### Author Topic: NASA - James Webb Space Telescope - Discussion and Updates  (Read 206140 times)

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #520 on: 08/01/2017 11:40 PM »
How long would BepiColombo have to wait if it missed it's window?

#### zubenelgenubi

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #521 on: 08/03/2017 04:59 PM »
How long would BepiColombo have to wait if it missed its window?

I don't know, given that this mission's flight path is about as far as possible from a simple Hohmann transfer orbit--7 years of solar electric propulsion on a delta-v EVVMMMMMM gravity assist trajectory.  (M = Mercury, V = Venus, E = Earth)

Here are some, if not all of the previous launch windows, taken from the BepiColombo thread:
August 2013
July 2014
August 2015
"mid-2016"
January 2017
? 2018
October 2018
« Last Edit: 08/03/2017 05:00 PM by zubenelgenubi »
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#### LouScheffer

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #522 on: 08/03/2017 05:21 PM »
How long would BepiColombo have to wait if it missed it's window?
The first two flybys are Earth and Venus.  Earth is always in the same position relative to Earth, so that's not a constraint.  But to get to Venus with about the same state, you'll need to start when Earth and Venus are in the same relative positions.  That happens every 19.6 months.  This agrees with the last launch window slip, which was January 2016 to October 2018.

So the next similarly good trajectory will be about 19 months later, or June 2020, more or less.

EDIT:  forgot 2018 is next year already.   Fixed the date.
« Last Edit: 08/04/2017 12:44 AM by LouScheffer »

#### pippin

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #523 on: 08/04/2017 12:03 AM »
2020

#### LouScheffer

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #524 on: 08/04/2017 01:56 AM »
How long would BepiColombo have to wait if it missed it's window?
The first two flybys are Earth and Venus.  [...]
So the next similarly good trajectory will be about 19 months later, or June 2020, more or less.
From the paper BEPICOLOMBO TRAJECTORY OPTIONS TO MERCURY IN 2016 AND 2017, there are other options in addition to waiting for the same planetary configurations to repeat.  They can modify the phase to the Earth flyby, or sometimes go direct to Venus.  Given all these options, it looks like windows are typically 6 months apart or so, though there was a one year gap in 2016-2017.  So a detailed analysis would be needed, but most likely it would not require waiting the full 19.6 months.

#### Star One

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #525 on: 08/09/2017 07:10 PM »
Sunshield Layers Fully Integrated on NASA’s James Webb Space Telescope

Quote
The five sunshield layers responsible for protecting the optics and instruments of NASA’s James Webb Space Telescope are now fully installed.

Northrop Grumman Corporation in Redondo Beach, California who designed the Webb telescope’s optics and spacecraft bus for NASA’s Goddard Space Flight Center in Greenbelt, Maryland, integrated the final flight layers into the sunshield subsystem. The team is now folding and stowing the layers, in preparation for deployment tests in August.

The sunshield layers work together to reduce the temperatures between the hot and cold sides of the observatory by approximately 570 degrees Fahrenheit. Each successive layer of the sunshield, made of kapton, is cooler than the one below. All layers were installed and tested in June and July 2017 at Northrop Grumman Corporation’s Space Park facility in Redondo Beach.

“This is a huge milestone for the Webb telescope as we prepare for launch,” said Jim Flynn, Webb sunshield manager, Northrop Grumman Aerospace Systems. “The groundbreaking tennis court sized sunshield will shield the optics from heat and assist in providing the imaging of the formation of stars and galaxies more than 13.5 billion years ago.”

"All five sunshield membranes have been installed and will be folded over the next few weeks," said Paul Geithner, deputy project manager - technical for the Webb telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The Webb telescope’s sunshield will prevent the background heat from the sun from interfering with the telescope’s infrared sensors. The five sunshield membrane layers, designed and manufactured by the NeXolve Corporation in Huntsville, Alabama, are each as thin as a human hair. Because the sunshield is the size of a tennis court, it helps solidify the Webb telescope as the largest ever built for space. The sunshield, along with the rest of the spacecraft, will fold origami-style into an Ariane 5 rocket.

The Webb telescope is the world’s next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, the Webb telescope will observe distant objects in the universe, provide images of the first galaxies formed and see unexplored planets around distant stars. The Webb Telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

https://www.nasa.gov/feature/goddard/2017/sunshield-layers-fully-integrated-on-nasa-s-james-webb-space-telescope

#### Phillip Clark

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #526 on: 09/06/2017 03:04 AM »
Excellent programme from the BBC World Service radio about the James Webb Space Telescope.

http://www.bbc.co.uk/programmes/w3csvnv2
I've always been crazy but it's kept me from going insane - WJ.

#### Star One

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #527 on: 09/06/2017 11:21 AM »
Excellent programme from the BBC World Service radio about the James Webb Space Telescope.

http://www.bbc.co.uk/programmes/w3csvnv2

Thanks for the link.

