Help - Search - Members - Calendar
Full Version: James Webb Space Telescope
Unmanned > Beyond.... > Telescopic Observations
Pages: 1, 2
The manufacture of the JWST mirror blanks has now been completed.

Despite this milestone, the fate of JWST is still somewhat precarious, because although the scientific bang from the telescope is expected to be huge, the bucks required have increased to a staggering $4.5 billion. A article on the squeeze in NASA's space-based astronomy plans gives some background.

The JWST home page can be found here.

The Space Telescope Science Institute, which runs Hubble, also has a site here. As does ESA.
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.


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

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 this New Scientist article.

Back in 2003, it was projected to cost $2.5 billion. I'll see if I can find some more info on what is driving up the cost.
Bob Shaw
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!
It seems JWST is safe from outright cancellation for the moment. A New Scientist article 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.
QUOTE (Redstone @ Aug 26 2005, 04:50 PM)
JWST was always billed as a near IR telescope, but the lack of any overlap with Hubble is going to hurt.

The overrun is about a billion dollars (so far), and the reduced mirror polishing will save $150M. They've got a few other cost cutting things to do, or somehow get more funding.

Does anyone know how much of the budget is a one time expense to do research on electro-mechanical devices that work at near absolute zero temperatures? I am kind of curious to know where the money for this project has gone, as it will give some guidance for future large space telescopes such as SIM and Terrestrial Planet Finder.
Bob Shaw
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.

Northrup press release.

The mirrors will be polished to tolerances as tight as 20 nanometers, or less than one millionth of an inch.

After initial polishing, the segments will be tested at roughly minus 400 degrees Fahrenheit (near absolute zero) in a cryogenic test chamber at NASA's Marshall Space Flight Center in Huntsville, Ala., and returned to Tinsley for further refinement and polishing. The entire polishing process takes about two-and-a-half years.

blink.gif No wonder this telescope costs a fortune.
"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."
Some more detail on the JWST delay to 2013. 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 this story.
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).
Full Text


So no one is denying that the JWST will be a first-rate telescope, perhaps even a revolutionary one. Just last August an independent assessment team charged by the project to review the telescope's science potential reported that "the scientific case for the JWST mission has become even stronger" since the Decadal Survey's endorsement in 2000. But what of its expense? NASA's latest budget puts the project's price tag, including $1 billion for a decade's worth of 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.

Nature also has an editorial ("Refocusing NASA's vision") on the subject in the same issue. Following is an excerpt:

It is now clear that when NASA first requested funds for a Next Generation Space Telescope a decade ago, the project's advertised price of under $1 billion was little more than a fiction. But it was a fiction that the space agency, the Congress and many in the astronomy community wanted to believe.

And, of course, there's the recent NASAWatch/Spaceref article "JWST Talking Points."
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.
QUOTE (dilo @ Aug 23 2005, 06:22 PM) *
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!

Guys have you seen the JWST talking points e-mail ? I think NASA watch had it on the website
James Webb Telescope Sunshield Membrane Passes Tests

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.
Astrophysics, abstract

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.
I'm looking forward to seeing alpha centauri images with this telescope. smile.gif
JWST is a partnership between ESA, NASA, and the Canadian Space Agency.

How much are various partners putting into this? How much is NASA being asked to pay?
QUOTE (DonPMitchell @ Jun 16 2006, 07:35 PM) *
How much are various partners putting into this? How much is NASA being asked to pay?

