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The James Webb Space Telescope (JWST), an infrared space observatory with an $8.8 billion budget, will be transported to South America to launch atop an Ariane 5 rocket, presumably in Spring 2019. The JWST was not intended to be serviceable at the Earth-Sun L2 point. Will there still be a "Golden Age of astronomy" even if the JWST fails?
[Due] to its steadily escalating cost and continually delayed send-off (which recently slipped from 2018 to 2019), this telescopic time machine is now under increasingly intense congressional scrutiny. To help satisfy any doubts about JWST's status, the project is headed for an independent review as soon as January 2018, advised NASA's science chief Thomas Zurbuchen during an early December congressional hearing. Pressed by legislators about whether JWST will actually launch as presently planned in spring of 2019, he said, "at this moment in time, with the information that I have, I believe it's achievable."
[...] Simply launching JWST is fraught with peril, not to mention unfurling its delicate sunshield and vast, segmented mirror in deep space. Just waving goodbye to JWST atop its booster will be a nail-biter. "The truth is, every single rocket launch off of planet Earth is risky. The good news is that the Ariane 5 has a spectacular record," says former astronaut John Grunsfeld, a repeat "Hubble hugger" who made three space-shuttle visits to low-Earth orbit to renovate that iconic facility. Now scientist emeritus at NASA's Goddard Space Flight Center in Maryland, he sees an on-duty JWST as cranking out science "beyond all of our expectations."
"Assuming we make it to the injection trajectory to Earth-Sun L2, of course the next most risky thing is deploying the telescope. And unlike Hubble we can't go out and fix it. Not even a robot can go out and fix it. So we're taking a great risk, but for great reward," Grunsfeld says.
There are, however, modest efforts being made to make JWST "serviceable" like Hubble, according to Scott Willoughby, JWST's program manager at Northrop Grumman Aerospace Systems in Redondo Beach, California. The aerospace firm is NASA's prime contractor to develop and integrate JWST, and has been tasked with provisioning for a "launch vehicle interface ring" on the telescope that could be "grasped by something," whether astronaut or remotely operated robot, Willoughby says. If a spacecraft were sent out to L2 to dock with JWST, it could then attempt repairs—or, if the observatory is well-functioning, simply top off its fuel tank to extend its life. But presently no money is budgeted for such heroics. In the event that JWST suffers what those in spaceflight understatedly call a "bad day," whether due to rocket mishap or deployment glitch or something unforeseen, Grunsfeld says there's presently an ensemble of in-space observatories, including Hubble, and an ever-expanding collection of powerful ground-based telescopes that would offset such misfortune.
Previously: Space science: The telescope that ate astronomy
Telescope That 'Ate Astronomy' Is on Track to Surpass Hubble
Launch of James Webb Space Telescope Delayed to Spring 2019
Launch of James Webb Space Telescope Could be Further Delayed
(Score: 3, Interesting) by takyon on Tuesday January 02 2018, @08:02AM (4 children)
It's less than 1/2 of one year of NASA funding, and will enable great infrared observations not achievable with any other telescopes. Some of the technology developed for JWST could be reused, such as in the proposed HDST [wikipedia.org].
The SLS [wikipedia.org] has already cost more than JWST without a single launch. One projection has the program costing $41 billion by 2025 with the first four 70 ton launches (SLS Block 1). SpaceX Falcon Heavy should be able to lift 63.8 tons to LEO at $90 million per launch. The maiden Falcon Heavy launch should be this month, with the maiden SLS launch no earlier than Dec. 19, 2019. SLS Block 2 (130 tons to LEO, always expendable) would be ready by 2030, plenty of time for it to be beaten by SpaceX BFR [wikipedia.org] (150 tons to LEO reusable, 250 tons expendable).
The actual 2011-2017 SLS expenditure appears to be $11,877.1 million, more than the $10 billion estimate.
