sensing): https://spectrum.ieee.org/james-webb-space-telescope-mirror
First Webb image of Mars:
https://www.newscientist.com/article/2338519-james-webb-space-telescope-captures-its-first-pictures-of-mars/
Re: image at top of article: "while the longer wavelength image reveals information about heat emitted from the Martian surface and atmosphere, as well as the concentrations of carbon dioxide in the atmosphere (bottom right, above)."
Note that the Hellas Basin (lower left of the lower right) shows up darker, which is "cooler", but i would have expected that low elevation area to be warmer. But i wonder if the thicker column of atmosphere (CO2) would have an effect?
---Bill
Thanks, Mike. That is a much better link. This initial Webb Data Dribble frequently has loose ends and we may get better data later.
Still, these are a wonderful preview of incredible images and data to come.
--Bill
This release describes the darker appearance of Hellas in detail. In a phrase, "higher pressure leads to a suppression of the thermal emission at this particular wavelength range."
https://blogs.nasa.gov/webb/2022/09/19/mars-is-mighty-in-first-webb-observations-of-red-planet/
First Webb imagery of Neptune:
https://webbtelescope.org/contents/news-releases/2022/news-2022-046#section-id-2
Just for reference, here are images from the VLT and Hubble. Of interest is the storm system shown with white clouds. And note that Webb is imaging in infrared wavelengths and is looking at things differently.
--Bill
I'd wondered why the ring arcs aren't visible, but assuming models 2 and 3 are on the money (#2: 820.1118 deg/day & #3: 820.1121 deg/day), the arcs are obscured by Neptune's disc.
Obs time: 2022-07-12 06:52:35
Ian, remember this is a NIR view of Neptune, and the rings/ring arcs may look different at those wavelenghts. I've not noticed anything more on this.
--Bill
On Europa and Enceladus, which will be studied for plume signatures, for the first of certainly more than one time, in November and December:
I'm curious about JWST's ability to identify the signature of complex organics, and how calibration work would even be performed to determine their spectra. With a somewhat unconstrained number of possible organic compounds to look for, that seems like a lot of laboratory work involving unusual conditions to develop a catalog of reference spectra. This would seem like a need that has perhaps never existed before, but will be needed for interpreting JWST spectra of many objects, including Titan, comets, nebulae, exoplanet atmospheres, protoplanetary discs, and maybe more.
One may think of Europa's and Enceladus's plumes as two more "exo"planet atmospheres for JWST to study. It's interesting to note that JWST will provide a kind of data that even missions that visit those worlds will not. Maybe we'll see the spectra published in 2023, but understanding them seems like it could be a long game.
If the report that I dare to make between the observations of these two very different targets is nevertheless valid, it will not be necessary to forget the technical problem, still under investigation, for the MRS mode of MIRI.
It's funny, Q, I also saw this story shortly after I posted. While it's definitely an interesting result, it is presented with qualifiers, "consistent with Polycyclic Aromatic Hydrocarbons," which indicates an educated hypothesis, but not proof, and also not very specific. I guess we're going to want to know a lot more about organics in the plumes of Europa and Enceladus, but of course, you take what you can get, and it's impressive that this sort of result can be had from light years away. We also have, in the case of Enceladus, some previous in situ sampling, and with Europa we expect that within a decade, so we will get to cross-reference one kind of data with another.
Images of Pillars of Creation. https://www.jwst.nasa.gov/content/webbLaunch/assets/images/images2022/pillars-STScI-01GFNMZESKZKXBMWGER9E0Z19G-2kpx.jpg
That new IR view of The Pillars adds anothee dimension.
JWST does Titan!
Pretty impressive. Must be raining up there.
https://blogs.nasa.gov/webb/2022/12/01/webb-keck-telescopes-team-up-to-track-clouds-on-saturns-moon-titan/
P
Brilliant inages by Keck and Webb, note that the extreme 300km atmospheric depth is shown from surface to haze top.. And Webb clearly shows surface features.
Well done!
Some understated drama from the NASA blog post linked to by antipde:
Based on Cassini's monitoring, it seems that it rains on any given location on Titan only once in several decades or centuries, although when it does, the volume is extremely heavy. Despite Titan's 100% coverage in haze, the presence of clouds like these is quite rare at any given place and time. Preparing a future mission for rain seems to be like preparing a mission to Earth for hurricanes.
Here are the abstracts from the JWST "First Science Results" conference held last week. These abstracts are, of course, much more broad than deep or detailed, but there's still plenty of interesting stuff here.
https://www.stsci.edu/files/live/sites/www/files/home/events/event-assets/2022/_documents/2022-conference-first-science-results-from-jwst-abstract-compendium.pdf
Poster abstracts from the same event:
https://www.stsci.edu/files/live/sites/www/files/home/events/event-assets/2022/_documents/First-Science-Results-from-JWST-Poster-Presentations.pdf
The TRAPPIST-1 abstracts include the fact that one transit is not sufficient for detecting atmospheric molecular composition, there's some optimism that four transits may be sufficient, but also a note that features on the star TRAPPIST-1 introduced some unexpected noise that is much larger than the expected signal from a transiting planet's atmosphere. (Perhaps it is nonetheless distinguishable from atmospheric absorption features?) Again, publications from before the JWST indicate that measuring the atmospheric composition would benefit, ideally, from observations made during dozens of transits, per planet – more than is likely feasible.