Canadians have already helped with the Shuttle arm and ESA has already worked with NASA on Hubble, Cassini-Huygens, Soho and other missions
to save money JWST will be launched by Ariane-5 in French Guiana S.America
James Webb Space Telescope Mirror Backplane Prototype Passes Critical NASA Space Readiness Tests

A prototype structure that holds the primary mirrors for the optical element of the James Webb Space Telescope (JWST) passed a key readiness milestone after undergoing a series of rigorous cryogenic tests at NASA's Marshall Space Flight Center in Huntsville, Ala.
- Telescope mirror nears completion
Engineers have finished making the 18 hexagonal elements that will come together to form the telescope's 6.6m primary mirror.
"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. smile.gif
This thread will be useless without pics. You have your assignment. Do it smile.gif

I'm on it boss. smile.gif
Some one has posted some pics (2) of the Full scale model here

I'm in dublin, this is fantastic about the technical review meeting here in Dublin. Can't wait to see the model for real smile.gif
That's two of you.


Do it. smile.gif

NASA Adds Docking Capability For Next Space Observatory
By Brian Berger
Space News Staff Writer,
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.

Click to view attachment Click to view attachment Click to view attachment Click to view attachment

Click here for the full res slideshow. 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:


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 FΑS apprentices – are spending four days
assembling the model in a large meadow at the back of the RHK.


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)

Dublin Institute for Advanced Studies Welcome (Ray)

JWST Science Objectives (Gardner)

JWST Mission Overview and Status (Menzel)

JWST Observatory Overview and Status (Lynch)


OTE and Wavefront Sensing Overview (Feinberg)

NIRCam (Rieke)

NIRSpec (Jakobsen)

Lunch (Baroque Chapel)
I just re-arranged my Monday schedule so I'll be there. smile.gif

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.
Click to view attachmentClick to view attachment

I also added another bunch of shots to the slideshow .
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. smile.gif
Helvick, do you know the rest of its schedule? Hoping it'll make a stop in Los Angeles...
QUOTE (helvick @ Jun 9 2007, 10:43 PM) *
It is scheduled to be displayed at the Rochester Museum & Science Center, in Rochester, New York starting on August the 26th.

That was actually a couple of years ago. We're still talking to Grumman about the exact repatriation date. Six weeks is just a ball-park number, however we will almost certainly move it from Kilmainham on or before the w/e of June 23rd. I'll keep you posted on a new location (top secret just now!).
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 FΑS, 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... smile.gif
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. smile.gif

Todays Agenda:
  1. Welcome - Tony Ray (DIAS) and John Mather.
  2. JWST Science Objectives - Gardiner
  3. Mission overview, Observatory Overview and Reformulation Summary - Menzel & Giampaoli
  4. OTE and Wavefront Sensing Overview - Feinberg
  5. NIRCam (Rieke)
  6. NIRSpec (Jakobsen
  1. FGS-TF (Hutchings)
  2. MIRI (Wright)
  3. Cooler (Larson)
  4. JWST Integration & Test (Diaz & Drury)
  5. Operations & Observing Policies (Johns & Sonneborn)
  6. Progress & Status (Sabelhaus)
John Mather – introduction
Gave a quick introduction and commented that he is glad to see the telescope that originally was scetched out on a blackboard in 1996 finally getting built with a remarkably similar set of features to the original rough design. He cracked a joke about the fact that the original budget was laughed at by some people who have since been proven correct but emphasized that in adjusted terms the project is now 2x the original budget – so it is over the original estimate but it is now realistic and being held tightly.

He made some brief comments about the relevance to JWST's mission of Spitzers recent work, the Hubble Ultra Deep Field and transit Exoplanets. He also made mention of the recent (probable) pair-instability super nova (SN 2006 GY) (he called it a Super Duper Nova smile.gif ) that has shown that this type of nova may be much more common than had been thought. Their immense brightness and this indication of their frequency pushes back JWST's reach even further out the edge.

You could tell that he was very pleased with the project. He then handed over briefly to Gillian Wright (I think) the co-Lead of the MIRI Science Team who briefly thanked the combined team for enabling a full day free of ITAR restrictions so everyone could attend. I was surprised that this got to the top of the agenda but I'm not complaining – I got a free pass in partly because of folks figuring this out. At that point she handed over to John Gardiner – GSFC Senior Project Scientist for the JWST

JWST Science Objectives - Gardiner
STScI will be managing the operations for JWST. (and as an aside go to for outline data)

JG gave a general purpose JWST overview for the masses – not much new in this but it was a nice intro for those outsiders (like me) who were allowed in for the day.

