Comments by "H. de Jong" (@h.dejong2531) on "James Webb Telescope Update and The Spy Satellite Mirrors" video.

  1. Don't be ridiculous. Picture and image are synonyms. The telescope is in space, anyone with a backyard telescope can verify JWST is where NASA says it is. Hubble was launched in 1990, SOFIA in 2007. SOFIA doesn't cover the same wavelengths as Hubble and it has to work inside the atmosphere so its image quality is worse. SOFIA's resolution is about 50 times lower than that of Hubble. Then there's the volume of observations. SOFIA is operated ~2 nights per month while Hubble works 24/7. You'd need a fleet of about 100 SOFIA aircraft to generate the same number of observations, NASA only has one. Really, why do you repeat talking points so shoddy they fall apart with 5 minutes of investigation?
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  2. you're right, that first photo looks more like a Hubble product.
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  3. What you're looking at is multilayer insulation (MLI). This consists of thin sheets of kapton with a layer of aluminium vapor-deposited onto it. A stack of these layers provides excellent insulation against extremes of temperature. MLI is applied to the outside of the spacecraft, it covers the spacecraft structure. What you're doing is the equivalent of looking at a house with clapboard sidings and assuming the house is built from clapboard only. You're arguing from ignorance.
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  4. That is multilayer insulation (MLI). This consists of thin sheets of kapton with a layer of aluminium vapor-deposited onto it. A stack of these layers provides excellent insulation against extremes of temperature.
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  5. Anyone can use basic tools to verify Earth isn't flat. The 'flat Earth' idea has been thoroughly disproven.
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  6. don't be ridiculous. Anyone with basic surveying tools can measure Earth's curvature.
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  7. We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4 These images are available for free on the NOAA website. And we have DISCOVR which can see Moon and Earth in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs, these images are available for free as well. These aren't video, but video is pointless at these distances anyway.
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  8. Don't be ridiculous. We have millions of photos of Earth from space. We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4 A few more sources: https://www.youtube.com/watch?v=JVBlQ31FzJU and Earth from the moon: https://www.youtube.com/watch?v=iTNTfSxP0HQ and DISCOVR images of Earth, incl Moon and Earth in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs
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  9. We don't have a spacecraft that can service Hubble at the moment.
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  10. The alignment images are limited-access until the end of the commissioning period, then they'll be released. This was done to prevent premature comments about the image quality, attempts to do astronomy on imperfect images etc.
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  11. Nothing is going on on the far side of the Moon.The LRO and DISCOVR missions can see the far side of the moon.
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  12. False. All images will be released.
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  13. Then it wouldn't fit on any current launcher.
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  14. We have millions of those (literally). We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4 A few more sources: Earth from space: https://www.youtube.com/watch?v=JVBlQ31FzJU and Earth from the moon: https://www.youtube.com/watch?v=iTNTfSxP0HQ and DISCOVR images of Earth, incl Moon and Earth in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs
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  15. You're mixing up JWST and NGR. NGR uses a mirror donated by the NRO which has stipulated that it must not be used to image Earth. NGR, like JWST will orbit the L2 point.
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  16. I spent some time investigating the links between Hubble and spy satellites; my conclusion is that those links are tenuous at best. By the time the Hubble project was started, spy satellites with 2.4 m mirrors were in operation. That meant there was confidence in the industry they could build high-quality 2.4 m mirrors. But the Hubble mirror contract went to Perkin-Elmer, who hadn't built a mirror larger than 1.5 meters yet. Ironically, the backup mirror contract went to Kodak, who did have experience, and made a mirror that had the correct shape. For checking the shape of the mirror, Perkin-Elmer reused an instrument that was built for those 1.5 m mirrors. They modified the instrument, but made a mistake that ended up putting a critical part of the instrument 1.3 mm out of place, which meant the mirror was ground incorrectly. Had the Hubble mirror been an off-the-shelf part, this error would have been found before. Hubble's control systems don't match spy satellites. Hubble's maximum rotation rate is too slow to do Earth observation, for example. And Hubble's instruments are all built to observe faint objects, whereas spy satellites work on daylit Earth. IR has limited usefulness for espionage. IR is absorbed by water in the atmosphere, so an IR photo of Earth shows the distribution of water vapor. Weather satellites use this.