There's been an interruption in the function of the NIRISS instrument on the JWST. The updates have been few and probably reflect a lack of certainty on the ground. A loss of that instrument would entail a serious loss of science, but this last update makes it sound like the team is optimistic pending more information.
https://blogs.nasa.gov/webb/2023/01/24/near-infrared-imager-and-slitless-spectrograph-operations-update/
NIRISS is back online. This update doesn't say much about the cause of the glitch, but it must not have involved hardware in any serious way.
https://www.stsci.edu/contents/news/jwst/2023/niriss-has-returned-to-science-operations
Silicate clouds in a hot Jupiter via this news release:
https://webbtelescope.org/contents/news-releases/2023/news-2023-105
The Cycle 2 observation plans are taking shape. General Observers approvals are listed here:
https://www.stsci.edu/jwst/science-execution/approved-programs/general-observers/cycle-2-go
It's impossible to summarize this succinctly, but I'll note a few:
A plan to coordinate JWST observations of Io with one of Juno's close passes.
Comprehensive spectra of Europa such as JWST can perform.
Observations of Jupiter Trojans.
Attempt to characterize Enceladus's plumes.
More TRAPPIST-1 plans (but not so many as in Cycle 1, it seems?).
Attempt to characterize the rocky surface of terrestrial planet LHS 3844 b.
Attempt to characterize the galaxy farthest known before JWST.
And hundreds more…
Bonsoir,
It's probably not lost on you, but the news still belongs here.
JWST detects a huge plume rising from Enceladus
https://www.nasa.gov/feature/goddard/2023/webb-maps-surprisingly-large-plume-jetting-from-saturn-s-moon-enceladus
Nicolas Biver * made this remark on a French forum, and I quote:
"It's just one more resolute observation between those made by Cassini and Herschel more than 10 years ago, which showed that encelade was ejecting ~8x10^27 water molecules per second (250 kg or liter/s) to feed a torus of water vapor ~50000km in cross-section diameter and encompassing encelade's orbit (238000 km in circumference.
So whether it's the distance LosAngeles - Buenos-Aires when it's just the tip of the iceberg... whose total diameter exceeds the Earth-Moon distance,.... it's all a question of knowing which part of the water vapor cloud we're talking about!
As the JWST pixel (in the IR) is much smaller than Herschel's, the image of the water vapor cloud is more resolute."
*N. Biver : Doctorate in astrophysics, having participated, among other things, in the European Rosetta space mission
A Webb Uranus image from April 2023.
And what do we make of that bright, bright cloud at 8:30 on the limb?
It's important to remember how sensitive these details are to the choice of wavelength, and comparing JWST images to those from other, seemingly-comparable telescopes, and be misleading, and I think this is actually a great example of it.
Uranus is very dark in certain IR wavelengths that are absorbed by methane. Among the many wavelengths available to JWST, the rings are comparatively much brighter in some of those, and high, "white" clouds may also be much brighter. The ratios can be much more dramatic than in images from Voyager, Hubble, or Keck. And I think that's the real story here. Probably nothing here is actually different from what was going on with Uranus at the time that images were being captured by Hubble and Keck, but the IR is showing us something very different. And then the people who are making the aesthetic choices in how to present the imagery are maybe doing something subtly deceptive by producing outputs that almost resemble the way we've been used to seeing Uranus and Neptune with these rare, isolated differences.
I am well aware of Webb's multispectral IR capability, and so forth, but it impressed me that this cloud was bright enought to cause diffraction spikes. In the Neptune image there is a cloud at 5:30 that may be be forming spikes, but they are indistinct. In the Jupiter image the somewhat linear polar aurorae are forming a diffraction spike at 90 and 270*. So despite the choice of colors used to create this image and how this image was processed, the presence of the spikes certainly suggests that this cloud is intrinsically bright.
--Bill
I know that cosmology and galaxies and so on is not the center of gravity of this board's discussion topics, but here's a nice overview of what JWST has been revealing about the early universe.
The TL;DR is: It looks like stars and galaxies evolved significantly faster at the beginning of the universe than theories had previously estimated, but not so much faster that everything we thought we knew was necessarily wrong.
https://www.pnas.org/doi/10.1073/pnas.2311963120
Stargaze, the current Cosmological model is based on our best interpretation(s) of available data. I fully expected Webb to expand that data and I anticipate that our model(s) will be changing.
--Bill
Yeah, that's certainly true of the messier stuff, like galaxy formation, which depends on all sorts of details like feedback and interactions. It's complicated enough that you can't just write down what will happen based on the fundamental laws of physics - you have to make all sorts of assumptions/guesses about what's important. No doubt Webb will help a lot there.
The bigger picture of cosmology (baryons, dark matter/energy, flatness, GR; what's usually referred to as "the cosmological model") is much more secure (apart from that niggly Hubble tension...).
CO2 ice detected on the surface of Europa:
https://www.nasa.gov/feature/goddard/2023/nasa-s-webb-finds-carbon-source-on-surface-of-jupiter-s-moon-europa
Candidate giant exoplanets around metal polluted white dwarfs.
https://arxiv.org/pdf/2401.13153.pdf
Given that only 4 WDs were in the survey and they found 2 candidates,
this potentially represents to first of many similar discoveries. WD
planets have been elusive - maybe not any more!
P
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