I didn't pick up much new (ie that isn't on the STScI web site) for the first three mission objectives:
  • The End of the Dark Ages: First Light and Reionization
  • The assembly of Galaxies
  • The Birth of Stars and Protoplanetary Systems
But he had quite an interesting segment on the final item.
  • Planetary Systems and the Origins of Life
In particular he specifically indicated that JWST will be targeting ExoMoons aswell as ExoPlanets for detection and spectroscopic analysis via combinations of inferior and anterior transits. He mentioned the recent Spitzer 8micron planetary surface mapping of HD 189733b and indicated that JWST should be able to do something similar for Earth like planets in the habitable zone of comparable stars.

He mentioned that coronograph assisted imaging should significantly expand the percentage of systems where JWST will be able to go planet hunting but did not go into much detail. (Later on in the morning Peter Jakobsen pointed out that the lack of a coronograph on NIRSpec means that the there are some additional constraints on what can be done in terms of analysis of non transit exoplanets)

Mission overview, Observatory Overview and Reformulation Summary - Menzel & Giampaoli
This was mega detailed and I probably missed more than 50% because I simply couldn't keep up while making notes. Fantastic stuff though from my point of view and I'd go back to one of Mike's talks in a heartbeat, he reminds me a bit of Rob Manning – seriously passionate about his machines. Mike said that the data was slightly edited to comply with ITAR because all of us foreigners where there but honestly I wouldn't have noticed if he hadn't specifically pointed out the one spot where some hard numbers had been removed. Anyway some details.

All 10 enabling technologies for the mission have now completed "Technology non-advocate review" and are ready for TRL6 more than 12 months ahead of schedule.

The major news however is the re-formulation of the project to mitigate some cost and program risks. Mike gave an incredibly detailed explanation of the changes that have been made, whay the were needed and what the impact would be. These were mostly in the arena of decoupling various test processes, equipment and resources (such as test facilities) so that schedule dependencies and interlocks could be removed. The argument and description of the final result was compelling and the major concern that I had when first hearing of this reformulation (that testing was being reduced or that the team was accepting lower specifications) certainly seem to me to not be true now that I have seen this new plan. In particular these changes have enabled the addition of more vibration analysis, cryocycling and cryometrology testing because programmatic interlocks and resource scheduling are now much simpler.

Some interesting news on the spacecraft design front are the physical changes that have been introduced with the B2 structural changes. For reference B1 is basically the layout that the large scale model is built to. In particular the following significant (ie visibly noticeable) items have been modified:

The Sunshield has changed from a 3-2-2 layout to a 4-2 layout.

Sunshield deployment mechanics now follows a 10 folding stage process using what NG call a unitized pallet system (this appears to me to be a rigid shell like shield enclosure for launch and final structure rigidity). This is down from the 24 folding stages in the video we've all seen so this seems to represent a major simplification in the deployment mechanics.

The deployed cryo-cooler\radiator system from B1 is now a fixed unit, again reducing the deployment mechanical complexity.

The Solar panels have been moved to a single tail-dragger format from the dual side wing format on the B1 layout.

The Bib (rhomboidal stray light shield at the base of the main mirror) and the Frill (stray light shield around the top rim of the main mirror) have been made larger.

Lots of mass savings have been made – in total about 100kg gross has been removed but some of that has been clawed back elsewhere.

Tuned Magnetic Dampers have been added to the secondary mirror mount – these were needed to closeout on a couple of problematic harmonics from the reaction wheels that were preventing the team meeting 70% engineering margins. (I think)

Overall project performance metrics are green or will be following the B2 structural changes.