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  17. False. Hubble, NGR or JWST observations are public. None of them can image Earth: their instruments are built for observation of faint, faraway objects. Hubble's attitude control system cannot keep up with Earth's rotation. etc. Spy satellites are run by the NRO, who have satellites for their exclusive use, which is much simpler than running a clandestine mission in the middle of a public project.
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  18. All NGR observations will be published.
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  19. Look at JWST's location: the L2 point. You can a draw a straight line from the Sun to Earth, and continue outwards to get to L2. JWST's vertical axis is parallel to this line. It can pitch up to +5º and -30º from this axis. To image Earth, it would have to pitch almost 90º, and that would expose the cold side of the telescope to direct sunlight, which would overheat the telescope.  It's pretty pointless to aim JWST at Earth: Earth's atmosphere is opaque at the wavelengths JWST is designed for, so you'd just see the distribution of water vapor in the atmosphere.  We don't need JWST to get high-res images of Earth. We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4 and we have lots of low-orbit Earth imaging programs (Landsat, SPOT, Maxar to name a few). Anyone can buy high-res satellite photos from several sources. And the images from those geostationary weather satellites are available for free on the NOAA website.
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  20. JWST can't image Earth or the Moon, because that would expose the cold side of the telescope to direct sunlight, which would overheat the telescope. Earth's atmosphere is opaque at the wavelengths JWST is designed for, so you'd just see the distribution of water vapor in the atmosphere.
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  21. There is no relationship between JWST and spy satellites.
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  22. No.
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  23. No. Hubble was used for astronomy before the lenses were corrected.
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  24. note that the NRO didn't donate a complete satellite: all NASA got was a mirror assembly.
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  25. I spent some time investigating the links between Hubble and spy satellites; my conclusion is that those links are tenuous at best. By the time the Hubble project was started, spy satellites with 2.4 m mirrors were in operation. That meant there was confidence in the industry they could build high-quality 2.4 m mirrors. But the Hubble mirror contract went to Perkin-Elmer, who hadn't built a mirror larger than 1.5 meters yet. Ironically, the backup mirror contract went to Kodak, who did have experience, and made a mirror that had the correct shape. For checking the shape of the mirror, Perkin-Elmer reused an instrument that was built for those 1.5 m mirrors. They modified the instrument, but made a mistake that ended up putting a critical part of the instrument 1.3 mm out of place, which meant the mirror was ground incorrectly. Had the Hubble mirror been an off-the-shelf part, this error would have been found before. Hubble's control systems don't match spy satellites. Hubble's maximum rotation rate is too slow to do Earth observation, for example. And Hubble's instruments are all built to observe faint objects, whereas spy satellites work on daylit Earth.
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  26. We have millions of real images of Earth already. We have geostationary weather satellites (GOES, Meteosat, Himawari) that take images of the entire hemisphere, see for example https://youtu.be/zoMRwyNhqJ4 The first GOES was launched in 1975. The current 2 GOES satellites and Himawari take full-disk images every 10 minutes, that's 87,000 full-disk images per satellite per year. Then there's DISCOVR, which sits at the L1 Lagrange point so it can take images of Earth and the Moon in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs For more detailed images, there's low-orbit satellites like Landsat, SPOT, the Maxar constellation and many more taking images every day.
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  27.  @JohnMichaelGodier  I'll have to disagree on that. The technology didn't die. We have lots of detailed information on the Saturn V and its engines. What died is outdated manufacturing methods: the F1 engine used manual brazing to create the engine bell, which is very laborintensive, in modern engines this has been replaced with new manufacturing processes. So while you could recreate a Saturn V from drawings, it'd be much easier to replace some of the parts (1960s guidance computers, for one) and redo other parts to take advantage of modern manufacturing methods.