#### Star One

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #528 on: 09/08/2017 07:08 PM »
Quote
Jeff Foust @jeff_foust
Scolese: JWST has survived a gov’t shutdown, derecho, snowstorm, and now hurricane. Hope when it goes to Calif. there’s not an earthquake.
5:32 pm · 8 Sep 2017

Quote
Jeff Foust @jeff_foust
Scolese: lost only a couple days of testing at JSC. Still on track for late 2018 launch, pending resolution of launch schedule conflicts.
5:44 pm · 8 Sep 2017

#### catdlr

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #529 on: 09/21/2017 11:23 PM »
Aligning the Primary Mirror Segments of the James Webb Space Telescope

James Webb Space Telescope (JWST)
Published on Sep 21, 2017

Engineers at NASA’s Johnson Space Center in Houston used light waves to align the James Webb Space Telescope’s mirror segments to each other, so they act like a single, monolithic mirror in the cryogenic cold of the center’s iconic Chamber A.

Part of the Webb telescope’s ongoing cryogenic testing in Chamber A at Johnson includes aligning, or “phasing,” the telescope’s 18 hexagonally shaped primary mirror segments so they function as a single 6.5-meter mirror. All of these segments must have the correct position and correct curvature; otherwise, the telescope will not be able to accurately focus on its celestial targets.

Tony De La Rosa

#### zubenelgenubi

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #530 on: 09/28/2017 02:14 PM »
JWST launch delayed to 2019, date TBD.

Quote
Jeff Foust @jeff_foust
Scolese: lost only a couple days of testing at JSC. Still on track for late 2018 launch, pending resolution of launch schedule conflicts.
5:44 pm · 8 Sep 2017

Cross-post from Arianespace launch schedule thread:
Quote
Susanne Auer‏ @AuerSusan
An interesting detail from the #Arianespace #IAC2017 presentation:
#BepiColombo will launch 2018
#JWST one year later in 2019 #ESA #NASA

I should clarify that that "one year later" here just means in 2019, not "365 days after BepiColombo". I could have phrased that better in the tweet.

Original source is Jacques Breton, Arianespace VP Sales & Customers, speaking at IAC2017

Calapine aka Susanne Auer

Reason:
Clash of launch site preparation places with BepiColombo which has a planetary launch window to chase in October 2018.
***

My opinion: not unexpected, given the celestial mechanics "facts of life."
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#### gongora

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #531 on: 09/28/2017 06:33 PM »
NASA’s James Webb Space Telescope to be Launched Spring 2019

NASA’s James Webb Space Telescope now is planning to launch between March and June 2019 from French Guiana, following a schedule assessment of the remaining integration and test activities. Previously Webb was targeted to launch in October 2018.

“The change in launch timing is not indicative of hardware or technical performance concerns,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at Headquarters in Washington. “Rather, the integration of the various spacecraft elements is taking longer than expected.”

As part of an international agreement with the ESA (European Space Agency) to provide a desired launch window one year prior to launch, NASA recently performed a routine schedule assessment to ensure launch preparedness and determined a launch schedule change was necessary. The careful analysis took into account the remaining tasks that needed to be completed, the lessons learned from unique environmental testing of the telescope and science instruments at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the current performance rates of integrating the spacecraft element.

Testing of the telescope and science instruments continues to go well and on schedule at NASA’s Johnson Space Center in Houston, Texas. The spacecraft itself, comprised of the spacecraft bus and sunshield, has experienced delays during its integration and testing at Northrop Grumman in Redondo Beach, California.

The additional environmental testing time of the fully assembled observatory--the telescope and the spacecraft--will ensure that Webb will be fully tested before launching into space. All the rigorous tests of the telescope and the spacecraft to date show the mission is meeting its required performance levels.

Existing program budget accommodates the change in launch date, and the change will not affect planned science observations.

“Webb’s spacecraft and sunshield are larger and more complex than most spacecraft.  The combination of some integration activities taking longer than initially planned, such as the installation of more than 100 sunshield membrane release devices, factoring in lessons learned from earlier testing, like longer time spans for vibration testing, has meant the integration and testing process is just taking longer,” said Eric Smith, program director for the James Webb Space Telescope at NASA Headquarters in Washington. “Considering the investment NASA has made, and the good performance to date, we want to proceed very systemmatically through these tests to be ready for a Spring 2019 launch.”

The launch window request has been coordinated with ESA, which is providing the Ariane 5 launch of Webb as part of its scientific collaboration with NASA.

The James Webb Space Telescope is NASA’s next great multi-purpose observatory and will be the world’s most powerful space telescope ever built, serving thousands of astronomers worldwide. The 21-foot (6.5-meter) diameter infrared-optimized telescope is designed to study an extremely wide range of astrophysical phenomena: the first stars and galaxies that formed; the atmospheres of nearby planets outside our solar system, known as exoplanets; and objects within our own solar system. Webb is an international project led by NASA with its partners ESA and the Canadian Space Agency.