Mass is now 5315kg vs a launcher limit of 6530kg. This is a margin of 22.9% vs a required margin of 19.7%. Even adding in some desirable additional items and this only drops to 21.1% which is still healthy.

Power subsystem is fine. No news move along.

The desirable addional items include spreader rings for the solar shield to improve it's 3D structure, modifications to the shiled spreader bars and a trailing aft shield\trim tab that can be used for spacecraft balancing (at least I think that's what he said).

Mike then gave more depth on a specific problem relating to the cables that connect the ambient portion of the ISIM (at ~300K) and the cryosection (at ~35K). These are only 4m long and there is a 270K temperature drop across them that is not currently adequately cooled. They are adding a four stage cooling system to these to resolve this.

Finally he put up a slide showing the underside (sun facing side) of the spacecraft bus showing the potential location for a lightweight grapple fixture that could (in theory) be used to facilitate a repair mission at some stage. This is a ~2kg mounting so adding it isn't a major deal in itself. The audience gave it a mixed reaction and Mike certainly seemed to be presenting it as "someone else's idea, not mine".

Bob Giampaoli gave a brief update on some of the current work on the deployment mechanics that is ongoing. He specifically invited anyone who was interested to visit the JWST Solar-shield full scale mock-up at the HiBay at NG in Redondo Beach where they will be working on the detailed folding\unfolding mechanism until the end of the year.

They are not using pyro's at all for the unfolding\deployment. All mechanical using common locking equipment and deployment motors. I found this very interesting especially since there are a number of points where a single failure will be catastrophic.

The addition of the TMD's has also resolved issues for the deployment of the secondary mirror booms – makes it much easier to find an acceptable trade off between the stiffness required for the mirror mount and the flexibility required to deploy.

Overall the design is coming in within the Ariane's limits with some minor deviations that they expect to iron out pretty soon.

OTE and Wavefront Sensing Overview - Lee Feinberg

I was unable to capture the hard numbers properly on this and haven't had a chance to double check them so be especially careful of errors here. If it looks or smells wrong to you, then it probably is.

The WSC system is the tuning and aiming system that melds those 18 Beryllium hexagonal mirrors into one near perfect optical element. It leverages the NIRCAM as its imaging sensor. The use of adjustable optics here is to eliminate vibration and keep the mirror PSF stable to within 2%. The WSC will periodically (every 14 days) carry out a full re-work of it's magic to ensure that everything remains precise. Each of the 18 elements have an independent 6 degree of freedom mount using redundant actuators and a single radius of curvature control actuator. Mirror element assembly is at the point where they are just beginning to be polished, all the base machining and light weighting has been done.

Lee gave numbers on the progressive improvement in optical accuracy as the WSC process steps through its refining stages =>Basic Alignment => Focus adjustment => Coarse Phasing => Fine Phasing (to <1 Lambda) => Multi field Alignment (<0.5 Lambda ?). The final RMS deviation for a point source is < 0.35 micron. I think, I was struggling to keep up with this.

Finally and most importantly Lee walked through the various testing regimes, double checks and independent processes that will be used to prevent a repeat of the Hubble error. Main testing stages:

Tinsley (Polishing) – ambient testing
Marshall – ambient and cryo testing
Johnson SC – Full system testing (cryo again I think)
An independent Test Plan Integrity and Review Team are in place to make absolutely sure there are no mistakes.
The PDR for the OTE is in November.

One item that is interesting here is that Lee definitely said that the WSC process would be executed every 14 days but a number of documentations elsewhere say that wavefront control adjustments would only be needed at greater than 1 month intervals. I'm not sure when this changed. Overall it means that the mission will lose ~12 days observing time per year for this vs 6.

NIRCam and NIRSpec reports to follow tomorrow.
Oh and I forgot to thank Ollapa for the inivtation - it was very much appreciated.
Good job - your forum title has been appropriately adjusted smile.gif

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!
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2020 Invision Power Services, Inc.