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  28. It looks like a white disk. At the wavelengths JWST observes at, the atmosphere is opaque. You'd mostly see the distribution of water vapor in the upper atmosphere.
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  29. Why not? Amateur astronomers can see JWST orbiting L2. With parallax measurements you can easily verify the spacecraft really is at L2.
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  30. Space is very empty: JWST will encounter micrograms of dust per year, on average. There's no need to clean the mirrors. At the moment, there are no plans to service the telescope. We don't have a spacecraft capable of it, so it wasn't designed to be serviceable. Hubble has large, easily accessible modules that can be swapped out. JWST doesn't. The only servicing that might be done is refueling, but even that requires a new spacecraft to be designed.
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  31. The USA has an entire agency (the NRO) tasked with building and running spy satellites. Why would NASA waste valuable observation time of NGR replicating what the NRO does?
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  32. No, it was donated from a project for a successor to KH-11, which got cancelled.
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  33. NGR is not a flagship like JWST that needs lots of development of new technology, so this'll be a lot closer to schedule.
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  34. JWST can't image Earth or the Moon, they would have to expose the cold side of the telescope to direct sunlight, which would overheat the telescope. If we overcame that problem, its resolution would be about 100 m/pixel. Luckily we don't need JWST to get high-res images of the Moon. We have the Lunar Reconnaissance Orbiter, which has photographed the entire Moon with a resolution of 0.5 m. LRO images of Apollo landing sites: https://www.youtube.com/watch?v=Pnhnx95LkCc
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  35. No, JWST is not a spy satellite, nor related to spy satellites. You didn't even watch the video, did you? The mirror for the Nancy Grace Roman telescope was originally made for a spy satellite. Only an idiot would place a spy satellite at the L2 point. At 1.5 million km from Earth, resolution is much lower than from low Earth orbit. Similarly, using IR sensors is pointless for a spy satellite: our atmosphere is opaque to IR, so all you'd see is the distribution of water vapor in the atmosphere.
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  36. Actual photo of exoplanet: https://youtu.be/ggfa0Bc8Rn4?t=386
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  37. The phrases 'dark matter' and 'dark energy' are just placeholders. We're very aware that our understanding of physics is wrong somewhere. These phrases give us a way to describe where the discrepancies are. 'Dark Matter' is shorthand for 'matter we can't see with our current sensors, but which does have a gravitational effect on large scales'. We con't know what is missing, exactly - and there are a number of astronomy projects trying to fill this gap in our knowledge.
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  38. One decade. The mirrors were donated in 2012.
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  39. Why would NASA allow NGR to be used like that, when the US Government already has a separate agency (NRO) operating dedicated spy satellites? Unlike NASA, the NRO has no obligation to publish its data, or to make its instruments available to astronomers. Also, NGR's instrumentation will be designed for faint objects, while spy satellites have to take short exposures in broad daylight.
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  40. That caveat is not going to impact NGR's mission (to look at the stars) in the slightest, so why scupper a mission over a non-issue?
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  41. don't be ridiculous.
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  42. we don't need JWST to Nancy Grace Roman to get high-res images of Earth. We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4 We also have programs like Landsat, SPOT and Maxar that have satellites in low Earth orbit for earth observation. These image Earth in much more detail than JWST ever could.
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  43. They aren't. Those images will be released immediately. They're just not telling us the targets for those first observations beforehand. All JWST images will be published (via the Mikulski space telescope archive). Most images will have an exclusive-access period so the astronomer who requested the images will be the first to analyze them. The target list for the first year (the General Observer program) is already public.
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  44. Have a look at the JWST blog.
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  45. Troll.
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  46. We have geostationary weather satellites that take images of the entire hemisphere every 10 minutes, see for example https://youtu.be/zoMRwyNhqJ4. You can buy high-res images from low-orbit satellites like the Landsat and SPOT programs, Maxar etc. So anyone has access to high-quality images of Earth from space. The only restriction the DOD has given NASA is not to publish spy satellite-quality images. The reasons for this are obvious.
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  47. Cannot legally look at Earth because that would reveal the capabilities of those spy satellites.