I wouldn't be shocked if SpaceX BFR gets a launch before SLS Block 1B (an intermediate 105 ton to LEO launcher currently scheduled to fly twice in 2022).
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(Score: 0) by Anonymous Coward on Tuesday January 02 2018, @07:31PM (3 children)
I'm not disputing the science it is supposed to produce, nor am I complaining about its cost. I'm just saying that many programs (at the time existing and proposed) have been gutted over the years because JWST was too big to fail. A lot of NASA resources, at the direction of Headquarters, went into that program at the expense of many others, and there are some internal hard feelings about that, because money was taken not just from other astrophysics programs, but across disciplines (JWST was gutting the astrophysics division so bad that NASA moved it out of the division and made it its own division). Not to mention the fact that because of the schedule delays, if it didn't take money from some programs, it added to their cost because they couldn't use the resources that JWST had taken (things like TVAC chamber time [spacenews.com]). It's great to be all "rah rah IR astronomy, but its a killer for you as the non-JWST scientist if the money that was going to be your new $10M program goes away to "feed the beast".
(Score: 2) by takyon on Tuesday January 02 2018, @07:38PM (2 children)
These may have been killed by JWST [wikipedia.org]:
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(Score: 1, Interesting) by Anonymous Coward on Tuesday January 02 2018, @11:15PM (1 child)
I was in that large mirror business back in those days (late 90's/early 2000's) when all of those missions were concepts (including JWST). I'll go off of my faulty memory instead of following your links, but in terms of technology, a lot of those missions were related. The grand goal (50+ years out) was to create a virtual large mirror by using a bunch of smaller mirrors, like the radio astronomers do. To do it right, you need to know and control your position to small fractions of a wavelength, which is "easy" for the radio astronomers who deal with wavelengths of tens of meters; for light, you're talking nanometers. You can do that stuff on the optical bench, but it becomes a whole lot more fun to do it on a floppy structure in space, or even better, on widely-separated spacecraft (I was in the "how do you measure the optical pathlength and its changes to a gnat's ass" part of the business).
As I recall, TPF started out as two or more spacecraft separated by hundreds, if not thousands of meters. Then it got scaled down to telescopes arrayed on a very long boom, then it got scaled down to a coronograph, then it disappeared. I remember SIM was something similar with mirrors held apart on very long structures, and I think LISA was supposed to be crazy-big. One variant of the X-ray telescope was since you need to reflect x-rays using very shallow grazing angles, the optics were going to be on a spacecraft that was at least a kilometer out in front of the imaging detector. I only vaguely remember SAFIR, but I think it had multiple large, lightweight and flexible mirrors, or maybe just one, I don't really remember. The NASA solar physics group also had a concept of a formation of spacecraft with spherical mirrors, but I don't remember its name anymore.
JWST was the least ambitious of all of those in terms of mirror design. Designing it for the IR because that is a lesser-studied region is one of the science arguments to have it built, but another reason is that the IR wavelengths are longer than the visible wavelengths, and thus it makes it easier on your measurement and positioning budget. JWST is like the Keck Observatory in that all its mirrors are abutted together. You don't get the benefit of a guide star to phase up your mirrors, but I believe they are (or this was the plan 10+ years ago) using Shack-Hartmann wavefront sensors and/or using image algorithms such as Phase Diversity.
Ah, but I ramble. Those were fun days, but now I'm much more of a PowerPoint Wrangler now.
(Score: 2) by takyon on Wednesday January 03 2018, @12:39AM
IR wavelengths are better for observing some of the most desirable targets in astronomy right now: exoplanets. Also "nearby" solar system objects such as Kuiper belt objects, other dwarf planets and their moons, and Planet Nine if it exists. Red dwarf stars are extremely common and are most luminous in the infrared. Same with brown dwarfs. Luhman 16, a binary brown dwarf system, is only 6.5 light years away but was discovered in 2013 by the Wide-field Infrared Survey Explorer.
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