#### Fequalsma

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #532 on: 09/30/2017 12:50 PM »
https://colloqsigma.larc.nasa.gov/past-colloquium-lectures/all-colloquium-lectures/sigma-october-3-2017/

Where Did We Come From, Where are We Going? Finding Out with the James Webb Space Telescope

Dr. John Mather

Tuesday, October 3, 2017 at 7:30 P.M. at the Virginia Air and Space Center in downtown Hampton, Virginia

Abstract

Where did we come from, and where are we going? I will outline a history of the universe from its early moments in the Big Bang, to the possible end. Our history is full of beneficial catastrophes, and we wouldn’t be here without them: stars explode, the Moon is formed in a giant collision with the Earth, the Earth is bombarded by asteroids and comets for hundreds of millions of years, and multiple extinction events through hot, cold, poison, and asteroid impacts cause rapid evolution of life. But here we are, our ancestors survived and thrived through it all. Now, we can tell the story, we can look for more details, and we can begin to adventure through the solar system and eventually beyond, in partnership with a new entity, artificial intelligence coupled with robotics. Scientific discovery has been propelled by competition (including war) for thousands of years, so it’s immensely important to public policy. I will illustrate with examples from NASA, including our measurements of the Big Bang, discoveries with the Hubble, and future telescopes like the James Webb Space Telescope (planned for 2018 launch) and beyond. Within a few decades, we may know that life is common in the universe, or perhaps not.

Speaker

Dr. John C. Mather is a Senior Astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where he specializes in infrared astronomy and cosmology. He received his BS in physics at Swarthmore College and his PhD in physics at the University of California at Berkeley.

As an NRC postdoctoral fellow at the Goddard Institute for Space Studies (New York City), he led the proposal efforts for the Cosmic Background Explorer (1974-76), and came to GSFC to be the Study Scientist (1976-88), Project Scientist (1988-98), and the Principal Investigator for the Far IR Absolute Spectrophotometer (FIRAS) on COBE. He and his team showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the Big Bang theory to extraordinary accuracy. The COBE team also discovered the cosmic anisotropy (hot and cold spots in the background radiation), now believed to be the primordial seeds that led to the structure of the universe today. It was these findings that led to Dr. Mather receiving the Nobel Prize in 2006.

Dr. Mather now serves as Senior Project Scientist (1995-present) for the James Webb Space Telescope, the successor to the great Hubble Space Telescope.

#### FutureSpaceTourist

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #533 on: 10/18/2017 04:34 PM »
Quote
Hertz: JWST telescope assembly completing thermal vacuum test at JSC; open up chamber next week.

#### FutureSpaceTourist

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #534 on: 10/18/2017 06:42 PM »
Quote
NASA’s Eric Smith says JWST delay will consume most of HQ reserves for the mission, but still remain within overall budget.

Quote
Smith adds the decision to delay JWST to “late spring” of 2019 had nothing to do with schedule conflict with BepiColombo launch in Oct ’18.

#### Blackstar

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #535 on: 10/18/2017 07:08 PM »
Smith adds the decision to delay JWST to “late spring” of 2019 had nothing to do with schedule conflict with BepiColombo launch in Oct ’18.

I know some knowledgeable people who would snort at that comment...

However, I think that this is kinda like a game of chicken and it was a question of who blinked first. NASA possibly could have just waited until ESA took the fall and blamed it on them, but both sides were having schedule issues. The good news is that there are no technical problems with JWST. It's just that integration is going to take longer than they predicted, because this is a very complex machine.

#### as58

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #536 on: 10/18/2017 07:46 PM »
Smith adds the decision to delay JWST to “late spring” of 2019 had nothing to do with schedule conflict with BepiColombo launch in Oct ’18.

I know some knowledgeable people who would snort at that comment...

Yeah, AAS, for example, apparently never got the memo...

https://aas.org/posts/blog/2017/10/jwst-launch-delayed-will-remain-within-cost-cap

edit: To add to what Blackstar wrote, I know a number of people working on JWST and long before the official delay and news about the schedule conflict with BepiColombo they were talking about launch 'hopefully in 2018'; I don't think anyone had much confidence that the official date of Oct 2018 would hold. But to say that BepiColombo had nothing to do with the delay, especially as long a delay as it turned out to be, is IMO dishonest.
« Last Edit: 10/18/2017 07:53 PM by as58 »

#### Star One

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##### NASA - James Webb Space Telescope - Discussion and Updates
« Reply #537 on: 10/18/2017 08:22 PM »
More of this conversation.

Quote
Jacob Aron
@jjaron
How else you going to solve it? In a turf war on an ESA launch site, seems like the ESA mission wins

@jeff_foust

I think we would have heard otherwise—particularly from members of Congress unhappy to spend NASA money to help an ESA mission.

« Last Edit: 10/18/2017 08:23 PM by Star One »

#### Blackstar

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #538 on: 10/18/2017 09:12 PM »
especially as long a delay as it turned out to be, is IMO dishonest.

...don't be surprised if JWST's launch date slips even further...

(I'm just sayin'...)

#### Star One

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##### Re: NASA - James Webb Space Telescope - Discussion and Updates
« Reply #539 on: 10/18/2017 09:26 PM »
especially as long a delay as it turned out to be, is IMO dishonest.

...don't be surprised if JWST's launch date slips even further...

(I'm just sayin'...)

Why would you say that?

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