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  48. Hubble wasn't based on a spy satellite bus. - Hubble's designed to be serviced, spy satellites aren't. - Hubble uses a different attitude control system that allows accurate pointing for long periods, but isn't fast enough to image targets on Earth - Hubble's instruments are designed for faint, faraway objects, spy satellites have fast cameras to work in Earth's daylight.
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  49. You're mixing up JWST and NGR. JWST would overheat when looking at Earth, NGR uses a mirror donated by the NRO which has stipulated that it must not be used to image Earth.
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  50. False. Anyone can buy high-resolution, recent satellite images from companies like Maxar and Satellite Imaging Corp. Old pictures in Google Earth are a Google problem, not a government problem.
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  51. A spy satellite is a satellite that's used by an intelligence agency to monitor enemy activity. This can be through imaging, but there are other methods as well (e.g. signals intelligence: monitoring radio communications). A spy satellite in low Earth orbit with a 2.4 m mirror has a resolution of about 0.3 m/pixel.
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  52. The NRO gave 2 mirrors to NASA.
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  53. Spy satellite imagery is published only occasionally (https://www.youtube.com/watch?v=rLmpXgdgNZM), most images remain secret until the program that created them ends.
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  54. several are in various stages of planning or construction. The next flagship proposal is LUVOIR, a segmented telescope like JWST, for UV, visible and IR, with a mirror diameter of 8 m or more. I don't think this proposal has been accepted yet.
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  55. We have millions of real images of Earth already. We have geostationary weather satellites (GOES, Meteosat, Himawari) that take images of the entire hemisphere, see for example https://youtu.be/zoMRwyNhqJ4 Then there's DISCOVR, which sits at the L1 Lagrange point so it can take images of Earth and the Moon in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs For more detailed images, there's Landsat (images available for free), SPOT, the Maxar constellation (commercial) and many more taking images every day.
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  56. We have millions of real images of Earth already. We have geostationary weather satellites (GOES, Meteosat, Himawari) that take images of the entire hemisphere, see for example https://youtu.be/zoMRwyNhqJ4 Then there's DISCOVR, which sits at the L1 Lagrange point so it can take images of Earth and the Moon in one shot: https://www.youtube.com/watch?v=xPM2kITNtTs For more detailed images, there's Landsat, SPOT, the Maxar constellation and many more taking images every day. JWST is optimized for mid-infrared. Those wavelengths are blocked by Earth's atmosphere, so JWST wouldn't see any details, just the distribution of water vapor in our atmosphere. And JWST can't be pointed at Earth, because that would expose the cold side of the telescope to direct sunlight and damage the instruments.
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  57. I spent some time investigating the links between Hubble and spy satellites; my conclusion is that those links are tenuous at best. By the time the Hubble project was started, spy satellites with 2.4 m mirrors were in operation. That meant there was confidence in the industry they could build high-quality 2.4 m mirrors. But the Hubble mirror contract went to Perkin-Elmer, who hadn't built a mirror larger than 1.5 meters yet. Ironically, the backup mirror contract went to Kodak, who did have experience, and made a mirror that had the correct shape. For checking the shape of the mirror, Perkin-Elmer reused an instrument that was built for those 1.5 m mirrors. They modified the instrument, but made a mistake that ended up putting a critical part of the instrument 1.3 mm out of place, which meant the mirror was ground incorrectly. Had the Hubble mirror been an off-the-shelf part, this error would have been found before. Hubble's control systems don't match spy satellites. Hubble's maximum rotation rate is too slow to do Earth observation, for example. And Hubble's instruments are all built to observe faint objects, whereas spy satellites work on daylit Earth.
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  58. doing VLBI at IR wavelengths is difficult: the short wavelength means you have to synchronize the observations to within fractions of a nanosecond to be useful. Even when two telescopes are next to each other, optical interferometry has problems.
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  59. Advancing the state of the art never comes cheap. It's not surprising this project went over budget. We shouldn't cancel this sort of advanced-technology projects when they turn out to get more expensive than we thought: we'll never advance if we do that.
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